Distributed Drive Vehicle Hill-start Control Based On Pneumatic EPB

Hill-start is a frequent situation in the process of driving.Due to the complex operating environment,dangerous situations,such as the vehicle's rollback,that endanger the life and property of the driver may easily occur when starting on an uphill.Especially for the distributed drive electric vehicle(DDEV),each driving wheel is independently controlled by the motor,and the driving torque can also be freely distributed according to the driving needs,which makes it more difficult to control the hill-start.Therefore,the in-depth research on the hill-start of DDEV is of great significance for improving the safety of DDEVs and for realizing intelligent driving.In this paper,the starting problem encountered by a DDEV independently driven by four-wheel hub motors when going uphill is taken as the research object.Based on the pneumatic electronic parking system(EPB),a hill-start control method adapted to its complex driving form is proposed.Firstly,in view of the distribution of the driving torque of the driving wheels of the vehicle,considering the transfer of the center of mass of the vehicle during the hill-start,a driving torque distribution strategy based on the dynamic load of front and rear axles is proposed;Then,for the release of parking brake force,in order to speed up the speed of EPB's brake pressure following control and improve the effect of distributed vehicle hill-start control,a logic threshold control method improved based on genetic algorithm is designed to ensure the brake pressure is quickly released at the right time.Secondly,in view of the bad road conditions such as ice and snow road,this paper adopts the speed control method based on the maximum road adhesion,through the real-time detection of the size and direction of the wheel speed,the demand torque of the drive motor can be adjusted in real time.Finally,AMESim software is used to build the EPB system model,Truck Sim software is used to build the test vehicle model,and Matlab/ Simulink software is used to build the driver model and EPB control system model.using three software co-simulation forms on basis of the built model to carry out simulation research on the proposed control strategy.The test results prove that the control strategy proposed in this paper can meet the evaluation indexes of non-slipping,lower starting i MPact and less brake wear under different road conditions.