Estimation method for road adhesion coefficient of four-wheel independent drive electric vehicle
A technology of road adhesion coefficient and four-wheel independent drive, applied in the direction of brakes, etc., can solve the problems of difficult measurement of road adhesion coefficient, complex estimation algorithm, and expensive sensors.
Active Publication Date: 2019-09-24
HARBIN INST OF TECH
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[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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[0024] The technical solution of the present invention will be further described below, but it is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be covered by the protection scope of the present invention middle.
[0025] The invention provides a method for estimating the road surface adhesion coefficient of a four-wheel independent drive electric vehicle, and the specific implementation steps are as follows:
[0026] Step 1: Calculate the vertical tire forces of the four wheels under the current driving state:
[0027]
[0028] Among them, F i,z is the vertical force of the i-th wheel (i=1, 2, 3, 4, respectively representing the left front, right front, left rear, right rear wheel), m is the mass of the vehicle, l f is the distance from the center of mass of the vehicle to the front axle, l r is the dis...
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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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IPC IPC(8): B60W40/064B60W40/068B60T8/172
Inventor 贾凤娇刘志远
Owner HARBIN INST OF TECH