Fault-tolerant control based on sliding mode technique for unmanned marine vehicles with thruster saturation

Traditional sliding mode fault-tolerant controller might cause unmanned marine vehicles (UMVs) to have smaller domains of attraction or even instability in the event of thruster saturation. To address this problem, a novel fault-tolerant control (FTC) strategy based on sliding mode technique is designed to compensate for thruster saturation. Based on input matrix full-rank decomposition technique, a sufficient condition of sliding mode in the form of linear matrix inequalities (LMI) is given. The lower bounds of fault information and saturation are estimated online by an adaptive mechanism. On this basis, a fault-tolerant controller is designed to compensate thruster saturation, thruster faults, and external disturbances. Compared with existing methods, the stability region is enlarged by introducing adjustable parameters, and the conservatism of the control algorithm is reduced. Finally, comparative simulation results have verified the effectiveness of the proposed control method.