A Method for Estimating Road Adhesion Coefficient Based on Coupling Characteristics of Motor and Wheel

Abstract

The invention discloses a road adhesion coefficient estimation method on basis of coupling characteristics of a motor and a wheel. The road adhesion coefficient estimation method is applicable to real-time monitoring of a road adhesion coefficient during running of an electric vehicle. According to the road adhesion coefficient estimation method, the relation between a longitudinal rigidity of the wheel and resonant frequency of an electric wheel is established, the longitudinal rigidity of the wheel can be solved on the basis of the resonant frequency obtained by utilization of motor torque, and the road adhesion coefficient is estimated according to the relation between the longitudinal rigidity of the wheel and the road adhesion coefficient. The road adhesion coefficient estimation method is convenient to apply since motor current and wheel speed signals are adopted, travel speed of the electric vehicle and information of longitudinal force of the wheel are not required, and the longitudinal slip rate of the wheel needs not to be computed; frequency domain information is utilized in estimation, so that the road adhesion coefficient estimation method is insensitive to wheel speed noise and errors, which explains the accuracy of the adhesion coefficient estimation method.

Description

technical field [0001] The present invention relates to the estimation of the road surface adhesion coefficient of the vehicle, in particular to a method for estimating the road surface adhesion coefficient of a distributed drive electric vehicle, which is based on the estimation of the road surface adhesion coefficient of the motor and the wheel coupling characteristics. Background technique [0002] Distributed electric drive vehicles install the driving motors in or near each wheel, and one motor independently drives one wheel. It has the advantages of fast response speed, short transmission chain, efficient transmission, and compact structure. It makes full use of the motor The characteristics of precise torque observation and fast controllability are an important development direction in the field of electric vehicles. However, there are still many problems that need to be improved in the current distributed electric drive vehicles, such as the impact caused by the torq...

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Problems solved by technology

[0004] In order to solve the disadvantages that the existing method of estimating the road surface adhesion coefficient with the slope of the μ-s curve is not suitable for small slip rate conditions, and has high sensitivity to wheel speed noise and steady-state error, the present invention proposes a new type of motor-wheel The road surface adhesion coefficient estimation method based on coupling characteristics is suitable for real-time monitoring and estimation of the road surface adhesion coefficient during the normal driving (constant speed or small acceleration / deceleration) of the electric drive vehicle. Wheel speed signal processing realizes the identification of the road conditions of each wheel

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