Safety-Critical Control for Underwater Vehicles with Model Uncertainties and External Disturbances

Safety is a crucial issue for underwater vehicles, which may be affected by narrow terrain and multiple obstacles. In addition, the model of the underwater vehicles are uncertain and susceptible to external disturbances such as water flow. This article utilizes model predictive control (MPC) and incremental nonlinear dynamic inversion (INDI) to design a robust control scheme for underwater vehicles. The position loop controller employs MPC to generate the required speed commands for the velocity loop controller. The velocity loop is designed with an INDI control scheme incorporating a second-order low-pass filter, effectively mitigating model uncertainties and external disturbances on the vehicles. Based on exponential control barrier functions (ECBFs), the input constraint and obstacle avoidance problems of underwater vehicles are solved. The results indicate that the proposed control scheme not only exhibits robustness but also effectively ensures safe obstacle avoidance.