| Acceleration Slip Regulation(ASR),as a key vehicle active safety control system,mainly solves the problem of excessive wheel slip.Because the power transmission and torque of the hub motor vehicle is different,the traditional drive ASR system cannot be directly applied,so it is very necessary to carry out the research on the ASR control of four-wheel independent drive hub motor electric vehicle.This paper mainly studies the acquisition of real-time slip rate and the observation of road state in the drive ASR control algorithm,and verifies the feasibility of the algorithm.The specific research work is as follows:Firstly,the dynamic model of the whole vehicle with seven degrees of freedom is established,and the tire model,wheel motor model and driver model are established too.In Carsim,the existing C-class vehicle model is used to configure relevant body,suspension,transmission and other parameters,and then realize the joint simulation with Simulink through the external interface to build a vehicle dynamics simulation test platform.Secondly,based on the seven-wheel vehicle model and the magic tire model,it on the volume Kalman filter technology and simultaneously combines the wheel state parameters.The longitudinal speed estimation of the four drive wheels was completed by using the vehicle speed estimator,and the real-time slip rate of the drive wheel was calculated on this basis.Then,based on the Burckhardt tire model,a road surface condition observer based on fuzzy theory is designed.The adhesion characteristic curves and related parameters of the six standard pavements are fully utilized,and the maximum adhesion coefficient of the current pavement and the corresponding optimal slip rate are accurately identified by the pavement condition observer.Finally,based on the longitudinal speed estimator and the road state observer,the ASR control algorithm is designed by combining the classical PID control with the fuzzy theory.Then,according to the different requirements of longitudinal and transverse adhesion performance of the drive wheels,the algorithm is modified to improve the stability of the drive ASR control system.After completing the design of the whole drive ASR control system,with the help of Simulink Coder toolbox,the designed drive ASR control algorithm was tested in the microprocessor-in-the-loop,and the accuracy and real-time performance of the algorithm were analyzed according to the test results. |
