Research On Regenerative Braking Control Strategy Of Electric Vehicle Based On Braking Intention Recognition

Pure electric vehicles have the characteristics of no emissions,high efficiency,and no need to rely on conventional energy sources and are widely regarded as the future development direction of the automobile industry.However,due to battery technology limitations,pure electric vehicles have a short cruising range,making it challenging to promote and apply.How to increase the cruising range of pure electric vehicles is a critical issue to be solved urgently.Regenerative braking technology is a technology that uses the electromagnetic characteristics of the motor to provide braking force and recovers and stores part of the braking energy,thereby increasing the energy utilization rate and increasing the cruising range of electric vehicles.Therefore,the study of regenerative braking technology is of great significance to promoting and applying electric vehicles.This thesis takes the front-wheel-drive electric vehicle equipped with a brake-by-wire system as the research object.Through studying the braking intention recognition algorithm,the braking force distribution optimization algorithm,and the regenerative braking control strategy,a regenerative braking control strategy method for electric vehicles based on braking intention identification was proposed.In ensuring the electric vehicle’s braking stability,the braking energy is recovered more,and the braking effect is better.The main research contents of this paper are as follows:(1)A recognition algorithm electric vehicle braking intention based on artificial bee colony and support vector machine is designed.By analyzing and processing the brake pedal data at the moment of braking,the brake pedal’s braking intention in one action is identified.(2)An optimized distribution algorithm of the braking force ratio between an electric vehicle’s front and rear axles is designed.In careful consideration of vehicle load and braking intensity,the corresponding braking force distribution curve is optimized according to the driver’s different braking intentions.The algorithm allows more braking force to be allocated to the front axle for energy recovery during mild braking intentions and a better braking effect for vehicles with moderate and emergency braking intentions.(3)A regenerative braking control strategy for electric vehicles is proposed.Based on the optimal distribution algorithm of braking force,fully considering the influence of motor characteristics and battery SOC(state of charge)on braking energy recovery,a regenerative braking control strategy is formulated to realize the reasonable secondary distribution the front axle braking force of the vehicle.The braking force provided by the electric motor accounts for a more significant proportion of the front axle’s total braking force so that the braking energy can be more recovered.(4)Design experiments verified the algorithm.Set up offline and online tests to verify the superiority of the braking intention recognition algorithm.At the same time,a model of the regenerative braking control system is established.Taking UDDS and NEDC two urban road cycling conditions as examples,the designed regenerative braking control strategy for electric vehicles based on braking intention recognition is verified by simulation experiments.The main innovations of this paper are:(1)To increase the braking intention recognition algorithm’s recognition speed and accuracy,the neighbourhood components analysis algorithm is used to process the braking moment’s time-domain data from 0 to 0.05 s.Then the artificial bee colony optimized support vector machine algorithm is used to identify,thereby improving Improved recognition speed and accuracy.(2)To recover more braking energy and obtain a better braking effect,first,optimize the corresponding braking force distribution curve according to different braking intentions,and then fully consider the influence of motor characteristics and power battery SOC on this basis,and formulate regeneration.The braking control strategy ensures that a better braking effect is obtained while increasing the braking energy recovery.