Underwater Vehicle near-surface dynamic positioning: Compensating sliding mode trajectory with robust optimal controller

Unmanned Underwater Vehicle(UUV) needs to keep its position and attitude steady when operating a near-surface task. However, the wave force and high damping characteristic brings great challenge to near-surface stabilization. To overcome these difficulties, firstly, we design a sliding mode controller with residuals to form a close-loop system driven by compensating error. Then, based on robust optimal control theorem a compensator is designed after a full exploitation of wave force frequency and thruster characteristics. Simulation results reveals its good performance in wave force compensation. Tuning principles of the handcrafted parameters are also summarized.