Hybrid Simulation Research For Automobile Electric Control Semi Active Suspension

This paper focus on the research of vehicle suspension system, to improve riding comfort and driving safety of vehicle as control targets. The thesis has designed a variety of control strategies for Magneto-rheological damper, to verify the effects of different control strategies by using virtual simulated method. Two suspension control systems were designed to improve the riding comfort and handling stability of vehicle (two control systems do not interfere with each other). The thesis has provided a modern mean and method for the development of automotive suspension systems. The major works were done as follows:(1) At first, according to the obtained parameters of the suspension, this paper established front and rear suspension virtual prototype model in the dynamics software ADAMS system. And then used the subsystem modules which the software already had to modify the parameters of the sub-template and template’s communicator, the thesis established the vehicle model and verified the model’s credibility.(2) The road was simulated by the discretized numbers by using sine wave superposition principle. A VB program was written to generate visual randomly road file generator. Users only need to enter road surface roughness coefficient to generate road files of national standards at all levels which could be used by ADAMS software in riding comfort simulation.(3) The front suspension was optimized by insight module, used all hard points’coordinates as design variables and five wheel positional parameters as the optimization objectives. The kinematic sensitivity analysis was taken on front suspension to elect the most influential hard-point coordinates, which were used by the Structural optimization test. According to second optimization analysis on these elected hard-points, the front suspension structure parameters were ultimately optimized and improved the capability of suspension.(4) This paper analyzed the characteristics of the magneto-rheological dampers, and then designed a magneto-rheological damping controller, which according to the methods of PID control, fuzzy control and fuzzy-PID compound control, based on vehicle riding comfort evaluation criteria. Ultimately the pros and cons of the three control strategies were compared and verified their suitability. (5) Threshold control and fuzzy control strategies were designed base on the vehicle handling and stability evaluation criteria. And then Snake-Change and ISO-Lane test were taken on the virtual prototype vehicle to analyze and compare the effect of two control strategies.The innovation:A new control method have been used to enhance the vehicle handling and stability capability, which taken suspension damper as the control object and designed damping force control method based on threshold control and fuzzy control strategies. Snake-Change and ISO-Lane test were used to confirm the effect of control strategies and ultimately verified the control strategies could improved performance of side-slip angle and vehicle body roll angle.