Active disturbance rejection control for marine fish cage

Autonomous fish cage is a kind of special ocean vehicle with multi-input and multi-output dynamic characteristics. To avoid the attack from winds, sea animals, floating ice and other disturbances, and also to avoid collision with vessels and other ocean vehicles, the control of autonomous fish cage with demanding requirements of robustness and adaptability is needed. Active disturbance rejection control (ADRC), as a control theory which is famous for its capability of disturbance rejection and energy-savings, is deployed in this paper. The tuning parameters will be N times of a single-input and single-output system according to the number of the system controlled state. Considering the motion characteristics and the weak coupling relation between loops of the autonomous fish cage, a same tuned ADRC is adopted in each loop to achieve the control goal. Simulation results verify the proposed control method in terms of decoupling capability, tracking performance and disturbance rejection.