Research On Vehicle Collision Simulation And Control Based On The Magnetorheoolgical Technology

With the rapid development of science and technology, today vehicle has becomethe main transportation method. But it has taken away many people’s life while bring ineffective and comfortable trip. As the first guard of vehicle safety, bumpers play animportant role in enhancing vehicles’ passive safety and reducing traffic accidentcasualty rates. However, the bumpers in current market can’t satisfy the requirements ofpeople because they neither have an ideal buffering effect nor only have a certain effectin specific conditions that is with a very complex structure. In this condition a newbuffering structure is required. A magnetorheological (MR) fluid absorber, as a smartdamping device, has the advantages of rapid response, low power, reversible viscousvariation and broad dynamic range, which can avoid the shortages of current bumpersand becomes one of bumper development trends. Therefore, on the basis of scenario ofvehicle collison, the design theory of the MR absorber and control stategy undercollison are studied thoroughly. To avoid the disadvantage of design theories, the MRabsorber is optimized on the basis of modified Bingham-plastic model and modified inorder to build a control model; a dynamical model of vehicle collision is built based onthe multi-body dynamics and the effects of vehicle collision with MR absorber is alsosimulated. The main contents in this study include the followings.(1) The application backgrounds of bumpers and vehicle safety technology areintroduced while the important significances of MR absorber be used in vehiclecollision are dicussed, the developments of MR absorber design and application aresummarized.(2) Focused on the inaccuracy of Bingham model used in the design of MRabsorber under high-speed conditions, a modified Bingham-plastic (BPM) model isderived and a fluid simulation is made by applying a fluid dynamic simulation softwareCFD on the MR absorber designed based on this BPM model, the results proven a highaccuracy of BPM model.(3) The performance of MR absorber used as a bumper is simulated by usingANSYS/LS-DYNA software. The results indicated MR absorber’s feasibility andeffectiveness in enhancing passive safety of vehicles and provided a basis for next stageof procession and test.(4) To test the buffering performance of MR absorber under four different drop heights, a drop tower facility is designed and built. BPM model’s precision is fullyproved by comparing the test value to the design value, and then a control model is builtbased on the BPM model to apply in a high-speed condition.(5) In terms of the control objectives of vehicle body including the maximumacceleration and deformation, control performance of the on-off control, skyhookcontrol, PI control and the fuzzy control were compared. The results show that eachcontrol strategy can improve the collison safety. The performance can only achieve atrade-off between two control objectives.