| The Electricity and intelligence have become important development directions for future automobiles.Vacuum assisted braking systems have gradually failed to meet the relevant requirements of people in the new era,the electric power assisted braking system can realize the power assisted braking through the motor,and it is easy to cooperate with other systems to realize the regenerative braking function,which is favored by the new energy automobile enterprises.In addition,the electric power brake system is easy to realize the active braking function,so it is favored by the intelligent driving industry.Therefore,the development of new electric power brake system and its control algorithm is of great significance to the future development of automobiles.This paper takes the electric power assisted braking system developed by the internship unit as the research object and mainly conducts the following research:Firstly,the basic research of the new electric power assisted braking system is carried out.Based on the theoretical analysis of the braking process of the target-matching vehicle,the maximum braking power demand of the vehicle is obtained,and the model selection of the electric power brake system is made based on this,and then the speed ratio of the transmission mechanism is checked and verified based on the selected motor parameters.Secondly,the strategy of electric power brake system is studied.The working characteristics of the vacuum booster brake,the motor characteristics,friction characteristics and the working characteristics of each sensor under different input forces of the target vehicle are analyzed through experiments.Adopts the logic threshold control method to design the brake intention recognition algorithm.Combined with the working characteristics of the vacuum booster brake,the motor characteristics and the system friction characteristics,a power-assisted braking strength control algorithm with relative displacement as input and a motor current as the target control variable closed-loop PID control strategy of the motor bottom segment.Finally,the electric power-assisted braking system bench and real vehicle test platform were built,and the electric power-assisted braking system and its power-assistedbraking control algorithm were tested and verified in conjunction with relevant evaluation indicators.The experimental results show that the developed electric power-assisted braking system can achieve similar power-assistance characteristics as the vacuum-assisted braking system;During the assisted braking test process,the braking intention is judged accurately,and the braking strength algorithm is reasonable The closed-loop control effect of the motor bottom current is good,which meets the project's expected requirements. |
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