Design and Modeling of Bionic Robot Arm Actuated by Pneumatic Artificial Muscles

In this paper, a 2-DOF bionic robot arm actuated by pneumatic artificial muscles (PAMs) is developed. As a new type of actuator, PAM has been widely utilized due to its superiorities of lightweight, strong output power, and inherent safety. This bionic arm, designed for human rehabilitation training, is a planar two-bar mechanism equipped with pretension springs and PAMs. The kinematics and dynamics of the bionic robot are obtained. Consequently, the workspace of the bionic robot is determined and experimentally tested. The motion accuracy of PAM is significantly affected by its hysteresis. As a result, PID control is used to compensate for the hysteresis in the swing angle control of the joints. The experimental results show that the swing angles of the two arms can follow the desired trajectory very well. The tracking errors of the upper and lower arms are within 0.25° and 0.3°, respectively. The experimental results demonstrate that PAM can be utilized to provide actuation for rehabilitation applications.