To improve hydraulic vehicle active suspension system control performance,the hydraulic actuators and the car vertical acceleration sensor fault diagnoses and isolation method were put forward.The half-vehicle four degree-of-freedom hydraulic active suspension system dynamical model was firstly built,considering ordinary fault of hydraulic actuator and sensor,the suspension fault models were then built.A fault detection filter was designed by pole placement,and the actuators' deadlocking and gain faults,the sensors' gain fault were diagnosed through the residual error information.To fix the fault place accurately,the faults were isolated by the correlation coefficients and fault vector length values.Finally,under the MATLAB/Simulink environment,the considerable simulations were carried out to the fault suspension systems.The results show that the actuators or the sensors faults can be diagnosed sensitively when the residual error fluctuation exceeds a threshold;the vehicle hydraulic active suspension actuators' faults can be isolated accurately by the maximal correlation coefficient,and the car vertical acceleration sensor fault can be isolated accurately by the maximal correlation coefficient and the minimal fault vector length value.
