PID control for the robotic exoskeleton: Application to lower extremity rehabilitation

The paper investigates the PID control of exoskeleton applied to robot-assisted lower extremity rehabilitation. The developed exoskeleton consists of 4 joints, which processes merits of back drivability, precise positioning capabilities, and zero backlash due to its embedded Harmonic drive transmission (HDT) and Elmo driver. For the trajectory tracking, a control based on PID has been presented and implemented in the Elmo servo driver. The experiments are conducted to verify the effectiveness of the proposed system and control approach.