A method for calculating the center-of-mass speed of a pure electric vehicle with four-wheel hub motors

Abstract

The invention relates to a method for calculating the center-of-mass speed of a four-wheel-hub motor pure electric vehicle. The method is modeled through two aspects. One is the calculation of the speed of the vehicle in straight-going conditions, considering the impact of the acceleration and braking force on the speed of the wheel motor during the straight-going process of the vehicle. The influence of the signal, the vehicle speed signal of each wheel motor is mapped to the vehicle speed signal of the vehicle center of mass point; the second is to establish a vehicle speed calculation model during the vehicle steering process, and map the vehicle speed signal of each wheel motor to the vehicle speed signal of the vehicle center of mass point ;Through the above two aspects of the mapped vehicle speed to carry out multiple average processing, so as to obtain the vehicle center of mass speed, take the vehicle center point as the vehicle center of mass point, calculate the vehicle center point speed is the vehicle center of mass point speed, which provides a basis for the calculation of vehicle speed Implementability and reliability, so as to ensure the accuracy of the vehicle speed signal.

Description

technical field [0001] The invention belongs to the technical field of traffic safety, and relates to a method for calculating vehicle speed, in particular to a method for calculating the velocity of a centroid of a pure electric vehicle with four-wheel hub motors. Background technique [0002] For the calculation of the speed of the electric vehicle with the in-wheel motor, the currently known method is to directly convert the motor speed into a vehicle speed signal according to the following formula: [0003] V=0.06×n×2πr [0004] Among them, r is the rolling radius of the wheel, and n is the motor speed. [0005] However, this calculation method has the following disadvantages and unstable factors: [0006] (1) When the wheel motor slips, the motor speed suddenly increases, but the actual motion state of the vehicle does not change. If the motor speed is directly used to calculate the vehicle speed, then the vehicle speed signal will suddenly increase, which will make t...

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Problems solved by technology

[0005] However, this calculation method has the following disadvantages and unstable factors:

[0006] (1) When the wheel motor slips, the motor speed suddenly increases, but the actual motion state of the vehicle does not change. If the motor speed is directly used to calculate the vehicle speed, then the vehicle speed signal will suddenly increase, which will make the vehicle control Create false acceleration control;

[0007] (2) When the wheel motor is locked, the motor speed suddenly decreases, but the actual motion state of the vehicle does not change. If the motor speed is directly used to calculate the vehicle speed, then the vehicle speed signal will suddenly decrease, which will make the vehicle control Create the illusion of deceleration control;

That will also cause a sudden change in the speed of the wheel motor, but the actual vehicle motion state does not change, resulting in inaccurate vehicle speed signals;

[0009] (4) During the steering process of the vehicle, the motor speed of the outer wheel of the vehicle is higher than the speed of the motor of the inner vehicle. If the calculation is only based on the motor speed signal and only the vehicle speed is calculated, it will inevitably lead to a large error in the speed signal.

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