Abstract: With the rapid development of intelligent driving technology, wire control technology is pushing brake booster system and active braking system towards electrification and integration. The characteristics of some One Box products integrated by brake booster system and electronic stability control system which produced by international well-known manufacturers are illustrated with examples as well as the transmission mechanism. An integrated brake-by-wire system based on single motor and bi-directional acting brake cylinder is proposed, compared with the traditional system combined by booster and ESC, this integrated Brake-by-Wire system can meet the function and space requirements more properly. The transmission mechanism can reduce the speed and increase the torsion and convert the motion type, which is the basis of the active pressure control of the integrated brake-by-wire system. By comparing the advantages and disadvantages of some transmission mechanism, the transmission mechanism mathematic model is established based on the braking objectives and motor performance. After calculation and simulation, two optimized transmission ratios are obtained with the help of constraint optimization method as well as the co-simulation model and controller created by Matlab/Simulink and AMESim. According to the finite element analysis results, the recommended parameters: the transmission ratio is 2.4, the number of driving gear teeth is 15, and the number of driven gear teeth is 36, which provides a favorable reference for production and application. Based on the results of theoretical analysis and simulation analysis, a prototype was developed, and a special test bench was designed and developed. The feasibility of the design method was proved by bench test, which provides a new idea and reference for the optimization design of similar braking system.

Key words: integrated brake-by-wire system, transmission mechanism, constrained optimization, modeling and simulation, transmission ratio