EP-4461612-B1 - FRONT-DRIVE VEHICLE TORQUE CONTROL METHOD AND VEHICLE

EP4461612B1EP 4461612 B1EP4461612 B1EP 4461612B1EP-4461612-B1

Inventors

CUI, Wenxia
CHANG, CHENG
CHEN, QILIN
CAO, ZHIMIN

Dates

Publication Date: 20260506
Application Date: 20230106

Claims (11)

A torque control method for a front-drive vehicle, the method comprising: a calculating step (S202) of calculating a ratio of an actual rotation speed to a reference rotation speed of a power mechanism such as a motor or an engine; and a reducing step (S203) of reducing an output torque of the power mechanism when the ratio is greater than or equal to a preset threshold calibrated based on experimental data; characterized in that, in response to a torque adjustment request generated based on a vehicle operating condition, the method comprises: a determining step (S201) of determining the reference rotation speed of the power mechanism based on a rear-wheel rotation speed and a reference driving speed determined by v = n π r, where v is the reference driving speed, n is the rear-wheel rotation speed, and r is a rear-wheel radius, wherein the determining step (S201) comprises: determining a vehicle-speed offset corresponding to the reference driving speed and the vehicle operating condition through a preset data table, wherein the preset data table comprises a correspondence between the reference driving speed, the vehicle operating condition, and the vehicle-speed offset; correcting the reference driving speed according to the vehicle-speed offset; and determining the reference rotation speed of the power mechanism according to the rear-wheel rotation speed and the corrected reference driving speed.
The torque control method for a front-drive vehicle as claimed in claim 1, wherein the step of (S201) determining a vehicle-speed offset corresponding to the reference driving speed and the vehicle operating condition through a preset data table comprises: determining, a first vehicle-speed offset component corresponding to the opening degree of the accelerator pedal, a second vehicle-speed offset component corresponding to the steering wheel angle, a third vehicle-speed offset component corresponding to the road slope, and a fourth vehicle-speed offset component corresponding to the wheel speed difference through the preset data table; and determining the vehicle-speed offset based on the first vehicle-speed offset component to the fourth vehicle-speed offset component.
The torque control method for a front-drive vehicle as claimed in claim 2, wherein the step of (S201) determining the vehicle-speed offset based on the first vehicle-speed offset component to the fourth vehicle-speed offset component comprises: summing the first vehicle-speed offset component, the second vehicle-speed offset component, the third vehicle-speed offset component, and the fourth vehicle-speed offset component to obtain the vehicle-speed offset.
The torque control method for a front-drive vehicle as claimed in claim 1, wherein the step of correcting the reference driving speed according to the vehicle-speed offset comprises: correcting the reference driving speed based on v'= (1+a)·v, wherein a is the vehicle-speed offset, v is the reference driving speed, and v' is the corrected reference driving speed.
The torque control method for a front-drive vehicle as claimed in claim 1, wherein the step of (S201) determining the reference rotation speed of the power mechanism according to the rear-wheel rotation speed and a corrected reference driving speed comprises: determining a corrected rear-wheel rotation speed according to the corrected reference driving speed and a rear-wheel radius; and determining the reference rotation speed of the power mechanism according to the corrected rear-wheel rotation speed and a preset speed ratio, wherein the preset speed ratio represents a relationship between the rear-wheel rotation speed and a rotation speed of the power mechanism.
The torque control method for a front-drive vehicle as claimed in claim 1, wherein the step of (S203) reducing an output torque of the power mechanism comprises: determining a weighting coefficient of the torque based on the ratio; wherein the ratio is inversely proportional to the weighting coefficient of the torque, and the weighting coefficient of the torque represents a degree of adjustment of the output torque of the power mechanism; and adjusting, the output torque of the power mechanism based on the weighting coefficient of the torque.
The torque control method for a front-drive vehicle as claimed in claim 6, wherein the step of adjusting the output torque of the power mechanism based on the weighting coefficient of the torque comprises: multiplying the weighting coefficient of the torque by the output torque of the power mechanism to calculate an adjusted output torque, and adjusting the output torque of the power mechanism according to the adjusted output torque; wherein the weighting coefficient of the torque is a value in a range of (0, 1).
The torque control method for a front-drive vehicle as claimed in claim 6, wherein the step of determining a weighting coefficient of the torque based on the ratio comprises: determining the weighting coefficient of the torque corresponding to the ratio based on a preset data table, wherein the preset data table stores a correspondence between the ratio and the weighting coefficient of the torque.
The torque control method for a front-drive vehicle as claimed in claim 1, wherein before responding to the torque adjustment request, the method further comprises: generating the torque adjustment request when the vehicle operating condition meets a preset condition; wherein, the vehicle operating condition meeting the preset condition comprises one or more of the following: a gear position is a forward gear position, the reference driving speed is within a preset vehicle speed range, an opening degree of an accelerator pedal is within a preset opening area, a steering wheel angle is less than a preset angle threshold, a road slope is less than a preset slope threshold, and a wheel speed difference between a rotation speed of a left front wheel and a rotation speed of a right front-wheel rotation speed is less than a speed threshold.
A vehicle, comprising an electronic device (500), the electronic device comprising a memory (502), a processor (501), and a computer program (503) stored in the memory (502) and executable on the processor (501), wherein, when executed by the processor (501), the computer program (503) implements the steps of the torque control method for a front-drive vehicle as claimed in in any one of claims 1 to 9.
A non-volatile computer-readable storage medium, the computer-readable storage medium storing a computer program (503), wherein, when executed by a processor (501), the computer program (503) implements the steps of the torque control method for a front-drive vehicle as claimed in any one of claims 1 to 9.

Description

TECHNICAL FIELD The present invention relates to the field of vehicle technology, and in particular, to a torque control method for a front-drive vehicle and a vehicle. BACKGROUND A front-drive vehicle refers to a vehicle that is driven by the front wheels. During the traveling of a front-drive vehicle, for example, when the vehicle is accelerating or braking to slow down over a speed bump, the front wheels will slip briefly. Since the friction coefficient of the speed bump is smaller than the friction coefficient of the road surface, the adhesion of the front wheels will decrease when the front wheels of the vehicle pass over the speed bump. Moreover, the vehicle is in the state of acceleration or braking deceleration. For example, if the accelerator pedal is kept at a certain position, the reduction in adhesion will cause the rotation speed of the front axle to soar rapidly, resulting in front-wheel slippage. When the front wheels slip, the vehicle body will skid to a certain extent, resulting in instability of the vehicle body. Although the vehicle has an ESP system (electronic stability program), which is able to intervene to keep the vehicle stable in the event of wheel slip, the ESP system does not intervene to keep the vehicle stable during this period as the vehicle's travel time on a speed bump is usually very short. CN 110 816 293 A discloses a method for realizing vehicle stability control based on a motor controller, wherein the method comprises: firstly, a slip rate of a vehicle is calculated, and whether the vehicle slips is judged through the slip rate; it is judged that the vehicle slips if the slip rate exceeds a threshold value for a certain period of time t, and a numerical value for reducing torque is determined according to the slip rate and the vehicle speed when the vehicle slips; and simultaneously, an anti-slip flag position is sent to a vehicle controller, whether the motor controller meets the anti-slip requirement is judged by the vehicle controller according to the vehicle requirement at the moment, if the motor controller does not meet the requirement, the motor controller is required to exit, and if the motor controller meets the requirement, the motor controller performs driving anti-slip. The threshold value of the slip rate and the threshold value of the judgment time are dynamic. SUMMARY TECHNICAL PROBLEMS It is an object of the present invention to provide a torque control method for a front-drive vehicle and a vehicle which can reduce the rotation speed of the front axle of the power mechanism and prevent the rotation speed of the front axle from increasing rapidly, thereby alleviating the degree of slippage of the vehicle's front wheels and solving the problem that the ESP system cannot intervene in a short period to maintain the stability of the vehicle body when the front wheels of the vehicle slip. TECHNICAL SOLUTIONS The object is achieved respectively by the features of one of the independent claims. Further embodiments are defined in the respective dependent claims. ADVANTAGEOUS EFFECTS The present invention provides a torque control method for a front-drive vehicle and a vehicle. When the front-drive vehicle accelerates or brakes to decelerate through a speed bump, for example, the adhesion of the front wheel is reduced, which causes the rotation speed of the power mechanism (such as a motor or an engine) to increase significantly, and the front wheel will slip. In the present invention, in view that the rear wheels of the front-drive vehicle will not experience the above-mentioned slip phenomenon, the reference rotation speed of the power mechanism at this time is determined by the rear-wheel rotation speed and the reference driving speed, thereby reflecting the normal rotation speed of the power mechanism. Afterwards, the ratio of the reference speed to the actual rotation speed of the power mechanism is calculated. When the ratio is greater than or equal to the preset threshold, it indicates that the actual rotation speed of the power mechanism may be significantly increased due to the above-mentioned slip phenomenon. Accordingly, the output torque of the power mechanism can be reduced to prevent the actual rotation speed of the power mechanism from increasing rapidly, thereby alleviating the extent of slipping of the front wheels. BRIEF DESCRIPTION OF THE DRAWINGS In order to more clearly illustrate the technical solutions of the present invention, the drawings used in the description of the invention or the prior art will be briefly introduced below. FIG. 1 is a schematic diagram of an application scenario of a torque control method for a front-drive vehicle;FIG. 2 is a schematic flow chart of the torque control method for a front-drive vehicle;FIG. 3 is a schematic diagram of a reference speed and an actual rotation speed of a motor;FIG. 4 is a schematic diagram of the structure of a torque control apparatus for a front-drive vehicle; andFIG. 5 is a schemat