The Theoretical And Experimental Investigation On Semi-active Vehicle Suspension Employing Magneto-rheological Technology

The ride comfort and safety of vehicle is more important than before. It can be concluded from the trend of international automobile industry and the reality of improving speed in domestic railway. All above is because of the vehicles' distinguished effect in maintaining people living and boosting national economy.This dissertation combine some content which have finished for the national science foundation Research on the Key Technology of Semi-active Vibration Control Based on Composite Structure(Granted No.50275132) and enterprise project Development and Research of oil damper for high speed railway with semi-active suspension researching. The theory and test is investigated on vehicle semi-active suspensions employing the magnetorheological fluid to solve some limitations of suspension.Because the passive suspension is still the main mode of common vehicles now, the oil damper used for high-speed railway is optimized only focused on its key structure. On the purpose to obtain high ride comfort, the modeling strategy which coupling the damper into the whole vehicle system is presented by equivalent linearization the oil damper model. The optimized data indicates that this idea is more suitable than the method by separated damper alone.Based on the reliability of passive suspension and controllable of semi-active suspension, a kind of compounded structure of magnetorheological damper(CMRD) is concluded. The modifying skill is acquired after analyze the error of its design mathematical model. And the next work, which using the optimized CMRD dimension, prove this skill is necessary.Influenced by road irregularities exciting by stochastic process simulation in time domain and the parameter variable of vehicle system, the Robust control which improving the ride comfort and safety is analyzed, considering the semi-active damping adjustable continuously. Then, the novel judging state and filtering acceleration H control strategy is discovered. The conclusion that these two methods is better than Reference model stems from analysis.The difference of semi-active with MRD from the others needs a multi-functional test system which resorts to the pseudodynamic tests. This test system which can be used for vertical or lateral damper alone and semi-active pseudodynamic tests is verified by experiment.In view of controlling the vibration, A sigmoid hysteretic loop model orienting to using for controller is presented by studying the hysteretic characteristic of MRD dynamic model. This model inosculates the experiment data well in precision after the parameter is identified according to the experiment data.In the end of this thesis, the matching property of sigmoid hysteretic loop model and judging state, filtering acceleration, reference model H control strategy is contrasted each other, judging state Hoo control strategy capture the essential contribution of all the work for its efficient and less energy needs.