Fault tolerant controller design of servo-valve controlled hydraulic propulsion systems

This paper proposes a robust fault tolerant controller design for an underwater hydraulic propulsion system. We design servo-valve controller of hydraulic thruster which is tolerant of faults and robust against disturbances. We assume oil-leakage and contamination faults as parametric variation of the servo-valve and disturbance inflow in it. To design the robust fault tolerant controller, we introduce H_∞ technique and derive controller design conditions in terms of linear matrix inequality and linear matrix equality. LMI Solver of MATLAB Robust Control Tool Box is employed to get their optimal solution. An illustrative example is provided to verify performances of the proposed controller.