Improved disturbance-observer-based fault-tolerant control for the linear system subject to unknown actuator faults and multiple disturbances

The problem of fault-tolerant control for the time-invariant system subject to actuator faults and multiple disturbances is focused. The multiple disturbances are composed of two kinds: one is a norm-bounded vector; the other described by an exogenous system is viewed as a harmonic signal with known amplitude and unknown frequency and phase. An improved disturbance observer is designed to obtain the modelled disturbance with partially known information. Based on this, two novel fault-tolerant control algorithms are put forward to the analysis and compensate two different types of actuator faults (one is norm-bounded, and the other is with an unknown boundary). The effectiveness and robustness of control schemes can be exhibited through some numerical simulations with different cases.