Control of functional electrical stimulation in the presence of electromechanical and communication delays

Abstract

In this paper, we show the feasibility of remotely controlling the elbow extension through functional electrical stimulation (FES) of the triceps muscle. Particularly, we present the experimental results obtained with the new automatic control method, designed to achieve position tracking between a user and the remote manipulator device. The major advantage of the controller is its ability to compensate for the electromechanical delay (EMD) during an FES and the communication delay (CD) due to a remote actuation. Another advantage of the developed FES controller is that only the error state and delay knowledge are required to elicit desired muscle contractions, i.e., the control implementation does not depend on model knowledge of highly nonlinear and time-varying muscle dynamics. The experimental results show its superior performance in comparison to the proportional integral derivative (PID) controller. The control performance of the PID controller and the new controller were tested for different values of a composite delay (EMD + CD).

Bilateral control of functional electrical stimulation and robotics-based telerehabilitation

“…Potentially, this telerehabilitation set up can be used as a muscle building intervention and as subjects have improvements due to neuroplasticity or their muscle strength improves, the proposed neural network-based framework can potentially adapt the therapy. This paper is an extension of our previous work [30, 31]. In this paper, the controller is further refined to improve the effectiveness of the neural networks by modifying the error structure and most importantly, the controller was validated through experiments on an able-bodied subject.…”

“…The proposed therapy method contained the benefits of FES, while incorporating the conveniences of telerehabilitation. In [31], a delay compensation controller developed in [32] to counteract the electromechanical delay associated with FES and a communication delay, was experimentally tested on a human arm. However, that controller was not developed to account for the communication delay in the feedback to a master robot.…”

Evaluation of Gait Phase Detection Delay Compensation Strategies to Control a Gyroscope-Controlled Functional Electrical Stimulation System During Walking

“…Sharma et al developed a controller with a predictor term that actively compensated for electromechanical delay [34]. A PID controller with a delay compensation algorithm to adjust for electromechanical and communication delays controlled elbow position more accurately than the PID controller alone, especially when the combined delay exceeded 35 ms [40]. However, this composite delay compensation assumed communication delays to be fixed.…”