Research On Active Control Of Vehicle Bumper Energy Absorber Based On Magnetorheological Fluid

The automobile has not only brought great convenience to people but also launched a challenge to people’s lives at the same time,so the traffic accidents have become an important threat to human’s safety.It is imperative and urgent to improve the passive safety of the vehicle,reduce the damage to the driver and passengers during the collision process and decrease the property loss.Increasing the buffer energy absorption properties is critical to improve the passive safety of the vehicle,because bumper is the first part when the vehicle encounters a head-on collision.In order to improve the energy absorption characteristics of automobile bumper,domestic and foreign scholars have made a lot of achievements in structural design optimization,application of new materials and installation of buffer energy absorbing devices.But these bumpers can not adjust the stiffness according to the change of the collision environment for Self-regulation.To address the problems of the uncontrolled stiffness,the poor adaptability to different collision environments and the poor use after deformation of traditional automobile bumper energy absorber,this article designs the magnetorheological fluid buffer energy-absorbing device used in the car bumper and carries out active control research based upon the characteristics of the short response time of magnetorheological fluid,the controllable damping force,low energy consumption and the large shear yield force.The main contents of this paper are as follows:(1)Study on collision energy decay characteristic of energy-absorbing bumper for vehicle crash.The finite element simulation of the vehicle with the traditional energy-absorbing bumper collision process is carried out by using the finite element software Hypermesh and LS-DYNA.The energy decay of the traditional energy-absorbing bumper vehicle collision process is studied.The deformation process and energy absorption characteristics of the crash box are analyzed.These provide the basis for the design and active control of the magneto-rheological fluid buffer energy absorption device.(2)Optimal design of vehicle bumper energy absorber based on magnetorheolofical fluid.Based on the characteristics of magnetorheological fluid and the modified Bingham model,the design of magneto reactor buffer energy absorption device is completed and the structural parameters are optimized.Through the collision simulation,the magneto-rheological fluid buffer energy absorption device can improve the passive safety of the car.(3)Active control of magnetorheological fluid buffer energy absorber based on fuzzy PID control.The dynamic model of vehicle collision control system is established.The fuzzy PID controller is designed based on the fuzzy PID control principle.The simulation results show that the fuzzy PID controller can effectively control the magneto-rheological fluid buffer energy absorption device,so that the rigidity of the collision process is controllable and the energy absorption effect is better.