Dynamic Modeling and Adaptive Control of Dielectric Elastomer Actuators Based on Koopman Theory
摘要
Soft robots are often powered by soft actuators, and the dielectric elastomer actuator (DEA) is widely recognized as a prospective soft actuators. Nevertheless, DEAs have complex nonlinear properties, which pose a formidable obstacle for their control. In this paper, a dynamic model of the DEA is established based on Koopman theory and the extended dynamic model decomposition method. This dynamic model is a low-dimensional linear model, which is simple and easy to implement in practical control. Then, to reduce the influence of model uncertainty and external disturbances on control accuracy, a single-neuron adaptive control method and a radial basis function (RBF) network-based adaptive control method are proposed for tracking control of the DEA. Next, to prevent damage to the DEA during the process of controller parameter tuning, a two-stage method is presented to tune the parameters of the single-neuron adaptive controller and RBF network-based adaptive controller. Finally, the efficiency of the proposed control methods is verified via actual tracking control experiments with three differential trajectories.