Feedforward Control for Pneumatic Artificial Muscles With Creep Compensation Using Rate-Dependent and Load-Dependent Models

抄録

Considering that the hysteresis described by the classical Prandtl-Ishlinskii (CPI) model is usually symmetric, this paper presents a modified generalized Prandtl-Ishlinskii (MGPI) model for pneumatic artificial muscles (PAMs), which can describe dynamic hysteresis nonlinearities by considering different loads and frequencies. Currently, it is still a challenging issue to achieve tracking control of PAMs because of their inherent characteristics such as dynamic hysteresis nonlinearities, output saturation, and creep. Unlike the commonly used rate-dependent PI model which linearly changes the weights or thresholds with the input rate, the proposed model changes the shape of envelope functions in GPI play operators. The MGPI model, in particular, has the advantage of directly describing the output-to-input relationship with fewer to-be-identified parameters, which reduces the computational burdens in real-time applications. To validate the efficacy and accuracy of the proposed model, a self-built PAM experiment platform is performed, and the obtained experimental results show that the proposed method achieves satisfactory tracking performance.