Adaptive impedance based force and position control for pneumatic compliant system

The compliant control of the robot is widely used in the Human-Machine Interface (HMI) and robot bionics. Because the system and the environment are mutually constrained, when the external environment changes, the control environment of the system will change with it, which deteriorates the control performance of the system. This article solves the problem of how to realize the compliant control with changing environment and proposes the adaptive impedance control and compensation based on a specific compliance system. We first model our compliance system by focusing on the system's internal cylinder, pressure difference transmitter its other components and then acquire its transfer function. Then we apply the impedance control and adaptive impedance control to the compliance system. Comparing these two methods, we prove that the adaptive impedance control has better tracking performance and robustness in uncertain environment. Furthermore, the stability of the adaptive impedance compliance system is proved by the Lyapunov function. Finally, we verify this algorithm with a flange experimental platform and design an experiment about contact force between the flange and different objects. The stability and practicability of the experimental algorithm are substantiated.