Adaptive Fuzzy Tracking Control of Autonomous Underwater Vehicles With Output Constraints

In this article, the trajectory tracking control is considered for an autonomous underwater vehicle (AUV) subjected to model uncertainties and output constraints. The tan-type barrier Lyapunov function (BLF) is adopted to deal with the requirement of output constraints. In order to cope with the existing system uncertainties, the adaptive fuzzy is employed to approximate the unknown system parameters of an AUV. Both state feedback tracking controller and output feedback tracking controller are proposed in this article. The state feedback tracking control scheme is designed by comprehensive application of tan-type BLF and adaptive control design provided that all system states are measurable. The output feedback tracking control scheme is proposed by employing a high-gain observer. Through analysis, it can be shown that the designed control laws are able to achieve the desired output constraints. In addition, all the signals of the resulting closed-loop system are semiglobally uniformly bounded. Finally, simulation is carried out to demonstrate the validity and feasibility of the designed control strategies.