Research On Responding Characteristics Control Of Car Hydraulic Booster Braking System By Wire

Based on "electric vehicle-assisted driving of key technologies research and product development" project of the Ministry of Science and Technology,taking the car brake system as the research object,producing reliable performance,pressure quickly,accurate pressure control system with independent research and development as the goal,this article research on the braking system control strategy of car.This paper establishes the hydraulic assisted braking system simulation model,completes the design and simulation verification of active building pressure,braking and ABS control strategy of the hydraulic brake system.After the simulation results meet the performance requirements,the prototype of the hydraulic power-assisted braking system is designed and developed according to the simulation results,and the hardware-in-the-loop test is performed to verify the performance of the brake system products.This article studies the following main elements:Firstly,the hydraulic braking system simulation model is established.Including:linear flow solenoid valve model,normally open solenoid valve model,normally closed solenoid valve model,master cylinder model,wheel cylinder model,high pressure accumulator model and vehicle three degrees of freedom dynamics model.Secondly,function check and structural optimization of the hydraulic assisted braking system.In order to meet the requirements of rapid pressurization and accurate pressure build-up of the wire control brake system,the working principle of the brake system is analyzed and verified from the structural point of view;at the same time,in order to make the brake system have good performance,the core components of the brake system simulation analysis to determine the brake system components parameters.Thirdly,the car brake system control parameters is optimized.At present,mostof the solenoid valves in the vehicle brake system are PID control,and the control parameters are obtained based on experience.Based on this situation,the multi-island genetic algorithm is used to optimize the control parameters of electromagnetic valve in the brake system.Through optimization,the optimal control parameters of each solenoid valve in the brake system are found,so as to ensure the vehicle has good response characteristics and can meet the requirements of active building pressure and precise pressure control requirements.Fourthly,ABS control strategy of hydraulic braking system of passenger car is designed.Firstly,the vehicle speed is estimated by EKF algorithm,and then the target pressure of the vehicle is obtained according to CMAC and PID parallel control.Based on the above work,the ABS control strategy of the vehicle is established and the joint simulation is carried out by Carsim software.Lastly,hardware in-loop test platform is established according to the brake system products,verifies the response characteristics of the brake system prototype,and improves the product quality according to the test results to improve the reliability of the brake system.