Motion Control of Pneumatic Muscle Actuator Using Fast Switching Valve

摘要

Considering the nonlinear and time-varying phenomena existing in pneumatic muscle actuators (PMAs), this paper deals with the modeling of tracking control of PMA using fast switching valves. A close-loop control scheme combined with feed-forward and feedback controllers is proposed to achieve high accuracy trajectory tracking control. First, the static model of the PMA is established using the data obtained from isometric experiment, and the dynamic model is developed based on the polytropic equation. Then, the hysteresis model and its inverse model is established, in which the air mass flow rate through the fast switching valve is evaluated using the Sanville equation. The PWM signal used to control the fast switching valves is generated referring to the pulse signal modulation method. Sequentially, the trajectory tracking control models of the PMA are derived by means of close-loop control scheme, which are implemented in the environment of MATLAB/Simulink. Finally, the simulation result is compared with the experiment result. The results indicate that the control model can achieve satisfactory performance and accuracy, which validates the feasibility of the proposed model and control scheme, providing an effective approach for high accuracy trajectory tracking control of PMA.