A Hybrid-FES Based Control System for Knee Joint Movement Control

Abstract

In this paper, a new control algorithm has been proposed which was designed based on a combination of functional electrical stimulation (FES) and an active mechanical actuator to control the knee joint movement. An adaptive controller and a PD controller have adjusted the motor torque and stimulation intensity, respectively. The FES controller was activated whenever a disturbance observer detected the presence of the external disturbance. In this manner, the occurrence of the muscle fatigue arises from the FES can be postponed. The simulation studies were carried out on a model of muscle-joint system along with a model of a servo-motor. The achieved results prove the ability of the proposed control strategy to not only reject the external disturbance but also compensate the muscle fatigue. In this research, the trajectories envisioned as the knee joint reference trajectory were designed using the recorded human data.

Lower limb exoskeleton robot and its cooperative control: A review, trends, and challenges for future research

“…The linkage force recognition of the thigh and shank requires that the exoskeleton lower limb be parallel with the user's lower limb, which is challenging or not easy to achieve due to the altered joint rotational immediate modification centers (Rastegar and Kobravi, 2021 ). Furthermore, the relaxation of the muscles in the lower limbs can generate a significant amount of noise or interfere with the detection or identification system.…”