Research On Fault-tolerant Control Of MR Semi-active Suspension With Partial Fault In Actuator Considering Temperature Effect

Magnetorheological fluid(MRF) is a kind of new intelligent material. Numbers of scholars pay more attention to MR dampers which is designed and manufactured based on MRF for its quick response speed, small power consumption and high yield strength. Besides, MR dampers has a good application prospect in civil engineering, vehicle engineering, mechanical engineering and so on. Compared with passive suspension, the semi-active suspension with MR damper increases the range of adjustable damping force and has better damping characteristics. However, in the work process, the performance of MR damper will be degraded for the settlement or abrasion of magnetic particles in MRF, or mechanical and electrical failure, etc. What’s more, the temperature changes of the external environment and damper itself will influence the output damping force. The temperature of MR damper comes to a dynamic equilibrium state after working for a while, and MR damper under the highest temperature is not totally failure, only partial fault. As a result, the control algorithm research on semi-active suspension system becomes more complex.So it’s necessary to study the fault tolerant control algorithm of MR semi-active suspension considering the failure of MR damper. Therefore, in this paper, the magnetorheological damper developed by our group is taken as research object. According to the results of temperature characteristic test, the failure factor is determined. Then the failure dynamic model of MR semi-active suspension considering the actuator partial failure under the temperature effect is established. Finally, a model-reference sliding-mode fault tolerant control method is derived to solve the problem. The simulation results verified the effectiveness of the control strategy proposed.The main contributions of the dissertation are as follows:① The research background and significance are introduced firstly, then the research and application status of MR damper in suspension, the research status of the control algorithm of MR semi-active suspension and fault tolerant control of systems with actuator failure are elaborated. The influence of temperature on the magnetorheological damper is mainly summarized, the research achievement on MR semi-active suspension considering temperature effects of is collected and collated.② In this paper, a series of research is developed about the single cylinder rod MR damper which is self-designed, and the temperature characteristic test of MR damper was conducted. Then, based on the theory of adaptive neural fuzzy inference system(ANFIS), the dynamic model of output damping force of MR damper on temperature, excitation current, the piston movement speed and displacement is derived.③ The dynamic model of a quarter vehicle suspension system is chosen as the research object. The effect of temperature on the dynamic response of the suspension system is analyzed. On the basis of the temperature characteristic test results of MR damper, the failure factor that MR actuator appears partial failure under the temperature effect was determined. Finally, the failure dynamic model of MR semi-active suspension considering the actuator partial failure under the temperature effect is established.④ Finally, optimal skyhook damping coefficient is determined by means of analyzing the ideal skyhook control strategy of vehicle suspension. Taken the ideal skyhook control suspension model as the reference model in this research, a model-reference sliding-mode fault tolerant control method is derived. The simulation analysis is implemented in the road conditions of sinusoidal, step, bump and random. And the results show that the fault-tolerant control strategy proposed is applicable to different road conditions and vehicle speeds, and the control method can compensate the decreased output damping force of MR damper and improve vehicle ride comfort and driving safety..