Estimation method of four-wheeled independent drive electric automobile road adhesion coefficient

Abstract

The invention discloses an estimation method of a four-wheeled independent drive electric automobile road adhesion coefficient. The method includes the steps: calculating vertical tire force of four wheels under a current vehicle driving state; calculating longitudinal tire force of the corresponding wheels under different road adhesion coefficients of current slipping rate; calculating current longitudinal tire force of the wheels; calculating a road friction coefficient; performing subtracting on the longitudinal tire force of the corresponding wheels under the different road adhesion coefficients of the current slipping rate and the current longitudinal tire force of the wheels, and taking a square; taking a minimum value of the difference square, judging the road adhesion coefficient corresponding to the minimum value as a current road adhesion coefficient, comparing the current road adhesion coefficient with the road friction coefficient, and taking a maximum value between the current road adhesion coefficient with the road friction coefficient; updating an estimation value of the current road adhesion coefficient if the duration time of an estimation value of the changed roadadhesion coefficient is longer than 0.5 second; keeping invariability of an estimation value of the road adhesion coefficient of previous moment. The method can be used for adjustment of drive anti-skid strategies, and the driving performance of a vehicle is improved.

Description

technical field [0001] The invention relates to a method for estimating the road surface adhesion coefficient, in particular to a method for estimating the road surface adhesion coefficient of each wheel at the moment when the vehicle drive anti-skid control is started. Background technique [0002] The road surface adhesion coefficient is an important parameter of the vehicle active safety control system. For example, the driving anti-skid control uses the road surface adhesion coefficient to plan the expected slip rate, and the vehicle stability control uses the road surface adhesion coefficient to plan the expected yaw rate. However, the road surface adhesion coefficient is difficult Measurements or sensors are relatively expensive, so the estimation of road surface adhesion coefficient is the basis for realizing active safety control of vehicles and plays an important role. [0003] The existing methods for estimating the road surface adhesion coefficient are mainly divi...

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Problems solved by technology

[0002] The road surface adhesion coefficient is an important parameter of the vehicle active safety control system. For example, the driving anti-skid control uses the road surface adhesion coefficient to plan the expected slip rate, and the vehicle stability control uses the road surface adhesion coefficient to plan the expected yaw rate. However, the road surface adhesion coefficient is difficult Measurements or sensors are relatively expensive, so the estimation of the road surface adhesion coefficient is the basis for realizing the active safety control of the vehicle and plays an important role

[0003] The existing methods for estimating the road surface adhesion coefficient are mainly divided into the following three categories: 1) The road surface friction coefficient is estimated mainly by means of the relationship between the slip rate of the wheel and the utilization rate of the road surface adhesion coefficient. This type of method can only estimate the road surface friction coefficient, that is, The utilization rate of the road surface adhesion coefficient; 2) The estimation algorithm is used to estimate the road surface adhesion coefficient, but most of the estimation algorithms are too complicated; 3) It can only be estimated that the four wheels of the vehicle are on the same road surface with the adhesion coefficient. For different wheels on different road surfaces It is difficult to estimate the adhesion coefficient

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