Dynamic Positioning based on Sliding Mode Output Feedback of Unmanned Marine Vehicles with Unknown Membership Functions

This paper investigates the T-S fuzzy dynamic positioning problem for unmanned marine vehicles with thruster faults via sliding mode output feedback control. A unified thruster fault type is built which includes loss of effectiveness, outage, and time-varying stuck fault. Differing from the traditional T-S fuzzy dynamic positioning control design method, the membership functions in this paper are assumed to be unknown and thus cannot be used in the controller design. A switching mechanism is constructed to cope with the unknown membership functions, which is incorporated into a compensator-based sliding mode controller design. The corresponding sliding mode stability is ensured by conditions in the form of easily solvable linear matrix inequalities (LMIs) while the designed reaching law can compensate for the effects of thruster faults and external disturbances. Simulations results have illustrated the effectiveness of the proposed design method.