Optimize motion energy of AUV based on LQR control strategy

Abstract

When AUV moves near the sea surface, it always affected by surface wave disturbances and torques, and its resistance increases more heavily than calm water resistance. Because of carried energy of AUV is always limited, it is urgent to minimize the resistance caused by the AUV motion so as to diminish the energy consumption. On the traditional motion control strategy of AUV, most investigation focus on minimizing the pitch angle and heave motion, and ignoring the influence of the added resistance. In this paper a control method is proposed based on establishing longitudinal resistance model, combines the pitching angle, heaving displacement, driving energy with added resistance of AUV as its integrated indicators. In order to obtain the stabilized position and decrease the energy consumption, a LQR controller is designed with optimizing parameters by using the genetic algorithm. As a result, not only the pitch angle of the AUV and heave motion are decreased, but also the resistance caused by the pitch motion. Simulation analysis verifies the correctness of the dynamic resistance model and proposed control method.