Dynamical Modeling and Motion Control of Electro-Conjugate Fluid With Complex Hysteresis Nonlinearity

Abstract

As a category of intelligent fluid drive technology, the electro-conjugate fluid (ECF) drive technology has a broad application prospect in the field of soft robotics, with its advantages of high output power density and simple drive structure. Since the driving principle of the ECF has not been exactly determined in physics, there are still a large number of gaps in its research. This article aims to fill the gap in the precise motion control of the ECF to promote its practical applications. To this end, the dynamical properties of the ECF are explored first. In the exploration experiment, the ECF shows complex hysteresis nonlinearity. Then, based on the modified Maxwell-slip (M-S) model, a control-oriented dynamical model of the ECF that can describe these intrinsic properties is constructed via the phenomenological modeling approach. Based on this dynamical model, an inverse hysteresis compensator (IHC)-dynamical sliding mode controller (DSMC) cascaded control framework is developed to realize the motion control of the ECF. In this control framework, the control law of the DSMC is designed following the backstepping approach to significantly reduce chattering. The stability of the control system is proved by theoretical analyses, and the effectiveness of the proposed control framework is demonstrated via actual experiments. To our best knowledge, this article is the first effort to establish the precise dynamical model of the ECF and to realize its precise motion control.