A new Sliding-Mode Control law for a Planar Dielectric Elastomer Actuator to Track wide-Band Trajectories

Abstract

Dielectric Elastomer Actuator (DEA) based soft robots are gaining widespread recognition for numerous applications such as; medical devices, bio-inspired systems and flexible prosthetics to name but a few. Due to their nonlinearity relating mostly to hysteresis and creep, most DEAs are subject to precision positioning challenges. To enable precise positioning, control-enabling DEA models and controllers are developed to curb the issues of their nonlinear dynamics. This paper presents a new Sliding-Mode Control (SMC) based on reaching law for precise position tracking of an adopted simplified and experimentally validated DEA model. The proposed reaching law incorporates a high-slope saturation function with an exponential denominator to drastically reduce chattering and enhance fast and finite convergence. The sliding-mode controller stability is validated using a Lyapunov candidate for asymptotic stable. Finally, Closed-loop simulations demonstrating the controller's effectiveness at suppressing chattering and tracking wide-band trajectories (triangular and sinusoidal) were implemented.