Showing papers by "Jean-Pierre Kenné published in 2010"

Development and control of a wearable robot for rehabilitation of elbow and shoulder joint movements

Abstract: We have been developing an exoskeleton robot (ExoRob) for assisting daily upper limb movements (i.e., shoulder, elbow and wrist). In this paper we have focused on the development of a 2DOF ExoRob to rehabilitate elbow joint flexion/extension and shoulder joint internal/external rotation, as a step toward the development of a complete (i.e., 3DOF) shoulder motion assisted exoskeleton robot. The proposed ExoRob is designed to be worn on the lateral side of the upper arm in order to provide naturalistic movements at the level of elbow (flexion/extension) and shoulder joint internal/external rotation. This paper also focuses on the modeling and control of the proposed ExoRob. A kinematic model of ExoRob has been developed based on modified Denavit-Hartenberg notations. In dynamic simulations of the proposed ExoRob, a novel nonlinear sliding mode control technique with exponential reaching law and computed torque control technique is employed, where trajectory tracking that corresponds to typical rehab (passive) exercises has been carried out to evaluate the effectiveness of the developed model and controller. Simulated results show that the controller is able to drive the ExoRob efficiently to track the desired trajectories, which in this case consisted in passive arm movements. Such movements are used in rehabilitation and could be performed very efficiently with the developed ExoRob and the controller. Experiments were carried out to validate the simulated results as well as to evaluate the performance of the controller.

Exoskeleton robot for rehabilitation of elbow and forearm movements

Abstract: To perform essential daily activities the movement of shoulder, elbow, and wrist play a vital role and therefore proper functioning of upper-limb is very much essential. We therefore have been developing an exoskeleton robot (ExoRob) to rehabilitate and to ease upper limb motion. Toward to make a complete (i.e., 7DOF) upper-arm motion assisted robotic exoskeleton this paper focused on the development of a 2DOF exoskeleton robot to rehabilitate the elbow and forearm movements. The proposed 2DOF ExoRob is supposed to be worn on the lateral side of forearm and provide naturalistic range movements of elbow (flexion/extension) and forearm (pronation/supination) motions. This paper also focuses on the modeling and control of the proposed ExoRob. A kinematic model of the ExoRob has been developed based on modified Denavit-Hartenberg notations. Nonlinear sliding mode control technique is employed in dynamic simulation of the proposed ExoRob, where trajectory tracking that corresponds to typical rehab (passive) exercises has been carried out to evaluate the effectiveness of the developed model and controller. Simulated results show that the controller is able to maneuver the ExoRob efficiently to track the desired trajectories, which in this case consisted in passive arm movements. These movements are widely used in rehab therapy and could be performed efficiently with the developed ExoRob and the controller.

Modeling and development of an exoskeleton robot for rehabilitation of wrist movements

Abstract: As a stage toward a complete upper-arm motion assisted exoskeleton robot (i.e., 7DOF) this paper focused on the development of a 2DOF exoskeleton robot to rehabilitate and to ease wrist joint movements. To perform essential daily activities the movement of shoulder, elbow, and wrist play a vital role and proper functioning of the upper-limb is essential. We therefore have been developing an exoskeleton robot (ExoRob) to rehabilitate and to ease upper limb motion. The proposed 2DOF ExoRob is designed to be worn on the lateral side of the forearm in order to provide naturalistic movements (i.e., flexion/extension and radial/ulnar deviation) of the wrist joint. This paper also focuses on the modeling and control of the proposed ExoRob. A kinematic model of ExoRob has been developed based on modified Denavit-Hartenberg notations. In dynamic simulations of the proposed ExoRob, a nonlinear sliding mode control technique is employed, where trajectory tracking that corresponds to typical rehab (passive) exercises has been carried out to evaluate the performances of the developed model and controller. Moreover experiments were carried out with PID controller to further evaluate the developed model regard to trajectory tracking. Simulated and experimental results show that the controller is able to maneuver the ExoRob efficiently to track the desired trajectories, which in this case consisted in passive arm movements. Such movements are typically used in rehabilitation and could be performed very efficiently with the developed ExoRob and the controller.

Feedback optimal control of dynamic stochastic two-machine flowshop with a finite buffer

Abstract: Article history: Received 1 May 2010 Received in revised form 6 June 2010 Accepted 7 June 2010 Available online 11 June 2010 This paper examines the optimization of production involving a tandem two-machine system producing a single part type, with each machine being subject to random breakdowns and repairs. An analytical model is formulated with a view to solving an optimal stochastic production problem of the system with machines having up-downtime non-exponential distributions. The model developed is obtained by using a dynamic programming approach and a semi-Markov process. The control problem aims to find the production rates needed by the machines to meet the demand rate, through a minimization of the inventory/shortage cost. Using the Bellman principle, the optimality conditions obtained satisfy the Hamilton-JacobiBellman equation, which depends on time and system states, and ultimately, leads to a feedback control. Consequently, the new model enables us to improve the coefficient of variation (CVup/down) to be less than one while it is equal to one in Markov model. Heuristics methods are used to involve the problem because of the difficulty of the analytical model using several states, and to show what control law should be used in each system state (i.e., including Kanban, feedback and CONWIP control). Numerical methods are used to solve the optimality conditions and to show how a machine should produce. © 2010 Growing Science Ltd. All rights reserved.

Joint production and supply control in three levels flexible manufacturing systems

Abstract: This paper considers a stochastic optimal control problem of a three stages Flexible Manufacturing System. The supplier (i.e., upstream FMS) and the transformation stage (i.e., FMS) are both subject to random events. Our objective is to find a feedback control policy for the supply and production activities that minimizes the incurred cost. It is shown that the considered joint production and supply control problem is difficult to tackle using a dissociated analytical approach. A simulation based approach is thus proposed to achieve a close approximation of the optimal policy. The advantages of the approach include possible extensions after numerical characterization of the optimal control policy.

Modeling the integration of occupational health and safety risks with operational risks associated with autonomous and multi-skilled work performed in uncertain environments

Abstract: Sharing information poses a significant challenge in attempting to integrate and manage occupational health and safety in response to operational risks where autonomous and multiskilled work is performed in uncertain environments. Managers and workers stand to benefit from a model developed as a prototype for an information system that is based on data flow technique, skills characteristic of autonomous and multi-skilled workers, and which rests on systemic analysis of the technological sub-system prevalent within a firm. Our knowledge of econometrics leads us to endorse training and exchanges aimed at promoting awareness of risks and upgrading job know-how among workers. Once the regulated risks and the risks unanimously recognized by health and safety experts have been controlled, we offer here a guide in reaching a preliminary decision that integrates parameters commonly associated with commercial efficiency and diligence in the pursuit of workplace health and safety. Lastly, findings have been validated through a case study carried out among firms engaged in the moving industry.