Modeling and Motion Control of Biomimetic Joint Actuated by Antagonistic Pneumatic Muscles

摘要

The characteristics of pneumatic muscle are very similar to the skeletal muscle, and mostly, a pair of antagonistic pneumatic muscles are applied to actuate a joint. In this article, a simplified model of pneumatic muscle is introduced through the method of linearization, and two parameters which are force-pressure coefficient and stifmess are proposed. Based on the linear model, the model of the biomimetic joint is got, and the relationship between the input pressure, the output angle and the joint stiffness are analyzed. From the analysis, we can get that one of the advantage of the biomimetic joint is that its position and stifmess can be controlled independently. Depending on the sequence of the input pressure, several ways of motion control of the joint are proposed and analyzed. Input shaping and feed-forward method are put forward and shows promise for the motion control of the joint. It is concluded that joint actuated by antagonistic actuators have many advantages over the joint actuated by single actuator, and this type of biomimetic joint can be applied in many areas required for safety and compliance.