As in the car industry for quite some time, dynamic simulation of complete vehicles is being practiced more and more in the development of off-road machinery. However, specific questions arise due not only to company structure and size, but especially to the type of product. Tightly coupled, non-linear subsystems of different domains make prediction and optimisation of the complete system's dynamic behaviour a challenge. Furthermore, the demand for versatile machines leads to sometimes contradictory target requirements and can turn the design process into a hunt for the least painful compromise. This can be avoided by profound system knowledge, assisted by simulation-driven product development. This paper gives an overview of joint research into this issue by Volvo Wheel Loaders and Linköping University on that matter, lists the results of a related literature review and introduces the term "operability". Rather than giving detailed answers, the problem space for ongoing and future research is examined and possible solutions are sketched.
http://arxiv.org/abs/cs/0305036
Evaluating the efficiency of wheel loader bucket designs and bucket filling s...Reno Filla
In this paper we outline how optimising bucket design and bucket filling is connected to improving the total energy efficiency of a wheel loader. Results from our work with particle simulations are shown and it is discussed that, while ideally such simulations should be coupled to models of the machine, operator and the work environment, it is nonetheless possible to simulate stand-alone and utilise simple performance indicators to compare different bucket designs and different bucket filling strategies in a reasonably fair manner. Suitable and less suitable performance indicators are derived and discussed in detail.
Optimizing the trajectory of a wheel loader working in short loading cyclesReno Filla
This document summarizes a study examining alternative trajectories for wheel loaders working in short loading cycles. It describes analyzing trajectories beyond the traditional V- or Y-cycle patterns. Different cycle variants were examined, including maintaining the classic cycle shape but varying parameters. The document outlines limitations in simplifying curves to circular arcs for analysis versus using clothoid curves. It also describes optimizing cycle parameters like reversing point angle and turning radii to minimize transport distance or time for given load receiver positions. The goal is to identify more efficient trajectories for applications like simulations, operator assistance, autonomous machines and hybrid energy management.
Alternative system solutions for wheel loaders and other construction equipmentReno Filla
- The document discusses alternative system solutions for wheel loaders and other construction equipment to reduce fuel consumption by 50% through hybrid technology.
- It analyzes wheel loaders as complex energy conversion systems and describes the key balances of force, motion, and power that must be maintained for high productivity, energy efficiency, and operability.
- Hybridization is proposed to maintain these balances through additional electric drive components that can assist both the hydraulic and drivetrain systems in parallel or series configurations.
Hybrid Power Systems for Construction Machinery: Aspects of System Design and...Reno Filla
This paper will examine the wheel loader as a system with two parallel energy conversion systems that show a complex interaction with each other and with the power source. Using a systematic design approach, several principle design solutions for hybridization can be found.
Furthermore, the human operator with his/her control actions needs to be considered as part of the total system. This paper will therefore also connect to results from ongoing and previous research into operator workload and operability.
http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-51999
http://dx.doi.org/10.1115/IMECE2009-10458
A Methodology for Modeling the Influence of Construction Machinery Operators ...Reno Filla
This paper is concerned with modeling the actions of a human operator of construction machinery and integrating this operator model into a large, complex simulation model of the complete machine and its environment. Because human operators to a large degree affect how the machine is run, adaptive operator models are a necessity when the simulation goal is quantification and optimization of productivity and energy efficiency. Interview studies and test series have been performed to determine how professionals operate wheel loaders. Two models using different approaches were realized and integrated into a multi-domain model for dynamic simulation. The results are satisfactory and the methodology is easily usable for other, similar situations.
http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-51998
http://dx.doi.org/10.1007/978-3-642-02809-0_65
Bombardier Transportation - Fast Tracking Rail Vehicle DesignAltair ProductDesign
1) Bombardier Transportation uses Altair HyperWorks software to rapidly generate finite element models of rail vehicles and components.
2) HyperMesh is used to create detailed FE models of carbodies, bogies, and other structures in less time compared to previous methods.
3) Structural optimization of components through topology optimization and thickness optimization has led to weight savings and cost reductions of various parts subjected to static, fatigue, and impact loading conditions.
Bombardier provides energy saving technologies for trains that can reduce energy consumption by up to 50%. These technologies include aerodynamic train design optimizations to reduce resistance, energy recovery systems, lighting weight bogies, and driver assistance systems to optimize energy usage. Bombardier has implemented these technologies successfully for many customers worldwide.
IRJET- Analysis and Design of Multistoreyed Parking Building Proposed at J...IRJET Journal
This document discusses the analysis and design of a proposed multistorey parking building near Jalahalli cross in Bangalore, India to address the lack of parking space. It begins with an introduction to parking types and the need for multi-level parking structures in urban areas with high land costs. The methodology section outlines the steps taken, including investigating the area, planning the building in AutoCAD, modeling in ETABS and Revit, analyzing loads, and designing foundations and structural elements. Floor plans show the basement and ground floor will be for car parking while upper floors are for motorcycle parking and commercial complexes. Finally, structural components like beams, columns, and footings are designed in ETABS to be constructed using M30 concrete
Evaluating the efficiency of wheel loader bucket designs and bucket filling s...Reno Filla
In this paper we outline how optimising bucket design and bucket filling is connected to improving the total energy efficiency of a wheel loader. Results from our work with particle simulations are shown and it is discussed that, while ideally such simulations should be coupled to models of the machine, operator and the work environment, it is nonetheless possible to simulate stand-alone and utilise simple performance indicators to compare different bucket designs and different bucket filling strategies in a reasonably fair manner. Suitable and less suitable performance indicators are derived and discussed in detail.
Optimizing the trajectory of a wheel loader working in short loading cyclesReno Filla
This document summarizes a study examining alternative trajectories for wheel loaders working in short loading cycles. It describes analyzing trajectories beyond the traditional V- or Y-cycle patterns. Different cycle variants were examined, including maintaining the classic cycle shape but varying parameters. The document outlines limitations in simplifying curves to circular arcs for analysis versus using clothoid curves. It also describes optimizing cycle parameters like reversing point angle and turning radii to minimize transport distance or time for given load receiver positions. The goal is to identify more efficient trajectories for applications like simulations, operator assistance, autonomous machines and hybrid energy management.
Alternative system solutions for wheel loaders and other construction equipmentReno Filla
- The document discusses alternative system solutions for wheel loaders and other construction equipment to reduce fuel consumption by 50% through hybrid technology.
- It analyzes wheel loaders as complex energy conversion systems and describes the key balances of force, motion, and power that must be maintained for high productivity, energy efficiency, and operability.
- Hybridization is proposed to maintain these balances through additional electric drive components that can assist both the hydraulic and drivetrain systems in parallel or series configurations.
Hybrid Power Systems for Construction Machinery: Aspects of System Design and...Reno Filla
This paper will examine the wheel loader as a system with two parallel energy conversion systems that show a complex interaction with each other and with the power source. Using a systematic design approach, several principle design solutions for hybridization can be found.
Furthermore, the human operator with his/her control actions needs to be considered as part of the total system. This paper will therefore also connect to results from ongoing and previous research into operator workload and operability.
http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-51999
http://dx.doi.org/10.1115/IMECE2009-10458
A Methodology for Modeling the Influence of Construction Machinery Operators ...Reno Filla
This paper is concerned with modeling the actions of a human operator of construction machinery and integrating this operator model into a large, complex simulation model of the complete machine and its environment. Because human operators to a large degree affect how the machine is run, adaptive operator models are a necessity when the simulation goal is quantification and optimization of productivity and energy efficiency. Interview studies and test series have been performed to determine how professionals operate wheel loaders. Two models using different approaches were realized and integrated into a multi-domain model for dynamic simulation. The results are satisfactory and the methodology is easily usable for other, similar situations.
http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-51998
http://dx.doi.org/10.1007/978-3-642-02809-0_65
Bombardier Transportation - Fast Tracking Rail Vehicle DesignAltair ProductDesign
1) Bombardier Transportation uses Altair HyperWorks software to rapidly generate finite element models of rail vehicles and components.
2) HyperMesh is used to create detailed FE models of carbodies, bogies, and other structures in less time compared to previous methods.
3) Structural optimization of components through topology optimization and thickness optimization has led to weight savings and cost reductions of various parts subjected to static, fatigue, and impact loading conditions.
Bombardier provides energy saving technologies for trains that can reduce energy consumption by up to 50%. These technologies include aerodynamic train design optimizations to reduce resistance, energy recovery systems, lighting weight bogies, and driver assistance systems to optimize energy usage. Bombardier has implemented these technologies successfully for many customers worldwide.
IRJET- Analysis and Design of Multistoreyed Parking Building Proposed at J...IRJET Journal
This document discusses the analysis and design of a proposed multistorey parking building near Jalahalli cross in Bangalore, India to address the lack of parking space. It begins with an introduction to parking types and the need for multi-level parking structures in urban areas with high land costs. The methodology section outlines the steps taken, including investigating the area, planning the building in AutoCAD, modeling in ETABS and Revit, analyzing loads, and designing foundations and structural elements. Floor plans show the basement and ground floor will be for car parking while upper floors are for motorcycle parking and commercial complexes. Finally, structural components like beams, columns, and footings are designed in ETABS to be constructed using M30 concrete
Design of Multi Link Structure for Rear Suspenion of a Heavy Vehicletheijes
Automobile systems today is going through major changes and as concert to comfort the suspension system and it’s working is very important. The study of four link suspension system and dynamic analysis are discussed in this paper. This paper discusses the design problem of vehicles using four-link suspension systems with the aim of totally optimizing vehicle handling and stability. Since this problem includes many evaluation items, and Four-link suspension system has interconnected behaviour, the optimization is so complicated. An efficient and computable model is indispensable for compromising the total optimization. This paper investigates a structure of objectives, introduces appropriate simulation models for respective items; we apply multi body dynamic analysis to plot the varies terms such as wheel travel, camber angle, caster angle, toe-in, toe-out etc. The result of optimization calculation shows the validity of the optimization model
This document summarizes a study of two alternatives for improving public transportation in a study area. Alternative A would reconstruct South Park Avenue and maintain existing storage capacity, while Alternative B would reduce storage capacity but require fewer upgrades initially. Both alternatives aim to eliminate the Special Events station and improve connections. Alternative B has a higher estimated total cost of $42.18 million compared to $32.78 million for Alternative A. The next steps are to choose an alternative to further develop, identify requirements, financing options, and provide a final report.
Lean&Mean Terminal Design benefits from advanced modelling (Terminal Operator...Yvo Saanen
This document discusses how simulation can be used to improve the cost, risk, and performance of new and existing container terminals. It begins by introducing simulation and explaining that it allows experiments to be conducted on a model of a system. The key steps in a simulation project are specified as model development, validation, experimentation, and analysis. The document then discusses how simulation can be applied to determine terminal dimensions, evaluate different handling systems and equipment types, and design terminal operating systems. It provides an example comparing different yard equipment options. The document emphasizes that simulation allows evaluation under varying conditions and separation of good and bad solutions to help reduce risk for terminal projects.
Fundamentals Of Oil & Gas Hydraulic System Simulationvchristiano
AMESim software can be used to simulate subsea oil and gas systems. It allows modeling of hydraulic power units, valves, actuators, accumulators, umbilicals, pipelines and other components. The software uses multi-domain modeling libraries to simulate dynamic behavior and optimize performance. System simulations can be run to analyze recovery time, emergency shutdown response and other scenarios. AMESim also enables closed-loop control system modeling and integration with other simulation tools.
The document discusses LMS Simulation Division's multi-domain system simulation solutions for the railway and train industry. It addresses challenges in the industry related to growing demand for public transport and rising fuel costs. LMS offers simulation solutions to help deliver cost-efficient development, covering various train types and components like electric powertrains, braking systems, heating and air conditioning.
IRJET- Analysis and Design of Residential Building with Floating ColumnIRJET Journal
This document analyzes and designs a residential building with floating columns in India. It discusses:
1) The building has G+6 floors and floating columns are used to provide open space for parking and other functions.
2) The floating columns are modeled and analyzed using ETABS software according to Indian design codes.
3) The analysis examines different cases of removing columns on different floors to study the building's behavior under various conditions. Transfer beams are designed to support the loads from the floating columns.
This document summarizes a technical paper about designing and tuning air suspensions for tractors. It discusses the challenges of achieving a balance between ride comfort and handling for tractor-trailer combinations, given their mass distribution and the influence of the trailer on dynamics. The paper presents the development of a new primary air suspension system for a Volkswagen tractor to improve comfort, protect fragile loads, and allow for different trailer configurations while maintaining other vehicle characteristics. A mixed suspension using springs in front and air bags in the rear was selected based on its benefits and ability to meet design goals. The tuning process and methods used to evaluate and optimize the suspension are also described.
This document discusses a co-simulation of a hybrid bus model between AMESim and RT-LAB. It provides an overview of Siemens and its sectors including industry automation. AMESim is introduced as a multi-physics modeling and simulation software. The document demonstrates a hybrid bus model co-simulation between AMESim and RT-LAB in real-time and discusses applications in the automotive sector and future developments including workshops and compatibility between tools.
IRJET- Design and Analysis of Flexible Pavement in Amaravati Governemnt C...IRJET Journal
This document summarizes the design and analysis of flexible pavements for a government complex in Amravati, India. It describes surveying the site using drones and GPS, testing the soil properties including moisture content and bearing capacity, and estimating traffic levels of 5 million standard axles over the design life. The flexible pavement design was performed using IRC code guidelines based on the soil test results and traffic estimate. Key layers of the flexible pavement include granular sub-base and bituminous surface.
Sr710 study update_power_point final finalpeggydrouet
The document summarizes several options being considered for the SR-710 project and their potential effects on the City of South Pasadena. The options discussed include:
1) A "No Build" option that would have no direct effects but other projects could still be built.
2) Bus Rapid Transit that could significantly affect local businesses through removal of parking and elimination of sidewalk extensions.
3) Light Rail Transit with two stations in the city and the entire segment underground to minimize construction and business impacts.
4) Transportation demand management and system management improvements at several intersections and streets in the city. The addition of reversible lanes on the SR-110 could also significantly impact South Pasadena.
5
The document provides details about Adarsh Dwivedi's summer training project at Lucknow Metro Rail Corporation. It discusses various aspects of metro construction including the casting yard where girders and beams are cast, underground construction involving diaphragm walls, piling, plunge columns and slab casting, and elevated structure construction with details on piling, pile caps, piers and U-girders. The training helped provide hands-on experience of metro construction processes.
The Delta Configured Modular Multilevel ConverterIISTech2015
This document introduces an alternative configuration for modular multilevel converters called the delta configuration. The delta configuration stacks phase legs in series, unlike the typical wye configuration. This allows for greater flexibility in scaling voltages and currents. The document derives single-ended and differential delta topologies, noting the differential topology reduces energy storage needs. It also lists tools like MATLAB/Simulink and PSPICE that were used and notes the configuration will result in both hardware outputs and simulations.
Conen 442 module1a: Elements of Traffic SystemWael ElDessouki
In this document, we focus on the characteristics of the components comprising traffic systems, namely: Road Users, Vehicles, Infrastructure, Control Devices, and the environment.
IRJET- Strength Evaluation of Tipper Chassis under Static and Dynamic Load Co...IRJET Journal
This document summarizes the modeling and analysis of a truck chassis under static and dynamic loading conditions. It describes the modeling of the chassis geometry in Pro-E and its finite element analysis in HyperMesh. The chassis was analyzed under different load cases representing uniform distributed loads and concentrated pivot loads. Material properties of steel and cast iron used for the chassis are provided. The load calculations for the chassis consider loads from the rear body weight, engine, transmission, fuel tank, and other components. The analysis aims to evaluate the stresses and strength of the chassis under various static and dynamic operating conditions.
For the joint IQPC Conferences "Automation & Connectivity for Mobile Machinery" and "HMI for Mobile Machinery", for which I also had the honor to serve as the conference chairman.
On Increasing Fuel Efficiency by Operator Assistance Systems in a Wheel LoaderReno Filla
This document discusses the potential for increasing fuel efficiency and productivity in wheel loaders through an operator assistant system. An empirical study found large variations between operators, with some achieving fuel efficiencies up to 200% higher and productivities up to 700% higher than others. The document argues that an operator assistant system could help all operators achieve the levels of the most efficient operators. It suggests a system that recommends optimal operations to the operator, with some automated functions, as a good starting point. Fuel efficiency improvements of 20-40% and productivity increases of 40-80% are estimated to be possible.
Hybrid Power Systems for Construction MachineryReno Filla
The search for energy efficient solutions goes on also for construction equipment, and hybrids are everyone’s topic. In the case of a wheel loader, drive train and hydraulics are both equally powerful and compete for the limited engine torque. There is a large theoretic potential for the increase of energy efficiency, but to leverage this, a holistic approach is needed. This presentation will examine the wheel loader as a system with drive train and hydraulics as two parallel energy conversion systems that show a complex interaction with each other and the power source. Using a systematic design approach, several principle design solutions for hybridization can be found.
Furthermore, the human operator with his/her control actions needs to be considered as part of the total system. Properties such as productivity, energy efficiency, and operability are all not only dependent on inherent machine properties and working place conditions, but also on how the operator uses the machine. In the case of a wheel loader, the momentary power distribution to drive train and hydraulics is specific for the working task at hand and is controlled by the operator, who ultimately balances the complete system and actively adapts to both the machine, the task at hand, and the working place.
Este documento proporciona instrucciones detalladas sobre la instalación y configuración del software de punto de venta MyBusiness POS, incluyendo la elección de hardware, la instalación del software, la configuración de dispositivos como impresoras y lectores de códigos de barras, y cómo dar de alta artículos, clientes y proveedores en el sistema. También explica los procedimientos básicos de venta, compra e inventario.
Selecting representative working cycles from large measurement data setsReno Filla
1. The document describes three methods for selecting representative work cycles from large datasets of machine usage data: the Mean Cycle Method, Synthetic Mean Method, and Least Error Method.
2. The Mean Cycle Method constructs an average cycle and selects the measured cycle closest to it. The Synthetic Mean Method constructs a cycle based on peak frequencies and amplitudes and selects the closest measured cycle. The Least Error Method compares all cycles and selects the one with the smallest deviations.
3. When tested on 100 wheel loader work cycles, the three methods produced similar but not identical results for the most representative cycle depending on the signals considered. Considering multiple important signals led to more agreement between the methods.
Electromobility and Construction MachineryReno Filla
The search for energy efficient solutions goes on also for construction machinery, and hybrids are a given topic. This seminar looks at related research and pre-development at Volvo Construction Equipment and focuses on wheel loaders. In these machines, drive train and hydraulics are both equally powerful and compete for the limited engine torque. There is a large theoretic potential for the increase of energy efficiency, but to leverage this, a holistic approach is needed. The wheel loader is examined as a system with drive train and hydraulics as two parallel energy conversion systems that show a complex interaction with each other and the power source. Using a systematic design approach, several principle design solutions for hybridization can be found and are discussed.
The document summarizes a presentation on driving energy efficiency through behavioral change. It discusses why it is difficult for people and societies to react to issues like climate change, citing behavioral biases, patterns, social conformity, and societal influences. It then provides recommendations for encouraging energy efficiency, emphasizing the need for leadership, a national plan, community-based and tailored approaches that identify and address behavioral, social and institutional barriers. The overall goal is to move energy efficiency from a niche issue to the norm through multi-pronged efforts.
- The seminar discussed types of heavy equipment including Volvo wheel loaders ranging from L60F to L220F models. It covered their various applications in industries like quarrying, construction, logging and more.
- Key specifications of Volvo wheel loaders like engine, transmission, hydraulics, axles and brakes were presented to understand their performance, productivity and durability.
- The seminar aimed to help participants identify heavy equipment types and components, as well as understand their functions and applications in different industries.
Design of Multi Link Structure for Rear Suspenion of a Heavy Vehicletheijes
Automobile systems today is going through major changes and as concert to comfort the suspension system and it’s working is very important. The study of four link suspension system and dynamic analysis are discussed in this paper. This paper discusses the design problem of vehicles using four-link suspension systems with the aim of totally optimizing vehicle handling and stability. Since this problem includes many evaluation items, and Four-link suspension system has interconnected behaviour, the optimization is so complicated. An efficient and computable model is indispensable for compromising the total optimization. This paper investigates a structure of objectives, introduces appropriate simulation models for respective items; we apply multi body dynamic analysis to plot the varies terms such as wheel travel, camber angle, caster angle, toe-in, toe-out etc. The result of optimization calculation shows the validity of the optimization model
This document summarizes a study of two alternatives for improving public transportation in a study area. Alternative A would reconstruct South Park Avenue and maintain existing storage capacity, while Alternative B would reduce storage capacity but require fewer upgrades initially. Both alternatives aim to eliminate the Special Events station and improve connections. Alternative B has a higher estimated total cost of $42.18 million compared to $32.78 million for Alternative A. The next steps are to choose an alternative to further develop, identify requirements, financing options, and provide a final report.
Lean&Mean Terminal Design benefits from advanced modelling (Terminal Operator...Yvo Saanen
This document discusses how simulation can be used to improve the cost, risk, and performance of new and existing container terminals. It begins by introducing simulation and explaining that it allows experiments to be conducted on a model of a system. The key steps in a simulation project are specified as model development, validation, experimentation, and analysis. The document then discusses how simulation can be applied to determine terminal dimensions, evaluate different handling systems and equipment types, and design terminal operating systems. It provides an example comparing different yard equipment options. The document emphasizes that simulation allows evaluation under varying conditions and separation of good and bad solutions to help reduce risk for terminal projects.
Fundamentals Of Oil & Gas Hydraulic System Simulationvchristiano
AMESim software can be used to simulate subsea oil and gas systems. It allows modeling of hydraulic power units, valves, actuators, accumulators, umbilicals, pipelines and other components. The software uses multi-domain modeling libraries to simulate dynamic behavior and optimize performance. System simulations can be run to analyze recovery time, emergency shutdown response and other scenarios. AMESim also enables closed-loop control system modeling and integration with other simulation tools.
The document discusses LMS Simulation Division's multi-domain system simulation solutions for the railway and train industry. It addresses challenges in the industry related to growing demand for public transport and rising fuel costs. LMS offers simulation solutions to help deliver cost-efficient development, covering various train types and components like electric powertrains, braking systems, heating and air conditioning.
IRJET- Analysis and Design of Residential Building with Floating ColumnIRJET Journal
This document analyzes and designs a residential building with floating columns in India. It discusses:
1) The building has G+6 floors and floating columns are used to provide open space for parking and other functions.
2) The floating columns are modeled and analyzed using ETABS software according to Indian design codes.
3) The analysis examines different cases of removing columns on different floors to study the building's behavior under various conditions. Transfer beams are designed to support the loads from the floating columns.
This document summarizes a technical paper about designing and tuning air suspensions for tractors. It discusses the challenges of achieving a balance between ride comfort and handling for tractor-trailer combinations, given their mass distribution and the influence of the trailer on dynamics. The paper presents the development of a new primary air suspension system for a Volkswagen tractor to improve comfort, protect fragile loads, and allow for different trailer configurations while maintaining other vehicle characteristics. A mixed suspension using springs in front and air bags in the rear was selected based on its benefits and ability to meet design goals. The tuning process and methods used to evaluate and optimize the suspension are also described.
This document discusses a co-simulation of a hybrid bus model between AMESim and RT-LAB. It provides an overview of Siemens and its sectors including industry automation. AMESim is introduced as a multi-physics modeling and simulation software. The document demonstrates a hybrid bus model co-simulation between AMESim and RT-LAB in real-time and discusses applications in the automotive sector and future developments including workshops and compatibility between tools.
IRJET- Design and Analysis of Flexible Pavement in Amaravati Governemnt C...IRJET Journal
This document summarizes the design and analysis of flexible pavements for a government complex in Amravati, India. It describes surveying the site using drones and GPS, testing the soil properties including moisture content and bearing capacity, and estimating traffic levels of 5 million standard axles over the design life. The flexible pavement design was performed using IRC code guidelines based on the soil test results and traffic estimate. Key layers of the flexible pavement include granular sub-base and bituminous surface.
Sr710 study update_power_point final finalpeggydrouet
The document summarizes several options being considered for the SR-710 project and their potential effects on the City of South Pasadena. The options discussed include:
1) A "No Build" option that would have no direct effects but other projects could still be built.
2) Bus Rapid Transit that could significantly affect local businesses through removal of parking and elimination of sidewalk extensions.
3) Light Rail Transit with two stations in the city and the entire segment underground to minimize construction and business impacts.
4) Transportation demand management and system management improvements at several intersections and streets in the city. The addition of reversible lanes on the SR-110 could also significantly impact South Pasadena.
5
The document provides details about Adarsh Dwivedi's summer training project at Lucknow Metro Rail Corporation. It discusses various aspects of metro construction including the casting yard where girders and beams are cast, underground construction involving diaphragm walls, piling, plunge columns and slab casting, and elevated structure construction with details on piling, pile caps, piers and U-girders. The training helped provide hands-on experience of metro construction processes.
The Delta Configured Modular Multilevel ConverterIISTech2015
This document introduces an alternative configuration for modular multilevel converters called the delta configuration. The delta configuration stacks phase legs in series, unlike the typical wye configuration. This allows for greater flexibility in scaling voltages and currents. The document derives single-ended and differential delta topologies, noting the differential topology reduces energy storage needs. It also lists tools like MATLAB/Simulink and PSPICE that were used and notes the configuration will result in both hardware outputs and simulations.
Conen 442 module1a: Elements of Traffic SystemWael ElDessouki
In this document, we focus on the characteristics of the components comprising traffic systems, namely: Road Users, Vehicles, Infrastructure, Control Devices, and the environment.
IRJET- Strength Evaluation of Tipper Chassis under Static and Dynamic Load Co...IRJET Journal
This document summarizes the modeling and analysis of a truck chassis under static and dynamic loading conditions. It describes the modeling of the chassis geometry in Pro-E and its finite element analysis in HyperMesh. The chassis was analyzed under different load cases representing uniform distributed loads and concentrated pivot loads. Material properties of steel and cast iron used for the chassis are provided. The load calculations for the chassis consider loads from the rear body weight, engine, transmission, fuel tank, and other components. The analysis aims to evaluate the stresses and strength of the chassis under various static and dynamic operating conditions.
For the joint IQPC Conferences "Automation & Connectivity for Mobile Machinery" and "HMI for Mobile Machinery", for which I also had the honor to serve as the conference chairman.
On Increasing Fuel Efficiency by Operator Assistance Systems in a Wheel LoaderReno Filla
This document discusses the potential for increasing fuel efficiency and productivity in wheel loaders through an operator assistant system. An empirical study found large variations between operators, with some achieving fuel efficiencies up to 200% higher and productivities up to 700% higher than others. The document argues that an operator assistant system could help all operators achieve the levels of the most efficient operators. It suggests a system that recommends optimal operations to the operator, with some automated functions, as a good starting point. Fuel efficiency improvements of 20-40% and productivity increases of 40-80% are estimated to be possible.
Hybrid Power Systems for Construction MachineryReno Filla
The search for energy efficient solutions goes on also for construction equipment, and hybrids are everyone’s topic. In the case of a wheel loader, drive train and hydraulics are both equally powerful and compete for the limited engine torque. There is a large theoretic potential for the increase of energy efficiency, but to leverage this, a holistic approach is needed. This presentation will examine the wheel loader as a system with drive train and hydraulics as two parallel energy conversion systems that show a complex interaction with each other and the power source. Using a systematic design approach, several principle design solutions for hybridization can be found.
Furthermore, the human operator with his/her control actions needs to be considered as part of the total system. Properties such as productivity, energy efficiency, and operability are all not only dependent on inherent machine properties and working place conditions, but also on how the operator uses the machine. In the case of a wheel loader, the momentary power distribution to drive train and hydraulics is specific for the working task at hand and is controlled by the operator, who ultimately balances the complete system and actively adapts to both the machine, the task at hand, and the working place.
Este documento proporciona instrucciones detalladas sobre la instalación y configuración del software de punto de venta MyBusiness POS, incluyendo la elección de hardware, la instalación del software, la configuración de dispositivos como impresoras y lectores de códigos de barras, y cómo dar de alta artículos, clientes y proveedores en el sistema. También explica los procedimientos básicos de venta, compra e inventario.
Selecting representative working cycles from large measurement data setsReno Filla
1. The document describes three methods for selecting representative work cycles from large datasets of machine usage data: the Mean Cycle Method, Synthetic Mean Method, and Least Error Method.
2. The Mean Cycle Method constructs an average cycle and selects the measured cycle closest to it. The Synthetic Mean Method constructs a cycle based on peak frequencies and amplitudes and selects the closest measured cycle. The Least Error Method compares all cycles and selects the one with the smallest deviations.
3. When tested on 100 wheel loader work cycles, the three methods produced similar but not identical results for the most representative cycle depending on the signals considered. Considering multiple important signals led to more agreement between the methods.
Electromobility and Construction MachineryReno Filla
The search for energy efficient solutions goes on also for construction machinery, and hybrids are a given topic. This seminar looks at related research and pre-development at Volvo Construction Equipment and focuses on wheel loaders. In these machines, drive train and hydraulics are both equally powerful and compete for the limited engine torque. There is a large theoretic potential for the increase of energy efficiency, but to leverage this, a holistic approach is needed. The wheel loader is examined as a system with drive train and hydraulics as two parallel energy conversion systems that show a complex interaction with each other and the power source. Using a systematic design approach, several principle design solutions for hybridization can be found and are discussed.
The document summarizes a presentation on driving energy efficiency through behavioral change. It discusses why it is difficult for people and societies to react to issues like climate change, citing behavioral biases, patterns, social conformity, and societal influences. It then provides recommendations for encouraging energy efficiency, emphasizing the need for leadership, a national plan, community-based and tailored approaches that identify and address behavioral, social and institutional barriers. The overall goal is to move energy efficiency from a niche issue to the norm through multi-pronged efforts.
- The seminar discussed types of heavy equipment including Volvo wheel loaders ranging from L60F to L220F models. It covered their various applications in industries like quarrying, construction, logging and more.
- Key specifications of Volvo wheel loaders like engine, transmission, hydraulics, axles and brakes were presented to understand their performance, productivity and durability.
- The seminar aimed to help participants identify heavy equipment types and components, as well as understand their functions and applications in different industries.
013016 COMMUNITY ACTIVIST VOGEL DENISE NEWSOME (Arabic)VogelDenise
17 USC § 107 (LIMITATIONS On EXCLUSIVE Rights - FAIR USE)
ENGLISH VERSION AT: http://www.slideshare.net/VogelDenise/013016-did-you-know-this-about-community-activist-vogel-denise-newsome
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الله سبق استراتيجيا
تم إقصاء الدولة التي اختيرت
في الوظائف الحكومية
(الاتحادية، الدولة والمدينة والمحلية)
لانتقال السلطة!
قد وضع الله الناس أحرارا من WHITE / مضطهديهم الصهيونية!
قد شعب الله يستيقظ وفهم القوة التي هي في داخلها!
1) On January 10, 2012, three Priority Mail packages were mailed from Cincinnati, Ohio and addressed to locations in Washington D.C.
2) Two packages were delivered on January 12, 2012 while the third required a notice left as no authorized recipient was available.
3) The tracking information shows the packages traveled from Cincinnati to Washington D.C. between January 10-15, 2012.
Faksimile ini memberikan informasi tentang tuduhan korupsi dan kejahatan oleh pemerintah Amerika Serikat, termasuk Presiden Barack Obama dan pejabat pemerintah lainnya. Tuduhan ini mencakup serangan 11 September 2001, serangan Benghazi 2012, dan berbagai tindakan korup lainnya. Faksimile ini meminta bantuan masyarakat internasional untuk membantu menyingkirkan pemerintah Amerika Serikat melalui proses hukum internasional.
BARACK OBAMA - May 2012 FOILED PLANE PLOTVogelDenise
The CIA and foreign partners thwarted an Al Qaeda plot to smuggle an experimental bomb onto an airliner bound for the US. The bomb was seized in the Middle East before it could be deployed by a suicide bomber from Yemen. The sophisticated bomb appeared to be the work of Al Qaeda's skilled bomb maker in Yemen. While the plot was foiled, it showed that Al Qaeda in Yemen remains determined to attack the US.
Simulating Operability of Wheel Loaders: Operator Models and Quantification o...Reno Filla
In this paper make the case that operability needs to be considered early on in the development of wheel loaders, alongside such established design targets as productivity and energy efficiency. We summarise research that shows how proper operator models can introduce a “human element” into dynamic simulations, providing more relevant answers with respect to operator-influenced complete-machine properties such as productivity and energy efficiency. We then show two ways of also drawing conclusions on the operability of wheel loaders by analysing either measurement data from physical tests or simulation results.
A study to compare trajectory generation algorithms for automatic bucket fill...Reno Filla
In this paper we study how automatic bucket filling can be realised in wheel loaders. Based on observations of how experienced operators use their machines in bucket applications, four algorithms for parametric generation of bucket trajectories are investigated. The algorithms have been developed and tuned using a simplistic static integration-based approach.
The Discrete Element Method is used to validate the predictive capability of the aforementioned algorithms. Results and limitations of the simplistic approach in comparison to the numerical results, as well as specific simulation-related challenges and findings are reported and discussed.
Representative Testing of Emissions and Fuel Consumption of Working Machines ...Reno Filla
Out of necessity, emission and fuel consumption test cycles are a simplified representation of the real-life use of a vehicle or component that is assumed to be most common. In reality, variations are introduced by both the driver and the environment – and to a lesser degree also by the vehicle itself through performance deviations because of tolerances in the components’ characteristics. However, since such simplified test cycles exist and are accepted (or even required by law), OEMs tend to use them also in product development to benchmark their products against the competition, and to make decisions on how to optimize design.
While this approach might give acceptable results for on-road vehicles, it fails to capture reality in the case of versatile working machines. Here, the variety of possible applications cannot be covered by one common application but rather demands a mix of several cycles. This has a large impact on the setup and evaluation of physical and virtual testing of working machines, especially those with alternative power systems like hybrids, which will be discussed in the paper.
Attempts to simplify the complexity of real-life applications are made in some testing standards and standard proposals, but they over-simplify with the result of prescribing a common cycle that is not representative and which therefore, however tempting, cannot be used for any meaningful benchmarking of emissions and fuel consumption.
http://papers.sae.org/2012-01-1946
Fuel efficiency in construction equipment – optimize the machine as one systemReno Filla
In order to further optimize the fuel efficiency and productivity of construction equipment, 3 main potentials have been identified:
• job site optimization
• machine use optimization
• machine optimization
The focus of this paper is the machine optimization on the example of a wheel loader.
Optimizing losses in individual components must be done, but it will not be a game changer for fuel efficiency improvement. Three areas for promising improvement potentials:
• Optimizing the systems interactions
• Decoupling of systems
• Reduction of losses
One example is shown for a total machine optimization approach: the “Reverse by Braking” function is using the machine operating brakes to slow down the machine during power shuttle instead of using the engine power.
Decoupling of systems requires continuously variable transmission (CVT) functionality for the driveline. This can be achieved with hydraulic or electric CVTs. Two examples for decoupling systems are shown: the Volvo hydrostatic powersplit CVT prototype and a series hybrid wheel loader.
Further future potentials are explored, while the driveline and hydraulic technology are the enablers for drastic improvements: electrified site, plug in hybrid, alternative fuels, and new machine concepts.
Dynamic Simulation of Construction Machinery: Towards an Operator ModelReno Filla
In dynamic simulation of complete wheel loaders, one interesting aspect, specific for the working task, is the momentary power distribution between drive train and hydraulics, which is balanced by the operator.
This paper presents the initial results to a simulation model of a human operator. Rather than letting the operator model follow a predefined path with control inputs at given points, it follows a collection of general rules that together describe the machine's working cycle in a generic way. The advantage of this is that the working task description and the operator model itself are independent of the machine's technical parameters. Complete sub-system characteristics can thus be changed without compromising the relevance and validity of the simulation. Ultimately, this can be used to assess a machine's total performance, fuel efficiency and operability already in the concept phase of the product development process.
http://arxiv.org/abs/cs/0503087
Study of a method for assessing operability of working machines in physical a...Reno Filla
In this study of eighteen wheel loader operators, test-driving a machine in three different traction force settings, we found strong support for the hypothesis that the operator’s control commands can be used to assess the machine’s operability, at least in form of ease of bucket filling.
The methods chosen to derive the control effort worked well and were computationally efficient.
http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-70392
Towards Finding the Optimal Bucket Filling Strategy through SimulationReno Filla
The purpose of earth-moving equipment like wheel loaders is to engage with the ground or other material. It is therefore obvious that the bucket filling phase must be included when studying optimal machine control over a complete working cycle because total productivity and efficiency of the machine are to a large extent determined by it. This paper reports and discusses the results of research into how to utilize Discrete Element Method simulations in combination with Optimal Control to find the optimal bucket filling strategy and what has been learned regarding preparing and conducting both simulations of bucket filling and physical testing for verification. This paper also discloses which bucket filling strategy appears to be optimal, based on the results so far – and why we cannot be completely certain.
IRJET- Design, Analysis and Optimisation of Shock AbsorberIRJET Journal
This document describes the design, analysis, and optimization of a shock absorber. Students at Maratha Mandal Engineering College designed a shock absorber model in CATIA and performed structural and modal analyses in ANSYS. Structural analysis was conducted to validate the strength of the design by varying the material of the spring between spring steel and phosphor bronze. Modal analysis determined the displacements at different frequencies to optimize the design. Comparing the results of both materials helped determine the best material for the spring. The modeling was done in CATIA and analysis in ANSYS.
An Event-driven Operator Model for Dynamic Simulation of Construction MachineryReno Filla
Prediction and optimisation of a wheel loader's dynamic behaviour is a challenge due to tightly coupled, non-linear subsystems of different technical domains. Furthermore, a simulation regarding performance, efficiency, and operability cannot be limited to the machine itself, but has to include operator, environment, and work task. This paper presents some results of our approach to an event-driven simulation model of a human operator. Describing the task and the operator model independently of the machine's technical parameters, gives the possibility to change whole sub-system characteristics without compromising the relevance and validity of the simulation.
http://arxiv.org/abs/cs/0506033
This document discusses the optimization of hydro-mechanical power split transmissions. It begins by providing background on continuously variable transmissions and why hydro-mechanical power split transmissions are promising. It then describes the optimization problem as designing the transmission to maximize average efficiency by selecting displacements of the hydraulic machines and gear ratios. An optimization algorithm using particle swarm methods is used to solve this problem. Finally, the optimization method will be applied to study transmissions for a compact loader and agricultural tractor.
This document describes the BMW Group's use of computational fluid dynamics (CFD) simulations in the aerodynamic development of passenger cars and motorcycles. It discusses how CFD is used at different stages of the development process to address various aerodynamic questions. It also provides details on BMW's simulation process using a Lattice-Boltzmann code, shows examples of validation cases demonstrating the achievable accuracy, and highlights practical applications of CFD including assessing aerodynamic loads, passenger comfort, and thermal management.
Automatized testing hil system for agile product-design environmentTritem
This document summarizes a paper presented at the 7th Transport Research Arena conference in Vienna, Austria in April 2018. The paper discusses the increasing demand for testing rail vehicles due to new safety standards, and how the hardware-in-the-loop (HIL) method used in automotive and aerospace has potential but high costs that do not fit the railway industry model of smaller batches. Tritem Microsystems developed a Virtual-HIL system using their ELMo simulation engine to decrease costs and increase portability. The document provides details on classic HIL approaches, limitations for rail, and how Virtual-HIL addresses these issues.
Test platform for electronic control units of high-performance safety-critica...IJECEIAES
In this paper we are mostly concerned with the problem of testing electronic control units of synchronized electric power actuators. This task is particularly complex for safety critical applications, where it is crucial that the control system properly reacts in response to the faults that are hard to reproduce and verify. A cost-effective flexible and reconfigurable test platform is proposed, discussing its architecture and implementation. The proposed system facilitates the phase of definition and development of the electronic control unit, allowing the interfacing towards both hydraulic and electromechanical actuators, and having a high flexibility as regards the I/O signals. Some results, obtained during the laboratory test activity, are also presented.
Quarter car active suspension systemdesign using optimal and robust control m...Mustefa Jibril
1) The document describes the design of optimal and robust controllers for a quarter car active suspension system using LQR and μ-synthesis control methods.
2) Mathematical models of the quarter car system and various road disturbances are presented.
3) LQR and μ-synthesis controllers are designed in MATLAB and tested on the quarter car model under different road disturbances to maximize ride comfort and handling.
4) Simulation results show the effectiveness of the active suspension system with the μ-synthesis controller.
Quarter car active suspension systemdesign using optimal and robust control m...Mustefa Jibril
1) The document describes the design of optimal and robust controllers for a quarter car active suspension system using LQR and μ-synthesis methods.
2) Mathematical models of the quarter car system and various road disturbances are presented.
3) LQR and μ-synthesis controllers are designed in MATLAB and tested on the quarter car model under different road disturbances to maximize ride comfort and handling.
4) Simulation results show the effectiveness of the active suspension system with the μ-synthesis controller.
Quarter car active suspension systemdesign using optimal and robust control m...Mustefa Jibril
This document describes the design of optimal and robust controllers for a quarter car active suspension system. It first presents the mathematical model of a quarter car system and describes various road disturbances that could be used as inputs, including bumps, random variations, sine waves, and white noise. Then it details the design of a μ-synthesis controller using robust control methods and an LQR controller using optimal control methods. Various performance metrics are evaluated through simulation against the different road disturbances. The results show that the active suspension system with a μ-synthesis controller provides the best overall performance compared to the LQR controller design.
A Case Study on Quantifying the Workload of Working Machine Operators by Mean...Reno Filla
This study examined operator workload in 18 wheel loader operators using psychophysiological measurements under different machine settings that limited engine speed and traction force. The findings did not support using these measurements to easily assess operator workload for machine testing, as other factors strongly influence workload. While workload-adaptive assistance could help with complex machines, different workload measurements may be needed for practical use by test engineers. The machine settings aimed to study the impact of limited traction force on workload during bucket filling, which requires simultaneously controlling multiple motions and is the most fuel-consuming part of the loading cycle. However, the results indicated operability is affected by many other machine and task factors beyond the settings tested.
Feasibility Study and Design of Electromagnetic Suspension Systems: A ReviewIRJET Journal
This document summarizes a review of research on the feasibility and design of electromagnetic suspension systems. It begins by comparing different suspension system designs and reviewing existing active and semi-active electromagnetic suspension systems. These systems use electromagnetic motors or magnetorheological dampers to sense the road surface and actively control wheel movement. The document then analyzes the advantages and disadvantages of different control strategies and mathematical models used to model vehicle dynamics. It concludes by proposing a hybrid electromagnetic suspension design that attempts to address limitations of current designs.
This document discusses the current state of forklift automation technology and considerations for organizations looking to implement it. While automation has been successful in manufacturing environments with predictable tasks, the less structured warehouse environment presents challenges. Current forklift automation solutions involve retrofitting manual forklifts with sensors, which can reduce reliability. The document outlines evaluation criteria for automation systems, including reliability, flexibility, scalability, and safety. It recommends carefully evaluating the application and ensuring organizational support for any automation project. The technology is still maturing, so a long-term strategy is important to guide deployment and protect investments.
Optimization of vehicle suspension system using genetic algorithmIAEME Publication
This document describes using a genetic algorithm to optimize the parameters of a vehicle suspension system. A quarter-car model with 5 parameters is developed in Matlab and Simulink. The objective is to minimize sprung mass acceleration. A genetic algorithm is run for 51 generations to optimize the parameters. The optimized parameters found are reported, and plots show the genetic algorithm converged on optimal solutions. The optimized suspension model response matches the goal of minimizing sprung mass acceleration compared to initial arbitrary parameter values.
Similar to Using Dynamic Simulation in the Development of Construction Machinery (20)
In support of removal of periodic calibration of Flight RecordersReno Filla
This is not a Position Paper on Periodic Pressure Altitude Calibration of FR.
This is a paper on why the above is not needed.
This document will not contain a technical discussion of if, how, why and when the accuracy of pressure sensors in Flight Recorders possibly deviates and whether it then varies with absolute altitude, calendar age, frequency of use or some other variable.
We will not present statistical evidence for either occurrence or non-occurrence of "drifting" of pressure readings. Nobody has these data anyway.
What we will do in this document is to deliberate why we in our sport measure altitude to begin with and what the “good enough” level of accuracy is. From there we will examine how this can be achieved in FAI's legal framework and address possible needs for adjustment of the Sporting Code, if necessary at all.
Spoiler alert: the conclusion will be that unlike regularly visiting a dentist, periodically having to calibrate the pressure sensor in your Flight Recorder is not actually good for you. It is at best an expensive nuisance and if we can get by without this recurring hassle then we all are off for the better.
Brave new electric world: will hydraulics survive and who needs hydraulics anyway? A provocation delivered by an unsentimental system integrator. A real engineer doesn't "love" or "hate" but makes balanced and well-considered technology decisions based on performance, efficiency, application, quality, robustness, cost, etc.
Reflections on Research (and a Fractal Perspective on Systems Engineering)Reno Filla
This round-kick presentation for the 2022 LINK-SIC workshop (https://liu.se/en/article/link-sic-workshop-2022) spans the arc from research and predevelopment to knowledge in general (vs belief and opinion), systems engineering and the ongoing specialization/fragmentation of engineering , uncertainty, the climate-change related challenges ahead - and more.
This document summarizes Reno Filla's presentation on electric roads (e-roads) and the experience from pilot projects in Germany and Sweden. It discusses the power requirements for electric trucks, including 250-300 kW for constant speed driving and additional 120 kW per 1% grade. It also notes challenges like adaptive driver assistance systems in certain weather conditions and catenary interruptions. The presentation evaluates having enough power capacity for varying operating conditions and argues that 250 kW per truck is not over-dimensioned given power needs for acceleration, battery charging, and only partial road electrification.
SEC lecture "Electrification of Future Transports"Reno Filla
The document discusses the electrification of future transports. It notes the four main drivers of sustainable transport as congestion, pollution, energy security, and climate change. Scania is a leading provider of transport solutions and is working with partners and customers to drive the shift towards a more sustainable transport system. The presentation outlines Scania's goals to cut emissions from its operations and products by 2025 to help fuel the transition to more sustainable options.
Presentation for graduate students: Zoom in to learn the basics and refine your knowledge, then zoom out for perspective and to make connections. Then repeat until convergence. Which you might attain until the next disruption. ;-)
Der Diplom-Ingenieur Reno Filla ist verheiratet und hat ein Kind. Nach seinem Abschluss 1998 an unserer Hochschule ging er zu Volvo nach Schweden, wo er bis heute mit seiner Familie lebt. Seine Freizeit verbringt er gerne mit Segelfliegen. Über seine Zeit des Studiums und sein Werdegang nach dem Studium berichtet er uns in diesem Interview.
https://www.hs-magdeburg.de/hochschule/einrichtungen/alumni-management/interviews.html
Keynote presentation held at the 15th Scandinavian International Conference on Fluid Power 2017 in Linköping, Sweden
It covers the topics energy efficiency, electromobility, operator assistance, automation, connectivity and site solutions.
Towards Finding the Optimal Bucket Filling Strategy through SimulationReno Filla
The document discusses using simulation to find the optimal bucket filling strategy for a construction vehicle. It analyzed 5781 trajectories with 5 different filling strategies (labeled A through E) through discrete element method simulation. Various problems were encountered in the simulations, such as particles jumping unpredictably and large upward forces on the bucket, and solutions were developed to address them, such as adjusting the time step or adding more particle layers. Overall strategy A seemed most efficient while B was very inefficient. The analysis noted several important factors that were not captured in the simulations, such as the full loading cycle and stability of the vehicle, and suggested coupled large-scale simulation and optimization of the machine, environment, and operator may be needed to fully address finding the optimal strategy
Gliding Contest Scoring: current and proposal 8.1.4 for the 2016 IGC plenaryReno Filla
This is a supporting presentation to explain how scoring currently works (visualizing the official equations in a rearranged way) and what the effect of Dutch proposal 8.1.4 will be
Classification of physiological signals for wheel loader operators using Mult...Reno Filla
This summarizes a research paper that presents a classification approach called MMSE-CBR to classify physiological parameters of wheel loader operators. It combines case-based reasoning (CBR) with multivariate multiscale entropy analysis (MMSE) to fuse data from multiple physiological sensors. The MMSE algorithm is used to extract features from signals measured by sensors like ECG, finger temperature, skin conductance, and respiration rate. These features are used to form cases in a case library. The CBR approach then classifies new cases by retrieving similar past cases. The approach was evaluated on data from 18 professional drivers and achieved 83.33% accuracy in classifying subjects as "stressed" or "healthy", comparable to an expert's
Mental State Monitoring System for the Professional Drivers Based on Heart Ra...Reno Filla
The consequences of tiredness, drowsiness, stress and lack of concentration caused by a variety of different factors such as illness, sleep depletion, drugs and alcohol is a serious problem in traffic and when operating industrial equipment. This is especially important for professional drivers since both expensive equipment and lives may be at stake, e.g. in mining, construction and personal transportation, reduced concentration, stress or tiredness are known to be the cause of many accidents. A system which recognizes the state of the driver and e.g. suggests breaks when stress level is too high or driver is too tired would enable large savings and reduces accident. Today different sensors enable clinician to determine a driver’s status with high accuracy. The aim of the paper is to develop an intelligent system that can monitor drivers’ stress depending on psychological and behavioral conditions/status using heart rate variability. An experienced clinician is able to diagnose a person’s stress level based on sensor readings. Here, we propose a solution using case-based reasoning to diagnose individual driver’s stress. During calibration a number of individual parameters are established. The system also considers the feedback from the driver’s on how well the test was performed The validation of the approach is based on close collaboration with experts and measurements from 18 driver’s from Volvo Construction Equipment are used as reference.
http://www.mrtc.mdh.se/index.php?choice=publications&id=3046
Climate Impact of Software Testing at Nordic Testing DaysKari Kakkonen
My slides at Nordic Testing Days 6.6.2024
Climate impact / sustainability of software testing discussed on the talk. ICT and testing must carry their part of global responsibility to help with the climat warming. We can minimize the carbon footprint but we can also have a carbon handprint, a positive impact on the climate. Quality characteristics can be added with sustainability, and then measured continuously. Test environments can be used less, and in smaller scale and on demand. Test techniques can be used in optimizing or minimizing number of tests. Test automation can be used to speed up testing.
Pushing the limits of ePRTC: 100ns holdover for 100 daysAdtran
At WSTS 2024, Alon Stern explored the topic of parametric holdover and explained how recent research findings can be implemented in real-world PNT networks to achieve 100 nanoseconds of accuracy for up to 100 days.
Cosa hanno in comune un mattoncino Lego e la backdoor XZ?Speck&Tech
ABSTRACT: A prima vista, un mattoncino Lego e la backdoor XZ potrebbero avere in comune il fatto di essere entrambi blocchi di costruzione, o dipendenze di progetti creativi e software. La realtà è che un mattoncino Lego e il caso della backdoor XZ hanno molto di più di tutto ciò in comune.
Partecipate alla presentazione per immergervi in una storia di interoperabilità, standard e formati aperti, per poi discutere del ruolo importante che i contributori hanno in una comunità open source sostenibile.
BIO: Sostenitrice del software libero e dei formati standard e aperti. È stata un membro attivo dei progetti Fedora e openSUSE e ha co-fondato l'Associazione LibreItalia dove è stata coinvolta in diversi eventi, migrazioni e formazione relativi a LibreOffice. In precedenza ha lavorato a migrazioni e corsi di formazione su LibreOffice per diverse amministrazioni pubbliche e privati. Da gennaio 2020 lavora in SUSE come Software Release Engineer per Uyuni e SUSE Manager e quando non segue la sua passione per i computer e per Geeko coltiva la sua curiosità per l'astronomia (da cui deriva il suo nickname deneb_alpha).
Let's Integrate MuleSoft RPA, COMPOSER, APM with AWS IDP along with Slackshyamraj55
Discover the seamless integration of RPA (Robotic Process Automation), COMPOSER, and APM with AWS IDP enhanced with Slack notifications. Explore how these technologies converge to streamline workflows, optimize performance, and ensure secure access, all while leveraging the power of AWS IDP and real-time communication via Slack notifications.
Enchancing adoption of Open Source Libraries. A case study on Albumentations.AIVladimir Iglovikov, Ph.D.
Presented by Vladimir Iglovikov:
- https://www.linkedin.com/in/iglovikov/
- https://x.com/viglovikov
- https://www.instagram.com/ternaus/
This presentation delves into the journey of Albumentations.ai, a highly successful open-source library for data augmentation.
Created out of a necessity for superior performance in Kaggle competitions, Albumentations has grown to become a widely used tool among data scientists and machine learning practitioners.
This case study covers various aspects, including:
People: The contributors and community that have supported Albumentations.
Metrics: The success indicators such as downloads, daily active users, GitHub stars, and financial contributions.
Challenges: The hurdles in monetizing open-source projects and measuring user engagement.
Development Practices: Best practices for creating, maintaining, and scaling open-source libraries, including code hygiene, CI/CD, and fast iteration.
Community Building: Strategies for making adoption easy, iterating quickly, and fostering a vibrant, engaged community.
Marketing: Both online and offline marketing tactics, focusing on real, impactful interactions and collaborations.
Mental Health: Maintaining balance and not feeling pressured by user demands.
Key insights include the importance of automation, making the adoption process seamless, and leveraging offline interactions for marketing. The presentation also emphasizes the need for continuous small improvements and building a friendly, inclusive community that contributes to the project's growth.
Vladimir Iglovikov brings his extensive experience as a Kaggle Grandmaster, ex-Staff ML Engineer at Lyft, sharing valuable lessons and practical advice for anyone looking to enhance the adoption of their open-source projects.
Explore more about Albumentations and join the community at:
GitHub: https://github.com/albumentations-team/albumentations
Website: https://albumentations.ai/
LinkedIn: https://www.linkedin.com/company/100504475
Twitter: https://x.com/albumentations
Sudheer Mechineni, Head of Application Frameworks, Standard Chartered Bank
Discover how Standard Chartered Bank harnessed the power of Neo4j to transform complex data access challenges into a dynamic, scalable graph database solution. This keynote will cover their journey from initial adoption to deploying a fully automated, enterprise-grade causal cluster, highlighting key strategies for modelling organisational changes and ensuring robust disaster recovery. Learn how these innovations have not only enhanced Standard Chartered Bank’s data infrastructure but also positioned them as pioneers in the banking sector’s adoption of graph technology.
Unlock the Future of Search with MongoDB Atlas_ Vector Search Unleashed.pdfMalak Abu Hammad
Discover how MongoDB Atlas and vector search technology can revolutionize your application's search capabilities. This comprehensive presentation covers:
* What is Vector Search?
* Importance and benefits of vector search
* Practical use cases across various industries
* Step-by-step implementation guide
* Live demos with code snippets
* Enhancing LLM capabilities with vector search
* Best practices and optimization strategies
Perfect for developers, AI enthusiasts, and tech leaders. Learn how to leverage MongoDB Atlas to deliver highly relevant, context-aware search results, transforming your data retrieval process. Stay ahead in tech innovation and maximize the potential of your applications.
#MongoDB #VectorSearch #AI #SemanticSearch #TechInnovation #DataScience #LLM #MachineLearning #SearchTechnology
UiPath Test Automation using UiPath Test Suite series, part 6DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 6. In this session, we will cover Test Automation with generative AI and Open AI.
UiPath Test Automation with generative AI and Open AI webinar offers an in-depth exploration of leveraging cutting-edge technologies for test automation within the UiPath platform. Attendees will delve into the integration of generative AI, a test automation solution, with Open AI advanced natural language processing capabilities.
Throughout the session, participants will discover how this synergy empowers testers to automate repetitive tasks, enhance testing accuracy, and expedite the software testing life cycle. Topics covered include the seamless integration process, practical use cases, and the benefits of harnessing AI-driven automation for UiPath testing initiatives. By attending this webinar, testers, and automation professionals can gain valuable insights into harnessing the power of AI to optimize their test automation workflows within the UiPath ecosystem, ultimately driving efficiency and quality in software development processes.
What will you get from this session?
1. Insights into integrating generative AI.
2. Understanding how this integration enhances test automation within the UiPath platform
3. Practical demonstrations
4. Exploration of real-world use cases illustrating the benefits of AI-driven test automation for UiPath
Topics covered:
What is generative AI
Test Automation with generative AI and Open AI.
UiPath integration with generative AI
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Unlocking Productivity: Leveraging the Potential of Copilot in Microsoft 365, a presentation by Christoforos Vlachos, Senior Solutions Manager – Modern Workplace, Uni Systems
Securing your Kubernetes cluster_ a step-by-step guide to success !KatiaHIMEUR1
Today, after several years of existence, an extremely active community and an ultra-dynamic ecosystem, Kubernetes has established itself as the de facto standard in container orchestration. Thanks to a wide range of managed services, it has never been so easy to set up a ready-to-use Kubernetes cluster.
However, this ease of use means that the subject of security in Kubernetes is often left for later, or even neglected. This exposes companies to significant risks.
In this talk, I'll show you step-by-step how to secure your Kubernetes cluster for greater peace of mind and reliability.
Encryption in Microsoft 365 - ExpertsLive Netherlands 2024Albert Hoitingh
In this session I delve into the encryption technology used in Microsoft 365 and Microsoft Purview. Including the concepts of Customer Key and Double Key Encryption.
Communications Mining Series - Zero to Hero - Session 1DianaGray10
This session provides introduction to UiPath Communication Mining, importance and platform overview. You will acquire a good understand of the phases in Communication Mining as we go over the platform with you. Topics covered:
• Communication Mining Overview
• Why is it important?
• How can it help today’s business and the benefits
• Phases in Communication Mining
• Demo on Platform overview
• Q/A
Observability Concepts EVERY Developer Should Know -- DeveloperWeek Europe.pdfPaige Cruz
Monitoring and observability aren’t traditionally found in software curriculums and many of us cobble this knowledge together from whatever vendor or ecosystem we were first introduced to and whatever is a part of your current company’s observability stack.
While the dev and ops silo continues to crumble….many organizations still relegate monitoring & observability as the purview of ops, infra and SRE teams. This is a mistake - achieving a highly observable system requires collaboration up and down the stack.
I, a former op, would like to extend an invitation to all application developers to join the observability party will share these foundational concepts to build on:
Observability Concepts EVERY Developer Should Know -- DeveloperWeek Europe.pdf
Using Dynamic Simulation in the Development of Construction Machinery
1. Paper 01
Using Dynamic Simulation
in the Development of Construction Machinery
Reno Filla (1) and Jan-Ove Palmberg (2)
(1) VOLVO WHEEL LOADERS AB, ESKILSTUNA, SWEDEN
(2) DEPT. OF MECHANICAL ENGINEERING, LINKÖPING UNIVERSITY, SWEDEN
Abstract
As in the car industry for quite some time, dynamic simulation of complete vehicles is
being practiced more and more in the development of off-road machinery. However,
specific questions arise due not only to company structure and size, but especially to the
type of product. Tightly coupled, non-linear subsystems of different domains make pre-
diction and optimisation of the complete system’s dynamic behaviour a challenge. Fur-
thermore, the demand for versatile machines leads to sometimes contradictory target
requirements and can turn the design process into a hunt for the least painful compro-
mise. This can be avoided by profound system knowledge, assisted by simulation-
driven product development. This paper gives an overview of joint research into this
issue by Volvo Wheel Loaders and Linköping University on that matter, and lists the
results of a related literature review. Rather than giving detailed answers, the problem
space for ongoing and future research is examined and possible solutions are sketched.
Keywords: simulation, complex systems, integrated product development
2. A witty quote proves nothing.
(Voltaire)
This paper has been published as:
Filla, R. and Palmberg, J.-O. (2003) “Using Dynamic Simulation in the Development of
Construction Machinery”. The Eighth Scandinavian International Conference on Fluid
Power, Tampere, Finland, Vol. 1, pp 651-667, May 7-9, 2003.
http://www.arxiv.org/abs/cs.CE/0305036
(Internet link refers to a Technical Report of the original paper)
3. Using Dynamic Simulation… 3
1 Introduction
The general motives for “Virtual Prototyping” are probably familiar to all engineers:
Stricter legal requirements (e.g. with regard to exhaust emissions and sound) and
tougher customer demands (e.g. with regard to performance and handling) lead to more
advanced, complex systems, which are harder to optimise. With traditional methods,
development will cost more and need more time. In contrast to this, increased competi-
tion demands lower development cost and shorter project times.
“Virtual Prototyping” has been generally adopted in the vehicle industry as a major
step towards solving this conflict both on the consumer side (cars) and on the commer-
cial side (trucks and buses). Having started with simulation of sub-systems, the state-of-
the-art is simulation of complete vehicles, mostly for evaluation of handling, comfort,
and durability but also for crash-tests.
One reason for the off-road equipment industry lagging behind can be found in the
size of these companies: being significantly smaller, broad investments in the latest
CAE tools (together with the necessary training) take longer until amortisation. The
other, and probably more important reason is that the products are very different to
those of the on-road vehicle industry – not only geometrically (size), but topologically
(sub-systems of various domains and their interconnections).
Cases have recently been published where complete machines were simulated for
evaluation of the simulation technique itself [1], sub-systems [2], comfort-related as-
pects [3], or durability [4]. This paper too, will deal with dynamic simulation of com-
plete machines, but for analysis and optimisation of overall performance and related
aspects. The focus will be on wheel loaders with hydrodynamic transmissions, but most
findings (and questions) will be also applicable to other off-road machinery.
Figure 1. Multi-body model of a Volvo L220E wheel loader, loading gravel
4. 4 Paper 01
2 Background
Due to the versatility of these machines, wheel loaders need to fulfil a great many re-
quirements, which are often interconnected and sometimes contradict each other. This is
true of essentially all industrial products and is widely recognised. Since this paper fo-
cuses on performance (and related issues), aspects such as total cost of ownership, mar-
ket availability, reliability etc. will not be discussed explicitly.
To give just a few examples, the following performance-related aspects are important
(varying with the working task):
- Geometric parameters (lift height, digging depth, dump reach, parallel
alignment)
- Loads, torques and forces (tipping load, break-out torque, lift force, traction
force)
- Speeds and cycle times (complete machine and sub-systems)
- Consumption and emissions (fuel consumption, exhaust emissions, sound
& vibration)
- Controllability (precision, feedback, response)
While some of the items are clearly determined by more than just one sub-system
(e.g. lift force, which is determined by hydraulics and load unit), others seem to be pos-
sible to attribute to one single sub-system (e.g. traction force). One might thus, wrongly,
be tempted to leave such aspects out of the optimisation loop when it comes to trading-
off product targets against each other when choosing technical solutions.
A modern wheel loader of hydro-dynamic design, however, consists of tightly cou-
pled, non-linear sub-systems of different domains. Since all sub-systems interact even
in seemingly simple cases, prediction and optimisation of the complete system’s dy-
namic behaviour is a challenge.
Figure 2 shows how the sub-systems of main interest are interacting when loading
gravel.
Figure 2. Simplified transfer scheme of a wheel loader, loading gravel
(TC = Torque Converter, ECU = Electronic Control Unit, V = Vehicle, I = Instrument)
5. Using Dynamic Simulation… 5
For loading granular material like gravel, the bucket first has to penetrate the pile.
This requires traction force, which is achieved by transferring torque from the engine
via a torque converter, transmission, axles, and wheels to the ground. A typical se-
quence for actually filling the bucket is then to break material by tilting backwards a
little, lifting a little, and penetrating even further. The lift and tilt functions require en-
gine torque to be transferred via hydraulic pumps (converting torque to hydraulic pres-
sure), cylinders (converting hydraulic pressure to longitudinal force), and loading unit.
As shown, the two different transfer paths compete for the limited engine torque.
Furthermore, in the act of loading, these two paths are brought together in the gravel
pile: the penetration establishes a reaction force at the bucket, which counteracts the
break-out force, as well as the lift force. Like a short circuit, loads can be transferred
back to the origin, in this case the engine, and lead to overload (greater interaction be-
tween the systems or the engine stops completely).
This has to be avoided by a design that carefully balances traction and lift/tilt. But
these functions can not be optimised without influencing others, e.g. machine speed and
lifting time. In addition to this, Figure 2 neglects the fact that loading unit geometry and
bucket design are of great importance for a smooth bucket filling. In addition, a ma-
chine operator who handles a loader in an unintelligent way can have difficulty in
achieving a favourable balance. In such cases (but not exclusively), implementing so-
phisticated electronic control strategies can be of great help.
Above, one single phase in one single (yet frequent) handling case has been de-
scribed. A typical loading cycle consists of several phases, where balance has to be es-
tablished in each. Additionally, there are a great many different handling cases, each
with its own requirements that need to be satisfied.
With the ambition of developing a product that is significantly better than its prede-
cessor every time, this becomes harder and harder to achieve. The trend towards more
electronic control is as striking in the off-road equipment industry as it is in the on-road
branch (passenger cars, trucks, and busses). In Figure 2, this is symbolised by five elec-
tronic control units, each serving a specific purpose (component or sub-system). The
ring represents the common data bus (CAN-bus) the ECUs are connected to.
3 Design Process, Current Position
Since this research project is being carried out at Volvo Wheel Loaders, parts of their
product development process will be used as examples throughout this paper. However,
there are several indications that the procedure is similar for other companies in the off-
road industry.
The intention is not to describe the entire development process, but rather to focus on
the parts that handle overall machine performance, as described in the previous section.
After setting up preliminary product targets, an initial calculation loop is started, with
the objective of finding a good balance between loading unit, drive train (including en-
6. 6 Paper 01
gine) and hydraulics. In this process, product targets are gradually refined, until the
overall system’s specifications are judged acceptable and feasible (Figure 3).
Figure 3. Initial calculation loop for balancing the main systems
After this step, which involved several assumptions, derivative analysis is performed
for all major sub-systems, which will either confirm those assumptions or require a re-
turn to the first loop with modified input parameters.
As sketched in section 2, a wheel loader (a complex system of tightly coupled, non-
linear sub-systems) shows complex (non-linear) behaviour in complex (real-life) situa-
tions. To optimise the first one, the latter two need to be understood as fully as possible.
In this case, there are multiple handling situations, each involving humans with complex
behaviour of their own. Since the initial loop only relies on static calculations (though
guided by valuable experience), there is the possibility that the supposedly found opti-
mum will not work flawlessly in a dynamic reality.
It is therefore praxis to build early, so-called “functional prototypes” as the next step.
Using them for extensive real-life tests, the intention is to uncover any static and dy-
namic problem at an early stage in the design phase, where reiteration is still inexpen-
sive. However, these functional prototypes are often not built with exactly the same
components as planned for the production machines, since those are still in develop-
ment and therefore only available as early prototypes (or not at all). This poses the risk
that dynamic shortcomings will not be detected until later.
One example is that engines have been found to be critical. Electronically controlled
engines can have higher response times than older, mechanically controlled ones. There
7. Using Dynamic Simulation… 7
are several reasons for this, one being that the ECU itself needs some time to collect all
the information from the sensors, process it, and calculate the appropriate action. Addi-
tionally, modern engines have to be certified according to the latest exhaust emission
legislation. Virtually no diesel engine today shows any sign of much visible smoke in
transient load situations. This is achieved by limiting the injected fuel quantity at low
turbo pressures, thus making the engine a little less responsive. A second example is
hydraulic pumps: modern wheel loaders consist of load-sensing hydraulic systems,
which in most cases are superior to the old open-centre design. In such LS-systems the
response time of the pump is a critical factor. If a functional prototype is built with one
or more pumps with incorrect dynamic behaviour, together with a diesel engine as de-
scribed above, the complete loader’s dynamics can differ significantly from those of a
series-manufactured one.
A requirement for the next stage, building “real” prototypes, is that all major compo-
nents are at least mature prototypes, close to series production. In this stage, all major
testing is done and detailed design enters its final phase. Due to the above mentioned
procedure for functional prototypes additional dynamic complications are sometimes
detected. This is unfortunate, but can be handled by evaluation and preparation of pos-
sible adjustments in advance.
In the next stage, building a so-called “production prototype”, all components have to
be series manufactured. Originally, this prototype was intended to allow the production
facility to test and refine assembly methods. But since even mature prototypes of major
components might show a different dynamic behaviour to those from series production,
this last prototype can also be used for one more validation. Any detected, performance-
related issue in this stage is very costly and can jeopardise the complete project time
schedule – but building pre-series machines with shortcomings in the next step is unac-
ceptable. Testing of this prototype (and its now updated predecessors) is therefore very
thorough, i.e. resource-consuming.
In general, evaluation of machine performance consists of several stages, such as
component validation (e.g. engine), sub-system testing (e.g. lift time and traction force),
and finally testing of the complete loader. The latter is first performed by experienced
test personnel at the company’s proving ground. Having passed those tests, the proto-
types are sent to selected customers, who use them in their everyday work. This ensures
that a greater variety of operators have the chance to judge the design.
Such a procedure is often referred to as a “V-approach”, where global targets are
broken-down into targets for sub-systems and components (top-down), with the valida-
tion being done the other way around (bottom-up). It is interesting that the more the
testing resembles real life, the less measurable the outcome becomes. Specifications of
isolated components are easily validated by measurements in test benches. Sub-systems
are a little harder to test, mainly because there are few test benches that are appropriate,
but also because not every aspect of the dynamic behaviour has been specified. Testing
complete machines by professional test personnel sometimes reveals that these people
are far more experienced than the average wheel loader operator. The risk of being bi-
ased, even involuntarily, exists. Despite this, with a limited proving ground and limited
personnel, it is impossible to take all variations of handling case and operating habit
8. 8 Paper 01
into account. Therefore, the machines are field-tested by selected customers. However,
in the last two scenarios the validation of complete machine performance relies strongly
on the operator and his/her subjective judgement. While the employed test personnel are
more used to expressing their impression in measurable terms, it is the voice of the cus-
tomer that counts in the market. The challenge is how to quantify the criteria for a well-
balanced machine. And how to quantify all boundary conditions during a measurement,
i.e. how to ensure repeatability.
4 Design Process, Vision
The aim of the present project is evolution of the current product development process,
rather than revolution by means of Design Science (see [5] for a critical review by
Frost). The research question is therefore how to augment the existing design process
with dynamic simulation. As mentioned before, the focus is on analysis and optimi-
sation of overall performance and related aspects.
The revised design process has to fulfil the following non-optional targets: Lead to
development of
… products of at least equal high performance, efficiency, and operability
… but with increased robustness
… in a shorter time
… at a lower development cost
compared with today. Saved resources (time, money, and people) can then be spent
on optimising one or all of the aspects mentioned in the first item in the list.
In an earlier project, a valuable lesson has been learned: speed matters when it comes
to iterations, especially in the concept phase. When Volvo’s old loading unit calculation
programme was to be replaced by a more modern version, this was done with a proprie-
tary simulation system, which was based on a multi-body system (MBS) and a modern
database. The development was done in-house. This new simulation system has proved
to be more flexible, more accurate, and especially more efficient for the user, except for
some pre-study engineers, who used the superior speed of the old calculation pro-
gramme to brute-force optimise loading unit geometries. Since the new system obtains
results by multi-body simulation, rather than calculation of hard-coded explicit equa-
tions, one run takes a couple of seconds longer than with the old programme. Brute-
force optimisations of the old type are no longer time efficient. If this had been known
before, i.e. if it had been included in the project targets, one could have developed a
special downscaled version, that was less accurate but faster. Introduction of the new
system forced those pre-study engineers to abandon a time-efficient technique that
worked well.
A similar risk can be seen with this research project: the current initial (static) calcu-
lation loop (Figure 3) is fast and reasonably accurate. The shortcoming today is rather
that the dynamic behaviour of the complete machine is first evaluated by testing a func-
9. Using Dynamic Simulation… 9
tional prototype, followed by testing a “real” prototype. Therefore a moderately revised
process (as shown in Figure 4) is proposed.
Figure 4. Revised design process
10. 10 Paper 01
As practised today, the process starts with feeding the product targets into the initial
static calculation loop. If no satisfactory solution can be found, the targets need to be
revised. The next step is described as “Dynamically augmented, static calculations” (see
below for an explanation). Here, as well as in the next step “Dynamic simulation of
complete machine”, non-fulfilled product targets do not necessarily lead to a reiteration,
as long as the deviation can be approved. Since product targets will probably never
cover all product properties (including dynamic behaviour), this checkpoint will give
the whole process some flexibility. Only if the deviation is too high will a new static
calculation loop need to be started (with the original product targets as input). If no al-
ternative layout candidate can be calculated, the product targets need to be revised.
Since simulating complete machines can take a long time, a quick check on whether
the solution from the initial loop is dynamically feasible, would be of great help. This is
supposed to be done in the second step “Dynamically augmented, static calculations”.
Concrete methods still need to be developed. However, one example can be given (ap-
plies to machines with hydrodynamic transmissions and LS-hydraulics): a critical phase
in a so-called “short loader cycle” (or V-cycle) is when the machine, coming backwards
with a full bucket, changes direction towards the load receiver (e.g. an articulated hauler
or a dump truck). During that time, there is a close interaction between the main subsys-
tems:
1. In order to reverse the machine, the operator lowers the engine speed (other-
wise the gear shifting will be jerky and the transmission couplings might wear
out prematurely). Less torque is available at lower speeds. Additionally, the
engine response is worse at lower speeds, mainly due to inertia of the turbo
charger (and smoke limiter settings, as explained earlier).
2. When switching gears from reverse to forward, the loader is still rolling back-
wards. This forces an abrupt change of rotational direction of the torque con-
verter’s turbine wheel, thus greatly increasing the slip, which leads to a sudden
increase in torque demand from the engine.
3. Some operators do not stop lifting the loading unit while reversing, thus requir-
ing high oil flow throughout the whole process. The oil flow is proportional to
the hydraulic pump’s displacement and shaft speed, and the load-sensing
pumps can be assumed to be directly connected to the engine crankshaft. Thus,
at lower engine speeds and high demand of oil flow, the displacement goes to-
wards maximum (simply put). The amount of torque that a pump demands of
the engine is proportional to its displacement and hydraulic pressure. Since the
loader’s bucket is full and due to the loading unit’s geometry, hydraulic pres-
sure is high. With displacement at maximum, this too leads to an increased
torque demand.
Both drive train and hydraulics thus suddenly apply higher load to an already weak-
ened engine. All depends on the time scale of these three concurrent phenomena, which
is why a satisfactory answer can only be given by a detailed dynamic simulation (or
testing of a real machine, i.e. a functional prototype). However, an approximate, less
11. Using Dynamic Simulation… 11
time-consuming first approach is possible: given the loader speed when switching gears
from reverse to forward, and given the engine speed at that time, the maximum slip be-
tween the pump wheel and the turbine wheel of the torque converter can be calculated,
and thus the maximum demanded engine torque (by using the torque converter’s speci-
fications). In the worst case scenario, hydraulic pressure and pump displacement can be
assumed to be maximal. Together with the engine speed, this gives the second engine
torque demand. If the sum of both torque demands is larger than the available steady-
state engine torque at that speed, the proposed system layout will almost certainly lead
to dynamic problems. If the available steady-state engine torque is considerably larger
than the sum of both torque demands, the system will most probably function as in-
tended. To check the case in between, it is important to consider that due to factors such
as turbo charger inertia and smoke limiter mentioned before, an accelerating engine
seldom has full steady-state torque at lower engine speeds. Therefore, checking against
the static torque curve might give a false sense of security.
Figure 5. Dynamic torque curve of a modern, turbo-charged diesel engine.
Less gap between static and dynamic torque at lower acceleration (grey, dashed curve)
due to faster boost pressure build-up relative to engine speed
12. 12 Paper 01
What is needed is a dynamic engine torque curve, measured at a typical acceleration
rate. Assuming the engine is released to low idle during reversing (worst case); the ac-
celeration rate is simply obtainable as the speed difference from the engines max torque
speed to low idle, divided by a typical time for the reversal phase. Using a test bench
with an electro-magnetic brake, an engine run-up with a forced acceleration as de-
scribed above can be performed. The amount of available torque during that phase
equals the necessary braking torque (Figure 5).
In Figure 5, the grey, dashed curves represent a test, where the engine was allowed to
accelerate less. In theory, this should not only generate more available torque because
the rotating parts consume less torque for acceleration, but also because there is more
time for turbo boost pressure to be built up. As can be seen in the first diagram, the en-
gine torque itself does not increase faster in time for the case with less forced accelera-
tion. Instead, confirming the theory, more torque is available relative to engine speed,
expressed as a smaller gap between static and dynamic torque curve for the slower ac-
celeration. If the engine were allowed to accelerate sufficiently slowly, the dynamic
torque curve (bold line style) would follow the static one (thin line style).
In order to quickly sort out system layout candidates that will lead to dynamic prob-
lems, more such checking methods need to be developed, together with refinement of
the existing rules of thumb.
Taking a critical look at the proposed revised design process, even if it has been la-
belled as “evolutionary rather than revolutionary” in the beginning of this section, it
implies a bigger change than might be obvious at first glance. With its introduction,
functional prototypes are only built to verify system layouts that have passed both steps
that check the dynamic behaviour. These steps are given the great responsibility of de-
ciding whether a certain system layout can be further pursued or is to be sent back for
reiteration. The worst scenario would be to reject cases that actually would work in real-
ity, but nobody will ever know since only approved cases enter the functional prototype
phase. To avoid this and to build confidence, there has to be a smooth transition be-
tween current practice and the proposed process.
In the literature, this is referred to as the change from simulation-verified design to
simulation-driven design. Campbell shows the usual charts and gives some practical tips
on this in [6]. T Larsson examines this topic from a research perspective in [7]. Even
though Murphy and Perera are writing about their findings on Discrete Event Simula-
tion, their paper [8] provides some valuable insight, such as classifying “Team build-
ing” as one major contribute factor for success, while “Software selection” is only men-
tioned as a minor factor. They also list the activity of making effective internal
promotion for simulation as a major success factor, advice that is similar to the findings
of [9], where Beskow and Ritzén present the findings of their research on change man-
agement in general.
13. Using Dynamic Simulation… 13
5 Puzzle Pieces
In order to fulfil the vision drafted in the previous section, progress needs to be made in
various areas. Some pieces of this puzzle have already fallen into place, though.
5.1 Simulation and Modelling Techniques
As shown earlier, off-road equipment consists of systems from various domains, and
most of them need to be taken into account when simulating performance of complete
machines – which is usually a collaborative activity. As noted by many researchers,
engineers have often already chosen one domain-specific simulation program that they
are familiar with. Instead of forcing migration to one monolithic simulation system that
can be used in several domains (but offers only limited functionality in the individual
domain), a better approach is to couple the specialised, single-domain tools. This has
the advantage that both pre- and post-processing are done decentralised, in the engi-
neer’s domain-specific tools. In [10] J Larsson develops a technique for such co-
simulation and applies it to a model of a complete wheel loader. The present research
project will use this approach and further develop it.
This paper focuses more on the early stage of product development, but simulation is
equally beneficial in all stages. As T Larsson notes in [7], the more knowledge is
gained, the more the level of detail increases on the way from concept development
over detail design to product support. Being able to reuse most of the model in all stages
demands a modular approach. With that, individual modules can be replaced with up-
dated versions (e.g. for increasing the level of detail for one specific sub-system) with-
out having to make changes to the surrounding modules. Once the model of the com-
plete machine has been divided into modules, communication between them is then
only allowed through their public interfaces. Thus, an update of a module’s internal
structure does not affect the surrounding modules, since the interface is not changed. In
multi-body systems, such an interface usually consists of some markers and transfer
variables. But in some special cases, other descriptions of module interaction such as
surface contact or field interaction need to be modelled (if the simulation tool does not
provide a feature for this). Sinha et al. write in [11] about the need for modelling inter-
action dynamics between modules as modules of their own. In the present research pro-
ject though, this should be avoidable by carefully selecting the module interfaces so that
they are still physically motivated and intuitive, yet allow rigid coupling of markers and
variables.
A hierarchical modular approach combined with co-simulation will give the engineer
great flexibility regarding model creation. An engine module for instance could be
modelled as a true multi-body module with pistons, piston rods, crankshaft, rotational
damper, flywheel etc. (combustion pressure to be modelled as a variable force acting on
the piston). This would give the possibility to study torsional vibrations throughout the
drive train. Or the engine could just be approximated as a set of explicit MBS-equations
acting on a flywheel (i.e. no additional 3D-parts are modelled). Combining this with co-
simulation, the MBS-equations could be replaced by a Matlab/Simulink model of the
engine, which delivers the torque value to the multi-body system, where it is applied to
14. 14 Paper 01
the flywheel. In either case, other drive train modules will always connect to the fly-
wheel and thus not be structurally affected by switching between different engine mod-
ules. However, their behaviour and that of the complete system are both affected by the
switch, since the different engine modules in this example have different levels of de-
tail.
Looking at the relation of level of detail to modelling, Finn and Cunningham observe
in [12] that “the process of constructing a mathematical model is an inexact activity,
which is not supported by any underlying theory or governing laws”. Others go so far as
to equate mathematical modelling with art, which is quite an uncomfortable thought for
an engineer. Brooks and Tobias published a comprehensive overview in [13] and pro-
vide valuable guiding considerations on level of detail and complexity: “The purpose of
a complexity measure is to characterise the model so that this information can aid the
choice of model by predicting model performance. Ideally we would like to have a sin-
gle, system independent definition and measure of complexity covering all the aspects
of the level of detail of a model and applicable to all conceptual models. However, no
such definition or measure exists and as a result the term complexity itself is a source of
confusion due to its usage in many different contexts.” Such as using this term for any-
thing that someone finds difficult to understand. The authors further note that “a single
absolute measure of model performance cannot be obtained, but a meaningful compari-
son of alternative models in similar circumstances should be possible”. However a
search of the available literature reveals that little progress has apparently been made
since these observations (1996).
Another aspect of modular modelling is that flexibility regarding input data procure-
ment is gained. Planning to reuse an existing model by parameter update implies that
exactly the same type of input data is available for the update, as it was for the original
model. If a hydraulic pump has been modelled in great detail with hundreds of parame-
ters, then an update is difficult if all the engineer has got is a characteristics curve. “The
more detailed a model is, the more time must be spent on defining the parameters, based
on measurements or theoretical engineering reasoning”, notes Makkonen in [14]. Test
data might not be compatible due to different measurement set-ups, and theoretical rea-
soning requires the engineer to reason in a similar (if not identical) way to the creator of
the original model. In practice, it might prove more time and cost efficient to just de-
velop a new module from scratch, but with an identical interface.
Later on, assembly and replacement of modules could be done semi-automatically
using macros. However, it is dangerous to create too rigid procedures that let the engi-
neer out of the loop. In order to replace just one module in a system, the new module
has to have a similar level of detail, otherwise the entire system's behaviour is affected.
Which level of detail will be chosen for the various modules is dependent on the phe-
nomena to be studied; an experienced engineer's knowledge is vital in this decision
process and should not be overruled by some automatic routine.
15. Using Dynamic Simulation… 15
5.2 Models
Naturally, since the goal is simulation of complete machinery for the purpose of analy-
sis and optimisation of overall performance (and related aspects), most of the machines
sub-systems and components need to be modelled in a modular way and in various lev-
els of detail. Despite some issues with input data procurement (see above), this is rela-
tively easy to achieve. The challenge lies in those parts of the system that are beyond
the company’s control: operator and environment.
The research on car driver models is significant and involves topics such as lane
change manoeuvres and path tracking. Recently, the research on driver models for ar-
ticulated heavy vehicles has increased. However, wheel loaders are a very different kind
of machinery and we are unlikely to find a suitable off-the-shelf operator model. Loader
operators need to maintain the delicate balance between hydraulics and drive train. In-
teraction with other road-users is non-existent (the only exception being the need to
match a certain time frame in order to co-operate effectively with operators of other
construction equipment, such as haulers or excavators). The driver model does not need
to include proper reaction to unforeseen events (parking car, red light etc.); and visual
orientation can be modelled roughly, because it can be assumed that a professional
driver knows the workplace very well. Nechyba presents his research in [15], demon-
strating how to model human control strategies from real-time human control data. His
application of these for a continuous model uses a flexible cascade neural-network
combined with extended Kalman filtering. For the discontinuous case, control actions
are modelled by individual statistical models. Kiencke et al. introduce a hybrid driver
model in [16], which describes the human perception process by discrete event tech-
niques and can be adapted to different driver types. The driver model, made in
SES/Workbench, was then evaluated in a co-simulation with a Matlab/Simulink vehicle
model.
The development of in-depth operator models is in itself a substantial task and will
be left out of the discussion in this paper. However, using the company’s extensive
knowledge of wheel loader operation in general, it is not too difficult to extract some
basic rules, which can, for example, be represented either by a model in Mat-
lab/Simulink or by means of IF/STEP-statements and timers directly in an MBS model.
Some promising results have already been obtained in this way.
Another important part of the overall system is a proper environment model. For
most work scenarios, this might be trivial to achieve. However, this is not the case for
bucket loading of gravel or other granular material. In [17] Singh presents the state-of-
the-art in automation of earth moving. Related to this are the studies made by Hemami
in [18] on the motion trajectory during bucket loading of an LHD-loader (Load-Haul-
Dump). A review of resistive force models for earthmoving processes is made by
Blouin et al. in [19]. In [20] Ericsson and Slättengren present a model for predicting
digging forces. This model, used at Volvo Wheel Loaders, is realised as a general force
subroutine in the multi-body system ADAMS and has been verified with measurements
of cylinder pressures from excavation of coarse gravel.
16. 16 Paper 01
5.3 Simulation Goals
Simulation-driven design implies using analysis to provide insight for synthesis. This
requires one to specify the goal of the conducted simulation. Besides the already men-
tioned expectations to reduce the cost and duration of product development, important
goals for Volvo Wheel Loader with this project are
- Optimisation of machine performance
- Optimisation of efficiency (with fuel efficiency as one aspect)
- Optimisation of operability (which driveability is just a subset of)
- Optimisation of a design’s robustness
These goals are at the same time overlapping and partly contradictory. In order to
solve this conflict, techniques for multi-objective optimisation will be needed – a re-
search area that Andersson gives an account of in [21]. This also includes a study on
achieving robust design by means of a genetic algorithm. A wealth of papers exists on
tolerance analysis and design of experiment techniques. Simpson et al. present in [22] a
review of such meta-modelling techniques as RSM (response surface methodology) and
Taguchi; but at the same time they warn that many applications using these methods are
“statistically questionable, because many analysis codes are deterministic in which error
of approximation is not due to random effects”.
Optimisation applied to a simulation of a complete machine like a wheel loader could
either be optimisation of the technical system or optimisation of the driver model, i.e. to
answer the question of how a machine of a given design should be operated to achieve
the highest fuel efficiency or highest performance. Optimisation of robustness is here
not limited to geometric tolerances, but includes variances of all possible parameters,
even such as workplace altitude (the barometric pressure heavily affects the response of
engines) or experience of the machine operator.
The term operability includes driveability as a subset, valid for the drive train only.
Operability, a term that later on in this project needs to be defined, considers the inter-
play of all sub-systems of the complete machine and includes such aspects as how well-
balanced an operator perceives a certain machine to be, or how efficiently a work cycle
can be performed. As touched upon in section 3, the operator’s subjective judgement
needs to be quantified in order to find an appropriate objective function for optimisa-
tion. Wicke presents his research on driveability and control aspects of vehicles with
Continuously Variable Transmissions in [23]. Insight gained there should be applicable
at least to the driveability-part of off-road machinery’s operability. Quantifying the lat-
ter also includes developing real-world test procedures that are compatible with those in
the virtual world, and vice versa.
17. Using Dynamic Simulation… 17
6 Conclusion and Outlook
This paper presented the joint research by Volvo Wheel Loaders and Linköping Univer-
sity on simulation of complete machines for analysis and optimisation of overall per-
formance. The motivation on the side of the industrial partner is to develop products of
equally high performance, efficiency, and operability, but with more robustness regard-
ing these aspects, in a shorter time and at a lower total development cost. A revised
product development process (with regard to the research topic) has been proposed.
Examples of areas for future research have also been presented.
Research in the immediate future will focus on a definition of operability (including
quantification), as well as practical simulation problems (such as defining modules and
physically motivated and intuitive interfaces between them).
In a longer perspective, a measure of complexity needs to be developed. Research
will be done on how to optimise operability, which will also include a look at control
strategies.
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