This paper presents a new robotic joint actuation concept called the Variable Mechanical Fuse (VMF) that can achieve both high position accuracy and safety. The VMF uses springs and a mechanism to vary the preload on the springs, allowing it to behave either rigidly for precision control or elastically for safety. A prototype was designed, modeled, and tested that demonstrated the VMF's ability to reduce impact forces by 30-60% compared to a conventional rigid joint, showing its intrinsic safety.
ELECTRONIC SYNCHRONOUS SHAFT FOR SWIVEL AXES DRIVEN BY COUPLED SELFLOCKING WO...ijmech
Coupling worm gears in large machine tool manipulator units (axes) can lead to overload damages under some operating conditions, like asymmetrical driving and emergency stop. This behaviour is caused by the self locking characteristic of worm gears with small pitch. If operated in the direction opposite to the designated one, self-locking can occur in the gears, subjecting the gears to an arbitrary torque which can be destructive. This condition can occur without counter torque on the driving side. In most gears, tooth engagement is based on a rolling motion. The slip component increases with a growing axis angle between the paired gears. In case of worm gears, the axis angle is 90_, and therefore the coupling is purely frictious.This friction coupling is important in modelling. Especially the transition between the static and dynamic friction, where the system parameters change abruptly by a factor of two, should not be neglected.Based on the evaluated model a synchronous controller has been developed. This controller gives the oppertunity to drive swiveling axes with coupled selflocking gears by a standard gantry topology with an overlayed state changing master-slave topology
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Fabrication and Analysis of Tensegrity Based Prism structureIRJET Journal
This document discusses the fabrication and analysis of a tensegrity-based prism structure. It begins with an introduction to tensegrity structures, which are composed of both compressive struts and tensile cables. The authors then describe how they fabricated a Class-I tensegrity model using UPVC pipes as struts and nylon rope as cables in the shape of a triangular prism. They performed material testing on the UPVC and nylon to characterize their properties. Finally, the authors discuss their methodology for designing the tensegrity prism and conclude that these structures have potential applications in construction due to their flexibility, economic efficiency, and light weight.
This document discusses different ways to achieve magnetic levitation, including mechanically constrained levitation using two magnets, diamagnetic levitation using materials that repel magnetic fields, and superconductors which expel magnetic fields due to the Meissner effect. It also outlines applications of magnetic levitation such as maglev trains which use electromagnetic or electrodynamic suspension, magnetic bearings for industrial machinery, levitation melting using induction heating, and maglev elevators employing electrodynamic suspension.
1. This document provides numerical and theory questions related to governors used in steam engines. Numerical questions involve calculating speed ranges, forces, and other parameters for various governor configurations.
2. Theory questions explain governing concepts like governor height, types of governors including Watt, spring loaded, and Proell, factors that affect stability, and how stability is determined from controlling force curves.
3. Questions also cover topics such as how governing is done in steam engines, effects of friction and central weights, controlling forces that determine stability, and comparing ball weights between Porter and Proell governors.
1. The document describes a weapon subsystem for a robot that has a maximum height of 45mm and length of 140mm. It includes calculations for inertia, angular velocity, and torque of the subsystem.
2. The subsystem parts include two V-belt pulleys, one V-belt, two bearings, one steel shaft, and one steel bar made of welded steel plates.
3. The objective is to be effective against opposition robots while meeting team and university requirements of durability, weight, length, torque, etc. It describes how each requirement is satisfied by the subsystem design.
This document discusses belt drives and their components. It describes different types of belt drives including open belt drives, crossed belt drives, and quarter turn belt drives. It also discusses different belt drive configurations that use idler pulleys, compound pulleys, stepped pulleys, and fast and loose pulleys to transmit power between shafts over varying distances and speed ratios. The key types of belts are described as flat belts, V-belts, and ropes along with their typical applications and materials. Factors for selecting a belt drive like power, speed, and distance between shafts are also outlined.
ELECTRONIC SYNCHRONOUS SHAFT FOR SWIVEL AXES DRIVEN BY COUPLED SELFLOCKING WO...ijmech
Coupling worm gears in large machine tool manipulator units (axes) can lead to overload damages under some operating conditions, like asymmetrical driving and emergency stop. This behaviour is caused by the self locking characteristic of worm gears with small pitch. If operated in the direction opposite to the designated one, self-locking can occur in the gears, subjecting the gears to an arbitrary torque which can be destructive. This condition can occur without counter torque on the driving side. In most gears, tooth engagement is based on a rolling motion. The slip component increases with a growing axis angle between the paired gears. In case of worm gears, the axis angle is 90_, and therefore the coupling is purely frictious.This friction coupling is important in modelling. Especially the transition between the static and dynamic friction, where the system parameters change abruptly by a factor of two, should not be neglected.Based on the evaluated model a synchronous controller has been developed. This controller gives the oppertunity to drive swiveling axes with coupled selflocking gears by a standard gantry topology with an overlayed state changing master-slave topology
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Fabrication and Analysis of Tensegrity Based Prism structureIRJET Journal
This document discusses the fabrication and analysis of a tensegrity-based prism structure. It begins with an introduction to tensegrity structures, which are composed of both compressive struts and tensile cables. The authors then describe how they fabricated a Class-I tensegrity model using UPVC pipes as struts and nylon rope as cables in the shape of a triangular prism. They performed material testing on the UPVC and nylon to characterize their properties. Finally, the authors discuss their methodology for designing the tensegrity prism and conclude that these structures have potential applications in construction due to their flexibility, economic efficiency, and light weight.
This document discusses different ways to achieve magnetic levitation, including mechanically constrained levitation using two magnets, diamagnetic levitation using materials that repel magnetic fields, and superconductors which expel magnetic fields due to the Meissner effect. It also outlines applications of magnetic levitation such as maglev trains which use electromagnetic or electrodynamic suspension, magnetic bearings for industrial machinery, levitation melting using induction heating, and maglev elevators employing electrodynamic suspension.
1. This document provides numerical and theory questions related to governors used in steam engines. Numerical questions involve calculating speed ranges, forces, and other parameters for various governor configurations.
2. Theory questions explain governing concepts like governor height, types of governors including Watt, spring loaded, and Proell, factors that affect stability, and how stability is determined from controlling force curves.
3. Questions also cover topics such as how governing is done in steam engines, effects of friction and central weights, controlling forces that determine stability, and comparing ball weights between Porter and Proell governors.
1. The document describes a weapon subsystem for a robot that has a maximum height of 45mm and length of 140mm. It includes calculations for inertia, angular velocity, and torque of the subsystem.
2. The subsystem parts include two V-belt pulleys, one V-belt, two bearings, one steel shaft, and one steel bar made of welded steel plates.
3. The objective is to be effective against opposition robots while meeting team and university requirements of durability, weight, length, torque, etc. It describes how each requirement is satisfied by the subsystem design.
This document discusses belt drives and their components. It describes different types of belt drives including open belt drives, crossed belt drives, and quarter turn belt drives. It also discusses different belt drive configurations that use idler pulleys, compound pulleys, stepped pulleys, and fast and loose pulleys to transmit power between shafts over varying distances and speed ratios. The key types of belts are described as flat belts, V-belts, and ropes along with their typical applications and materials. Factors for selecting a belt drive like power, speed, and distance between shafts are also outlined.
A prize winning presentation on "TENSEGRITY architecture" under the topic of "SMART STRUCTURES" for 8 minutes on "BUILDOFEST 2017"
Tensegrity, tensional integrity or floating compression is a structural principle based on the use of isolated components in compression inside a net of continuous tension, in such a way that the compressed members (usually bars or struts) do not touch each other and the prestressed tensioned members (usually cables or tendons) delineate the system spatially.
This document contains 4 problems related to the design of mechanical springs. Problem 1 asks the reader to calculate the axial load and deflection per turn for a helical spring with given dimensions and material properties. Problem 2 involves designing a spring for a balance that can measure loads from 0-1000N over 80mm and fits inside a 25mm casing. Problem 3 asks the reader to design a compression spring for 1000N load over 25mm deflection using a spring index of 5. Problem 4 asks the reader to design a close-coiled helical compression spring that can handle loads from 2250-2750N over 6mm deflection with a spring index of 5.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
This document outlines a student project to create a levitating display using magnetic levitation. It presents the objective to make a display that levitates without physical support. It reviews literature on previous magnetic levitation projects and describes the functional diagram, components used like an Arduino board and electromagnet, and the working procedure. The project would apply magnetic levitation principles and provide advantages like stability and low cost.
Transducer for Tension Force Measurement and Control of Fine-Winding MaterialsIDES Editor
In this paper has been designed a facility
(electromechanical system) for regulation the tension force
of winding fine materials. In winding fine strip material such
a thread it is important to get homogeneous density of the
wound package, to get high quality material in next processing
of this package. In order to achieve this goal, the designed
facility controls the thread tension force during winding
process and the driving motor speed. And it allows adjusting
the tension force of the winding thread to the desired value,
which is variable and depends on the radius of the package.
This gives the required homogeneous density of the wound
package material. The suggested facility consists of simple
electronic circuit, lever, pulley, electromagnetic coils and other
simple components. The suggested system is provided by an
adjusting element in order to set the tension force of winding
material at the required reference value.
1. The document discusses different types of clutches including positive clutches and friction clutches. It describes the key components and operation of a single plate clutch commonly used in automotive applications.
2. Formulas are presented for calculating the torque capacity of clutches under uniform pressure and uniform wear conditions based on geometric parameters, pressure, and coefficient of friction.
3. The document provides an example problem demonstrating the use of the formulas to design a multi-plate clutch meeting specific torque and speed requirements.
This document summarizes a Finite Element Analysis (FEA) project evaluating the stress on a pulley design. The initial simulation found unexpected high stress, so boundary conditions were adjusted by adding restraints on the pulley bores. However, a re-entrant edge at the shaft-bore connection caused stress singularities. Adding a 1mm fillet removed this issue, and subsequent local mesh refinement showed stress values converging, validating the design.
1. The document presents a case study on the design of jaw crushers conducted by a group of students guided by professors.
2. It describes the working of single toggle and double toggle jaw crushers, showing diagrams of their components and mechanisms.
3. A static force analysis is performed to calculate the various forces acting on components of a single toggle jaw crusher, using a kinematic model and considering the equilibrium of forces at moving joints. Diagrams show the free-body models of the crank, coupler, and rocker used in the analysis.
Mechanical engineering focuses on designing, producing, and improving technical objects with moving parts. The chapter discusses various mechanical functions including linking parts, guiding motion, transmitting motion, and transforming motion. Motion transmission systems relay motion without changing its nature, while transformation systems alter the motion's nature. Examples of transmission systems are gear trains, chains, belts, and friction gears, while transformation systems include rack and pinion gears, screws, cams, sliders, and eccentrics. Speed and torque considerations are also discussed.
The document discusses how a lever can be used to lift an elephant. It explains that a lever is a simple machine that rotates around a fulcrum and uses effort and load forces. When the fulcrum is closer to the load, less effort is required. The document then gives an example calculation to determine the length of the rod needed for a man weighing 250N to lift an elephant weighing 50,000N when the fulcrum is 3m from the elephant. Through lever calculations, it is determined the length would need to be 6m.
ANALYSIS OF FRICTION INDUCED VIBRATION DURING ENGAGEMENT OF CLUTCHESIAEME Publication
Safety aspect in automotive engineering is of prime importance and given priority in design and development of vehicle. This vehicle development needs to meet safety requirement. Braking system along with good suspension systems, good handling and safe cornering, is one of the most critical system in the vehicle. The objective of this work is to design, analyze and investigate the temperature distribution of rotor disc during braking operation using suitable numerical tools. The numerical study uses the finite element analysis techniques to predict the temperature distribution on the full and ventilated brake disc. This analysis is further used to identify the critical temperature of the rotor by varying geometric design of the disc. The analysis also gives us, the heat flux distribution for the disc rotors with various groove patterns.
Magnetically Actuated and Guided Milli-Gripper for Medical ApplicationsKanika Dheman
The document describes a magnetically actuated and guided milli-gripper designed for medical applications. It consists of a compliant gripper attached to an electromagnetic coil and permanent magnet. Passing a current through the coil causes the gripper jaws to close via magnetic interaction. The permanent magnet also allows external magnetic field guidance of the device. Kinematics and finite element modeling were used to optimize the design for maximum gripping stroke. Experiments showed successful actuation of the gripper and guidance in both tethered and untethered configurations, demonstrating its potential for minimally invasive procedures.
Design of Flat belt, V belt and chain drivesDr. L K Bhagi
Geometrical relationships, Analysis of belt tensions, Condition for maximum power transmission, Characteristics of belt drives, Selection of flat belt, V- belt, Selection of V belt, Roller chains, Geometrical relationship, Polygonal effect, Power rating of roller chains, Design of chain drive, Introduction to belt drives and belt construction, Introduction to chain drives
A simple machine is a mechanical device that changes the direction or magnitude of a force. The document focuses on levers, which are simple machines that use a rigid object and fulcrum to multiply applied force. Levers have three classes defined by the relative positions of the load, fulcrum, and applied force. Examples are provided to calculate distances and forces using levers based on given weights and measurements.
This document discusses magnetic levitation, including its definition, principles, types of methods, and applications. It describes electromagnetic suspension and electrodynamic suspension as two types of magnetic levitation. It also discusses Faraday's law and Lenz's law as they relate to magnetic levitation. Some applications mentioned include maglev trains, floating cities, and space launch systems. The document further discusses MEMS, VLSI, MOSFET fabrication, and VHDL constructs.
Finite Element Analysis of Mercury III Hyperloop Scale Model Pod FrameWilliam Steppe
The document summarizes a finite element analysis of a Hyperloop pod frame. Three loading scenarios were analyzed: initial acceleration, constant velocity, and power failure impact. The frame was modeled in CREO and analyzed in ANSYS. The maximum stress of 19.2 GPa occurred during a power failure impact scenario. A mesh independence study refined the mesh to 3.1 million elements. Reinforcements will be added to stress concentrations to ensure the frame withstands expected loads.
This document discusses work, power, simple machines, and compound machines. It defines work as a force acting through a distance, and power as the rate at which work is done. Six simple machines are described: inclined planes, wedges, screws, levers, pulleys, and wheels and axles. Compound machines combine two or more simple machines to make work easier by changing the input force, distance, or direction of force. The mechanical advantage of machines allows work to be done with less input force.
IRJET- Structural and Vibration Analysis of Propeller Blade in Small AircraftIRJET Journal
This study analyzed the structural and vibration characteristics of propeller blades made from aluminum alloy and carbon fiber-reinforced epoxy composite material. Finite element analysis was conducted in ABAQUS to evaluate stress and modal analysis under different loading conditions. For stress analysis, the maximum displacement was found to be 22.38mm for aluminum and 93.33mm for composite, while the maximum stress was 167MPa and 94MPa respectively. Modal analysis determined the first eight natural frequencies and mode shapes. The natural frequencies were approximately half as high for composite compared to aluminum across all modes. The study provides a comparison of propeller blade performance and vibration characteristics for different materials.
Design and Simulation of MEMS Based GyroscopeIOSR Journals
This document describes the design and simulation of a MEMS-based gyroscope. It includes:
1) An overview of the mechanical design of the gyroscope, which uses a square plate resonator supported by 4 anchors and driven by comb electrodes.
2) A simulation of the gyroscope in COMSOL Multiphysics to analyze performance, including eigenfrequency analysis and matching the drive and sense modes.
3) Calculation of sensitivity based on the capacitive change measured between the proof mass and detection electrode, resulting from Coriolis acceleration induced by rotation.
This document discusses belt drives and friction in bearings. It describes the components and functioning of belt drives, including types of belts, pulleys, velocity ratio calculations considering slippage, power transmission, and centrifugal effects. It also covers flat and conical pivot bearings, describing methods to calculate friction forces and wear for uniform pressure and wear distributions. Key points covered include belt material properties, V-belt wedging action, open and crossed belt drive configurations, and friction force calculations for flat and conical bearings.
This document proposes a new robotic joint actuation concept called the Variable Mechanical Fuse (VMF) which aims to realize intrinsic safety for human-robot interaction through an elastic behavior and high position control through a rigid behavior. Simulation and experimental results on a prototype VMF joint show it achieves lower impact forces during collisions and greater position stability under external forces compared to no preload or partial preload configurations. Future work will investigate the effect of gravity, design a 4 DOF robot arm using the VMF concept, and validate the intrinsic safety and control capabilities of the VMF for human-robot cooperation applications.
This document provides information about cartoons and cartoonists. It discusses how cartoons first started in newspapers and magazines before being animated for movies. Some famous cartoon characters and their creators are listed, such as Mickey Mouse created by Walt Disney and Snoopy created by Charles Schultz. Common verbs in the past tense are demonstrated like "created" and "studied". Biographies in paragraph form are written about three influential cartoonists - Walt Disney, Charles Schultz, and Pat Sullivan.
A prize winning presentation on "TENSEGRITY architecture" under the topic of "SMART STRUCTURES" for 8 minutes on "BUILDOFEST 2017"
Tensegrity, tensional integrity or floating compression is a structural principle based on the use of isolated components in compression inside a net of continuous tension, in such a way that the compressed members (usually bars or struts) do not touch each other and the prestressed tensioned members (usually cables or tendons) delineate the system spatially.
This document contains 4 problems related to the design of mechanical springs. Problem 1 asks the reader to calculate the axial load and deflection per turn for a helical spring with given dimensions and material properties. Problem 2 involves designing a spring for a balance that can measure loads from 0-1000N over 80mm and fits inside a 25mm casing. Problem 3 asks the reader to design a compression spring for 1000N load over 25mm deflection using a spring index of 5. Problem 4 asks the reader to design a close-coiled helical compression spring that can handle loads from 2250-2750N over 6mm deflection with a spring index of 5.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
This document outlines a student project to create a levitating display using magnetic levitation. It presents the objective to make a display that levitates without physical support. It reviews literature on previous magnetic levitation projects and describes the functional diagram, components used like an Arduino board and electromagnet, and the working procedure. The project would apply magnetic levitation principles and provide advantages like stability and low cost.
Transducer for Tension Force Measurement and Control of Fine-Winding MaterialsIDES Editor
In this paper has been designed a facility
(electromechanical system) for regulation the tension force
of winding fine materials. In winding fine strip material such
a thread it is important to get homogeneous density of the
wound package, to get high quality material in next processing
of this package. In order to achieve this goal, the designed
facility controls the thread tension force during winding
process and the driving motor speed. And it allows adjusting
the tension force of the winding thread to the desired value,
which is variable and depends on the radius of the package.
This gives the required homogeneous density of the wound
package material. The suggested facility consists of simple
electronic circuit, lever, pulley, electromagnetic coils and other
simple components. The suggested system is provided by an
adjusting element in order to set the tension force of winding
material at the required reference value.
1. The document discusses different types of clutches including positive clutches and friction clutches. It describes the key components and operation of a single plate clutch commonly used in automotive applications.
2. Formulas are presented for calculating the torque capacity of clutches under uniform pressure and uniform wear conditions based on geometric parameters, pressure, and coefficient of friction.
3. The document provides an example problem demonstrating the use of the formulas to design a multi-plate clutch meeting specific torque and speed requirements.
This document summarizes a Finite Element Analysis (FEA) project evaluating the stress on a pulley design. The initial simulation found unexpected high stress, so boundary conditions were adjusted by adding restraints on the pulley bores. However, a re-entrant edge at the shaft-bore connection caused stress singularities. Adding a 1mm fillet removed this issue, and subsequent local mesh refinement showed stress values converging, validating the design.
1. The document presents a case study on the design of jaw crushers conducted by a group of students guided by professors.
2. It describes the working of single toggle and double toggle jaw crushers, showing diagrams of their components and mechanisms.
3. A static force analysis is performed to calculate the various forces acting on components of a single toggle jaw crusher, using a kinematic model and considering the equilibrium of forces at moving joints. Diagrams show the free-body models of the crank, coupler, and rocker used in the analysis.
Mechanical engineering focuses on designing, producing, and improving technical objects with moving parts. The chapter discusses various mechanical functions including linking parts, guiding motion, transmitting motion, and transforming motion. Motion transmission systems relay motion without changing its nature, while transformation systems alter the motion's nature. Examples of transmission systems are gear trains, chains, belts, and friction gears, while transformation systems include rack and pinion gears, screws, cams, sliders, and eccentrics. Speed and torque considerations are also discussed.
The document discusses how a lever can be used to lift an elephant. It explains that a lever is a simple machine that rotates around a fulcrum and uses effort and load forces. When the fulcrum is closer to the load, less effort is required. The document then gives an example calculation to determine the length of the rod needed for a man weighing 250N to lift an elephant weighing 50,000N when the fulcrum is 3m from the elephant. Through lever calculations, it is determined the length would need to be 6m.
ANALYSIS OF FRICTION INDUCED VIBRATION DURING ENGAGEMENT OF CLUTCHESIAEME Publication
Safety aspect in automotive engineering is of prime importance and given priority in design and development of vehicle. This vehicle development needs to meet safety requirement. Braking system along with good suspension systems, good handling and safe cornering, is one of the most critical system in the vehicle. The objective of this work is to design, analyze and investigate the temperature distribution of rotor disc during braking operation using suitable numerical tools. The numerical study uses the finite element analysis techniques to predict the temperature distribution on the full and ventilated brake disc. This analysis is further used to identify the critical temperature of the rotor by varying geometric design of the disc. The analysis also gives us, the heat flux distribution for the disc rotors with various groove patterns.
Magnetically Actuated and Guided Milli-Gripper for Medical ApplicationsKanika Dheman
The document describes a magnetically actuated and guided milli-gripper designed for medical applications. It consists of a compliant gripper attached to an electromagnetic coil and permanent magnet. Passing a current through the coil causes the gripper jaws to close via magnetic interaction. The permanent magnet also allows external magnetic field guidance of the device. Kinematics and finite element modeling were used to optimize the design for maximum gripping stroke. Experiments showed successful actuation of the gripper and guidance in both tethered and untethered configurations, demonstrating its potential for minimally invasive procedures.
Design of Flat belt, V belt and chain drivesDr. L K Bhagi
Geometrical relationships, Analysis of belt tensions, Condition for maximum power transmission, Characteristics of belt drives, Selection of flat belt, V- belt, Selection of V belt, Roller chains, Geometrical relationship, Polygonal effect, Power rating of roller chains, Design of chain drive, Introduction to belt drives and belt construction, Introduction to chain drives
A simple machine is a mechanical device that changes the direction or magnitude of a force. The document focuses on levers, which are simple machines that use a rigid object and fulcrum to multiply applied force. Levers have three classes defined by the relative positions of the load, fulcrum, and applied force. Examples are provided to calculate distances and forces using levers based on given weights and measurements.
This document discusses magnetic levitation, including its definition, principles, types of methods, and applications. It describes electromagnetic suspension and electrodynamic suspension as two types of magnetic levitation. It also discusses Faraday's law and Lenz's law as they relate to magnetic levitation. Some applications mentioned include maglev trains, floating cities, and space launch systems. The document further discusses MEMS, VLSI, MOSFET fabrication, and VHDL constructs.
Finite Element Analysis of Mercury III Hyperloop Scale Model Pod FrameWilliam Steppe
The document summarizes a finite element analysis of a Hyperloop pod frame. Three loading scenarios were analyzed: initial acceleration, constant velocity, and power failure impact. The frame was modeled in CREO and analyzed in ANSYS. The maximum stress of 19.2 GPa occurred during a power failure impact scenario. A mesh independence study refined the mesh to 3.1 million elements. Reinforcements will be added to stress concentrations to ensure the frame withstands expected loads.
This document discusses work, power, simple machines, and compound machines. It defines work as a force acting through a distance, and power as the rate at which work is done. Six simple machines are described: inclined planes, wedges, screws, levers, pulleys, and wheels and axles. Compound machines combine two or more simple machines to make work easier by changing the input force, distance, or direction of force. The mechanical advantage of machines allows work to be done with less input force.
IRJET- Structural and Vibration Analysis of Propeller Blade in Small AircraftIRJET Journal
This study analyzed the structural and vibration characteristics of propeller blades made from aluminum alloy and carbon fiber-reinforced epoxy composite material. Finite element analysis was conducted in ABAQUS to evaluate stress and modal analysis under different loading conditions. For stress analysis, the maximum displacement was found to be 22.38mm for aluminum and 93.33mm for composite, while the maximum stress was 167MPa and 94MPa respectively. Modal analysis determined the first eight natural frequencies and mode shapes. The natural frequencies were approximately half as high for composite compared to aluminum across all modes. The study provides a comparison of propeller blade performance and vibration characteristics for different materials.
Design and Simulation of MEMS Based GyroscopeIOSR Journals
This document describes the design and simulation of a MEMS-based gyroscope. It includes:
1) An overview of the mechanical design of the gyroscope, which uses a square plate resonator supported by 4 anchors and driven by comb electrodes.
2) A simulation of the gyroscope in COMSOL Multiphysics to analyze performance, including eigenfrequency analysis and matching the drive and sense modes.
3) Calculation of sensitivity based on the capacitive change measured between the proof mass and detection electrode, resulting from Coriolis acceleration induced by rotation.
This document discusses belt drives and friction in bearings. It describes the components and functioning of belt drives, including types of belts, pulleys, velocity ratio calculations considering slippage, power transmission, and centrifugal effects. It also covers flat and conical pivot bearings, describing methods to calculate friction forces and wear for uniform pressure and wear distributions. Key points covered include belt material properties, V-belt wedging action, open and crossed belt drive configurations, and friction force calculations for flat and conical bearings.
This document proposes a new robotic joint actuation concept called the Variable Mechanical Fuse (VMF) which aims to realize intrinsic safety for human-robot interaction through an elastic behavior and high position control through a rigid behavior. Simulation and experimental results on a prototype VMF joint show it achieves lower impact forces during collisions and greater position stability under external forces compared to no preload or partial preload configurations. Future work will investigate the effect of gravity, design a 4 DOF robot arm using the VMF concept, and validate the intrinsic safety and control capabilities of the VMF for human-robot cooperation applications.
This document provides information about cartoons and cartoonists. It discusses how cartoons first started in newspapers and magazines before being animated for movies. Some famous cartoon characters and their creators are listed, such as Mickey Mouse created by Walt Disney and Snoopy created by Charles Schultz. Common verbs in the past tense are demonstrated like "created" and "studied". Biographies in paragraph form are written about three influential cartoonists - Walt Disney, Charles Schultz, and Pat Sullivan.
El documento resume varias ordenanzas y decretos de diferentes municipalidades y el gobierno peruano. La Municipalidad de La Victoria aprobó la creación de un consejo consultivo de niños y adolescentes y exoneró el pago de tasas para organizaciones de base. Otras municipalidades modificaron ordenanzas relacionadas a seguridad y sanciones administrativas. El gobierno declaró días no laborables y estableció actividades económicas esenciales exceptuadas de esta medida para garantizar servicios a la comunidad.
The document provides guidance on creating movie trailers. It discusses the history and purpose of trailers, noting that they were originally shown after films but were moved to before films as people would leave. It describes the components of trailers, including using a three act structure, quick cuts of exciting moments, and leaving the resolution unknown. The document also provides tips on voiceovers, text, music, and fonts to match the genre. It recommends including website and social media links at the end.
Este documento presenta información sobre el pensamiento estratégico de las empresas. Explica conceptos clave como la visión, misión, objetivos y estrategia a diferentes niveles. También describe cómo el entorno empresarial ha cambiado a lo largo del tiempo y cómo esto afecta el enfoque estratégico de las empresas. Finalmente, analiza los componentes de la estrategia a nivel corporativo, de negocio y funcional.
El documento proporciona 10 claves para ser un estudiante virtual exitoso. Estas incluyen mantener las materias al día dedicando horas diarias al estudio, hacer preguntas en clase para aclarar dudas, tener fortaleza y paciencia para afrontar errores, aplicar técnicas de estudio como resúmenes y cuadros sinópticos, organización a través de calendarios y apuntes, autonomotivación, tomar buenos apuntes en clase, permanecer enfocado en las tareas, y interesarse en los temas de
This document provides information about the company Forever, which was founded in 1978 and has over $2.6 billion in turnover. It operates in over 150 countries and has sales over £50 million in the UK. The document discusses Forever's product lines, which include aloe vera gels and lotions, toothgel, soap, shampoo, supplements, and more. These products contain aloe vera and other natural ingredients for health, beauty, and nutrition. The document promotes Forever as a remarkable business opportunity.
Cyberbullying is a growing problem, especially among teens. It involves using the internet or other digital technologies to harass or threaten someone in a repeated manner. Examples include sending mean, vulgar, or threatening messages via social media, texting, or other online mediums.
História de Santa Catarina - parte 2 de 3Elton Zanoni
Durante o Período Monárquico no Brasil (1822-1889), Santa Catarina passou de capitania a província e finalmente a estado. A província experimentou ondas de colonização européia, principalmente alemã e italiana, que estabeleceram diversas colônias e ajudaram a povoar a região. A Revolução Farroupilha também teve impacto em Santa Catarina durante este período.
Starting with 8.5 tonnes of general waste going to landfill, the Fresh Olive Company implemented an environmental campaign to achieve zero landfill status. Being a food manufacturer with 130 employees it was imperative the employees get on board and fully back the initiative. This was both an environmental and internal communications challenge.
Working closely with Veris, they developed a creative stakeholder communications programme – Ready, Steady, Green! that was fun and resulted in operational improvements. The programme educated and inspired employees to do more with less through interactive workshops and visual communications tools. The interest and enthusiasm of the employees is maintained with additional seasonal campaigns.
The results were impressive, with green behaviours being embedded as a central focus of the business. Zero landfill status has been achieved, items have been donated to local charities and inedible food waste is now sent to Anaerobic Digestion which saves an impressive amount of carbon. Together, they proved that sustainable behaviours don’t need to be tedious or boring.
Presented by Stuart Goodman, stakeholder engagement specialist, Veris Strategies
Questões de História de Santa CatarinaElton Zanoni
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II. São apresentadas diversas questões sobre esses temas, com imagens, textos e afirmações a serem analisadas.
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A Novel Robotic Joint Actuation Concept VMF
1. A Novel Robotic Joint Actuation Concept:
The Variable Mechanical Fuse, VMF
Yoichiro Dan1
and Oussama Khatib2
1
Artificial Intelligence Laboratory, Stanford University, Stanford, CA 94305, USA
yoichir2@stanford.edu
2
Artificial Intelligence Laboratory, Stanford University, Stanford, CA 94305, USA
ok@cs.stanford.edu
Abstract. This paper presents a novel robotic joint actuation concept, the Variable
Mechanical Fuse, VMF. This actuation system realizes a rigid behavior for high
control performance and an elastic behavior for safer human-robot interaction.
The VMF adapts its behavior throughout a motion to ensure that both endpoints
have high position accuracy and the intermediate trajectory maintains safety.
Since the VMF changes its behavior passively from rigid to elastic, this actuation
system is intrinsically safe even when unexpected collisions occur. A compact
prototype has been designed and fabricated to verify its performance and safety.
Keywords: Elastic joint, SEA, variable stiffness joint, compliant motion and
torque control
1 Introduction
Industrial robots have been used in unmanned environments for a long time.
Safety is enforced by not having humans within close proximity of robots in oper-
ation. However, applications that require robots to cooperate with humans are ex-
pected to increase in the near future. This has sparked a wide variety of research
on safer robots. The research on human safe robot design started with SEA [1] de-
veloped by Pratt et al. SEA has springs as elastic components that allow compliant
motions against external forces. Edsinger et al. developed a robot that is equipped
with SEAs for safe human-robot interactions [2]. Due to the elasticity in SEAs,
they usually have limited position accuracy. In order to overcome this problem,
elastic mechanisms with variable elasticity were developed. Wolf et al. developed
a variable stiffness joint [3, 4] and realized a mechanism that has variable elastic
2. 2 Yoichiro Dan and Oussama Khatib
constants by non-linear cams and rollers. Morita et al. developed a variable stiff-
ness joint that has a cantilever with a variable active length [5]. Tsagarakis et al.
developed a variable stiffness joint that has springs and a lever [6]. Their design
uses a separate mechanism to vary the pivot point of the lever that connects to the
springs. Using a multi-stage elastic actuator concept, Kuan et al. developed a SEA
with two springs of different constants [7]. However it is observed that these de-
signs still do not have position accuracy that comes close to that of rigid joints.
A safe mechanism that does not sacrifice position accuracy while maintaining
acceptable level of safety is required in industry. Zinn et al. developed a macro-
mini actuation system that implements safety while being able to produce highly
responsive position control [8]. However the performances such as position accu-
racy and frequency response are still not high enough compared to conventional
rigid joints. The VMF concept attempts to solve the safety vs. performance trade-
off by having two vastly different behaviors.
2 Principle
High position accuracy and safety of robot arms can be achieved in a single
mechanism. The VMF actuation concept introduced here achieves both a rigid and
elastic behavior by setting the threshold to external forces.
Fig.1 shows the basic elastic joint principle of the VMF. The VMF has a spe-
cific stiffness and a variable threshold to external forces. When the external force
is lower than the threshold, the VMF shows a rigid behavior because the force is
not large enough to produce a displacement. When the external force is higher
than the threshold, the VMF shows an elastic behavior similar to that of an SEA.
Since the threshold can be set to any value, the VMF can display a purely elastic
behavior when the threshold is set to zero.
Fig. 1 Principle of VMF
3. The New Concept of Elastic Joint Mechanism: VMF (Variable Mechanical Fuse) 3
3 Analysis
Fig. 2 shows a schematic diagram of a VMF model. The VMF has springs as
elastic components between a motor and a link. The threshold is produced by ap-
plying preloads on the springs. The dynamic equation of the VMF is expressed by
the following two equations.
exll
lm
fDJ
fDJ
,
,
(1)
where Jm and Jl show inertia of the motor and the link respectively, Dl shows fric-
tion coefficient between the motor and the link. and show angle of the motor
and the link respectively. and ex show torque of the motor and external torque
that is applied on the link respectively.
The torque applied by the springs is described by the function f that contains
the preload on the springs.
,
,sgn
,
pp
lp K
f
0
0
(2)
where sgn is the sign function implemented to express the preload on springs. p
and Kl show the preload and the spring constant respectively.
Fig. 3 shows a simulation result of position step responses with various preload
values. The preload can be set from zero to the maximum value that is large
enough to cancel acceleration torque and holding torque of payloads. From the
graph, the oscillation on the trajectory of is reduced with increased preloads.
Eventually the trajectory of matches the trajectory of at 100% preload which
corresponds to the behavior of a rigid joint.
Fig. 4 shows a comparison of impact forces between an ordinary rigid joint and
the VMF. Here is assumed that a weight of 250g is placed at the tip of the link of
250mm length, and the weight is collided with an obstacle at the angular velocity
rad/s. The impact force of the VMF is reduced by approximately 40% to 60%
compared to a rigid joint. It indicates that the VMF is safer than ordinary rigid
joints even when unexpected collisions are occurred while the VMF shows rigid
behavior with the maximum preload.
4. 4 Yoichiro Dan and Oussama Khatib
Fig. 2 Schematic diagram of VMF model
Fig. 3 Position step response of VMF with different preloads
Fig. 4 Comparison of impact forces between a rigid joint and VMF
5. The New Concept of Elastic Joint Mechanism: VMF (Variable Mechanical Fuse) 5
4 Mechanism
4.1 Design of VMF
A VMF prototype for a single joint has been designed and assembled. Fig. 5
shows a picture of the prototype. This joint has an elastic unit with springs and a
mechanism to produce the preload on the springs for setting the threshold to ex-
ternal forces. The mechanism supports an encoder for sensing the angular dis-
placement of the elastic unit. An important characteristic of a VMF is that this unit
also works as a torque sensor and allows compliant motions by torque control.
Fig. 6 shows the cross-sectional CAD image of the elastic unit. This unit is
equipped with a small geared electric motor coupled to a slide screw that is placed
in the center of the unit. When the slide screw is rotated by the motor, it drives a
preload generator downward in the picture to deform the springs and produce the
preload. When an external force is applied to the link shown in Fig. 2, a pushing
rotor that is placed in the center is rotated to the direction of the blue arrow since it
is connected directly to the link. Then the pushing rotor pushes the spring on ei-
ther side via a pushing plate to the direction of the red arrows. When the force ap-
plied to the spring by the pushing rotor is smaller than the preload, this unit shows
a rigid behavior. When the force exceeds the preload, this unit shows an elastic
behavior.
This mechanism is applicable to joints of a robot arm. When precise motion is
required such as for positioning, the arm can show high position accuracy by the
VMF’s rigid behavior. When safe motion is required during any interaction with
the robot, the arm can show compliant motion by the VMF’s elastic behavior.
Fig. 5 Prototype of VMF
6. 6 Yoichiro Dan and Oussama Khatib
Fig. 6 Cross-sectional image of the elastic unit
4.2 Specification
Table 1 shows the specifications of the prototype. This prototype is designed to
be incorporated into an elbow joint of a human sized robot arm. This design as-
sumes a 0.5kg payload at the tip of the link with a length of 0.25m. The torque ca-
pacity is set at 1.3Nm by the joint stiffness that is determined by the spring con-
stant and the maximum angular displacement. The maximum preload is set at
1.1Nm by the spring constant and the maximum stroke of preload generator. Since
this value is large enough to cancel the holding torque and the acceleration torque
of the payload, the unit can realize rigid behavior at any posture and velocity.
Table 1 Specifications of VMF
Parameters Unit Value
Max. payload kg 0.5
Length of link m 0.25
Joint stiffness Nm/rad 7.3
Max. angular displacement rad (deg) 0.17 (10)
Torque capacity Nm 1.3
Max. preload Nm 1.1
7. The New Concept of Elastic Joint Mechanism: VMF (Variable Mechanical Fuse) 7
5 Experiment
An experiment of collisions was performed to investigate the VMF’s safety.
Fig. 7 shows the experimental setup. A weight of 250g is placed at the tip of the
link of 250mm length. The weight is collided with the load cell at the angular ve-
locity rad/s and stopped safely within the maximum displacement of the elastic
unit. A rigid joint collision is also performed in the same condition. Fig. 8 shows
the results of the experiment. Depending on the preload value, the collision forces
are reduced by 30% to 60% compared to a conventional rigid joint. The collision
forces vary from around 90N to 200N linearly. These results correspond approxi-
mately to the simulation results described above. It was confirmed that the VMF
has intrinsic safety in any value of the preload.
Fig. 7 Experimental setup
Fig. 8 Results of collision experiment with different preloads
8. 8 Yoichiro Dan and Oussama Khatib
6 Conclusion
In this paper, we proposed the concept of VMF (Variable Mechanical Fuse) to
address the challenge of achieving both performance and safety in an actuation
system. Our study has shown this novel actuation system to realize high control
performance while providing intrinsic safety. A compact single DOF prototype
has designed and an experiment of collisions has been performed to confirm the
intrinsic safety. The experiment has demonstrated reductions of 30% to 60% of
the collision forces compared to conventional rigid joints. Further experiments
such as step response and frequency response are going to be performed soon.
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