Velocity Estimation Of Four-wheel Drive Electric Vehicle And Slip Rate Control Method Research

4-wheel indenpendently drive electric vehicle driven antiskid control is used to prevent that vehicle appears out of control phenomenon with vehicle fastly accelerating and driving on the low adhesion coefficient road,that is extremely important for improving the safety performance of electric car.the main problem of driven antiskid control is estimation and control of wheel slip rate,and slip rate estimation must be solved through the precise speed.For this,the paper studies the speed estimation and discusses wheel slip rate control problem based on it.The vehicle speed estimation that this paper discusses is in the cars with wheel speed sensor and the center of mass of vehicle longitudinal acceleration sensor.This paper considers the relationship between road slope and the vehicle mass center sensor information and establishes single degree of freedom vehicle kinematics model based on the assumption that the road slope changes slowly, based on this model, the paper proposes a varible gain of speed and road slope joint and the relationship between the gain and wheel speed and the longitudinal acceleration is discussed in detail.And with the lyapunov stability theory and input to state stability theory it analyzes the algorithm convergence and the performance is proved through a variety of simulation conditions using.Based on obtaining wheel slip ratio by the estimation speed, for 4-wheel indenpendently drive electric vehicle slip rate control, the paper establishes tire longitudinal slip rate multiple cell LPV(Linear Parameter Varying) control model using the wheel dynamic and vehicle longitudinal dynamic. On the basis of analyzing the characteristics of this model, the wheel slip ratio robust PI controller is designed and the control gains are obtained by using the robust state feedback controller design method. Then the PI control is verified under different simulation conditions in the vehicle simulation software ve DYNA. Results show the designed controller has good control performance and can achieve the expected control effect.In order to the running effect that the speed estimation algorithm is downloaded into the vehicle controller, this paper conducts the vehicle estimation algorithm hardware in the loop simulation test. The HIL test environment is completed with the help of data acquisition card by NI equipment and its compatibility labview software and this paper simulates the brake pedal, the acceleration pedal, gear sensor signals and combines the d SPACE to complete the hardware in loop real-time simulation system test. Finally,the speed estimation algorithm is for the offline test using the data obtained from the real vehicle tests to verity the algorithm effective.