Model Predictive Trajectory Tracking Control of an Underactuated Bionic Underwater Vehicle

This article presents a study on trajectory tracking control for an underactuated bionic underwater vehicle that is propelled by undulating fins. The vehicle's propulsion mechanism is inspired by marine organisms, and its working principle is briefly introduced. Accurate trajectory tracking control is challenging due to the coupling of fin motions and the lack of control degree of freedom. The multi-input and multi-output characteristics of the tracking control task, coupled with the existence of system constraints, impose high requirements for the controller. To solve these problems, a novel dynamics model-based predictive control strategy is proposed and the control output at the dynamics level is obtained. To stabilize the underactuated dynamics, a practical sidesway compensator is designed and integrated into the control framework. The convergence of the approach is guaranteed. Real-time precise tracking control is realized. Extensive simulations and real-world experiments are carried out and compared with other control methods. Reliability and superiority of the proposed approach is demonstrated with up to an 80% reduction in trajectory tracking sidesway errors.