Abstract:
Although pneumatic artificial muscle-actuated parallel robots have both rigid and compliant characteristics, their control accuracy is easily affected by the hysteresis characteristic in pneumatic artificial muscles, and the overall control performance depends on the coordination abilities of all robotic arms. Therefore, a hysteresis inverse compensation-based synchronous control method is proposed in this paper, to achieve the expected tracking performance of pneumatic artificial muscle-actuated parallel robots. Specifically, the Bouc-Wen hysteresis model is modified to accurately express the input-output relationship of pneumatic artificial muscles, and the control accuracy can be improved by applying the corresponding inverse model to feedforward compensation. Meanwhile, the motion synchronization can be enhanced by establishing the error signal transmission between robotic arms. Then, an adaptive pressure controller is designed in the framework of fully actuated system approaches because of the fully actuated characteristic of pneumatic artificial muscle-actuated parallel robots, to ensure the asymptotic convergence of tracking errors and synchronization errors. Finally, the stability analysis of the closed-loop system is completed, and comparative tests of hysteresis fitting and motion control are conducted on the hardware platform. The comparative results show that the fitting accuracy of the proposed hysteresis model and the tracking accuracy of the proposed control method are superior to the comparative method, fully verifying the feasibility of the proposed method.