Fault-tolerant Control Strategy Research For Vehicle Active Suspension System

With the development of vehicle industry technology and the raise of comsuption level, peoplepay more and more attention to vehicle ride comfortable, operation stability, use reliability andsecurity.Vehicl active suspension system is made up of vehicle suspension and sensors and controllerand actuators. Its performance, such as vehicle ride comfortable and vehicle operation stability etc,can be obviously improved by active control on vehicle active suspension. But in vehicle activesuspension system, some cause from increase use time and fatigue and ageing of component willresult in minuscule variation of system parameters and parameters uncertainty which will affectcontrol robust performance. Once sensor which is major component of signal measure channel andactuator which is major component of control input channel have fault, then those will result in faultcontrol of controller designed under intact condition, even partial or whole forfeit of control effect,so as not to achieve desired effect. In addition, if a controller has fault, then vehicle activesuspension system will emerge disorder phenomenon. All of this will not only affect vehicle ridecomfortable but also affect vehicle operation stability and use reliability and quality.Considering vehicle active suspension system as object and combining the exiting shortage andproblem of the current vehicle avtive suspension control research which is based on intactcomponent, based on the fault-tolerant control theory and aimed to improvement of controlreliability and use quality and optimization of suspension design methods, the dissertation authorinvestigates technology of fault detection and diagnosis and isolation on vehicle active suspensionwith sensor fault or actuator fault, key technology of fault-tolerant control on vehicle activesuspension system with faults. The main research work of dissertation includes the followingaspects:（1）Fault actuator model and fault sensor model were built on the basis of in-depth and overallanalysis of their fault probability in vehicle active suspension system.Fault suspension model withsensor fault and fault suspension model with actuator fault were built respectively, and so was faultsuspension model with parameter disturbance and actuator fault simultaneously.（2）Considering actuator fault of vehicle active suspension system, technology of fault detectionand diagnosis and isolation were researched on vehicle active suspension system based on residualerror information. Considering sensor fault of vehicle active suspension system, firstly, technologyof fault detection and diagnosis and isolation were researched on vehicle active suspension systembased on residual error information. Then, so were fault detection and isolation based on Kalmanfilter groups.（3）Considering the parameter disturbance and actuator faults of seven-degree-of-freedomvehicle with active suspension system, optimal robust fault-tolerant controller is derived and designed by linear matrix inequality method. Research of passive fault-tolerant control on fullvehicle with fault suspension system is made. Not only performance comparison between the intactseven-degree-of-freedom vehicle with active suspension system and fault suspension under thenormalH₂/H_∞controller is made, but also that under optimal robust fault-tolerant controller ismade too.（4）By adaptive theory and linear matrix inequality methods, sensor fault estimation system isderived and designed for seven-degree-of-freedom vehicle with output feedback control activesuspension system which sensor break down. The sensor ordinary faults is estimated and studied. Onthe basis of the design of sensor faults estimation system and the estimation of sensor faults activefault-tolerant control on fault suspension system is researched based on sensor signal reconfiguration.Performance comparison between the intact vehicle active suspension system controlled by activecontrol law and fault suspension system controlled by active fault-tolerant control law is made.（5）Considering seven-degree-of-freedom vehicle with active suspension system whichactuator breaks down, a robust observer is designed to restrain disturb road input. Detection andon-line diagnosis of actuator fault is realized by output residual error obtained from the robustobserver. Base on this, active fault-tolerant control based on control law reconfiguration is designedand active fault-tolerant control is researched for vehicle active suspension system with actuatorfault. Performance comparison between the intact vehicle active suspension system controlled byactive control law and fault suspension system controlled by active fault-tolerant control law is madetoo.（6）In order to prove the theory result of active fault-tolerant, test bench of quarter vehicle withsemi-active suspension system is constructed. Force-speed performance relational datas of solenoidvalve damper which damper force is adjustable is obtained by test. Base on test datas, hardware-in--the-loop active fault-tolerant control test based on LabView is researched for vehicle semi-activesuspension with actuator fault. In the course of hardware-in-the-loop test, both active control test forintact vehicle semi-active suspension and active fault-tolerant control test for fault suspension withactuator fault is made. Performance comparison between the intact vehicle semi-active suspensionsystem controlled by active control law and fault suspension system controlled by active fault-tolerant control law is made.（7）In the end, the research work and research achievement of the whole dissertation isconcluded. Besides, combining the practice of research, the area and suggestion that need detailedresearch are poined out.