PID Position Control of McKibben Pneumatic Artificial Muscle Using Only Pressure Feedback

This study experimentally investigates that tracking control performance of an unscented-Kalman-filter(UKF)-based position control system for a McKibben pneumatic artificial muscle (PAM), using only a pressure sensor. Because nonlinearities in the PAM cause a mismatch in the PAM's length and inner pressure, achieving acceptable tracking performance using position control based on pressure measurement is challenging. This study employs the UKF to estimate the PAM's length using a measured inner pressure, and demonstrates the tracking performance of a UKF-based proportional-integral-derivative (PID) control system, comparing it with a position-feedback control system. This demonstration concludes that the UKF-based position control system using only a pressure sensor is practical.