The Study Of Brake Force Distribution And Control Method Based On Brake-by-wire Of Four Wheel Independent Brake

New energy intelligent connected vehicles are the main directions of development of modern automotive technology. The actuators of Brake-by-wire system are electric drive components. BBW used in vehicle network transmission braking information, has the advantages of high efficiency, energy saving and good controllability, is the future direction of development of new energy inte lligent connected vehicles braking system. The braking performance of automobile is an important guarantee for the safety of automobile. Study on the brake force distribution and brake stability control of vehicle is of great significance. In this thesis, the main research for brake-by-wire system of four-wheel independent break included:The structure and working principle of the brake-by-wire system is analyzed. The dynamic analysis of the vehicle in the straight road is carried out. To improve braking performance and stability, an optimal braking force distribution strategy for brake-by-wire system of four-wheel independent break based on slip ratio and a real time optimization calculation method for the constrained optimization problem are proposed. A co-simulation model of Car Sim and MATLAB/Simulink is established to simulate and experiment. The simulation results show that the optimal braking force distribution strategy based on slip ratio can always ensu re the front wheel slip ratio greater than the rear wheels’ and the rear wheel slip ratio is optimal under different braking conditions, which improves vehicle braking stability and obtains shorter braking distance. At last, the optimal braking force distribution strategy algorithm is verified and it meets the requirements of the real-time.The reasons for instability of vehicle cornering braking are analyzed. The vehicle dynamics model is established and the influence of the braking force distribution on the vehicle cornering braking stability is analyzed. The vehicle yaw rate and sideslip angle as control variables of vehicle cornering braking stability control scheme is designed. The control strategy of the target wheel braking torque is established and the fuzzy PID controller is designed for the vehicle cornering b raking stability control scheme. A co-simulation model of Car Sim and MATLAB/Simulink for the vehicle cornering braking stability control strategy is established and the simulation test is carried out on the dry asphalt, wet asphalt and snow road surface. The simulation results verify the effectiveness of the control strategy of the vehicle cornering braking stability in this thesis.