H-Infinity Observer for Vehicle Steering System with Uncertain Parameters and Actuator Fault

In this paper, an actuator fault diagnosis and reconfiguration problem is discussed for an uncertain vehicle steering system with external disturbances. Aiming at the factors affecting the control performance, a fault reconstruction strategy based on H-infinity observer is designed to improve the vehicle stability under complex conditions when the actuator fails. Firstly, aiming at the uncertain part caused by the road condition transformation, a mathematical model of dual input and dual output four-wheel steering system is established. Secondly, an augmented system is constructed in which the augmented state vector consists of the original state and actuator faults. Thirdly, the H-infinity observer is designed, and the gain of the observer is obtained by the Lyapunov function and linear matrix inequality. Finally, the effectiveness of the proposed strategy is verified by MATLAB/Simulink and Carsim co-simulation.