Application of Robust Optimal Sliding Mode Control for Underactuated AUV System with Uncertainties

Abstract

To realize the robust control of underactuated Autonomous Underwater Vehicle (AUV) with uncertainties of un-modeled dynamics, parameter perturbations and random disturbances, a robust optimal sliding mode control approach is proposed based on Linear quadratic optimal regulator (LQR) and sliding mode control. Firstly, the AUV model in vertical plane is given. Secondly, based on the State Dependent Riccati Equation (SDRE), the optimal controller is designed for the AUV nominal system without uncertainties, which makes the quadratic performance index optimal. Then, considering the uncertainty of the system, the robust optimal integral sliding mode control law is designed based on SDRE nominal controller, which makes the AUV system satisfy the requirement of the performance index, and it is robust to the parameter perturbations and random disturbances. Finally, the validity and robustness of the presented control approach is demonstrated by a dynamic model of the Remote Environmental Unit (REMUS) AUV.