Tracking Control of Dielectric Elastomer Actuators for Soft Robots Based on Inverse Dynamic Compensation Method

Abstract In recent years, the dielectric elastomer actuators (DEAs) have been increasingly used to drive the soft robots. This paper proposes a tracking control method for the DEA based on the inverse dynamic compensation method. Firstly, a dynamical model of the DEA is established to depict its asymmetric hysteresis, rate dependent hysteresis and creep nonlinear behaviors simultaneously. Next, according to the inverse of the dynamical model, an inverse dynamic feedforward compensator (IDFC) is devised to compensate the hysteresis nonlinearity and creep nonlinearity of the DEA. Then, a PI feedback controller is designed to collaborate with the IDFC, which can enhance the robust performance of the whole control system. Finally, the tracking control experiments with different target trajectories are carried out. The root-mean-square errors of all control results are less than 1 % and the maximum value of the relative tracking errors is less than 8 % , which illustrates that the proposed tracking control method is effective and excellent.