Structure Research And Performance Simulation Of Magnetorheological Fluid ABS Brake

Magnetorheological fluid can produce a successive, reversible and instantaneous rheological effect in the magnetic field. This kind of rheological characteristic makes MRF suitable for automobile brake, and it can realize a fast and continuous and stepless viscosity of MRF through a rational design of structure and current controls in magnetic circuits, so as to achieve the purpose of controlling braking torque according to actual needs. When aided by wheel rolling and sliding state detection, it can regulate the braking torque timely according to the variation of tire-road friction coefficient to achieve a more accurate antilock brake effect than traditional ABS, and the system can realize a electronically controlled braking process completely, and so it can meet the futural development direction of intelligent vehicle.The paper expounds the mechanism of the rheological effect from macro and micro two-aspects, and introduces the component and preparation methods of MRF; In addition, it discusses the actual needs and feasibility of developing MRF brake; Based on the analysis of working principle of MRF devices and the theory of vehicle braking, The article designs a kind of impeller-type MRF brake working on the mode mixed shear and flow mode and the corresponding electromagnetic control device to make the brake produce a output of 1656N·m brake torque while the current is 3A as the input, so as to satisfy braking torque requirements of small and medium-sized vehicles in the limited wheel-inner-space; Adopting a design work of integrating the electromagnetic clutch with brake through decorating reasonably on the driving and driven wheels that can effectively avoid following loss.The corresponding simulation model established on three aspects which range from the influence of brake structural parameters on the braking torque and the simulation braking process of ABS to the simulation of brake cooling under several working conditions are simulated through MATLAB/Simulink software. The results show that the relationship between its braking torque and magnetic induction presents a logarithmic change rule, while the corresponding relation with the working gap presents a negative exponential law; The radial dimensions, number and thickness of blades have considerable influence on braking torque respectively; As the response between the current and braking torque displays a nonlinear and rapidly saturate relationship, The redress through correctional circuit can make it present a linear relationship which is suitable for operation habit; Magnetorheological brake can also play a good braking performance in the ABS braking process; The braking temperature of brake is kept in allowing range.