Adaptive Microtracking Control for an Underwater IPMC Actuator Using New Hyperplane-Based Sliding Mode

Abstract

The ionic polymer metal composite (IPMC) actuator is one of the most promising smart actuators that possesses unique advantages and is suitable for underwater applications. However, there are challenges to employ it directly in such applications for precise tracking. The IPMC suffers from high nonlinearity due to the existence of inherent creep and hysteresis phenomena. Furthermore, the IPMC actuator is always subject to uncertainty and external disturbance due to the working environment. Therefore, to cope with the aforementioned restrictions and to make the IPMC applicable for real-life applications, designing a high-accuracy tracking control technique is an urgent demand. In this article, a new integral nonlinear hyperplane-based sliding mode controller is dedicated for an underwater IPMC actuator. The proposed controller employs an adaptive tuning law in the discontinuous part to overcome any prerequisite for knowing the upper bound of the model uncertainty and external disturbance. Extensive experiments have been carried out to verify practical effectiveness of the proposed controller in comparison with conventional nonsingular terminal sliding mode in terms of fast convergence, accurate tracking, and the robust performance.