Brake Control Strategy Of Hybrid Electric Vehicle Based On Braking Intention Recognition

Brake energy recovery is one of the most effective ways to save fuel in hybrid vehicles.In order to ensure the braking performance and allow the motor to recover as much braking energy as possible,an appropriate regenerative braking control strategy should be established to properly distribute the strength of the electric brake and the mechanical brake.At present,researches of the regenerative braking control strategy mainly focuses on the braking force distribution of the regenerative braking and the mechanical braking.The identification of the driver's braking intention only depends on the single parameter of the brake pedal opening degree.The result of the identification of the braking intention only based on the brake pedal opening is not yet accurate.A new method of braking intention identification is proposed from the perspective of frequency domain,and various braking intention identification parameters are compared.A suitable braking intention identification parameter is selected after the discussion of different parameters.A braking experiment was conducted on campus in order to explore the feasibility of the braking intention identification method.Four drivers' brake pedal signals were collected and processed to get a clear classification of the braking intention.A new front-rear axle braking force distribution strategy is formulated combined with the advantages of various methods.According to the magnitude of the braking intensity,the braking force distribution strategy is divided into four parts,and the timing of switching in each case is deduced.Combined with the information of braking intention recognition,vehicle speed and SOC,the distribution method of front axle regenerative braking force and mechanical braking force is worked out.The braking force distribution model and vehicle model were built in AMESim and Matlab/Simulink respectively.AMESim and Matlab/Simulink were used for joint simulation.Then the simulation results of the front and rear axle braking torque and regenerative braking torque of the vehicle under NEDC operating conditions are analyzed and compared with the simulation results of the traditional braking force distribution strategy to verify the accuracy of the braking force distribution strategy.The brake pedal simulator is designed and the hardware in the loop simulation test bench is set up.The hardware in the loop simulation experiment is carried out.The driver's brake pedal signal is collected and the braking intention recognition is carried out.And the real-time performance of the braking intention recognition method is verified.