This paper deals with a multi-objective optimization of a mechatronic system. The objective funct... more This paper deals with a multi-objective optimization of a mechatronic system. The objective functions to minimize are the motor torque and the fluctuation of the system velocity. These goals are achieved by simultaneously finding the best motor in a list, to drive the system and the best distribution of the inertia of the mechanical system parts. This led us to formulate a global optimization problem where all the inertia parameters of the mechanism and the different motors are considered simultaneously. The problem is then presented as a multi-objective optimization one with continuous and discrete variables. A second generation Multi-Objective-Genetic Algorithm method, called Non-dominated Sorting GA-II (NSGA-II), was used to solve this problem. The obtained solutions form what is called a "Pareto front". They are analyzed for several different design conditions. We showed, in particular, that the proposed method, compared to electromechanical design strategy, proved to be more efficient in finding the optimal combination of the mechanical system and the driving motor besides minimizing the power consumption without the need of sophisticated controllers.
Design and Modeling of Mechanical Systems—III, 2017
This paper focuses on a dynamic simulation of a partial unloaded walking motion within a gait tra... more This paper focuses on a dynamic simulation of a partial unloaded walking motion within a gait training machine using the simulation tool: MATLAB SimMechanics. This training machine emulates the walking through: a body weight support device and a cable driven leg manipulator. The human body is modeled as a multi-segment articulated mechanism. Length and inertia specifications of body segments are determined based on anthropometric data. The main external forces acting on the human body are the unloading force applied to the upper body, the ground reaction force and the actuation wrench produced by the leg manipulator. The Matlab SimMechanics software is used to simulate dynamically the walking motion in order to calculate the required wrench to drive the lower limb during a cycle of a normal gait. In fact, the human body is created according to kinematic and dynamic modeling, and besides, the external forces are applied to the body segments. Considering a body having a mass of 100 kg and a height of 1.7 m, curves of actuation wrench are retrieved.
In this paper, we investigate an inverse dynamic study of an upright unloaded walking. This motio... more In this paper, we investigate an inverse dynamic study of an upright unloaded walking. This motion is produced through a gait training machine that emulates the overground walking through: a body weight support device and a cable driven legs trainer. The input motion is the kinematics of a normal gait and the output information is the required actuation wrench to drive the lower limb during gait simulation. The dynamic study is carried out using two methods: Newton-Euler approach and Matlab SimMechanics model. The effect of gait simulation parameters on the behaviour of the actuation wrench is discussed. These results are very useful in estimating optimal gait training parameters and also to design the gait trainer.
In the textile manufacturing, development of sewing mechanisms with optimal performances is very ... more In the textile manufacturing, development of sewing mechanisms with optimal performances is very significant. Obviously, the quality of sewing, decrease the sewing machine vibration and the optimal mechanical advantage are greatly dependent on the design criteria of the sewing mechanism. Therefore, this paper presents a multi-objective design optimization of a sewing machines. The needle jerk, the coupler tracking error and the transmission angle index are minimized simultaneously. The aim is to reduce the sewing machine vibration, guarantee a proper stitch formation and ensure the most effective transmission of motion, respectively. The multi-objective colonial competitive algorithm (MOCCA) is used to perform the design optimization. The obtained results confirm improvement of the required design criteria of the sewing mechanism in this study. It is also concluded that the optimized mechanism has 35% less needle Jerk and 20% reduction in term of the transmission angle index (TA) th...
Muscle activation can be quantified by surface Electromyography (EMG) measurements. Indeed, EMG i... more Muscle activation can be quantified by surface Electromyography (EMG) measurements. Indeed, EMG is a technique used to measure the potential charge of muscle fibers during isometric, concentric or eccentric contractions. The aim of this paper is to design an embedded electronic system allowing the detection of the EMG signals. The measured data is then sent through a wireless transmission system to the host computer. Wireless transmission has the advantage of facilitating the capture of the human movement and eliminates electrical wires. The paper is divided into three sections. Firstly, this work will begin with the realization of an embedded system to measure EMG signals. This signal is detected by surface electrodes placed on the muscles. Then, EMG signal analysis will be performed by different processing methods. Finally, these experimental data will be manipulated and used as inputs to musculoskeletal model for estimate isometric muscle forces. As a result, the modelling method...
Sewing is one of the most commonly used manufacturing processes in the world. In the textile indu... more Sewing is one of the most commonly used manufacturing processes in the world. In the textile industry, development of sewing machines with optimal performances has found a great attention during recent years. Therefore, this work deals with the multiobjective design optimization of a sewing machine viewed as a mechatronic system. The mechatronic model of the machine is developed based on the coupling of the needle-bar-and-thread-take-up-lever (NBTTL) dynamic model and the DC motor model. Based on the mechatronic model, the DC motor current and its fluctuation are minimized, simultaneously, in order to minimize the load on the motor and the machine vibration. The multiobjective imperialist competitive algorithm (MOICA) is used to solve this problem. The obtained results are presented as a Pareto front, since the two objective functions are shown to be contradictory. Out of the solutions presented in the Pareto front, the designer can choose the one with the best compromise for his ap...
The Anti-lock Braking System (ABS) is an active safety system for two wheeled vehicles (TWV). It ... more The Anti-lock Braking System (ABS) is an active safety system for two wheeled vehicles (TWV). It is used to control the dynamics of a TWV during an emergency braking phase and to improve its driving safety. The main objective of this study is to establish a virtual model of a TWV equipped with a control scheme for an ABS system. The developed model will be used to investigate the reliability of an ABS system when used with a TWV. For this purpose, firstly a TWV multi-body dynamic model was constructed using ADAMS/View. Furthermore, a control model of the ABS system was created using MATLAB/Simulink. Then, a co-simulation approach is established using MATLAB/Simulink and ADAMS/Control. The performance of the co-simulation model is assessed by simulations for different initial speeds and for different road conditions. The obtained results show the benefits of using a co-simulation approach in studying such a complex systems. Moreover, the effects of the active safety system (ABS) on t...
This paper deals with the prediction of the 3-UPU translational parallel manipulator position err... more This paper deals with the prediction of the 3-UPU translational parallel manipulator position error caused by the design parameter uncertainties. An algorithm, based on the interval analysis is developed and used to estimate the distribution of the position error within the robot workspace. As a result, we represented the distribution of the position error in different sections of the workspace and we showed that the minimum of the position error is located in the neighborhoods of base center. In general, the minimum position error is reached for higher sections of the workspace. Moreover, the effect of each design parameter uncertainty on the manipulator precision at different sections of the workspace is discussed. At the extreme points of the workspace, the most influent design parameters on the position error are the leg position angles and the radius of the base and the platform uncertainties. The actuator lengths uncertainties are supposed constant and have no effect on the pl...
Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics, 2016
This paper focuses on the design and the optimization of a semi-active suspension system used in ... more This paper focuses on the design and the optimization of a semi-active suspension system used in a full dynamic model of a two-wheeled vehicle. The two-wheeled vehicle is considered as a multibody system. The equations of motion are obtained by applying an approach used widely in the robotic modeling field. Two basic strategies, called the continuous skyhook and the modified skyhook, are used to control the semi-active suspension system. Using the developed model, a multi-objective optimization procedure, based on Genetic Algorithms (NSGA-II), is proposed. The objective is to optimize the parameters of the two control laws of the semi-active suspension systems, in order to improve the ride comfort and the safety. To study the effectiveness of this approach, the results of the optimization are used in different simulations and the results are compared with those obtained from a simulation of a two-wheeled vehicle equipped with a passive suspension system. The results show that both c...
Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2018
This work deals with the estimation and the sensitivity analysis of the 3-UPU parallel robot erro... more This work deals with the estimation and the sensitivity analysis of the 3-UPU parallel robot error. Based on the Newton–Euler formalism, the robot dynamic model is given in a closed form. This model is validated by the software ADAMS. Using the interval analysis method, a new algorithm is proposed, which estimates the errors in the motion of the end-effector and the errors in the actuator forces as a function of the design parameters uncertainties. The obtained results show that the kinematic errors are minimal at the workspace center. Moreover, these errors increase as the platform moves along the vertical axis. It is also shown that kinematic errors in the actuator joints are the most influential parameters on the manipulator accuracy. Therefore, using actuators with a higher accuracy can highly reduce the errors in motion of the platform.
The International Journal of Advanced Manufacturing Technology, 2018
This paper deals with the development of an analytical model to solve the dynamic problem of a 3-... more This paper deals with the development of an analytical model to solve the dynamic problem of a 3-RRR spherical parallel manipulator (SPM). This robot is made of three legs with three revolute joints each, which makes the dynamic behavior very complicated. In order to formulate the dynamic model, an improved method is then developed, which leads to reduce the computational time by eliminating the redundancy of the equations. By decomposing the mechanism into its simplest parts, a new basis is obtained. Using this elementary basis, the kinematic model and the forces applied to each element are easily implemented. This description leads to project all forces and torques into their motion direction to deduce the equations of motion. A good agreement between the obtained results and the multi-body software simulation is found. Moreover, the developed model is compared to other methods in order to show the advantages of this method. Then, this approach is used to analyze the effect of external forces and torques applied on the moving platform.
Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics, 2016
In this paper, an analytical mechatronic dynamic design model of a full rail vehicle system is de... more In this paper, an analytical mechatronic dynamic design model of a full rail vehicle system is developed. Based on the rail vehicle motion, its degree of freedom can be reduced to only 38. This reduction is necessary for the model simplicity. The developed model is validated with experimental result and compared with other one from literature. The real characteristics of the actuators are discussed, and its controller is designed. A mechatronic model that expresses the controlled tracking error as function of the vehicle dynamics and the actuator characteristics is developed. This model is used by the linear quadratic regulator approach to identify the mechatronic rail vehicle proportional–integral–derivative controller’s gains. The mechatronic rail vehicle comfort is evaluated in terms of the passenger displacement, acceleration and frequency as a response of a rail irregularities caused by a lateral and two vertical track irregularities. The simulations of vibration analysis are o...
This paper deals with a multi-objective optimization of a mechatronic system. The objective funct... more This paper deals with a multi-objective optimization of a mechatronic system. The objective functions to minimize are the motor torque and the fluctuation of the system velocity. These goals are achieved by simultaneously finding the best motor in a list, to drive the system and the best distribution of the inertia of the mechanical system parts. This led us to formulate a global optimization problem where all the inertia parameters of the mechanism and the different motors are considered simultaneously. The problem is then presented as a multi-objective optimization one with continuous and discrete variables. A second generation Multi-Objective-Genetic Algorithm method, called Non-dominated Sorting GA-II (NSGA-II), was used to solve this problem. The obtained solutions form what is called a "Pareto front". They are analyzed for several different design conditions. We showed, in particular, that the proposed method, compared to electromechanical design strategy, proved to be more efficient in finding the optimal combination of the mechanical system and the driving motor besides minimizing the power consumption without the need of sophisticated controllers.
Design and Modeling of Mechanical Systems—III, 2017
This paper focuses on a dynamic simulation of a partial unloaded walking motion within a gait tra... more This paper focuses on a dynamic simulation of a partial unloaded walking motion within a gait training machine using the simulation tool: MATLAB SimMechanics. This training machine emulates the walking through: a body weight support device and a cable driven leg manipulator. The human body is modeled as a multi-segment articulated mechanism. Length and inertia specifications of body segments are determined based on anthropometric data. The main external forces acting on the human body are the unloading force applied to the upper body, the ground reaction force and the actuation wrench produced by the leg manipulator. The Matlab SimMechanics software is used to simulate dynamically the walking motion in order to calculate the required wrench to drive the lower limb during a cycle of a normal gait. In fact, the human body is created according to kinematic and dynamic modeling, and besides, the external forces are applied to the body segments. Considering a body having a mass of 100 kg and a height of 1.7 m, curves of actuation wrench are retrieved.
In this paper, we investigate an inverse dynamic study of an upright unloaded walking. This motio... more In this paper, we investigate an inverse dynamic study of an upright unloaded walking. This motion is produced through a gait training machine that emulates the overground walking through: a body weight support device and a cable driven legs trainer. The input motion is the kinematics of a normal gait and the output information is the required actuation wrench to drive the lower limb during gait simulation. The dynamic study is carried out using two methods: Newton-Euler approach and Matlab SimMechanics model. The effect of gait simulation parameters on the behaviour of the actuation wrench is discussed. These results are very useful in estimating optimal gait training parameters and also to design the gait trainer.
In the textile manufacturing, development of sewing mechanisms with optimal performances is very ... more In the textile manufacturing, development of sewing mechanisms with optimal performances is very significant. Obviously, the quality of sewing, decrease the sewing machine vibration and the optimal mechanical advantage are greatly dependent on the design criteria of the sewing mechanism. Therefore, this paper presents a multi-objective design optimization of a sewing machines. The needle jerk, the coupler tracking error and the transmission angle index are minimized simultaneously. The aim is to reduce the sewing machine vibration, guarantee a proper stitch formation and ensure the most effective transmission of motion, respectively. The multi-objective colonial competitive algorithm (MOCCA) is used to perform the design optimization. The obtained results confirm improvement of the required design criteria of the sewing mechanism in this study. It is also concluded that the optimized mechanism has 35% less needle Jerk and 20% reduction in term of the transmission angle index (TA) th...
Muscle activation can be quantified by surface Electromyography (EMG) measurements. Indeed, EMG i... more Muscle activation can be quantified by surface Electromyography (EMG) measurements. Indeed, EMG is a technique used to measure the potential charge of muscle fibers during isometric, concentric or eccentric contractions. The aim of this paper is to design an embedded electronic system allowing the detection of the EMG signals. The measured data is then sent through a wireless transmission system to the host computer. Wireless transmission has the advantage of facilitating the capture of the human movement and eliminates electrical wires. The paper is divided into three sections. Firstly, this work will begin with the realization of an embedded system to measure EMG signals. This signal is detected by surface electrodes placed on the muscles. Then, EMG signal analysis will be performed by different processing methods. Finally, these experimental data will be manipulated and used as inputs to musculoskeletal model for estimate isometric muscle forces. As a result, the modelling method...
Sewing is one of the most commonly used manufacturing processes in the world. In the textile indu... more Sewing is one of the most commonly used manufacturing processes in the world. In the textile industry, development of sewing machines with optimal performances has found a great attention during recent years. Therefore, this work deals with the multiobjective design optimization of a sewing machine viewed as a mechatronic system. The mechatronic model of the machine is developed based on the coupling of the needle-bar-and-thread-take-up-lever (NBTTL) dynamic model and the DC motor model. Based on the mechatronic model, the DC motor current and its fluctuation are minimized, simultaneously, in order to minimize the load on the motor and the machine vibration. The multiobjective imperialist competitive algorithm (MOICA) is used to solve this problem. The obtained results are presented as a Pareto front, since the two objective functions are shown to be contradictory. Out of the solutions presented in the Pareto front, the designer can choose the one with the best compromise for his ap...
The Anti-lock Braking System (ABS) is an active safety system for two wheeled vehicles (TWV). It ... more The Anti-lock Braking System (ABS) is an active safety system for two wheeled vehicles (TWV). It is used to control the dynamics of a TWV during an emergency braking phase and to improve its driving safety. The main objective of this study is to establish a virtual model of a TWV equipped with a control scheme for an ABS system. The developed model will be used to investigate the reliability of an ABS system when used with a TWV. For this purpose, firstly a TWV multi-body dynamic model was constructed using ADAMS/View. Furthermore, a control model of the ABS system was created using MATLAB/Simulink. Then, a co-simulation approach is established using MATLAB/Simulink and ADAMS/Control. The performance of the co-simulation model is assessed by simulations for different initial speeds and for different road conditions. The obtained results show the benefits of using a co-simulation approach in studying such a complex systems. Moreover, the effects of the active safety system (ABS) on t...
This paper deals with the prediction of the 3-UPU translational parallel manipulator position err... more This paper deals with the prediction of the 3-UPU translational parallel manipulator position error caused by the design parameter uncertainties. An algorithm, based on the interval analysis is developed and used to estimate the distribution of the position error within the robot workspace. As a result, we represented the distribution of the position error in different sections of the workspace and we showed that the minimum of the position error is located in the neighborhoods of base center. In general, the minimum position error is reached for higher sections of the workspace. Moreover, the effect of each design parameter uncertainty on the manipulator precision at different sections of the workspace is discussed. At the extreme points of the workspace, the most influent design parameters on the position error are the leg position angles and the radius of the base and the platform uncertainties. The actuator lengths uncertainties are supposed constant and have no effect on the pl...
Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics, 2016
This paper focuses on the design and the optimization of a semi-active suspension system used in ... more This paper focuses on the design and the optimization of a semi-active suspension system used in a full dynamic model of a two-wheeled vehicle. The two-wheeled vehicle is considered as a multibody system. The equations of motion are obtained by applying an approach used widely in the robotic modeling field. Two basic strategies, called the continuous skyhook and the modified skyhook, are used to control the semi-active suspension system. Using the developed model, a multi-objective optimization procedure, based on Genetic Algorithms (NSGA-II), is proposed. The objective is to optimize the parameters of the two control laws of the semi-active suspension systems, in order to improve the ride comfort and the safety. To study the effectiveness of this approach, the results of the optimization are used in different simulations and the results are compared with those obtained from a simulation of a two-wheeled vehicle equipped with a passive suspension system. The results show that both c...
Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2018
This work deals with the estimation and the sensitivity analysis of the 3-UPU parallel robot erro... more This work deals with the estimation and the sensitivity analysis of the 3-UPU parallel robot error. Based on the Newton–Euler formalism, the robot dynamic model is given in a closed form. This model is validated by the software ADAMS. Using the interval analysis method, a new algorithm is proposed, which estimates the errors in the motion of the end-effector and the errors in the actuator forces as a function of the design parameters uncertainties. The obtained results show that the kinematic errors are minimal at the workspace center. Moreover, these errors increase as the platform moves along the vertical axis. It is also shown that kinematic errors in the actuator joints are the most influential parameters on the manipulator accuracy. Therefore, using actuators with a higher accuracy can highly reduce the errors in motion of the platform.
The International Journal of Advanced Manufacturing Technology, 2018
This paper deals with the development of an analytical model to solve the dynamic problem of a 3-... more This paper deals with the development of an analytical model to solve the dynamic problem of a 3-RRR spherical parallel manipulator (SPM). This robot is made of three legs with three revolute joints each, which makes the dynamic behavior very complicated. In order to formulate the dynamic model, an improved method is then developed, which leads to reduce the computational time by eliminating the redundancy of the equations. By decomposing the mechanism into its simplest parts, a new basis is obtained. Using this elementary basis, the kinematic model and the forces applied to each element are easily implemented. This description leads to project all forces and torques into their motion direction to deduce the equations of motion. A good agreement between the obtained results and the multi-body software simulation is found. Moreover, the developed model is compared to other methods in order to show the advantages of this method. Then, this approach is used to analyze the effect of external forces and torques applied on the moving platform.
Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics, 2016
In this paper, an analytical mechatronic dynamic design model of a full rail vehicle system is de... more In this paper, an analytical mechatronic dynamic design model of a full rail vehicle system is developed. Based on the rail vehicle motion, its degree of freedom can be reduced to only 38. This reduction is necessary for the model simplicity. The developed model is validated with experimental result and compared with other one from literature. The real characteristics of the actuators are discussed, and its controller is designed. A mechatronic model that expresses the controlled tracking error as function of the vehicle dynamics and the actuator characteristics is developed. This model is used by the linear quadratic regulator approach to identify the mechatronic rail vehicle proportional–integral–derivative controller’s gains. The mechatronic rail vehicle comfort is evaluated in terms of the passenger displacement, acceleration and frequency as a response of a rail irregularities caused by a lateral and two vertical track irregularities. The simulations of vibration analysis are o...
This paper deals with the robust safety design optimization of a rail vehicle system moving in sh... more This paper deals with the robust safety design optimization of a rail vehicle system moving in short radius curved tracks. A combined multi-objective imperialist competitive algorithm and Monte Carlo method is developed and used for the robust multi-objective optimization of the rail vehicle system. This robust optimization of rail vehicle safety considers simultaneously the derailment angle and its standard deviation where the design parameters uncertainties are considered. The obtained results showed that the robust design reduces significantly the sensitivity of the rail vehicle safety to the design parameters uncertainties compared to the determinist one and to the literature results.
Ces notes sont un support du cours de conception des systèmes mécaniques (15H). C'est une présent... more Ces notes sont un support du cours de conception des systèmes mécaniques (15H). C'est une présentation succincte et condensée du contenu réel du module et qui ne prétend pas être un ouvrage détaillé dans la matière. Pour bien comprendre le contenu de ce document, il est impératif d'assister aux séances de cours Ce fascicule de cours est un recueil des principales approches d'analyse cinématique des systèmes mécaniques et plus particulièrement les mécanismes plans. Dans un premier chapitre on s'intéressera aux notions de base de la conception des systèmes mécaniques en insistant sur la terminologie et les définitions. Dans le second chapitre nous aborderons la problème de modélisation des mécanismes en vue d'introduire la notion de modèle mécanique et les hypothèses y afférant. Nous resterons dans le cadre des hypothèses de liaison parfaite et de solide indéformable et nous nous détaillons en particulier la notion de graphe de liaisons ainsi que les torseurs associés aux liaisons. Nous consacrerons ensuite le quatrième chapitre à l'étude de la mobilité et de l'hyperstatisme des systèmes mécaniques avec leurs différentes configurations (chaînes cinématiques ouvertes, liaisons parallèles, chaînes complexes, etc. L'analyse cinématique des mécanismes plan fera l'objet du quatrième chapitre de ce document. Après avoir détaillé le paramétrage des mécanismes plans, nous introduisons ensuite les outils d'analyse (analytique et graphique) des vitesses et des accélérations. Le dernier chapitre de ce document sera consacré à l'étude des mécanismes à cames. 2
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