Research On Active Fault Tolerant Control For Vehicle Electromagietic Hybrid Suspension

The vehicle active suspension system can greatly improve the driving performance of the vehicle,but when the active suspension fails,the dynamic characteristics and safety of the vehicle will deteriorate.In order to improve the dynamic characteristics of suspension in normal state and fault state,and enhance the safety of vehicles,this paper designs an electromagnetic hybrid active suspension system and its active fault-tolerant control strategy,and studies it from various angles.Based on the analysis of the structural composition and working principle of electromagnetic hybrid active suspension,two degree of freedom suspension model,seven degree of freedom suspension model,linear motor model,solenoid valve damper model,road roughness model and suspension actuator fault model are established respectively.An unknown input observer is designed to observe the suspension state variables in real time.According to the obtained state observation values such as sprung mass acceleration and its residual,a fault diagnosis and fault-tolerant control method is designed.The first mock exam is based on the unknown mass spring acceleration of the input observer,and the suspension mode is determined.If the first mock exam is repeated several times beyond the set threshold,the failure of the current mode is determined.The failure mode is switched to the next mode,and the other parts are used to compensate the control force to achieve fault tolerant control,The performance of unknown input observer,fault diagnosis effect,control force compensation effect and fault-tolerant control effect are simulated and analyzed by using Matlab software.Finally,the physical prototype of electromagnetic hybrid active suspension is trial produced and bench test is carried out to verify the effectiveness of fault-tolerant control of electromagnetic hybrid suspension.Under the fault-tolerant control of electromagnetic hybrid active suspension,compared with normal fault-free,the fault-tolerant effects of sprung mass acceleration,suspension working space and dynamic tire load are 32.33%,30.19%and 36.74%respectively,which are close to the dynamic characteristics of normal state,and the fault-tolerant effect is obvious.The bench test results show that under normal conditions,the relative error between the test results of sprung mass acceleration and the simulation results is 3.68%,and the test results are basically consistent with the simulation results.In case of fault,the root mean square value of sprung mass acceleration is 1.203m·s-2.After fault-tolerant control compensation,the root mean square value of sprung mass acceleration is 0.883m·s-2.Compared with the fault state,the root mean square value of sprung mass acceleration under fault-tolerant control is reduced by 26.60%.The rationality of the designed fault-tolerant control strategy is shown.