Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Optimal backstepping control of quadrotor UAV using gravitational search opti...journalBEEI
Quadrotor unmanned aerial vehicle (UAV) has superior characteristics such as ability to take off and land vertically, to hover in a stable air condition and to perform fast maneuvers. However, developing a high-performance quadrotor UAV controller is a difficult problem as quadrotor is an unstable and underactuated nonlinear system. The effort in this article focuses on designing and optimizing an autonomous quadrotor UAV controller. First, the aerial vehicle's dynamic model is presented. Then it is suggested an optimal backstepping controller (OBC). Traditionally, backstepping controller (BC) parameters are often selected arbitrarily. The gravitational search algorithm (GSA) is used here to determine the BC parameter optimum values. In the algorithm, the control parameters are calculated using an integral absolute error to minimize the fitness function. As the control law is based on the theorem of Lyapunov, the asymptotic stability of the scheme can be ensured. Finally, several simulation studies are conducted to show the efficacy of the suggested OBC.
Compensation of Data-Loss in Attitude Control of Spacecraft Systems rinzindorjej
In this paper, a comprehensive comparison of two robust estimation techniques namely, compensated closed-loop Kalman filtering and open-loop Kalman filtering is presented. A common problem of data loss in a real-time control system is investigated through these two schemes. The open-loop scheme, dealing with the data-loss, suffers from several shortcomings. These shortcomings are overcome using compensated scheme, where an accommodating observation signal is obtained through linear prediction technique -- a closed-loop setting and is adopted at a posteriori update step. The calculation and employment of accommodating observation signal causes computational complexity. For simulation purpose, a linear time invariant spacecraft model is however, obtained from the nonlinear spacecraft attitude dynamics through linearization at nonzero equilibrium points -- achieved off-line through Levenberg-Marguardt iterative scheme. Attempt has been made to analyze the selected example from most of the perspectives in order to display the performance of the two techniques.
Effect of Parametric Variations and Voltage Unbalance on Adaptive Speed Estim...IAES-IJPEDS
Speed Estimation without speed sensors is a complex phenomenon and is overly dependent on the machine parameters. It is all the more significant during low speed or near zero speed operation. There are several approaches to speed estimation of an induction motor. Eventually, they can be classified into two types, namely, estimation based on the machine model and estimation based on magnetic saliency and air gap space harmonics. This paper analyses the effect of incorrect setting of parameters like the stator resistance, rotor time constant, load torque variations and also Voltage unbalance on various adaptive control based speed estimation techniques fed from the machine model. It also shows how the convergence mechanisms of the adaptation schemes are affected during these conditions. The equivalent models are built and simulated offline using MATLAB/SIMULINK blocksets and the results are analysed.
Output feedback trajectory stabilization of the uncertainty DC servomechanism...ISA Interchange
This work proposes a solution for the output feedback trajectory-tracking problem in the case of an uncertain DC servomechanism system. The system consists of a pendulum actuated by a DC motor and subject to a time-varying bounded disturbance. The control law consists of a Proportional Derivative controller and an uncertain estimator that allows compensating the effects of the unknown bounded perturbation. Because the motor velocity state is not available from measurements, a second-order sliding-mode observer permits the estimation of this variable in finite time. This last feature allows applying the Separation Principle. The convergence analysis is carried out by means of the Lyapunov method. Results obtained from numerical simulations and experiments in a laboratory prototype show the performance of the closed loop system.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Optimal backstepping control of quadrotor UAV using gravitational search opti...journalBEEI
Quadrotor unmanned aerial vehicle (UAV) has superior characteristics such as ability to take off and land vertically, to hover in a stable air condition and to perform fast maneuvers. However, developing a high-performance quadrotor UAV controller is a difficult problem as quadrotor is an unstable and underactuated nonlinear system. The effort in this article focuses on designing and optimizing an autonomous quadrotor UAV controller. First, the aerial vehicle's dynamic model is presented. Then it is suggested an optimal backstepping controller (OBC). Traditionally, backstepping controller (BC) parameters are often selected arbitrarily. The gravitational search algorithm (GSA) is used here to determine the BC parameter optimum values. In the algorithm, the control parameters are calculated using an integral absolute error to minimize the fitness function. As the control law is based on the theorem of Lyapunov, the asymptotic stability of the scheme can be ensured. Finally, several simulation studies are conducted to show the efficacy of the suggested OBC.
Compensation of Data-Loss in Attitude Control of Spacecraft Systems rinzindorjej
In this paper, a comprehensive comparison of two robust estimation techniques namely, compensated closed-loop Kalman filtering and open-loop Kalman filtering is presented. A common problem of data loss in a real-time control system is investigated through these two schemes. The open-loop scheme, dealing with the data-loss, suffers from several shortcomings. These shortcomings are overcome using compensated scheme, where an accommodating observation signal is obtained through linear prediction technique -- a closed-loop setting and is adopted at a posteriori update step. The calculation and employment of accommodating observation signal causes computational complexity. For simulation purpose, a linear time invariant spacecraft model is however, obtained from the nonlinear spacecraft attitude dynamics through linearization at nonzero equilibrium points -- achieved off-line through Levenberg-Marguardt iterative scheme. Attempt has been made to analyze the selected example from most of the perspectives in order to display the performance of the two techniques.
Effect of Parametric Variations and Voltage Unbalance on Adaptive Speed Estim...IAES-IJPEDS
Speed Estimation without speed sensors is a complex phenomenon and is overly dependent on the machine parameters. It is all the more significant during low speed or near zero speed operation. There are several approaches to speed estimation of an induction motor. Eventually, they can be classified into two types, namely, estimation based on the machine model and estimation based on magnetic saliency and air gap space harmonics. This paper analyses the effect of incorrect setting of parameters like the stator resistance, rotor time constant, load torque variations and also Voltage unbalance on various adaptive control based speed estimation techniques fed from the machine model. It also shows how the convergence mechanisms of the adaptation schemes are affected during these conditions. The equivalent models are built and simulated offline using MATLAB/SIMULINK blocksets and the results are analysed.
Output feedback trajectory stabilization of the uncertainty DC servomechanism...ISA Interchange
This work proposes a solution for the output feedback trajectory-tracking problem in the case of an uncertain DC servomechanism system. The system consists of a pendulum actuated by a DC motor and subject to a time-varying bounded disturbance. The control law consists of a Proportional Derivative controller and an uncertain estimator that allows compensating the effects of the unknown bounded perturbation. Because the motor velocity state is not available from measurements, a second-order sliding-mode observer permits the estimation of this variable in finite time. This last feature allows applying the Separation Principle. The convergence analysis is carried out by means of the Lyapunov method. Results obtained from numerical simulations and experiments in a laboratory prototype show the performance of the closed loop system.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
On tracking control problem for polysolenoid motor model predictive approach IJECEIAES
The Polysolenoid Linear Motor (PLM) have been playing a crucial role in many industrial aspects due to its functions, in which a straight motion is provided directly without mediate mechanical actuators. Recently, with several commons on mathematic model, some control methods for PLM based on Rotational Motor have been applied, but position, velocity and current constraints which are important in real systems have been ignored. In this paper, position tracking control problem for PLM was considered under state-independent disturbances via min-max model predictive control. The proposed controller forces tracking position errors converge to small region of origin and satisfies state including position, velocity and currents constraints. Further, a numerical simulation was implemented to validate the performance of the proposed controller.
Optimal tuning linear quadratic regulator for gas turbine by genetic algorith...IJECEIAES
For multiple input-multiple output (MIMO) systems, the most common control strategy is the linear quadratic regulator (LQR) which relies on state vector feedback. Despite this strategy gives very good result, it still has trial and error procedure to select the values of its weight matrices which plays a important role in reaching to the desiered system performance. In order to overcome this problem, the Genetic algorithm is used. The design of genetic algorithm based linear quadratic regulator (GA-LQR) utilized Integral time absolute error (ITAE) as a cost function for optimization. The propsed procedure is implemented on a linear model of gas turbine to control the generator spool’s speed and the output power.
ENHANCED DATA DRIVEN MODE-FREE ADAPTIVE YAW CONTROL OF UAV HELICOPTERijics
An enhanced data driven model-free adaptive yaw control tracking control scheme is proposed for the yaw
channel of an unmanned-aerial-vehicle (UAV) helicopter which is non-affine in the control input in this paper. Through dynamic linearization and observer techniques, the proposed control algorithm is only based on the pseudo-partial derivative (PPD) parameter estimation derived online from the I/O data of the yaw channel of an UAV helicopter, and Lyapunov-based stability analysis is utilized to prove all signals of
close-loop control system are bounded. Compared with the traditional model free adaptive control
(MFAC), the proposed enhanced MFAC algorithm can make the close-loop control system with stronger robustness and better anti-jamming ability. Finally, simulation results of the UAV yaw channel are offered to demonstrate the effectiveness of the proposed novel control technique.
Tracking and control problem of an aircraftANSUMAN MISHRA
Here our main focus is to monitor and maneuver the flight for a particular distance in a time-scale with absolute control. For this a rigorous formulation of flight mechanics and theories associated with advanced control systems are simplified and analyzed to obtain a feasible & optimized solution.
It is also important to remember that this idea basically involves handling problems of maneuvering control and other pilot-issues of an inner-loop flight-control system and does not dwell on outer loop control systems .
The operational significance of this maneuver is that it allows the pilot to slew quickly without increasing the normal acceleration and turning.
Direct digital control scheme for controlling hybrid dynamic systems using AN...XiaoLaui
An Estimator Based Inverse Dynamics Controller (EBIDC), which utilizes an Artificial Neural Network (ANN) based state estimation scheme for nonlinear autonomous hybrid systems which are subjected to state disturbances and measurement noises that are stochastic in nature, is proposed in this paper. A salient feature of the proposed scheme is that it offers better state estimates and hence a better control of non-measurable state variables with a non linear approach in correcting the a priori estimates by avoiding statistical linearization involved in existing approaches based on derivative free estimation methods. Simulation results guarantees significant reduction in Integral Square Error (ISE) and standard deviation (σ) of error, between the controlled variable and set point and control signal computation time when compared with best existing related work based on Unscented Kalman Filter (UKF) and Ensembeled Kalman Filter (EnKF). Detailed analysis of the experimental results on real plant under different operating conditions such as servo and regulatory operations, initial condition mismatch, and different types of faults in the system, confirms robustness of proposed approach in these conditions and support the simulation results obtained. The main advantage of the proposed controller is that the control signal computation time is very much less than the selected sampling time of the process, so direct control of the plant is possible with this approach.
Predicting aircraft landing overruns using quadratic linear regressionPrerit Saxena
The aim of the project is to predict landing overrun for an aircraft given the airstrip length of the airport. The methodology used is quadratic linear regression. Mean R-squared of 98% is achieved with MSE being just 9% of the mean landing distance.
A New Induction Motor Adaptive Robust Vector Control based on Backstepping IJECEIAES
In this paper, a novel approach to nonlinear control of induction machine, recursive on-line estimation of rotor time constant and load torque are developed. The proposed strategy combines Integrated Backstepping and Indirect Field Oriented Controls. The proposed approach is used to design controllers for the rotor flux and speed, estimate the values of rotor time constant and load torque and track their changes on-line. An open loop estimator is used to estimate the rotor flux. Simulation results are presented which demonstrate the effectiveness of the control technique and on-line estimation.
Model Validation and Control of an In-Wheel DC Motor Prototype for Hybrid El...Scientific Review SR
In this paper, a mathematical model and a controller for a DC motor are developed for the
construction of an in-wheel motor. In-wheel motors can be used in hybrid electric vehicles to provide traction
force of front or rear wheels. The model identification is achieved using a simple and low cost data acquisition
system. An Arduino Uno embedded board system is used to collect data from sensors to a computer and for
control purposes. Data processing is performed using Matlab/Simulink. Validations of the devel oped
mathematical model and controller performance are carried out by comparing simulation and experimental results.
The results obtained show that the mathematical model is accurate enough to assist in speed controller design and
implementation.
Tracy–Widom distribution based fault detection approach: Application to aircr...ISA Interchange
The fault detection approach based on the Tracy–Widom distribution is presented and applied to the aircraft flight control system. An operative method of testing the innovation covariance of the Kalman filter is proposed. The maximal eigenvalue of the random Wishart matrix is used as the monitoring statistic, and the testing problem is reduced to determine the asymptotics for the largest eigenvalue of the Wishart matrix. As a result, an algorithm for testing the innovation covariance based on the Tracy–Widom distribution is proposed. In the simulations, the longitudinal and lateral dynamics of the F-16 aircraft model is considered, and detection of sensor and control surface faults in the flight control system which affect the innovation covariance, are examined.
Model Predictive Current Control of a Seven-phase Voltage Source Inverteridescitation
The paper elaborate finite set model based predictive
current control of a seven-phase voltage source inverter. The
current control is carried out considering a finite set of control
actions. The space vector model of a seven-phase voltage source
inverter (VSI) yields 27 = 128 space voltage vectors, with 126
active and two zero vectors. The control method described in
this paper discard some switching states from the whole set
and employs reduced number of switching states to track the
commanded current. Three sets of space vectors are used for
switching actuation, in one case only 15 vectors are used (14
active and one zero), in second case 29 vectors are used (28
active and one zero) and finally 43 vectors (42 active and one
zero) are employed. Optimal algorithm is employed to find
the vector which minimizes the chosen cost function. The
effect of selecting the cost function, the number of space
vectors and the sampling time is investigated and reported.
The developed technique is tested for RL load using simulation
and experimental approaches.
We are one of the distinguished names in industry, engaged in manufacturing, supplying and exporting a wide assortment of Stainless Steel Industry Products.
On tracking control problem for polysolenoid motor model predictive approach IJECEIAES
The Polysolenoid Linear Motor (PLM) have been playing a crucial role in many industrial aspects due to its functions, in which a straight motion is provided directly without mediate mechanical actuators. Recently, with several commons on mathematic model, some control methods for PLM based on Rotational Motor have been applied, but position, velocity and current constraints which are important in real systems have been ignored. In this paper, position tracking control problem for PLM was considered under state-independent disturbances via min-max model predictive control. The proposed controller forces tracking position errors converge to small region of origin and satisfies state including position, velocity and currents constraints. Further, a numerical simulation was implemented to validate the performance of the proposed controller.
Optimal tuning linear quadratic regulator for gas turbine by genetic algorith...IJECEIAES
For multiple input-multiple output (MIMO) systems, the most common control strategy is the linear quadratic regulator (LQR) which relies on state vector feedback. Despite this strategy gives very good result, it still has trial and error procedure to select the values of its weight matrices which plays a important role in reaching to the desiered system performance. In order to overcome this problem, the Genetic algorithm is used. The design of genetic algorithm based linear quadratic regulator (GA-LQR) utilized Integral time absolute error (ITAE) as a cost function for optimization. The propsed procedure is implemented on a linear model of gas turbine to control the generator spool’s speed and the output power.
ENHANCED DATA DRIVEN MODE-FREE ADAPTIVE YAW CONTROL OF UAV HELICOPTERijics
An enhanced data driven model-free adaptive yaw control tracking control scheme is proposed for the yaw
channel of an unmanned-aerial-vehicle (UAV) helicopter which is non-affine in the control input in this paper. Through dynamic linearization and observer techniques, the proposed control algorithm is only based on the pseudo-partial derivative (PPD) parameter estimation derived online from the I/O data of the yaw channel of an UAV helicopter, and Lyapunov-based stability analysis is utilized to prove all signals of
close-loop control system are bounded. Compared with the traditional model free adaptive control
(MFAC), the proposed enhanced MFAC algorithm can make the close-loop control system with stronger robustness and better anti-jamming ability. Finally, simulation results of the UAV yaw channel are offered to demonstrate the effectiveness of the proposed novel control technique.
Tracking and control problem of an aircraftANSUMAN MISHRA
Here our main focus is to monitor and maneuver the flight for a particular distance in a time-scale with absolute control. For this a rigorous formulation of flight mechanics and theories associated with advanced control systems are simplified and analyzed to obtain a feasible & optimized solution.
It is also important to remember that this idea basically involves handling problems of maneuvering control and other pilot-issues of an inner-loop flight-control system and does not dwell on outer loop control systems .
The operational significance of this maneuver is that it allows the pilot to slew quickly without increasing the normal acceleration and turning.
Direct digital control scheme for controlling hybrid dynamic systems using AN...XiaoLaui
An Estimator Based Inverse Dynamics Controller (EBIDC), which utilizes an Artificial Neural Network (ANN) based state estimation scheme for nonlinear autonomous hybrid systems which are subjected to state disturbances and measurement noises that are stochastic in nature, is proposed in this paper. A salient feature of the proposed scheme is that it offers better state estimates and hence a better control of non-measurable state variables with a non linear approach in correcting the a priori estimates by avoiding statistical linearization involved in existing approaches based on derivative free estimation methods. Simulation results guarantees significant reduction in Integral Square Error (ISE) and standard deviation (σ) of error, between the controlled variable and set point and control signal computation time when compared with best existing related work based on Unscented Kalman Filter (UKF) and Ensembeled Kalman Filter (EnKF). Detailed analysis of the experimental results on real plant under different operating conditions such as servo and regulatory operations, initial condition mismatch, and different types of faults in the system, confirms robustness of proposed approach in these conditions and support the simulation results obtained. The main advantage of the proposed controller is that the control signal computation time is very much less than the selected sampling time of the process, so direct control of the plant is possible with this approach.
Predicting aircraft landing overruns using quadratic linear regressionPrerit Saxena
The aim of the project is to predict landing overrun for an aircraft given the airstrip length of the airport. The methodology used is quadratic linear regression. Mean R-squared of 98% is achieved with MSE being just 9% of the mean landing distance.
A New Induction Motor Adaptive Robust Vector Control based on Backstepping IJECEIAES
In this paper, a novel approach to nonlinear control of induction machine, recursive on-line estimation of rotor time constant and load torque are developed. The proposed strategy combines Integrated Backstepping and Indirect Field Oriented Controls. The proposed approach is used to design controllers for the rotor flux and speed, estimate the values of rotor time constant and load torque and track their changes on-line. An open loop estimator is used to estimate the rotor flux. Simulation results are presented which demonstrate the effectiveness of the control technique and on-line estimation.
Model Validation and Control of an In-Wheel DC Motor Prototype for Hybrid El...Scientific Review SR
In this paper, a mathematical model and a controller for a DC motor are developed for the
construction of an in-wheel motor. In-wheel motors can be used in hybrid electric vehicles to provide traction
force of front or rear wheels. The model identification is achieved using a simple and low cost data acquisition
system. An Arduino Uno embedded board system is used to collect data from sensors to a computer and for
control purposes. Data processing is performed using Matlab/Simulink. Validations of the devel oped
mathematical model and controller performance are carried out by comparing simulation and experimental results.
The results obtained show that the mathematical model is accurate enough to assist in speed controller design and
implementation.
Tracy–Widom distribution based fault detection approach: Application to aircr...ISA Interchange
The fault detection approach based on the Tracy–Widom distribution is presented and applied to the aircraft flight control system. An operative method of testing the innovation covariance of the Kalman filter is proposed. The maximal eigenvalue of the random Wishart matrix is used as the monitoring statistic, and the testing problem is reduced to determine the asymptotics for the largest eigenvalue of the Wishart matrix. As a result, an algorithm for testing the innovation covariance based on the Tracy–Widom distribution is proposed. In the simulations, the longitudinal and lateral dynamics of the F-16 aircraft model is considered, and detection of sensor and control surface faults in the flight control system which affect the innovation covariance, are examined.
Model Predictive Current Control of a Seven-phase Voltage Source Inverteridescitation
The paper elaborate finite set model based predictive
current control of a seven-phase voltage source inverter. The
current control is carried out considering a finite set of control
actions. The space vector model of a seven-phase voltage source
inverter (VSI) yields 27 = 128 space voltage vectors, with 126
active and two zero vectors. The control method described in
this paper discard some switching states from the whole set
and employs reduced number of switching states to track the
commanded current. Three sets of space vectors are used for
switching actuation, in one case only 15 vectors are used (14
active and one zero), in second case 29 vectors are used (28
active and one zero) and finally 43 vectors (42 active and one
zero) are employed. Optimal algorithm is employed to find
the vector which minimizes the chosen cost function. The
effect of selecting the cost function, the number of space
vectors and the sampling time is investigated and reported.
The developed technique is tested for RL load using simulation
and experimental approaches.
We are one of the distinguished names in industry, engaged in manufacturing, supplying and exporting a wide assortment of Stainless Steel Industry Products.
Growth and characterization of EDTA doped BupropionHydrochlorideinventy
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Characterization of leachates of the special handling wastes with different s...inventy
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
I wrote a post (in Indonesian) on this topic in my infrequently updated blog. I think some people are really interested on this topic, hence I made this presentation.
Challenges Management and Opportunities of Cloud DBAinventy
Research Inventy provides an outlet for research findings and reviews in areas of Engineering, Computer Science found to be relevant for national and international development, Research Inventy is an open access, peer reviewed international journal with a primary objective to provide research and applications related to Engineering. In its publications, to stimulate new research ideas and foster practical application from the research findings. The journal publishes original research of such high quality as to attract contributions from the relevant local and international communities.
The variants of New delhiMetallo – lactamase-1: A Comparative Assessmentinventy
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Optimal Siting And Sizing Of Distributed Generation For Radial Distribution S...inventy
Research Inventy provides an outlet for research findings and reviews in areas of Engineering, Computer Science found to be relevant for national and international development, Research Inventy is an open access, peer reviewed international journal with a primary objective to provide research and applications related to Engineering. In its publications, to stimulate new research ideas and foster practical application from the research findings. The journal publishes original research of such high quality as to attract contributions from the relevant local and international communities.
State Estimation based Inverse Dynamic Controller for Hybrid system using Art...XiaoLaui
Authors have proposed State Estimation Based Inverse Dynamics Controller (SEBIDC), which utilizes an Artificial Neural Network (ANN) based state estimation scheme for nonlinear autonomous hybrid systems which are subjected to state disturbances and measurement noises that are stochastic in nature. A salient feature of the proposed scheme is that it offers better state estimates and hence a better control of non-measurable state variables with a non linear approach in correcting the a priori estimates by avoiding statistical linearization involved in existing approaches based on derivative free estimation methods. Simulation results guarantees significant reduction in Integral Square Error (ISE) and standard deviation (σ) of error, between the controlled variable and set point and control signal computation time when compared with best existing related work based on Unscented Kalman Filter (UKF) and Ensemble Kalman Filter (EnKF). Detailed analysis of the experimental results on real plant under different operating conditions such as servo and regulatory operations, initial condition mismatch, and different types of faults in the system, confirms robustness of proposed approach in these conditions and support the simulation results obtained. The main advantage of the proposed controller is that the control signal computation time is very much less than the selected sampling time of the process, so direct control of the plant is possible with this approach.
Robust control for a tracking electromechanical systemIJECEIAES
A strategy for the design of robust control of tracking electromechanical systems based on 𝐻∞ synthesis is proposed. Proposed methods are based on the operations on frequency characteristics of control systems designed and developed using the MATLAB robust control toolbox. Determination of the singular values for a transfer matrix of the control system reduces the disturbances and guarantees its stability margin. For selecting the weighted transfer functions, the basic recommendations are formulated. The efficiency of the proposed approach is verified by robust control of an elastically coupled two-mass system whose parameter values are adjusted by matching them with the parameters of one of the supplied robots. The simulation results confirm that the proposed strategy of design of robust control of twomass elastic coupling system using the 𝐻∞ synthesis is very efficient and significantly reduces the perturbation of parameters of the controlled plant.
2-DOF Block Pole Placement Control Application To: Have-DASH-IIBITT MissileZac Darcy
In a multivariable servomechanism design, it is required that the output vector tracks a certain reference
vector while satisfying some desired transient specifications, for this purpose a 2DOF control law
consisting of state feedback gain and feedforward scaling gain is proposed. The control law is designed
using block pole placement technique by assigning a set of desired Block poles in different canonical forms.
The resulting control is simulated for linearized model of the HAVE DASH II BTT missile; numerical
results are analyzed and compared in terms of transient response, gain magnitude, performance
robustness, stability robustness and tracking. The suitable structure for this case study is then selected.
2-DOF Block Pole Placement Control Application To: Have-DASH-IIBITT MissileZac Darcy
In a multivariable servomechanism design, it is required that the output vector tracks a certain reference
vector while satisfying some desired transient specifications, for this purpose a 2DOF control law
consisting of state feedback gain and feedforward scaling gain is proposed. The control law is designed
using block pole placement technique by assigning a set of desired Block poles in different canonical forms.
The resulting control is simulated for linearized model of the HAVE DASH II BTT missile; numerical
results are analyzed and compared in terms of transient response, gain magnitude, performance
robustness, stability robustness and tracking. The suitable structure for this case study is then selected.
Design of GCSC Stabilizing Controller for Damping Low Frequency OscillationsIJAEMSJORNAL
This paper presents a systematic procedure for modeling and simulation of a power system equipped with FACTS type Gate Controlled Series Compensator (GCSC) based stabilizer controller. Single Machine Infinite Bus (SMIB) power system was investigated for evaluation of GCSC stabilizing controller for enhancing the overall dynamic system performance. PSO algorithm is employed to compute the optimal parameters of damping controller. Eigenvalues of system under various operating condition and nonlinear time domain simulation is employed to verify the effectiveness and robustness of GCSC stabilizing controller in damping low frequency oscillations (LFO) modes.
Signature PSO: A novel inertia weight adjustment using fuzzy signature for LQ...journalBEEI
Particle swarm optimization (PSO) is an optimization algorithm that is simple and reliable to complete optimization. The balance between exploration and exploitation of PSO searching characteristics is maintained by inertia weight. Since this parameter has been introduced, there have been several different strategies to determine the inertia weight during a train of the run. This paper describes the method of adjusting the inertia weights using fuzzy signatures called signature PSO. Some parameters were used as a fuzzy signature variable to represent the particle situation in a run. The implementation to solve the tuning problem of linear quadratic regulator (LQR) control parameters is also presented in this paper. Another weight adjustment strategy is also used as a comparison in performance evaluation using an integral time absolute error (ITAE). Experimental results show that signature PSO was able to give a good approximation to the optimum control parameters of LQR in this case.
2-DOF BLOCK POLE PLACEMENT CONTROL APPLICATION TO:HAVE-DASH-IIBTT MISSILEZac Darcy
In a multivariable servomechanism design, it is required that the output vector tracks a certain reference
vector while satisfying some desired transient specifications, for this purpose a 2DOF control law
consisting of state feedback gain and feedforward scaling gain is proposed. The control law is designed
using block pole placement technique by assigning a set of desired Block poles in different canonical forms.
The resulting control is simulated for linearized model of the HAVE DASH II BTT missile; numerical
results are analyzed and compared in terms of transient response, gain magnitude, performance
robustness, stability robustness and tracking. The suitable structure for this case study is then selected.
PRACTICAL IMPLEMENTION OF GAOPF ON INDIAN 220KV TRANSMISSION SYSTEMecij
This paper presents the practical implementation of developed genetic algorithm based optimal power flow algorithms. These algorithms are tested on IEEE30 bus system and the results were presented in the paper [8]. The same algorithms now tested on 220KV Washi zone Indian power transmission system . The GAOPF with fixed penalty and Fuzzy based variable penalty tested on 220KV transmission system consists of 52 bus and 88lines. The fuel costs ,computational time and the system condition were studied and the results are presented in this paper .Also the available load transfer capability of the 220KV system for congestion management is also presented
Experimental dataset to develop a parametric model based of DC geared motor i...IJECEIAES
This paper presents the application of a System Identification based on Particle Swarm Optimization (PSO) technique to develop parametric model of experimental dataset of DC Geared motor in feeder machine. The experimental was conducted to measure the input (voltage) and output (speed) data. The actual data is used to be optimized using PSO algorithm. The parameter emphasized is Time, Man Square Error (MSE) and Average Time. One of the best model has been chosen based on the optimum parameters.
—This paper presents a new image based visual servoing (IBVS) control scheme for omnidirectional wheeled mobile robots with four swedish wheels. The contribution is the proposal of a scheme that consider the overall dynamic of the system; this means, we put together mechanical and electrical dynamics. The actuators are direct current (DC) motors, which imply that the system input signals are armature voltage applied to DC motors. In our control scheme the PD control law and eye-to-hand camera configuration are used to compute the armature voltages and to measure system states, respectively. Stability proof is performed via Lypunov direct method and LaSalle's invariance principle. Simulation and experimental results were performed in order to validate the theoretical proposal and to show the good performance of the posture errors. Keywords—IBVS, posture control, omnidirectional wheeled mobile robot, dynamic actuator, Lyapunov direct method.
Optimal control of load frequency control power system based on particle swar...theijes
In this work, PSO is proposed to set the gains of PID controller for LFC in single power systems area. This work has very significant issue because of persistent and random change load through working of power system. The proposed algorithm offer fluent performance, stable, and fast convergence to target value. Simulation results using MATLAB R2015a demonstrate that the proposed controller has more efficient of dynamic performance, better convergence, fast response from the other methods depend on rise and settling time of frequency deviation.
Optimization of Modified Sliding Mode Controller for an Electro-hydraulic Act...IJECEIAES
This paper presents the design of the modified sliding mode controller (MSMC) for the purpose of tracking the nonlinear system with mismatched disturbance. Provided that the performance of the designed controller depends on the value of control parameters, gravitational search algorithm (GSA), and particle swarm optimization (PSO) techniques are used to optimize these parameters in order to achieve a predefined system’s performance. In respect of system’s performance, it is evaluated based on the tracking error present between reference inputs transferred to the system and the system output. This is followed by verification of the efficiency of the designed controller in simulation environment under various values, with and without the inclusion of external disturbance. It can be seen from the simulation results that the MSMC with PSO exhibits a better performance in comparison to the performance of the similar controller with GSA in terms of output response and tracking error.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
An improved swarm intelligence algorithms-based nonlinear fractional order-PI...TELKOMNIKA JOURNAL
This paper presents a nonlinear fractional order proportional integral derivative (NL-FOPID) for autonomous underwater vehicle (AUV) to solve the path tracking problem under the unknown disturbances (model uncertainty or external disturbances). The considered controller schemes are tuned by two improved swarm intelligence optimization algorithms, the first on is the hybrid grey wolf optimization with simulated annealing (HGWO-SA) algorithm and an improved whale optimization algorithm (IWOA). The developed algorithms are assessed using a set of benchmark function (unimodal, multimodal, and fixed dimension multimodal functions) to guarantee the effectiveness of both proposed swarm algorithms. The HGWO-SA algorithm is used as a tuning method for the AUV system controlled by NL-FOPID scheme, and the IWOA is used as a tuning algorithm to obtain the PID controller’s parameters. The evaluation results show that the HGWO-SA algorithm improved the minimal point of the tested benchmark functions by 1-200 order, while the IWOA improved the minimum point by (1-50) order. Finally, the obtained simulation results from the system operated with NL-FOPID shows the competence in terms of the path tracking by 1-15% as compared to the PID method.
LMI based antiswing adaptive controller for uncertain overhead cranes IJECEIAES
This paper proposes an adaptive anti-sway controller for uncertain overhead cranes. The state-space model of the 2D overhead crane with the system parameter uncertainties is shown firstly. Next, the adaptive controller which can adapt with the system uncertainties and input disturbances is established. The proposed controller has ability to move the trolley to the destination in short time and with small oscillation of the load despite the effect of the uncertainties and disturbances. Moreover, the controller has simple structure so it is easy to execute. Also, the stability of the closed-loop system is analytically proven. The proposed algorithm is verified by using Matlab/ Simulink simulation tool. The simulation results show that the presented controller gives better performances (i.e., fast transient response, no ripple, and low swing angle) than the state feedback controller when there exist system parameter variations as well as input disturbances.
predictive current control of a 3-phase inverterAppanaRajesh
MPC-model predictive control.
here we uses mpc controller,for current control in 3-phase inverter...
converter model,
load model,
cost function.
Similar to Analytical Evaluation of Generalized Predictive Control Algorithms Using a Full Vehicle Multi-Body Dynamics Model For Mobility Enhancement (20)
Experimental Investigation of a Household Refrigerator Using Evaporative-Cool...inventy
The objective of this paper was to investigate experimentally the effect of Evaporative-cooled condenser in a household refrigerator. The experiment was done using HCF134a as the refrigerant. The performance of the household refrigerator with air-cooled and Evaporative-cooled condenser was compared for different load conditions. The results indicate that the refrigerator performance had improved when evaporative-cooled condenser was used instead of air-cooled condenser on all load conditions. Evaporativecooled condenser reduced the energy consumption when compared with the air-cooled condenser. There was also an enhancement in coefficient of performance (COP) when evaporative-cooled condenser was used instead of air-cooled condenser. The Evaporative cooled heat exchanger was designed and the system was modified by retrofitting it, instead of the conventional air-cooled condenser by making drop wise condensation using water and forced circulation over the condenser. From the experimental analysis it is observed that the COP of evaporative cooled system increased by 13.44% compared to that of air cooled system. So the overall efficiency and refrigerating effect is increased. In minimum constructional, maintenance and running cost, the system is much useful for domestic purpose. This study also revealed that combining a evaporative cooled system along with conventional water cooled system under the condition that the defrost water obtained from the freezer is used for drop wise condensation over condenser and water cooled condensation of the condenser at the bottom using remaining defrost water would reduce the power consumption, work done and hence further increase in refrigerating effect of the system. The study has shown that such a system is technically feasible and economically viable
Copper Strip Corrossion Test in Various Aviation Fuelsinventy
This research work takes in to account of corrosiveness test on various aviation fuels in the state of Telengana (India). The purpose of this experiment is to determine the corrosiveness test of fuels. This determination will be accomplished by using copper strip corrosion test by using the copper strip experiment we can determine the corrosive property of the fuel and hence the efficiency of fuel. The research covers the importance of knowing the corrosive property of different petroleum fuels including aviation turbine fuel.
Additional Conservation Laws for Two-Velocity Hydrodynamics Equations with th...inventy
A series of the differential identities connecting velocities, pressure and body force in the twovelocity hydrodynamics equations with equilibrium of pressure phases in reversible hydrodynamic approximation is obtaned.
Comparative Study of the Quality of Life, Quality of Work Life and Organisati...inventy
People’s lives are increasingly centred on work; they spend at least one-third of their time within the organisations that employ them. Investigating the factors that interfere with employees’ well-being and the organisational environment is becoming an increasing concern in organisations. This article identifies the criteria of the quality of life (QoL), quality of working life (QWL) and organisational climate instruments to point out their similarities. For bibliographic construction and data research, articles were sought in national and international journals, books and dissertations/articles in SciELO, Science Direct, Medline and Pub Med databases. The results show direct relationships amongst QoL, QWL and organisational climate instruments. The relationship between QoL and QWL instruments is based on fair compensation, social interaction, organisational communication, working conditions and functional capacity. QWL and organisational climate instruments are related through social interaction and interfaces. QoL and organisational climate instruments are related based on social interaction, organisational communication, and work conditions.
A Study of Automated Decision Making Systemsinventy
The decision making process of many operations are dependent on analysing very large data sets, previous decisions and their results. The information generated from the large data sets are used as an input for making decisions. Since the decisions to be taken in day to day operations are expanding, the time taken for manual decision making is also expanding. In order to reduce the time, cost and to increase the efficiency and accuracy, which are the most important things for customer satisfaction, many organisations are adopting the automated decision making systems. This paper is about the technologies used for automated decision making systems and the areas in which automated decisions systems works more efficiently and accurately.
Crystallization of L-Glutamic Acid: Mechanism of Heterogeneous β -Form Nuclea...inventy
The mechanism of heterogeneous nucleation of β-form L-glutamic acid was deeply investigated in cooling crystallization. The present study found that the β-form crystals were epitaxially grown on the α-form crystals and they were preferably crystallized on the (011) and (001) surfaces instead of the (111) surfaces of α- form crystals. This result was explained via the molecular simulation. The molecular simulation indicated that the different surfaces of α-form crystals provided different functional groups, resulting in different sites for the heterogeneous nucleation of β-form crystals. Here, the functional group were COO- , C=O and O-H on the (011) and (001) surfaces of α-form crystals, respectively, while it was the NH3 + on the (111) surfaces of α-form crystals. As such, the degree of lattice matching (E) between the β-form crystals and the various surfaces of α- form crystal was distinguished, where the degree of lattice matching (E) between the β-form crystals and the (011), (001) and (111) surfaces of α-form crystal were estimated as 5.30, 5.25 and 2.39, respectively, implying that the (011) and (001) surfaces of α-form crystal were more favorable to generate the heterogeneous nucleation of β-form crystals than the (111) surfaces of α-form crystal
Evaluation of Damage by the Reliability of the Traction Test on Polymer Test ...inventy
In recent decades, polymers have undergone a remarkable historical development and their use has been greatly imposed by gradually dethroning most of the secular materials. These polymer materials have always distinguished themselves by their simple shaping and inexpensive price, their versatility, lightness, and chemical stability but despite their massive use in everyday life as well as in advanced technologies. Generally, these materials still not understood which requires a thorough knowledge of their chemical, physical, rheological and mechanical properties. This paper, we study the mechanical behavior of an amorphous polymer: Acrylonitrile Butadiene Styrene “ABS” by means of uniaxial tensile testing on pierced test pieces with different notch lengths ranging between 1 to 14mm.The proposed approach consists in analyzing the evolution of the global geometry of the obtained strain curves by taking into account the zones and characteristic points of these curves as well as the effect of the damage on the mechanical behavior of the polymer ABS, in order to visualize the evolution of the damage by a static model
Application of Kennelly’model of Running Performances to Elite Endurance Runn...inventy
: The model of Kennelly between distance (Dlim) and exhaustion time (tlim) has been applied to the individual performances of 19 elite endurance runners (World-record holders and Olympic winners) from P. Nurmi (1920-1924) to M. Farah (2012) whose individual best performances on several different distances are known. Kennelly’s model (Dlim = k tlim ) can describe the individual performances of elite runners with a high accuracy (errors lower than 2 %). There is a linear relationship between parameters k and exponents of the elite runners and the extreme values correspond to S. Coe (k = 15.8; = 0.851) and E. Zatopek (k = 6.57; = 0.984). Exponent can be considered as a dimensionless index of aerobic endurance which is close to 1 in the best endurance runners. If it is assumed than maximal aerobic speed can be maintained 7 min in elite endurance runners, exponent is equal to the normalized critical speed (critical speed/maximal aerobic speed) computed from exhaustion times equal to 3 and 12.5 min in these runners.
Development and Application of a Failure Monitoring System by Using the Vibra...inventy
In this project, a failure monitoring system is developed by using the vibration and location information of balises in railway signaling. A lot of field equipment in railway are loosening and broken in time period so that they need maintenance due to the vibrations that occur due to high speed trains traffic and railway vehicles impact. Among the field equipment, balises have very important role of communication in terms of transmitting information to trains. In this scope, it is aimed to make maintenance works more efficient, have no delayed trains, detect previously failure location and intervene in failure timely, by detecting and controlling balise cases such as loosening, out of place and the data consistency error that happens because of balise physical state. In this project, the communication is provided with I2C, Modbus RTU (Remote Terminal Unit) and RS485 standards by using Arduino Uno cards and MPU6050 IMU (Inertial Measurement Unit) sensors in laboratory. Each used sensors are in slave mode and computer interface designed with C# is in master mode. Fault situations in the system are checked instant by the interface. (it is assumed to mount the IMU sensor and the Arduino circuit on the balise) it is seen that the interface responds to the sensor movements instant and the system works well in the end of test processes.
The Management of Protected Areas in Serengeti Ecosystem: A Case Study of Iko...inventy
The study assessed the management of protected areas in Serengeti ecosystem using the case of IGGRs. Specifically, the study aimed at identifying the strategies used for natural resources management; examining the impacts of those strategies; examining the hindrances of the identified strategies; and lastly, examining the methods for scaling up the performance of strategies used for natural resources in the study area. The study involved two villages among 31 villages bordering IGGRs where in each village; at least 5% of the households were sampled. Both Primary data and secondary data were collected and analyzed both manually and computer by using SPSS software. The study revealed that, study population ranked IGGRs performance on protection of natural resources, especially on conserving wildlife for future generation and in reducing poaching to be good(53.3%). In addition, the relationship with IGGRs was said to be considerable good (46.7%). In the aspect of reducing poaching, the findings show that poaching has been reduced by 96.2% from 2009 to 2012. Furthermore, 81.4% of respondents said they use different strategies to control loss of natural resources which in turn has considerably improved the relationship between protected areas and the surrounding communities in some of the aspects. Despite of above successes, the study findings has revealed a number of challenges that hinders the full attainment of conservation objectives. Among the challenges are loss of life and properties (86.4%), shortage of water for livestock (68.9%) since water sources such as Grumeti and Rubana rivers are within protected area while the adjacent local communities do not have a free access to those water sources. Other challenges especially on the IGGRs management include insufficient fund base, working facilities and inadequate staffs. Based on the above findings, the study concluded that the strategies used for natural resources management of protected areas in Serengeti ecosystem is fairly sustainable and need functional participatory approaches of local people and other stakeholders in order to bring about a collaborative natural resources management network in the ecosystem. Furthermore, based on the findings above, equity in benefit sharing accrued from natural resource management in protected areas, more financial support to IGGRs and local community, the use of non-lethal deterrents for crop protection, integration of croplivestock production systems, adoption of land use plans as a solution to land conflicts, strengthens of community based conservation (CBC), adoption of modern information technology such as geographical information system (GIS) and remote sensing are recommended.
Size distribution and biometric relationships of little tunny Euthynnus allet...inventy
This study is taken from data of commercial fishing of the little tunny, Euthynnus alletteratus (Rafinesque, 1810) caught in the Algerian coast, sampled between november 2011 and april 2016. Data were collected in order to determine size distributions of the population and biometric relationships of species including the size - weight relationships. A total of 601 fish ranged from 30.9 and 103 cm fork length (FL) were observed. The size distribution of Euthynnus alletteratus shows multiple modal values witch the most important cohort corresponds to the age class 2 (42-46 cm). The value of the allometric coefficient (b) of the FL/TW relationship is lower than 3, indicating a negative allometric growth.
Removal of Chromium (VI) From Aqueous Solutions Using Discarded Solanum Tuber...inventy
Industrial polluting effluents containing heavy metals are of serious environmental concern in India. Chromium is frequently used in industries like electroplating, metal finishing, cooling towers, dyes, paints, anodizing and leather tanning and is found as traces in effluents finding their way to natural water bodies causing hazardous toxicity to the health of humans, animals and aquatic lives directly or indirectly. Many methods for the removal of Chromium such as chemical reduction, precipitation, ion exchange, electrochemical reduction, evaporation, reverse osmosis and adsorption using activated carbon etc. have been reported but all being expensive and complicated to operate. Experimental practices reveal that adsorption by agricultural and horticultural wastes are quite simple, inexpensive and efficient method. Agra is famous for Potato farming, a lot of discarded potato waste from cold storages is thrown along road side drains causing solid waste generated which either creates solid waste disposal problem or otherwise it finds way to Yamuna river resulting high BOD and posing a serious threat to the aquatic environment. For developing countries like India adsorption studies using discarded potato (Solanum tuberosum) waste from cold storages (DPWC) a solid waste as low cost adsorbent for Chromium removal was dual beneficial i.e., an ideal solution to these solid wastes disposal problem of Agra and removal of Chromium from tannery effluents and thereby saving aquatic life from Chromium contamination in Yamuna river. Keeping this in view batch experiments were designed to study the feasibility of discarded potato waste from cold storages to remove chromium (VI) from the aqueous solutions. During the study various affecting parameters, such as pH, adsorbent does, initial concentration, temperature, contact time, adsorbent grain size and start up agitation speed were optimized as 5.0, 10-20 g/l, 50 mg/l, 250C, 135 minutes, average size and 80 rpm respectively on chromium removal efficiency. Various Isotherms such as Langmuir, Freundlich, Tempkin also fitted suitably and various corresponding constants determined from these Isotherms favor and support the adsorption. Thermodynamic constants ∆G, ∆H and ∆S were found to be 0.267 KJ/mole, 0.288 KJ/mole and 0.0013 KJ/mole respectively.
Effect of Various External and Internal Factors on the Carrier Mobility in n-...inventy
The effect of various external (temperature, electric field, light) and intracrystalline (doping, initial resistivity) factors on the mobility of carriers in layered n-InSe semiconductor experimentally have been investigated. Scientific explanations of the results are proposed
Transient flow analysis for horizontal axial upper-wind turbineinventy
This study is to carry out a transient flow field analysis on the condition that the wind turbine is working to generate turbine, the wind turbine operating conditions change over time, Purpose of this study is try to find out the rule from the wind turbine changing over time . In transient analysis, the wind velocity on inlet boundary and rotation speed in the rotor field will change over time, and an analytical process is provided that can be used for future reference. At present, the wind turbine model is designed on the concept of upwind horizontal axis type. The computer engineering software GH Bladed is used to obtain the relationship between the rotor velocity and the wind turbine. Then the ANSYS engineering software is used to calculate the stress and strain distribution in the blades over time. From the analytical result, the relationship between the stress distribution in the blades and the rotor velocity is got to be used as a reference for future wind turbine structural optimization.
Choice of Numerical Integration Method for Wind Time History Analysis of Tall...inventy
Wind tunnel tests are being performed routinely around the world for designing tall buildings but the advent of powerful computational tools will make time-history analysis for wind more common in near future. As the duration of wind storms ranges from tens of minutes to hours while earthquake durations are typically less than a three to four minutes, the choice of a time step size (Δt) for wind studies needs to be much larger both to reduce the computational time and to save disk space. As the error in any numerical solution of the equation of motion is dependent on step size (Δt), careful investigations on the choice of numerical integration methods for wind analyses are necessary. From a wide variety of integration methods available, it was decided to investigate three methods that seem appropriate for 3D-time history analysis of tall buildings for wind. These are modal time history analysis, the Hilber-Hughes-Taylor (HHT) method or α-method with α=- 0.1, and the Newmark method with β=0.25 and γ=0.5 ( i.e., trapezoidal rule). SAP2000, a common structural analysis software tool, and a 64-story structure are used to conduct all the analyses in this paper. A boundary layer wind tunnel (BLWT) pressure time history measured at 120 locations around the building envelope of a similar structure is used for the analyses. Analyses performed with both the HHT and Newmark-method considering P-delta effects show that second order effects have a considerable impact on both displacement and acceleration response. This result shows that it is necessary to account P-delta effect for wind analysis of tall buildings. As the direct integration time history analysis required very large computation times and very large computer physical memory for a wind duration of hours, a modal analysis with reduced stiffness is considered as a good alternative. For that purpose, a non-linear static analysis of the structure with a load combination of 1.0D + 1.0L is performed in SAP2000 and the reduced stiffness of the structure after the analysis is used to conduct an eigenvalue analysis to extract the mode shapes and frequencies of this structure. Then the first 20- modes are used to perform a modal time history analysis for wind load. The result shows that the responses from modal analysis with “20-mode (reduced stiffness)” are comparable with that from the P-Δ analyses of Newmark-method
Impacts of Demand Side Management on System Reliability Evaluationinventy
Electricity demand in Saudi Arabia is steadily increasing as electrical loads grows at a rate of about 7% per year, this represents a high rate by all standards, and largely due to population growth, as well as due to government subsidies which may lead to prices much lower than actual production cost. This growth represents a challenge that requires Saudi Electricity Company (SEC) to invest huge amounts of money every year, for the construction of additional generation capacity along with the reinforcement of transmission network to meet the consumption growth.Also the demand varies frequently throughout the day, causing a waste of a large part of the energy. SEC believes the optimum solution lies in altering the load shape in order to have a better balance between customer’s consumption and SEC’s generation, This paper describes the method for improving the power system reliability by shifting the portion of peak load to off-peak periods This load management scheme can be achieved by lifting the generation during off peak periods and utilizing the stored energy during peak periods. A hybrid set up involving solar and wind energy along with batteries can also be used to store energy and utilize it during peak periods.
Reliability Evaluation of Riyadh System Incorporating Renewable Generationinventy
In this paper, the experience of Saudi Electricity Company (SEC) in analyzing the generation adequacy for Year 2013 is presented. This analysis is conducted by calculating several reliability indices for Riyadh system hourly load during all four seasonal periods. The reliability indices are gauged against the international utility practice. SEC also plans to introduce renewable energy into the network in order to secure the environmental standards and reduce fuel costs of conventional generation. Thus, the reliability improvement due to different integration levels of Solar and Wind generating sources has also been investigated. The capacity value provided by these variable renewable energy sources (VERs) to reliably meet the system load has been calculated using effective load carrying capability (ELCC) technique with a loss of load expectancy metric.
The effect of reduced pressure acetylene plasma treatment on physical charact...inventy
The capacitors are increasingly being used as energy storage devicesin various power systems. The scientists of the world are tryingto maximize the electrical capacity of the supercapacitors. To achieve this purpose, numerous method sare used: the surface activation of electrodes, the surface etching using the electronbeam, the electrode etching with variousgasplasma, etc. The purpose of this work is toresearch how the properties of carbon electrodes depend on the plasma parameters at whichtheywere formed. The largest surface area ofcarbonelectrodeof47.25m2 /gis obtainedat 15 ofAr/C2H2gasratio. Meanwhile, theSEMimages show that the disruption of structures with low bond energies and the formation of new onesare taking place when the carbon electrodes are etched at acetylene plasma and placed on carbon electrode. The measurements of capacitance showthat capacitors with affectedelectrodes have about10-15% highercapacity than those not treated with acetyleneplasma.
Experimental Investigation of Mini Cooler cum Freezerinventy
In general cases the refrigerator could be converted into an air conditioner by attaching a fan. Thus a cooler as well as freezer is obtained in a single set up. The freezer can be converted to an air conditioner when the outside air is allowed to flow beside the cooling coil and is forced outside by an exhaust fan. In this case a mini scale cooler cum freezer using R134a as refrigerant was fabricated and tested In our mini project work we had designed, fabricated and experimentally analysed a mini cooler cum freezer. From the observations and calculations, the results of mini cooler cum freezer are obtained and are compared.
Growth and Magnetic properties of MnGeP2 thin filmsinventy
We have successfully grown MnGeP2 thin films on GaAs (100) substrate. A ferromagnetic transition near 320 K has been observed by temperature dependent magnetization and resistance measurements. Field dependent magnetization experiments have shown that the coercive fields at 5, 250, and 300 K are 3870, 1380 and 155 Oe, respectively. Magnetoresistance and Hall measurements have displayed that hole conduction is dominant in MnGeP2. PACS: 75.50.Pp, 75.70.-i, 85.70.-w, 73.50.-h
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
Neuro-symbolic is not enough, we need neuro-*semantic*Frank van Harmelen
Neuro-symbolic (NeSy) AI is on the rise. However, simply machine learning on just any symbolic structure is not sufficient to really harvest the gains of NeSy. These will only be gained when the symbolic structures have an actual semantics. I give an operational definition of semantics as “predictable inference”.
All of this illustrated with link prediction over knowledge graphs, but the argument is general.
Generating a custom Ruby SDK for your web service or Rails API using Smithyg2nightmarescribd
Have you ever wanted a Ruby client API to communicate with your web service? Smithy is a protocol-agnostic language for defining services and SDKs. Smithy Ruby is an implementation of Smithy that generates a Ruby SDK using a Smithy model. In this talk, we will explore Smithy and Smithy Ruby to learn how to generate custom feature-rich SDKs that can communicate with any web service, such as a Rails JSON API.
Elevating Tactical DDD Patterns Through Object CalisthenicsDorra BARTAGUIZ
After immersing yourself in the blue book and its red counterpart, attending DDD-focused conferences, and applying tactical patterns, you're left with a crucial question: How do I ensure my design is effective? Tactical patterns within Domain-Driven Design (DDD) serve as guiding principles for creating clear and manageable domain models. However, achieving success with these patterns requires additional guidance. Interestingly, we've observed that a set of constraints initially designed for training purposes remarkably aligns with effective pattern implementation, offering a more ‘mechanical’ approach. Let's explore together how Object Calisthenics can elevate the design of your tactical DDD patterns, offering concrete help for those venturing into DDD for the first time!
Builder.ai Founder Sachin Dev Duggal's Strategic Approach to Create an Innova...Ramesh Iyer
In today's fast-changing business world, Companies that adapt and embrace new ideas often need help to keep up with the competition. However, fostering a culture of innovation takes much work. It takes vision, leadership and willingness to take risks in the right proportion. Sachin Dev Duggal, co-founder of Builder.ai, has perfected the art of this balance, creating a company culture where creativity and growth are nurtured at each stage.
Dev Dives: Train smarter, not harder – active learning and UiPath LLMs for do...UiPathCommunity
💥 Speed, accuracy, and scaling – discover the superpowers of GenAI in action with UiPath Document Understanding and Communications Mining™:
See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
Get an exclusive demo of the new family of UiPath LLMs – GenAI models specialized for processing different types of documents and messages
This is a hands-on session specifically designed for automation developers and AI enthusiasts seeking to enhance their knowledge in leveraging the latest intelligent document processing capabilities offered by UiPath.
Speakers:
👨🏫 Andras Palfi, Senior Product Manager, UiPath
👩🏫 Lenka Dulovicova, Product Program Manager, UiPath
Slack (or Teams) Automation for Bonterra Impact Management (fka Social Soluti...Jeffrey Haguewood
Sidekick Solutions uses Bonterra Impact Management (fka Social Solutions Apricot) and automation solutions to integrate data for business workflows.
We believe integration and automation are essential to user experience and the promise of efficient work through technology. Automation is the critical ingredient to realizing that full vision. We develop integration products and services for Bonterra Case Management software to support the deployment of automations for a variety of use cases.
This video focuses on the notifications, alerts, and approval requests using Slack for Bonterra Impact Management. The solutions covered in this webinar can also be deployed for Microsoft Teams.
Interested in deploying notification automations for Bonterra Impact Management? Contact us at sales@sidekicksolutionsllc.com to discuss next steps.
UiPath Test Automation using UiPath Test Suite series, part 3DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
Topics covered:
UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Software Delivery At the Speed of AI: Inflectra Invests In AI-Powered QualityInflectra
In this insightful webinar, Inflectra explores how artificial intelligence (AI) is transforming software development and testing. Discover how AI-powered tools are revolutionizing every stage of the software development lifecycle (SDLC), from design and prototyping to testing, deployment, and monitoring.
Learn about:
• The Future of Testing: How AI is shifting testing towards verification, analysis, and higher-level skills, while reducing repetitive tasks.
• Test Automation: How AI-powered test case generation, optimization, and self-healing tests are making testing more efficient and effective.
• Visual Testing: Explore the emerging capabilities of AI in visual testing and how it's set to revolutionize UI verification.
• Inflectra's AI Solutions: See demonstrations of Inflectra's cutting-edge AI tools like the ChatGPT plugin and Azure Open AI platform, designed to streamline your testing process.
Whether you're a developer, tester, or QA professional, this webinar will give you valuable insights into how AI is shaping the future of software delivery.
Software Delivery At the Speed of AI: Inflectra Invests In AI-Powered Quality
Analytical Evaluation of Generalized Predictive Control Algorithms Using a Full Vehicle Multi-Body Dynamics Model For Mobility Enhancement
1. Research Inventy: International Journal Of Engineering And Science
Vol.05, Issue 01 (January 2015), PP: 43-55
Issn (e): 2278-4721, Issn (p):2319-6483, www.researchinventy.com
43
Analytical Evaluation of Generalized Predictive Control
Algorithms Using a Full Vehicle Multi-Body Dynamics Model For
Mobility Enhancement
Ross Brown, Muthuvel Murugan*, Marcus Mazza+
U.S. Army Research Laboratory-Vehicle Technology Directorate
Aberdeen Proving Ground, Maryland 21005, USA.
+
U.S Army Materiel Systems Analysis Activity (AMSAA), Aberdeen Proving Ground, MD 21005, USA.
ABSTRACT: This paper discusses research conducted by the U.S. Army Research Laboratory (ARL) - Vehicle
Technology Directorate (VTD) on advanced suspension control. ARL-VTD has conducted research on advanced
suspension systems that will reduce the chassis vibration of ground vehicles while maintaining tire contact with
the road surface. The purpose of this research is to reduce vibration-induced fatigue to the Warfighter as well
as to improve the target aiming precision in-theater. The objective of this paper was to explore the performance
effectiveness of various formulations of the Generalized Predictive Control (GPC) algorithm in a simulation
environment. Each version of the control algorithm was applied to an identical model subjected to the same
ground disturbance input and compared to a baseline passive suspension system. The control algorithms
considered include a GPC with Implicit Disturbances, GPC with Explicit Disturbances, and GPC with Preview
Control. A two-axle tactical vehicle with independent front and rear suspensions was modeled in the TruckSim
full-vehicle dynamics simulator. The control algorithms were compared based on their effectiveness in
controlling peak acceleration and overall average acceleration over a range of vehicle speeds. The algorithms
demonstrated significant reductions in the chassis acceleration and pitch of the full-vehicle model.
Keywords: Vehicle vibration control, vehicle dynamics simulation, control algorithm, advanced suspension,
generalized predictive control.
I. INTRODUCTION
Passive suspension systems for Army wheeled vehicles are optimized for off-road passenger comfort
and maneuverability, while maintaining acceptable on-road handling. These two goals often lead to conflicting
design requirements. With a view toward available suspension systems that would improve both performance
metrics, the Vehicle Technology Directorate (VTD) of the U.S. Army Research Laboratory (ARL) has
underway a research program aimed at developing active suspension systems for implementation on the next
generation of Army vehicles. The overall objective is to reduce vibration-induced fatigue as well as improve
target aiming precision in-theater, while maintaining on-road handling. There are basically two main groups of
active suspension systems: semi-active and fully active. Semi-active suspension systems vary spring and damper
properties to store or remove energy from the system according to some applied control algorithm. Usually, this
is achieved through variable damping components such as variable orifice valves or magneto-rheological fluids.
Fully active suspension systems use force actuators to add and remove energy from the system. This can be
achieved using hydraulic, pneumatic, or electromechanical actuators. Current research at VTD is addressing
both types of systems. However, this paper focuses on fully-active controls and the application of a predictive
control technique known as Generalized Predictive Control (GPC). GPC is a linear, time-invariant, multi-
input/multi-output method that uses an Auto Regressive eXogenous (ARX) model to represent the input-output
behavior of the system and to design the controller [3, 4, 8, 7, 9]. Three variants of the techniques have been
evaluated. In the first variant, no explicit account is taken of the disturbances acting on the system during system
identification and controller design [4, 8]. This version is called GPC with Implicit Disturbance in this paper.
The second and third variants take explicit account of measurable disturbances. The first of these two (called
GPC with Explicit Disturbance herein) uses only the past values of the measured disturbances while the latter
(called GPC with Preview in this paper) additionally uses measurements (or predictions) of future disturbances
[3, 7, 9]. The purpose of this paper is to present the results of numerical simulations of the application of the
aforementioned GPC variants to a multi-body dynamic model of an Army tactical vehicle with nonlinear
suspension systems. The paper begins with a summary of the key equations describing the underlying method
including system identification, computation of the control law, and calculation of the commands sent to the
actuators. Then, a brief discussion of the simulation environment and the vehicle model are presented. This is
followed by a description of the three road profiles used as disturbances in the simulations. Representative
2. Analytical Evaluation of Generalized…
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results from the numerical simulations are then presented. The paper finishes with some concluding remarks on
the results of the numerical study and comments on the nature of some planned future work.
II. CONTROL METHODOLOGY
The steps in developing a GPC-based controller are system identification and derivation of the control
law. System identification is based on the derivation of a multi-step output prediction equation using the
Observer Markov Parameters (OMP) that comprise the ARX model that is used to characterize the system. The
control law then follows from the minimization of a quadratic performance equation involving the predicted
response and the control command. A summary of the key steps of the process, adapted from the more extensive
development present in reference [4], is given below. Since GPC is a multi-input/multi-output controller, the
control command, , measured response, , and external disturbance, can be vectors whose elements
correspond to the values of a specific actuator or sensor at time t.
GPC with Implicit Disturbance
The relationship between the input and output time histories of a linear, time-invariant multi-input/multi-output
system can be described by an ARX model of the form:
(1)
This equation says that the output, y(t), at the current time step, t, may be estimated by using p sets of the
previous input and output measurements, u(t-1), …, u(t-p), y(t-1),…,y(t-p), and the current input, u(t). The
integer p denotes the order of the ARX model. The coefficient matrices i and i are called Observer Markov
Parameters and are the quantities computed by the identification process [2].
To start the identification process, the system is excited with band-limited white noise. These independent
random excitations are applied concurrently to all of the rc control inputs. The rc control inputs and the m
response outputs are recorded for L samples. The resulting input and output time histories, u and y, are then used
to form the data matrices, y and V.
(2)
where
(3)
and
(4)
Throughout this paper, the dimensions of the matrices and vectors are noted below key equations. The order of
the ARX model, p, and the number of samples, L, are specified by the user. Some guidelines for their selection
are given in reference [2]. The matrix , containing the OMP, i and i, follows from equation 2 by inversion
and has the form:
(5)
The one-step-ahead output prediction equation given by equation 1 is the starting point for deriving the multi-
step output prediction equation that is needed for deriving the GPC controller. This equation is obtained by
replacing t by t+j in equation 1, and letting j range over the set of values j=1, 2, … hp-1, where hp is the
prediction horizon (the number of time steps for which the future responses are predicted). The resulting
equations can be assembled into a multi-step output prediction equation having the form:
(6)
The coefficient matrices , , and are formed from combinations of the OMP. The quantity is the vector
containing the future predicted responses, whereas is the vector containing the (unknown) future control
commands. The integer is the control horizon (the number of time steps over which future control is assumed
to act). The quantities and are vectors containing the previous p sets of control commands, and measured
responses, respectively.
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(7)
where the coefficients are calculated using the following relations:
(8a)
(8b)
(8c)
In this formulation the size of the ARX model, p, is set equal to the number of future predicted responses, hp,
(prediction horizon) and future commands, hc, (control horizon). Generally, these three parameters can differ
from one another [3, 8].
The optimal control law is obtained by minimizing an objective function. To accomplish this, one defines a
quadratic objective function as follows,
(9)
where
Q is a symmetric positive semi-definite matrix that assigns weights to the predicted responses,
R is a symmetric positive definite matrix that assigns weights on the future control commands,
The superscript T indicates the vector or matrix transpose.
Substituting the expanded equation for [y] yields,
(10)
The minimum is obtained by taking the partial derivative of the function with respect to future commands,
and setting it equal to zero.
(11a)
(11b)
Solving for control commands, yields the following optimal future commands:
(12)
Defining the following control law matrices,
(13a)
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(13b)
yields control laws that calculate the next hc sets of commands,
(14)
where corresponds to the control commands hc time steps into the future.
However, only the first set of control commands will be applied to the system, thus only the first rc rows of
{ } are needed. The remaining rows are discarded.
(15)
GPC with Explicit Disturbance
Generalized Predictive Controller with Explicit Disturbance, as discussed in [3, 9], is similar to GPC with
Implicit Disturbance, except that now the external disturbances are explicitly measured and included in the
model. Time histories of controls commands, measurement responses, and, now, disturbance measurements are
used to generate the ARX model for the system. The V matrix with disturbance information is shown below.
(16)
The new matrix , containing the OMP has the form:
(17)
This OMP values are used to predict future responses based on past responses (including external disturbances)
and control commands.
(18a)
(18b)
As before, the next control commands are calculated by minimizing the objective function and taking the partial
derivative with respect to control commands; the rows corresponding to future control commands are dropped.
Using this extension, the measured disturbance information can be used.
(19)
GPC with Preview Control
Preview Control or Look-Ahead Control measures the external disturbance before it affects the vehicle and
incorporates this information into the control algorithms. Preview Control was first published in [1], and is
further developed in [5, 6] for linear full-state feedback control.
Generalized Predictive Controller with Preview Control is a direct extension of GPC with Explicit Disturbance.
If it is possible to generate a model of the explicit disturbance in order to predict future disturbances [9]; this
future information can be used in conjunction with the control command, external disturbance, and measured
response time histories to generate the future control commands. This research, however, assumes that the future
disturbance can be directly measured using vehicle based sensors. Again, time histories of controls commands,
measurement responses, and disturbance measurements are used to generate the ARX model for the system. The
matrix is identical to equation (17). These are used to predict future responses based on past responses, past
and future disturbances, and past and future control commands. In this formulation, it is assumed that the current
and future disturbance can be measured. The matrix is the component of the ARX model that corresponds to
the current and future disturbances.
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(20)
As before, the future control commands are calculated by minimizing the objective function and taking the
partial derivative with respect to control commands; only the rows corresponding to the next immediate control
commands are retained. Using this extension, both the future and the previous measured disturbance information
can be used.
(21)
The difference in control command between GPC with Explicit Disturbance and GPC with Preview Control is
solely due to the presence of the future disturbance term. The control matrices, C, C, and C are the same for
both control laws.
Modeling and Simulation
TruckSim is a widely utilized, commercially available software tool used to simulate and analyze the dynamic
behavior of wheeled vehicles. It is employed in conjunction with Matlab/Simulink in order to simulate the
effects of the GPC algorithms on a full-vehicle model.
Figure 1 - TruckSim Modified HMMWV model on Perryman 3.
The Truck Sim model takes the full vehicle and terrain into consideration, including: driver controls and
steering, road geometry, suspensions, tires, and powertrain. Component parameters are input into TruckSim via
constants, linear coefficients, non-linear tables and algebraic formulas.
The driver model controls the vehicle steering and throttle in order to follow a specified path and speed profile.
Truck Sim removes artificial vehicle constraints; therefore, vehicle speed and direction can deviate from the
specified profile.
Full three-dimensional (3-D) road geometry is specified at 0.1 meter increments. The steering system captures
the steer of each wheel due to the steering system geometry and compliances. The suspension system models
capture the full non-linear kinematical behaviors and compliances of the front and rear suspensions. These
models include data for springs, dampers, and jounce/rebound stops. The tire model is an internal table-based,
single point contact model. Non-linear tables using actual measured tire data represent vertical force, lateral
force, longitudinal force, aligning moment, and overturning moment as functions of deflection, slip, load, and
camber. The powertrain model includes engine torque, torque convertor characteristics, and transmission gear
ratios and efficiencies. A representative TruckSim tactical vehicle model is shown in Figure 1.
TruckSim provides a generalized two-axle tactical vehicle model (HMMWV) with an independent front and
rear suspension system. Figure 2 contains a graphical layout of the suspension as modeled in SuspensionSim.
Figure 2 - Representative HMMWV Suspension
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For this research, we modified some of the basic HMMWV vehicle parameters to study the performance of GPC
algorithms on various terrain profiles. The vehicle mass was doubled. The suspension springs were stiffened,
and the front damping coefficient was reduced. This is shown in Table 1.
Table 1 - Vehicle parameters for modified HMMWV model
Basic
HMMWV
Modified
HMMWV
Sprung Mass 2210 kg 5000 kg
Front spring 150 N/mm 250 N/mm
Front damper 30 kNs/m 15 kNs/m
Rear spring 150 N/mm 400 N/mm
Rear damper 30 kNs/m 30 kNs/m
The equations of motion in the TruckSim math models are ordinary differential equations (ODE)
derived from the first principles for full nonlinear 3-D motions of multiple connected rigid bodies. The sprung
mass of the vehicle is a rigid body with six degrees of freedom (DOF). Each wheel has one spin DOF. Each
independent suspension axle has two multi-body DOF for the vertical movements of the wheel centers. Other
suspension motions such as camber, lateral position, etc., are constrained as nonlinear functions of the
independent variables. Each suspension has six compliance DOF. Each tire has two dynamic DOF, one for
lagged lateral slip and one for lagged longitudinal slip.
Because the GPC algorithms are implemented in Matlab and Simulink, TruckSim uses co-simulation to update
the math model and the algorithm calculations simultaneously. TruckSim provides an S-function block to
communicate with Simulink. The control algorithms run in Simulink using the discrete integration method with
a fixed time-step of 0.001 seconds (1000 Hertz). TruckSim uses the Adams-Moulton second-order integration
(AM-2) method; the time-step for this integration method is fixed at half the Simulink simulation rate. The
model is integrated before and after each communication step with Simulink.
Within Simulink, the GPC algorithms sample the vehicle sensors once every 0.01 seconds (100 Hz). The
actuator commands to TruckSim are, also, updated every 0.01 seconds. For this work, the control algorithms
optimize commands for force actuators at each of the four suspension corners to minimize the sprung mass
motion. TruckSim uses the External Springs option to introduce outside forces from the actuators. Additionally,
the absolute road heights at the tire contact patch and at the preview sensor location are sent to the algorithms.
Road Profiles :
Three road profiles were used to evaluate the algorithms: Sine, Curb, and Perryman 3. In each case, the
road profiles were provided as an array of ground distances and vertical heights.
Sine
This road profile was defined by a sine wave with a half-amplitude of 0.10 meters and a wavelength of 10
meters. The intent was to provide a single-frequency disturbance that relates to vehicle speed, in this case, 1
meter/second (3.6 kph) of speed corresponds to 0.1 Hz excitation. There is a 30 meter flat stretch to allow the
model to reach steady state after startup. Figure 3 shows a portion of this type of road profile.
Figure 3 - Sine road profile.
Curb
This road profile is defined by a 0.10 meter step rise followed by 10 meters of level surface, and then a 0.10
meter step drop, as shown in Figure 4. The intent was to provide a step input disturbance into the system. There
is a 30 meter flat stretch to let the initial oscillations die out and the vehicle reach steady state.
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Figure 4 - Curb road profile.
Perryman3
Perryman 3 is an off-road test track located at the Aberdeen Proving Ground. This road profile, shown in Figure
5, is intended to evaluate the algorithms against a challenging, “real-world” course.
Figure 5 - Perryman 3 road profile.
Simulation Results
Simulations were run until the vehicle traveled 150 meters. The open loop model was run in parallel with
closed-loop GPC with Implicit Disturbance, GPC with Explicit Disturbance, and GPC with Preview Control for
performance comparison studies. All measurements assumed no noise or offset-bias. Initial conditions for the
suspension system state variables were set to zero. Vehicle speed was held at a constant value for the entire run.
For this work the system identification for each algorithm was pre-computed. Band-limited white noise was
used to excite the four actuators. The vehicle was run over Perryman 3 terrain profile at 40 kph. This provided
broadband random disturbance inputs out to 50 Hertz with large peaks from 0.5 to 3 Hertz.
The following objective functions were used as metrics in several comparisons of algorithm performance:
(22a)
(22b)
(22c)
where “lowpass” denotes a 4th order digital low-pass Butterworth filter with a cutoff frequency of 1 Hz.
Using the cosine double angle formula, it can be shown that the square of a signal will have a steady offset
component and a high frequency component that is twice the frequency of the original signal. The low-pass
filter removes the oscillatory component, leaving only the steady offset, which is related to the amplitude of the
fast-fourier transform of the original signal. Because the cutoff frequency is higher than the lowest frequency of
excitation in the road profiles, there is a small low frequency oscillation in the objective function, J. The low
frequency oscillation is removed by averaging the objective function over the entire run-time.
For each simulation, the averaged values of J were plotted for a series of vehicle speeds up to 80 kph. The
closed-loop responses were normalized by the corresponding values of the open-loop responses at each speed.
(23)
This normalization allows a more meaningful comparison of the algorithms despite the variation in actuator
force or power.
(24a)
(24a)
Simulation results based on the Modified HMMWV parameters are presented in Figures 6 through 12. These
figures were generated using the following algorithm parameters, as shown in Table 2.
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Table 2 - Algorithm tuning parameters used for modified HMMWV vehicle.
GPC with
Implicit
Disturbance
GPC with
Explicit
Disturbance
GPC with
Preview
Control
actuators, rc 4
disturbances, rd 4
sensors, m 3
Q
50 (vertical acceleration), 10 (pitch), 1
(roll)
R range { 1e-7 to 5e-6 }
ARX model size, p 8
Prediction
Horizon, hp
8
Control Horizon,
hc
8
Preview Horizon - - 8 (0.08s)
ID sample size, L 400 points
Disturbance for ID Perryman 3 at 40 kph
Actuator ID signal white noise
Actuator Limit 1.5e5 N
Effects of Control Weighting
The modified HMMWV model was run with GPC with Preview Control over the Sine road profile from
0 to 80 kph. The objective function, actuator force, and actuator power are averaged over a 150-meter
simulation. The speed range corresponds to a sinusoidal excitation of 0 to 2.2 Hz. This is repeated several times
for a range of control weights (R matrix values); the response weights (Q matrix values) were held constant.
This effect of the Control Weighting matrix is shown in Figures 6(a) through 6(f).
An order of magnitude decrease in the control weight matrix produces a significant improvement in response
and a corresponding increase in the required force and power. The force normalized effectiveness shows that the
curves for each weight coalesce in the same regions; the exception of R = 0.1e-6 occurs because the forces
required are at the limit for the actuator. This suggests that as long as the commanded forces are within the
capability of the actuator, the level of the response is linear with control loads. However, when comparing the
actuator power, the power-normalized effectiveness decreases as the control weights decreases. This shows that
the actuator power costs increase much faster than the responses decrease. Actuator power, then, becomes the
driving factor for choosing control weights.
(a) (b)
(c) (d)
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(e) (f)
Figure 6 - Effect of control weights on GPC with Preview Control on sine road profile.
Comparison of Algorithms
A short comparison of the three control laws operating on the three road courses (disturbance inputs) is
presented in the discussion below. The control weight for GPC with Explicit Disturbance was R=1.0e-7 over the
entire speed range. To simplify analysis, the control weights for the other two algorithms were chosen such that
the magnitude of the measured responses matched GPC with Explicit Disturbance at each speed. Again, the
objective function and the actuator force are averaged over the 150-meter run for sinusoidal disturbances from 0
to 80 kph (corresponding to 0 to 2.2 Hz). Figures 7(a) through 7(d) show a comparison of the three algorithms
versus vehicle speed.
The open loop response reaches a peak at 50 kph; representing the vehicle’s pitch mode resonance
frequency. The closed-loop algorithms reduce the peak by 60%; effectively attenuating the natural frequency.
The normalized data shows that, GPC with Explicit Disturbance and GPC with Preview Control have similar
performance; requiring the same actuator force and power. However, GPC with Implicit requires significantly
greater actuator force and power, almost twice the actuator power at 80 kph. The addition of road disturbance
information to the GPC algorithm greatly reduces the actuator loads for the closed loop system.
(a) (b)
(c) (d)
Figure 7 - Effect of GPC algorithms on sine road profile.
Figures 8(a) through 8(d) show the time-history of the measured responses and actuator forces for each
algorithm as the vehicle maneuvers over the Sine road profile at 50 kph, which represents a single frequency
disturbance of 1.4 Hz.
All three versions of the GPC algorithm reduce the chassis vertical acceleration and pitch. Chassis roll increases,
due to the very low response weight assigned to chassis roll. GPC with Implicit Disturbance performs worse on
controlling chassis vertical acceleration, but slightly better at reducing chassis pitch. Since the chassis pitch is
the dominant term in the objective function, this results in similar levels for the response objective function. It is
clear that GPC with Implicit Disturbance requires much higher actuator loads than the other two algorithms.
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(a) (b)
(c) (d)
Figure 8 - Time History of Control Algorithms for Light Vehicle parameters on Sine course at 50 kph.
The same simulations were run using the Perryman 3 road profile; the algorithm performance is shown in
Figures 9(a) through 9(d). The GPC algorithms reduce the overall response by more than 25% from the highest
open loop response. Much like the performance on the Sine road profile, GPC with Explicit Disturbance and
GPC with Preview Control have almost identical response and actuator objective functions. Once again, GPC
with Implicit Disturbance requires significantly higher actuator forces and loads to match the response objective
function.
(a) (b)
(c) (d)
Figure 9 - Effect of GPC algorithms for Modified HMMWV on Perryman 3 road profile
The GPC algorithms reduce the peaks of the chassis pitch compared to open loop cases. This dominant sensor
makes up for the slight increases in closed-loop roll and vertical acceleration. Without measured knowledge of
the disturbance, GPC with Implicit Disturbance must wait until the sign of the responses change before applying
a countering force. This results in the large, but brief forces as the algorithm catches up to the changing slope of
the disturbance. The algorithms with disturbance information have a much quicker response, thus reducing the
peaks. The time history of the vehicle on Perryman 3 is shown in Figures 10(a) through 10(d).
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(a) (b)
(c) (d)
Figure 10 - Time History of GPC Algorithms for Modified HMMWV parameters on Perryman 3 course at 50
kph
The performance of the algorithms for the Curb road profile is shown in Figures 11(a) through 11(d). Again, all
three GPC algorithms reduce the response objective function, by as much as 14% at the highest speed. However,
this time, there is a surprising difference between the actuator force and power of the algorithms. GPC with
Explicit Disturbance requires the highest actuator loads, double the force and power as required for GPC with
Implicit Disturbance. GPC with Preview Control requires the least power of the three variants; less than 200
Watts above 50 kph as shown in Figure 11(d).
(a) (b)
(c) (d)
Figure 11 - Effect of GPC algorithms on curb road profile.
Previously, GPC with Explicit Disturbance was nearly indistinguishable from GPC with Preview Control.
Figures 12(a) through 12(d) provide a closer look at the actuator forces experienced as the vehicle encounters
the step height increase of the road. When the GPC with Explicit Disturbance encounters a step increase in the
disturbance height (basically, a very steep slope), this steep slope produces a high control command. The steep
slope is in the disturbance history for 8-timesteps. On the other hand, GPC with Preview Control issues small
commands (100 N) for the 8-timesteps prior to the start of the curb. This reduces the peak force required once
the tire contacts the curb, resulting in the lowest peak force. Additionally, after the tire contacts the curb, the
future disturbance contains 8 time-steps of flat data to further temper the control commands.
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As before, GPC with Implicit Disturbance is unaware of the disturbance and can only respond after the
measured responses are affected by the curb. Thus, it commands high peaks, but not in response to an infinite
slope.
(a) (b)
(c) (d)
Figure 12 - Time History of GPC Algorithms for Light Vehicle parameters on Curb course at 72 kph.
Concluding Remarks
The results of numerical simulations directed at evaluating the effectiveness of a predictive control
method known as Generalized Predictive Control (GPC) for active control of chassis suspension systems in
Army wheeled vehicles have been summarized. GPC is a linear time-invariant, multi-input/multi-output
predictive control method that uses an ARX model to describe the input-output relationship characterizing the
system. The coefficient matrices of the ARX equation are determined using system identification techniques and
then used to form the matrices comprising the GPC control law. Key equations in the formulation of the method
were summarized. Three variants of the basic GPC algorithm were investigated. The first assumes that the
disturbances are unknown and computes the control law taking implicit account of the disturbances acting on
the system (GPC with Implicit Disturbance). The second assumes that the past values of the disturbances can be
measured and uses that information in deriving the control law (GPC with External Disturbance). The third
variant assumes that the disturbances ahead of the vehicle can be measured and additionally uses that data when
deriving the control law (GPC with Preview Control). Closed-loop behavior of the system was simulated using a
full-vehicle nonlinear model of a two-axle tactical vehicle moving over three types of road profile disturbances
for each of the three variants of GPC and compared to the open-loop behavior of the system. These comparisons
show significant reductions in chassis motions of the model. Through simulation, it has been shown that, for a
given algorithm, the control weights reduce sensor objective function at the same rate that it increases actuator
objective function. Thus the control weight can be directly used to scale the total force available to a controller.
GPC with Implicit Disturbance consistently requires higher actuator forces and more power than GPC with
Preview Control or GPC with Explicit Disturbance when given a tonal or broad band disturbance. GPC with
Preview Control performs nearly identically to baseline GPC with Explicit Disturbance; however, the preview
control algorithm does drastically reduce the initial pulse due to step inputs. Despite the presence of disturbance
information, GPC with Explicit Disturbance performs poorly on step road profile, even worse than having no
disturbance information at all. In summary, for the three road course profiles investigated, GPC with Preview
Control performs better overall than the other GPC variants for reducing vehicle-chassis acceleration and pitch.
The simulation results show that GPC with Preview Control is capable of reducing the vehicle-chassis
acceleration by as much as 25% on average for the most challenging terrain profile course simulated. The
differences in the performance of the various algorithms studied in this research effort are currently being
examined further to understand the main causes for the observed performance differences. In future, these GPC
algorithms will be tested using a two-degree-of freedom suspension test rig at the Army Vehicle Research
Laboratory to verify and validate these algorithms.
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Nomenclature
ARL U.S. Army Research Laboratory
ARX AutoRegressive eXogenous input
d disturbance inputs
F control actuator force
GPC Generalized Predictive Control
hp, hc prediction and control horizons
Hz Hertz
kph kilometers per hour
L number of samples used for system
identification
LVDT Linear Velocity Displacement
Transducer
m meter
m, rc, rd number of response outputs, control
inputs, disturbance inputs
N Newton
OMP Observer Markov Parameters
p order of the ARX model
Q, R response penalty, control penalty
s seconds
t index of current time step
u control inputs
u(t), y(t), d(t) vectors of current inputs, outputs,
and disturbances at time step t
u(t-j) ,y(t-j), d(t-j) vectors of past inputs, outputs, and
disturbances at time step (t-j)
u(t+j) ,y(t+j), d(t+j) vectors of future inputs, outputs, and
disturbances at time step (t+j)
V system identification data matrix
VTD Vehicle Technology Directorate
y response outputs
matrix of observer Markov
parameters
i, ii observer Markov parameters
cccc control law gain matrices
coefficient matrices in multi-step
output prediction equation