A tracking control method with thruster fault tolerant control for unmanned underwater vehicles

In this paper, a tracking control method with thruster fault tolerant control is proposed for unmanned underwater vehicles. First, a cascaded control method is briefly introduced for the robust tracking control. Then it deals with the tracking control problem when thrusters have faults. For the cases that thrusters are completely malfunctioned, different control strategies are used to reallocate the thruster forces. Weighted pseudo inverse and quantum particle swarm optimization (QPSO) is introduced to do the hybrid fault tolerant control for different cases. To perform an appropriate control reallocation, an infinity norm cost function is introduced in QPSO as the optimization criterion to find the solution of the control reallocation problem within the limits. Compared with the weighted pseudo-inverse method, the QPSO algorithm does not need truncation or scaling to ensure the feasibility of the solution because its particles search for the solution in the feasible space. The proposed controller is implemented in order to evaluate its performance in different faulty situations and the efficiency is demonstrated through simulations results.