Robust variable stiffness control of McKibben type pneumatic artificial muscle arm by using multiple model error compensators

Abstract

When human co-exists with robots, the secure flexible motion will be required for the robots. The soft-actuator will be a key to make a safe robot. McKibben type pneumatic artificial muscle (PAM) is representative soft actuator, and has been used widely in many fields. However, there is a trade-off between the soft actuation and the precise control. This study aims to an accurate variableness stiffness control of PAM arm. To control the PAM arm, the angle, pressure and stiffness controllers are designed using Model Error Compensator (MEC) to increase robustness. According to flexibility and accuracy requirement selectively, the variable stiffness control system is implemented. Finally, the effectiveness of proposed method is evaluated by experiment using one link PAM arm.