Research On Design And Control Of Automotive Semi-Active Suspension Based On Magneto-Rheological Damper

Highway network construction and extension, point to point transportation, and the increasing requirements for travel and transport efficiency promote the rapid development of the automobile industry. As the speed of cars'has improved, there are demands for cars'safety, comfortableness, handling stability, and road-friendliness. In order to improve vehicle performance and meet people's requirements, modern electronic, information, computer and automation technology have been applied. Cars have become a testing field for modern technology and embody the level of a country's technological development.Active/semi-active suspension is not only one of the important parts to control the vehicle chassis, but also an important part for the improvement of the vehicle operating performance. Magneto-rheological damper (MRD) made with magneto-rheological fluids, which are one of"smart materials", has features of fast response, wide dynamic range, low power consumption, simple structure and so on. The applications in buildings, bridges and vehicle are the present research hotspots. MRD provides a new way for the development and application of semi-active suspension shock absorber. However, apart from the magneto-rheological damper produced by the U.S. Lord company, which are installed in the Cadillac cars, magneto-rheological semi-active suspension is still in theoretical and laboratory studies at home and abroad. The main reason is magneto-rheological semi-active suspension is a complex nonlinear system with uncertainty. Semi-active control algorithm aimed at specific issues has achieved certain degree of control effect, but not from the perspective of vehicle suspension control as a whole. Meanwhile, the design and manufacturing technology of magneto-rheological damper is still not perfect. Previous studies used two-end out pole, bypassing, or other structures mostly, which cannot meet the shock absorber requirements of cars. Therefore, the design of magneto-rheological damper, considering vehicle magneto-rheological semi-active suspension control, not only has a very high theoretical research value, but also has a wide application prospects.In the paper, based on the design and manufacture of magneto-rheological damper, mathema- tical modeling of vehicle semi-active suspension and vehicle testing have been completed. We designed fuzzy control, adaptive variable universe fuzzy control,robust control and robust/ adaptive variable universe fuzzy compound control systems. Large numbers of simulations and experiments have been done. Mainly include the following:(1) Firstly, reviews the automotive suspension technology development and research status at home and abroad. Then, analysis magneto-rheological damper research status and problems. Finally, gives the content of this research and innovation points. (2) Magneto-rheological damper mathematical modeling and theoretical analysis was completed based on a careful analysis of magneto-rheological damper dynamic model. Conceptual design of two magneto-rheological dampers according to the suspension requirements of cars will provide the foundation for samples production and research.(3)On the basis of previous chapter, two front and rear MRDs have been manufactured based on simulation studies. Large numbers of experiments have been carried out which will provide design and experiment conditions for semi-active suspension control design on the next step.(4) Firstly, MRD semi-active suspension modeling under the condition of vehicle steering was completed. Secondly, excitation and verification of road signal has been studied. Thirdly, vehicle fuzzy controller and adaptive variable universe fuzzy controller,which adjustable factor is change by fuzzy controller, have been designed. Finally, simulations and comparisons were conducted. Simulation results show that adaptive variable universe fuzzy control effect is better than the fuzzy control.(5)In base the design of robust control of vehicle, the robust/ adaptive variable universe fuzzy combined controller was designed. Through the simulation, robust control and the composite control strategy effectiveness was compared. Simulation indicates: robust control and robust/ adaptive variable universe fuzzy composite control can effectively improve the vehicle's ride, but the composite control is better than robust control.( 6 ) Using four self-made magneto-rheological dampers completed the semi-active experimental vehicle conversions, to arm LPC2292 as the core formed a control system that utilizes embedded real-time operating systemμC/OS-Ⅱtransplant a control algorithm, bench test, a road pulse inpu, and random road test is conducted.(7) Summarize up the research and put forward some suggestions for the next stage of study.