UIO-Based Practical Fixed-Time Fault Estimation Observer Design of Nonlinear Systems

Abstract

A practical fixed-time fault estimation observer strategy for non-linear systems using an unknown input observer scheme is investigated. The external disturbances of non-linear systems are decoupled by an unknown input observer technique; therefore, the constructed error dynamics do not include these disturbances. The fixed-time fault estimation observer is then constructed. Moreover, a non-linear fault estimator with two power functions is proposed to improve the convergence speed of fault estimation. Finally, simulation results of a non-linear Lorenz chaotic system are provided to demonstrate the feasibility of the presented strategy.