Fault-Tolerant Control for Active Suspension Systems Based on Fault Estimation and Compensation

This paper investigates fault-tolerant control for active suspension systems with some actuator faults. The objective is to design a fault-tolerant controller such that the closed-loop systems are stable while having a prescribed level of disturbance attenuation performance. First, by introducing an output vector to describe the actuator faults, a quarter-car active suspension model including actuator faults is obtained. Second, based on the linear quadratic optimal control technique and linear matrix inequality theory, the optimal feedback controller is obtained such that the closed-loop system achieves desirable disturbance attenuation performance. Moreover, the fault estimation and compensation methods are also discussed based on matrix techniques and mathematical operations. The proposed method estimates online both the system's critical state variables and the actual fault force of the actuator, which demonstrates strong practicality. In the end, simulation results demonstrate that the obtained observer can achieve high-precision estimation of state variables and fault forces. Moreover, when the suspension system is controlled by the obtained fault-tolerant controller, the root mean square values of body vertical acceleration and suspension dynamic travel are decreased by 14.59% and 16.98% respectively, compared with the controller without fault consideration. The effectiveness of the proposed method is verified.