Study On Acceleration Slip Regulation Control Algorithm For Parallel Hybrid Electric Vehicle

As active safety technology, the acceleration slip regulation is to prevent drivenwheel spinning, improve the performance of vehicle's acceleration, climbing andgetting through sand road, to ensure lateral stability of the car. For the demand ofsecurity on the driving conditions, Hybrid vehicles equipped with multi-power sourceincrease the driving torque adjustment, which brings a new challenge to conventionalAcceleration Slip Regulation. This paper studies on Acceleration Slip Regulationcontrol algorithm for parallel hybrid electric vehicle.In hybrid electric vehicle, acceleration slip regulation is in the first technologyblockade stage of the foreign, technology of the algorithm is still forefront in CHINA.The paper studies on acceleration slip regulation algorithm for parallel hybrid electricvehicle.This paper includes:(1) This paper studies on state identification and parameter calculation foracceleration slip regulation control algorithm in parallel hybrid vehicle. Using thethreshold method is to identify the different working conditions and road. Key controlparameters are computed in the algorithm of ASR. Taking into account of thesteering angle, the actual slip rate can be calculated in straight and corningconditions.The conditions of the driving wheel and vehicle estimates the adhesioncoefficient between tire and road.Based on different working conditions, road surfaceand the different speed stage, the target of driving wheels' speed, its speeddifference and driving axis's speed can be determined.(2) The paper studies on target torque control algorithm and allocation strategies foracceleration slip regulation control algorithm in parallel hybrid vehicle. The targetdrive torque control algorithm includes Feedforward and feedback control modules. Using of the driving resistance equation is to get the target drive torque infeedforward control modules. With the target and actual value of shaft speed, fuzzyPID controller acquires target torque variation in feedback control module. With thewheel speed's target and actual value, the target braking torque control algorithmacquires the target braking torque in fuzzy PID controller, and thus acquires thetarget brake pressure. Taking into account of the driving mode and the demand foranti-slip, the drive torque allocation algorithm can be determined in hybrid electricvehicle. According to the target drive torque, the vehicle controller calculates thetarget torque of engine and motor. According to the target pressure of the wheelbrake cylinder and estimated the actual pressure of wheel cylinders and mastercylinder, hydraulic braking force control algorithm is determined to control thestrategy of hydraulic pump and valve. Based on actual demand and test analysis, thecarrier frequency and duty cycle of hydraulic pump or valve can be calculated. Usingthe control of PWM, the target brake pressure can be turned in anti-slip algorithm.(3) The paper studies on acceleration slip regulation control algorithm's offlinesimulation in parallel hybrid vehicle. In MATLAB/Simulink environment, offlinesimulation platform is builded for a parallel hybrid electric vehicle. The simulationplatform includes the vehicle's dynamics model, its subsystem dynamics model andcontrol algorithm model. The vehicle's dynamics model includes the manipulationand kinematic dynamic model. The vehicle's subsystem dynamics model includesengine model, tire model, the drive motor model, battery model and brake model.The algorithm of the state estimation, parameter calculation, the target torque controland the torque distribution strategy establish the control algorithm. Based on low-muroad, mu-jumped road, the split road and cornering conditions, offline simulationvalidates the effectiveness of the algorithm.(4) The paper studies on the algorithm's hardware in the loop simulation. Based onthe MATLAB/xPC Target real-time workshop, hardware in the loop simulationplatform is built for a hybrid electric vehicle. The hardware-in-the-loop test platform includes xPC Target real-time simulation platform, the hardware part and softwarepart. The xPC Target real-time platform includes the host computer, the targetmachine, a multifunction data acquisition card and the terminal board and the powerdrive amplifier circuit boards. The hardware part includes a test bed bracket, brakingsystems, motors and sensors. The software part includes the vehicle's model andcontrol algorithm model. The vehicle's model includes tire model, engine model, thetransmission model, and the vehicle dynamics model. Based on low-mu road,mu-jumped road, the split road and cornering conditions, hardware-in-the-loop testverifies the effectiveness of the control algorithm.