Fault Estimation And Active Fault-Tolerant Control Of Energy-Feeding Semi-Active Suspension

In order to meet people’s increasing demand for the performance of automobile chassis,automobile suspension systems have gradually developed from passive suspensions to controllable suspensions such as semi-active and active suspensions.However,due to the harsh working environment of the suspension system,its actuators or sensors may suffer fatigue or aging due to long-term use,which will cause the semi-active suspension system to malfunction and cause the actuators to fail to reach the expected control target of the controller,and even cause the performance of the vehicle to decrease.This paper is based on the energy-feeding semi-active suspension of a few degrees of freedom parallel mechanism,and takes the possible gain failure and deviation failures of the semi-active suspension as the research object,and aims to improve the comfort and stability of the vehicle under fault conditions.Research on fault estimation and fault-tolerant control of semi-active suspension systems,including the following aspects:Firstly,the two-degree-of-freedom vehicle dynamics model and the seven-degree-offreedom vehicle dynamics model based on semi-active suspension are established,and the road input model is established according to the road roughness coefficient.The gain change and deviation fault model of the actuator are established under the condition that the sensor fault is considered.Secondly,design the skyhook-groundhook control strategy,and use the particle swarm algorithm to optimize the controller parameters.The current hysteresis control is used as the control algorithm of the actuator to realize the tracking of the controller signal.It is used as the conventional controller of semi-active suspension.Based on the related theories of the generalized sliding mode observer and linear matrix inequality,the fault observer is designed,which can realize the correction estimation of the failure value of the suspension actuator based on the sensor data of the motion state of the sprung mass and the unsprung mass under the premise that the sensor fault value is bounded.The fault-tolerant control strategy is designed to realize the fault-tolerant control of the semi-active suspension,and the simulation verification is carried out.Taking into account the invalidation of the actuator,a fuzzy compensation controller is designed.When a certain semi-active suspension actuator invalid,it can suppress the deterioration of the body state and improve vehicle performance by compensating the damping force of the non-failed semi-active suspension actuator,and simulation verification has been carried out.Finally,through the joint simulation of Car Sim and MATLAB/Simulink,the effectiveness of the designed fault-tolerant controller is verified,which can improve the performance of the vehicle’s ride comfort and handling stability caused by the fault of the semi-active suspension.This research laid a theoretical foundation for the later bench test.