CN-121990047-A - Vehicle drift mode control method based on steer-by-wire and vehicle

CN121990047ACN 121990047 ACN121990047 ACN 121990047ACN-121990047-A

Abstract

The invention discloses a vehicle drift mode control method based on steer-by-wire and a vehicle, and belongs to the technical field of vehicle steering control. The method comprises the steps of obtaining a preset steering wheel soft dead center and an expected vehicle speed range, calculating a first target transmission ratio according to the preset steering wheel soft dead center and the expected vehicle speed range to achieve tail flick, and calculating a second target transmission ratio to achieve stable drifting after the vehicle is judged to enter a drifting first stage. The invention designs the transmission ratio in stages, combines the dynamic feedback of the rear wheel slip ratio, combines the steps of state verification and drifting and exiting, presets the steering wheel soft dead center and adopts stepless smooth output, thereby avoiding the uncontrolled drifting and the steering wheel beater. The invention also protects the vehicle executing the method, has the advantages of controllable drift, safety and good operability, and solves the defects of poor adaptation and difficult control of the posture in the prior art.

Inventors

ZHOU JIAMING
ZHONG YILIN
LIU CHANGJIU
LI YANQIN
DAI SONGWEI

Assignees

比亚迪股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260228

Claims (10)

1. A vehicle drift mode control method based on steer-by-wire, comprising: acquiring a preset steering wheel soft dead center and an expected vehicle speed range; According to the expected vehicle speed range and the rear wheel slip ratio, calculating to obtain a first target transmission ratio, and outputting the first target transmission ratio to a steer-by-wire system to realize tail flick; and after the vehicle is judged to enter the first drifting stage according to the rear wheel slip rate, calculating to obtain a second target transmission ratio, and outputting the second target transmission ratio to the steer-by-wire system to realize stable drifting.
2. The method of claim 1, wherein the predetermined steering wheel soft dead center is obtained by receiving a steering wheel maximum rotation angle threshold manually set by a driver or invoking a vehicle predetermined default parameter, and wherein the desired vehicle speed range is obtained by receiving a desired vehicle speed range manually set by a driver or invoking a vehicle predetermined drift adaptation vehicle speed range parameter.
3. The method according to any one of claims 1 or 2, wherein the rear wheel slip ratio is calculated according to the formula: rear wheel slip ratio= (vehicle speed-rear wheel speed)/vehicle speed×100%.
4. The method of claim 1, wherein the first target gear ratio is calculated by coupling a first preset algorithm by combining the preset steering wheel soft dead center and a first stage target slip ratio interval on the basis of the expected vehicle speed range and the rear wheel slip ratio, the first stage target slip ratio interval is determined according to the maximum value of the expected vehicle speed range, specifically, a first corresponding relation model of different vehicle speed maximum values and drift tail flick adaptive slip ratio ranges is established through pre-calibration, the maximum value of the expected vehicle speed range is input, and the corresponding slip ratio range is obtained through matching of the first corresponding relation model, namely the first stage target slip ratio interval.
5. The method according to claim 1, wherein the first stage of drifting is a transition stage after tail flick and before stable drifting, and the determination mode is that the duration of the rear wheel slip ratio is in a first stage target slip ratio interval and the difference value between the rear wheel speed and the vehicle speed is smaller than a preset threshold value.
6. The method of claim 1, wherein the second target transmission ratio is calculated by combining a second stage target slip rate interval corresponding to the preset steering wheel soft dead center and the vehicle speed and is used for adapting the reverse driving operation of a driver, the second stage target slip rate interval is calculated by establishing a second corresponding relation model of different real-time vehicle speeds and stable drift adaptation slip rate ranges through pre-calibration, and when the vehicle enters a drift first stage, inputting the current real-time vehicle speed, and obtaining the corresponding slip rate range through matching of the second corresponding relation model, namely the second stage target slip rate interval.
7. The method of claim 1, wherein the output of the first and second target gear ratios to the steer-by-wire system is a stepless smooth output.
8. The method of claim 1, further comprising vehicle condition verification, the verification conditions including one or more of vehicle speed being in the desired vehicle speed range, steering wheel angle being within the preset steering wheel soft dead center, steer-by-wire system supporting variable gear ratio and soft dead center functions, electronic stability and traction control system having been shut down.
9. The method of claim 1, further comprising exiting a drift mode when a driver return to the steering wheel or a brake-on operation is detected, wherein the steer-by-wire system resets and automatically turns on an electronic stability and traction control system.
10. A vehicle for performing the vehicle drift mode control method according to any one of claims 1 to 9.

Description

Vehicle drift mode control method based on steer-by-wire and vehicle Technical Field The invention relates to the technical field of vehicle steering control, in particular to a vehicle drift mode control method based on steer-by-wire and a vehicle. Background With the development of vehicle electronic technology, the steer-by-wire system can realize flexible adjustment of steering transmission ratio due to the fact that mechanical connection between a steering wheel and a steering wheel is canceled, and is gradually applied to various vehicles. The drift is as a special vehicle running state, requires the vehicle rear wheel to produce controllable slip, and the front wheel is accurate to turn to in order to maintain the drift gesture simultaneously, and the mechanical steering system of traditional vehicle is difficult to realize the accurate control of drift process, easily appears steering wheel beating, drift gesture out of control, drift tail and stable drift linking unsmooth scheduling problem, influences drift experience and driving safety. Disclosure of Invention The application provides a vehicle drifting mode control method based on steer-by-wire and a vehicle, which realize stable and controllable drifting process and improve drifting experience and driving safety by designing steering transmission ratio in stages, accurately controlling rear wheel sliding state and limiting steering wheel rotating angle. A vehicle drifting mode control method based on steer-by-wire is provided, and comprises the steps of obtaining a preset steering wheel soft dead center and an expected vehicle speed range, calculating to obtain a first target transmission ratio according to the expected vehicle speed range and a rear wheel slip ratio, outputting the first target transmission ratio to a steer-by-wire system to achieve tail flicking, and calculating to obtain a second target transmission ratio after the vehicle is judged to enter a drifting first stage according to the rear wheel slip ratio, and outputting the second target transmission ratio to the steer-by-wire system to achieve stable drifting. With reference to the first aspect, in one possible implementation manner, the preset steering wheel soft dead center may be obtained by receiving a steering wheel maximum rotation angle threshold manually set by a driver or calling a vehicle preset default parameter, and the desired vehicle speed range may be obtained by receiving a desired vehicle speed range manually set by the driver or calling a vehicle preset drift adaptation vehicle speed range parameter. With reference to the first aspect, in one possible implementation manner, the preset steering wheel soft dead center may be obtained by receiving a steering wheel maximum rotation angle threshold manually set by a driver or calling a vehicle preset default parameter, and the desired vehicle speed range may be obtained by receiving a desired vehicle speed range manually set by the driver or calling a vehicle preset drift adaptation vehicle speed range parameter. With reference to the first aspect, in one possible implementation manner, the rear wheel slip ratio is calculated according to a formula, where the formula is rear wheel slip ratio= (vehicle speed-rear wheel speed)/vehicle speed×100%. With reference to the first aspect, in one possible implementation manner, the first target transmission ratio is obtained by coupling and calculating the preset steering wheel soft dead center and a first stage target slip ratio interval through a first preset algorithm on the basis of the expected vehicle speed range and the rear wheel slip ratio, and the first stage target slip ratio interval is determined according to the maximum value of the expected vehicle speed range, specifically, a first corresponding relation model of different vehicle speed maximum values and drift tail flick adaptive slip ratio ranges is established through pre-calibration, the maximum value of the expected vehicle speed range is input, and the corresponding slip ratio range is obtained through matching of the first corresponding relation model, namely the first stage target slip ratio interval. With reference to the first aspect, in one possible implementation manner, the first stage of drifting is a transition stage after tail flick and floating and before stable drifting is continued, and the determining manner is that the duration of the rear wheel slip ratio is in a first stage target slip ratio interval and a difference value between a rear wheel speed and a vehicle speed is smaller than a preset threshold value. In combination with the first aspect, in one possible implementation manner, the second target transmission ratio is calculated by combining a second stage target slip ratio interval corresponding to the preset steering wheel soft dead center and the vehicle speed and is used for adapting the reverse driving operation of the driver, and the second stage target slip ratio interva