Development of a closed-loop fes system using a 3-d magnetic position and orientation measurement system

Abstract

Abstract-We have developed a closed-loop FES system using a magnetic 3-D position and orientation measurement system (FASTRAK, Polhemus Inc.). The purpose of this development was to resolve some experimental difficulties involved in our previous goniometer-based experimental system. The new system enabled us to perform FES control experiments on the multi-joint musculoskeletal system of the upper limbs including forearm pronation/supination. In this paper, we evaluated the system by some single-joint tracking tasks in order to compare its control performance with that of the previous system. Four muscles (ECRL(B), ECU, FCR, and FCU) of neurologically intact subjects were stimulated to control the wrist joint's two degrees of freedom movement. Stimulation currents were determined by a multi-channel PID controller that was designed for a musculoskeletal system with redundancy (i.e. the number of muscles stimulated is more than that of the degree-of-freedom of the movement). The results showed that the system had sufficient control performance on tracking desired trajectories. Moreover, the system could compensate for unwanted external disturbances.

Computer Simulation Tests of Feedback Error Learning Controller with IDM and ISM for Functional Electrical Stimulation in Wrist Joint Control

“…Since the difference in ME between with and without the ISM was not so large, the feedback controller was considered to perform well. However, control performance of the feedback FES controller sometimes deteriorated in tracking control because of nonlinear characteristics of the musculoskeletal system to electrical stimulation [16] although the feedback controller has been shown to perform properly [10,11]. Therefore, the ISM is expected to become useful in controlling before IDM learning.…”

“…The multichannel feedback FES controller has to solve the ill-posed problem in regulating stimulation intensities because the number of stimulated muscles is larger than that of controlled joint angles. The feedback FES controller based on the Proportional-Integral-Derivative (PID) control algorithm that we developed could provide a way of solving the ill-posed problem [10,11]. In our previous work, the FEL controller for FES (FEL-FES controller) using the PID controller was found to be feasible in controlling 1-Degree-Of-Freedom (1-DOF) of wrist joint movement (dorsi-and palmar flexions) stimulating 2 muscles [12].…”

An Effective Method on Applying Feedback Error Learning Scheme to Functional Electrical Stimulation Controller

“…One of main topics of FES research work is to realize the controller that restores movements appropriately and stably. We developed a multi-channel proportionalintegral-derivative (PID) controller that could provide a way of solving ill-posed problem in regulating stimulation intensities [1], [2]. The PID controller made it possible to apply the Feedback Error Learning (FEL) scheme [3] to FES control.…”