Experimental Study on Set-Point Regulation of Human Elbow Joint by Electric Stimulation Under Various Visual Feedback Rate

摘要

Stimulating human muscles with programmed low-energy electrical pulses has many applications, especially in rehabilitation. Most studies on closed-loop control of electrical stimulation have been focused on neuromuscular-skeletal models and robust control strategies in order to restore voluntary motor functions. There has been less attention paid to the factor of feedback frequency in closed-loop control, especially within the context of accurate set-point regulation. In this primary study, we investigate the issue of accurate set-point regulation of elbow joint by electric stimulation under visual feedback rate ranging from 10 Hz to 200 Hz. In order to focus on the factor of feedback rate in closed-loop control, set-point regulation under pure feedback control (PID control) method is implemented by simplifying human elbow joint as a rotating joint of one degree of freedom (DOF). Results showed that under a desired accuracy of ±1.0° in image coordinates, a higher visual feedback rate contributed to a better converge of set-point regulation.