Recursive PID controller for automatically adjusting M-wave size during H-reflex operant conditioning

摘要

This paper presents a recursive proportional-integral-derivative (rPID) controller for automatically adjusting M-wave size during H-reflex operant conditioning. H-reflex operant conditioning is a recently developed rehabilitation method for the recovery of movement following spinal cord injury and other neuromuscular disorders. During this protocol, researchers and clinicians manually control the M-wave size-an electromyographic (EMG) indicator of electrical stimulation intensity. Here, we compare the present method for manually controlling M-wave size to two versions of the rPID controller ($ext{rPID}_{eta= 0.45}$ and $ext{rPID}_{eta=0.95}$) during H-reflex operant conditioning trials of the flexor carpi radialis. Initial experiments with three participants show that the manual controller and the $ext{rPID}_{eta=0.95}$ controller successfully maintained M-wave size with similar success rates, mean squared errors, and number of trials before the first trial within ±20% of the target M-wave size. Our new automated system—with further testing and optimization—will allow researchers and clinicians to focus more on participants, reducing the amount of training they require to perform H-reflex operant conditioning, and potentially improving the efficiency and efficacy of H-reflex operant conditioning protocols.