Adaptive sliding mode control of AUV to optimize the voyage

Energy is usually the most limiting resource on activity of AUVs. It is urgent to minimize the resistance caused by the AUV motion so as to diminish the propulsion energy consumption, when AUV sails near the water surface. In this paper, to optimize the energy consumption, the dynamic resistance mathematical model of AUV, which states the relationship between the resistance and the motion/velocity of AUV, is built. An adaptive sliding mode controller with PID tuning method is presented for above problem. Moreover, in order to achieve system robustness against parameter variations and external disturbances, suitable PID control gain parameters can be systematically on-line computed based on the proposed adaptive law. The asymptotic stability property can be guaranteed according to the Lyapunov stability theorem. As a result, not only the pitch angle of the AUV is decreased by the adaptive sliding mode control method efficiently, but also the resistance caused by the pitch motion. Simulation analysis verifies the correctness of the dynamic resistance model and proposed control method.