CN114987442B

CN114987442B - Vehicle control method, device, vehicle and storage medium

Info

Publication number: CN114987442B
Application number: CN202210622768.7A
Authority: CN
Inventors: 牟恒达
Original assignee: Guangzhou Xiaopeng Motors Technology Co Ltd
Current assignee: Guangzhou Xiaopeng Motors Technology Co Ltd
Priority date: 2022-06-01
Filing date: 2022-06-01
Publication date: 2025-05-30
Anticipated expiration: 2042-06-01
Also published as: CN114987442A

Abstract

The embodiment of the application provides a vehicle control method, a vehicle control device, a vehicle and a storage medium. The method is applied to a vehicle, the vehicle adopts distributed driving, and the method comprises the steps of obtaining current actual torque of a first wheel in coaxial wheels of the vehicle under the condition that the vehicle is monitored to run on a split road, determining expected torque of a second wheel in the coaxial wheels based on the current actual torque of the first wheel, and controlling the second wheel to work according to the expected torque of the second wheel. In the embodiment of the application, when the vehicle runs on the designated road condition, the torque of the wheels on the high side is controlled to be reduced along with the reduction of the actual torque of the wheels on the low side, at the moment, the yaw rate of the vehicle is close to zero, the yaw rate is not suddenly increased and is always kept at a lower level, so that the control difficulty of a driver on the vehicle can be reduced, the occurrence probability of safety accidents caused by overlarge yaw rate is reduced, and the running safety of the vehicle is improved.

Description

Vehicle control method, device, vehicle and storage medium

Technical Field

The present application relates to the field of automotive technologies, and in particular, to a vehicle control method, device, vehicle, and storage medium.

Background

Yaw rate refers to the deflection of the vehicle about a vertical axis, the magnitude of which represents the degree of stability of the vehicle. Wherein the greater the yaw rate, the more unstable the vehicle.

When the coaxial wheels of the vehicle travel on the road surfaces having large differences in adhesion coefficient, respectively, the torque decreases due to the wheels slipping on the road surfaces on the low adhesion coefficient side, and the torque of the wheels on the road surfaces on the high adhesion coefficient side remains unchanged, at which time the yaw rate of the vehicle increases, resulting in a decrease in the degree of stability of the vehicle.

Disclosure of Invention

The embodiment of the application provides a vehicle control method, a vehicle control device, a vehicle and a storage medium.

In a first aspect, an embodiment of the present application provides a vehicle control method, where the vehicle is driven in a distributed manner, and the method includes acquiring a current actual torque of a first wheel in coaxial wheels of the vehicle when it is monitored that the vehicle is driven on a split road, determining a desired torque of a second wheel in the coaxial wheels based on the current actual torque of the first wheel, where an attachment coefficient of a road surface on which the first wheel is driven is smaller than an attachment coefficient of a road surface on which the second wheel is driven, and the current actual torque of the second wheel is greater than the desired torque of the second wheel, and controlling the second wheel to operate according to the desired torque of the second wheel.

In a second aspect, an embodiment of the application provides a vehicle control device, which comprises a torque acquisition module, a torque determination module and a control module, wherein the torque acquisition module is used for acquiring the current actual torque of a first wheel in coaxial wheels of a vehicle under the condition that the vehicle is monitored to run on a split road surface, the torque determination module is used for determining the expected torque of a second wheel in the coaxial wheels based on the current actual torque of the first wheel, the attachment coefficient of the road surface on which the first wheel runs is smaller than that of the road surface on which the second wheel runs, the current actual torque of the second wheel is larger than that of the second wheel, and the control module is used for controlling the second wheel to work according to the expected torque of the second wheel.

In a third aspect, an embodiment of the present application provides a vehicle comprising a processor, a memory storing computer program instructions that are invoked by the processor to perform a vehicle control method as in the first aspect.

In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium having program code stored therein, the program code being invoked by a processor to perform the vehicle control method as in the first aspect.

In a fifth aspect, embodiments of the present application provide a computer program product which, when executed, enables the vehicle control method as in the first aspect to be implemented.

The embodiment of the application provides a vehicle control method, which is characterized in that under the condition that a vehicle is monitored to run on a specified road condition (coaxial wheels respectively run on a road surface with a high attachment coefficient and a road surface with a low attachment coefficient), the vehicle determines the expected torque of a high attachment side wheel (namely a second wheel) based on the actual torque of a low attachment side wheel (namely a first wheel), then the high attachment side wheel is controlled according to the expected torque of the high attachment side wheel, and the expected torque of the high attachment side wheel is smaller than the actual torque of the high attachment side wheel before the control, namely the torque of the high attachment side wheel is reduced along with the reduction of the actual torque of the low attachment side wheel, at the moment, the yaw angular acceleration of the vehicle is close to zero, the yaw angular velocity of the vehicle is not suddenly increased, and the vehicle is always kept at a lower level, so that the control difficulty of a driver on the vehicle can be reduced, the occurrence probability of a safety accident caused by overlarge yaw angular velocity is reduced, and the running safety of the vehicle is increased.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic diagram of a vehicle provided in the related art traveling in a double open circuit.

Fig. 2 is a graph of torque versus vehicle speed, yaw rate versus vehicle speed for a vehicle traveling in an open-ended situation, as provided by the related art.

Fig. 3 is a schematic diagram of a vehicle running on a split road according to an embodiment of the present application.

Fig. 4 is a graph of torque versus vehicle speed, yaw rate versus vehicle speed for an open-ended vehicle according to one embodiment of the present application.

Fig. 5 is a schematic view of a vehicle provided in one embodiment of the application.

Fig. 6 is a flowchart of a vehicle control method provided in one embodiment of the application.

Fig. 7 is a flowchart of a vehicle control method according to another embodiment of the present application.

Fig. 8 is a block diagram of a vehicle control apparatus provided in an embodiment of the application.

Fig. 9 is a functional block diagram of a vehicle provided by an embodiment of the present application.

Fig. 10 is a block diagram of a computer-readable storage medium according to an embodiment of the present application.

Detailed Description

Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present application and are not to be construed as limiting the present application.

In order to enable those skilled in the art to better understand the solution of the present application, the following description will make clear and complete descriptions of the technical solution of the present application in the embodiments of the present application with reference to the accompanying drawings. It will be apparent that the described embodiments are only some, but not all, embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

Technical terms related to the embodiments of the present application are described below.

Split road surface, i.e. road surface with great difference of adhesion coefficients of the coaxial wheels of the vehicle. For example, the adhesion coefficient of the road surface driven by the first wheel of the coaxial wheels is x1, the adhesion coefficient of the road surface driven by the second wheel of the coaxial wheels is x2, and if the absolute value of the difference between x1 and x2 is greater than a preset adhesion coefficient threshold value a, the road surface driven by the vehicle is indicated to be open.

The adhesion coefficient is the ratio of the adhesion force to the normal force of the wheels, can be approximately considered as the friction coefficient of the road surface, has the advantages of high adhesion coefficient (such as stone road, asphalt road and the like), low possibility of slipping of vehicles, safe running, low adhesion coefficient (such as snow, ice and the like), easy slipping of vehicles and high potential safety hazard.

Torque, namely torque for enabling an object to rotate, which is equal to the product of force and the arm of force, and the international unit is N.m of ox meters.

The inventors have long studied and found that, when a vehicle is driven in a split-road mode, wheels on the ground with a low adhesion coefficient (hereinafter referred to as low-adhesion-side wheels) lose grip due to slip, while wheels on the ground with a high adhesion coefficient (hereinafter referred to as high-adhesion-side wheels) still travel forward according to the original torque, and at this time, the vehicle receives a yaw force to generate yaw acceleration and yaw rate, and at this time, it is difficult for a driver to control the vehicle, so that the probability of occurrence of a safety accident of the vehicle increases.

Referring to fig. 1, there is shown a schematic operation of a vehicle provided by the related art. The vehicle 110 is a four-drive vehicle, the wheels 111 and 112 travel on the ground with a high adhesion coefficient, and the wheels 113 and 114 travel on the ground with a low adhesion coefficient, and at this time, the vehicle 110 generates yaw acceleration and yaw velocity as shown in the figure, which makes it difficult for the driver to control the vehicle 110.

Referring to fig. 2, there is shown a torque-vehicle speed relationship diagram at the time of vehicle operation provided by the related art. Where curve 1 represents the driver requested torque, curve 2 represents the actual torque of the high-side wheels, curve 3 represents the actual torque of the low-side wheels, and curve 4 represents the yaw rate of the vehicle. As can be seen from fig. 2, when the vehicle is running on the split road, the actual torque of the low-side wheels is significantly reduced, and the vehicle yaw rate is significantly increased as the actual torque of the low-side wheels is reduced, while the torque of the high-side wheels remains unchanged.

In view of the problems of the prior art, the inventor studied a vehicle control method, apparatus, vehicle and storage medium, by determining a desired torque of a high-side wheel (i.e., a second wheel) based on an actual torque of a low-side wheel (i.e., a first wheel) in a case where it is monitored that the vehicle is traveling on a specified road condition (the on-axis wheels are traveling on a road surface with a high attachment coefficient and a road surface with a low attachment coefficient, respectively), and then controlling the high-side wheel according to the desired torque of the high-side wheel, because the desired torque of the high-side wheel is smaller than the actual torque of the high-side wheel before the control, i.e., the torque of the high-side wheel is reduced as the actual torque of the low-side wheel is reduced, at this time, the yaw rate of the vehicle tends to zero, the yaw rate does not increase suddenly, and is always maintained at a low level, so that the difficulty of controlling the vehicle by a driver can be reduced, the probability of occurrence of a safety accident due to an excessive yaw rate is reduced, and the traveling safety of the vehicle is increased.

Referring to fig. 3, there is shown a schematic operation of a vehicle provided by the related art. The vehicle 310 is a four-drive vehicle, the wheels 311 and 312 run on the ground with a high adhesion coefficient, the wheels 313 and 314 run on the ground with a low adhesion coefficient, and the torque of the wheels on the high adhesion side is controlled according to the vehicle control scheme provided by the inventor, at this time, the yaw rate acceleration of the vehicle 310 approaches zero, the yaw rate does not continuously increase, and the vehicle 310 can continue to run normally.

Referring to fig. 4, a torque-vehicle speed relationship diagram is shown for a vehicle operating in accordance with an embodiment of the present application. Where curve 1 represents the driver requested torque, curve 2 represents the actual torque of the high-side wheels, curve 3 represents the actual torque of the low-side wheels, and curve 4 represents the yaw rate of the vehicle. According to fig. 4, it can be seen that when the vehicle is running in the open-circuit, the actual torque of the low-side wheel is obviously reduced, and when the vehicle control method provided by the embodiment of the application is used for controlling the torque of the high-side wheel, the torque of the high-side wheel is reduced along with the reduction of the torque of the low-side wheel, the yaw rate of the vehicle is not suddenly increased, and the yaw rate of the vehicle is always maintained at a lower level, so that the control of the vehicle by a driver is facilitated.

Referring to fig. 5, a schematic diagram of a vehicle 500 according to an embodiment of the application is shown. The vehicle 500 employs distributed driving. The vehicle 500 is an electric vehicle.

In some embodiments, the vehicle 500 is a four-drive car, i.e., four wheels of the vehicle 500 are each controlled with four motors. In other embodiments, the vehicle 500 is a three-drive vehicle in which the two wheels of the rear axle are controlled using different motors and the two wheels of the front axle are controlled using the same motor.

In the embodiment of the application, the vehicle 500 has a torque control function, and when the vehicle 500 runs on a split road, the torque on the high side is controlled to be reduced, so that the sudden increase of the yaw rate of the vehicle is avoided, the control of the vehicle by a driver is facilitated, the occurrence probability of safety accidents caused by the overlarge yaw rate is reduced, and the running safety of the vehicle 500 is improved. In the embodiment of the present application, the vehicle 500 also has a road condition monitoring function for monitoring whether the vehicle 500 is running in the open road.

Referring to fig. 6, a flowchart of a vehicle control method according to an embodiment of the application is shown. The method is applied to a vehicle, and comprises the following steps.

In step S601, when it is monitored that the vehicle is traveling on a split road, a current actual torque of a first wheel among coaxial wheels of the vehicle is obtained.

The split road surface refers to a road surface on which the difference in adhesion coefficient between the road surfaces on which two of the coaxial wheels travel is greater than a first threshold value.

The first threshold is set experimentally or empirically, which is not limited in this embodiment of the application. Illustratively, the first threshold is 0.5. In a specific example, the first adhesion coefficient is 0.1, the second adhesion coefficient is 0.8, and the absolute value of the difference between the first adhesion coefficient and the second adhesion coefficient is 0.7, and the absolute value is greater than the first threshold value, which indicates that the vehicle is currently running on the designated road condition.

The torque is the product of the torque and the distance from the action point to the torque action direction, and the measuring method comprises at least one of strain type torque measurement, piezomagnetic type torque measurement and photoelectric type torque measurement. The embodiment of the application is only illustrated by taking a photoelectric torque measurement method as an example. The rotating shaft of the first wheel of the vehicle is fixedly provided with two disc gratings, bright and dark areas of the two gratings are just shielded from each other under the condition that the rotating shaft does not bear torque, no light of a light source irradiates the photosensitive element through the gratings, the photosensitive element does not output signals, under the condition that the rotating shaft bears torque, the rotating shaft deforms to enable the two gratings to generate relative rotation angles, part of light irradiates the photosensitive element through the gratings, and the photosensitive element generates output signals. The larger the torque is, the larger the torsion angle is, the larger the luminous flux passing through the grating is, the larger the output signal is, and the torque can be calculated according to the output signal of the photosensitive element.

It should be noted that a road surface on which the difference in adhesion coefficient between the road surfaces on which two wheels of the coaxial wheels travel is less than or equal to the first threshold value may be referred to as a uniform road surface. The embodiment of the application does not provide a matrix control scheme for high-side wheels in the case of a vehicle running on a uniform road surface.

Step S602 determines a desired torque of a second wheel of the on-axis wheels based on a current actual torque of the first wheel.

The adhesion coefficient of the road surface on which the first wheel is driven is smaller than that of the road surface on which the second wheel is driven, and the current actual torque of the second wheel is larger than the expected torque of the second wheel. The manner in which the desired torque of the second wheel is determined will be explained in the following embodiments.

In the embodiment of the application, when the vehicle runs on the split road, the vehicle can control the torque of the high-side wheel (namely the second wheel) based on the actual torque of the low-side wheel (namely the first wheel), specifically, the torque of the high-side wheel is controlled by the vehicle to be reduced along with the reduction of the torque of the low-side wheel, so that the yaw rate of the vehicle cannot be suddenly increased, and the yaw rate of the vehicle is always maintained at a lower level, thereby being beneficial to the control of the vehicle by a driver, reducing the occurrence probability of safety accidents caused by the yaw rate and improving the running safety of the vehicle.

In some embodiments, step S602 may alternatively be implemented as a sub-step as follows.

In step S602a, an operating parameter of a first wheel is obtained.

The operating parameters of the first wheel include at least one of angular acceleration information of the first motor, rotational inertia information of the first motor, angular acceleration information of the first wheel, rotational inertia information of the first wheel, and a gear ratio between the first wheel and the first motor. The first motor is a motor for controlling the first wheel.

The angular acceleration information of the first motor refers to a physical quantity describing the magnitude and direction of the angular velocity of the first motor with respect to the time change rate. In some embodiments, an angular accelerometer is provided on the first motor to measure angular acceleration information of the first motor. Specifically, the angular accelerometer comprises an angular velocity measurement module and a differentiating circuit, wherein the angular velocity measurement module is used for measuring an angular velocity signal of the first motor, and the differentiating circuit is used for carrying out differential calculation on the measured angular velocity signal to obtain angular acceleration information of the first motor.

The moment of inertia information of the first motor is a measure of the inertia (the characteristic of the rotating object to keep its uniform circular motion or stationary) of the first motor as it rotates. The vehicle may measure the moment of inertia information of the first motor by at least one of a three-wire pendulum method, a torsion pendulum method, a compound pendulum method, and the like.

The angular acceleration information of the first wheel refers to a physical quantity describing the magnitude and direction of the angular velocity of the first wheel with respect to the time change rate. In some embodiments, an angular accelerometer is provided on the first wheel to measure angular acceleration information of the first wheel.

The moment of inertia information of the first wheel is a measure of the inertia of the first wheel as it rotates (the property of the rotating object to maintain its uniform circular motion or to be stationary). The vehicle may measure the moment of inertia information of the first wheel by at least one of a three-wire pendulum method, a torsion pendulum method, a compound pendulum method, and the like.

The transmission ratio refers to the ratio of the angular speeds of two rotating members in the mechanism, and the transmission ratio between the first wheel and the first motor, that is, the ratio between the angular speed of the first wheel and the angular speed of the first motor. In some embodiments, angular velocity sensors are provided on the first motor and the first wheel, respectively, the angular velocity of the first motor is measured by the angular velocity sensor provided on the first motor, the angular velocity of the first wheel is measured by the angular velocity sensor provided on the first wheel, and then the ratio between the angular velocity of the first wheel and the angular velocity of the first motor is determined as the transmission ratio between the first wheel and the first motor.

Step S602b, determining a loss value based on the operating parameter of the first wheel.

The current actual torque of the first wheel has losses at both the first motor and the first wheel, and in order to quantify such losses, the vehicle determines a loss value based on the operating parameters of the first wheel.

In some embodiments, step S602b may instead be implemented as a sub-step of determining a product between the angular acceleration information of the first motor and the moment of inertia information of the first motor as a first loss component, determining a product between the angular acceleration information of the first wheel and the moment of inertia information of the first wheel as an intermediate value, determining a gear ratio of the intermediate value to the first wheel as a second loss component, and determining a sum of the first loss component and the second loss component as a loss value.

The first loss component, i.e. the moment of momentum of the first motor, is an amount describing the rotational state of the first motor. The intermediate value, i.e. the moment of momentum of the first wheel, is an amount describing the rotational state of the first wheel.

Step S602c, obtaining the current actual torque of the first wheel, the loss value and the preset compensation value, and determining the expected torque of the second wheel.

The vehicle determines the sum of the specified difference, i.e. the difference between the current actual torque of the first wheel and the loss value, and the preset compensation value as the desired torque of the second wheel. The preset compensation value is a deviation value determined based on the speed of the vehicle and the yaw rate variation, which is experimentally or empirically set.

In some embodiments, the desired torque of the second wheel is calculated by the following calculation.

Wherein, M _H refers to the desired torque of the second wheel, M _L refers to the current actual torque of the first wheel, d _mot refers to the angular acceleration information of the first motor, J _mot refers to the moment of inertia information of the first motor, d _wheel refers to the angular acceleration information of the first wheel, J _wheel refers to the moment of inertia information of the first wheel, ikin refers to the transmission ratio, and offset refers to the preset compensation value.

Step S603 controls the second wheel to operate according to the desired torque of the second wheel.

In summary, according to the technical solution provided in the embodiments of the present application, when it is monitored that the vehicle is traveling on a specified road condition (the on-axis wheels are traveling on a road surface with a high attachment coefficient and a road surface with a low attachment coefficient, respectively), the vehicle determines the desired torque of the high attachment side wheel (i.e., the second wheel) based on the actual torque of the low attachment side wheel (i.e., the first wheel), and then controls the high attachment side wheel according to the desired torque of the high attachment side wheel.

Referring to fig. 7, a flowchart of a vehicle control method according to an embodiment of the application is shown. The method is applied to a vehicle, and comprises the following steps.

In step S701, when it is detected that the vehicle is traveling on a split road, yaw rate information of the vehicle is acquired.

The yaw rate information is used to characterize the yaw rate of the vehicle and the yaw rate of the vehicle.

The yaw rate of the vehicle means the yaw rate of the vehicle about the vertical axis, the magnitude of which represents the degree of stability of the vehicle, and the greater the yaw rate of the vehicle, the more unstable the vehicle, and the smaller the yaw rate of the vehicle, the more stable the vehicle.

The yaw acceleration of the vehicle is used to determine the stage at which the yaw rate is located. The yaw rate is indicated to be in an acceleration stage when the yaw rate of the vehicle is greater than zero, in a deceleration stage when the yaw rate of the vehicle is less than zero, and in a uniform motion when the yaw rate of the vehicle is equal to zero.

In some embodiments, a yaw rate accelerometer is provided on the vehicle to measure yaw rate acceleration information. Specifically, the yaw-rate accelerometer comprises a yaw-rate measuring module and a differentiating circuit, wherein the yaw-rate measuring module is used for measuring a yaw rate signal of the vehicle, and the differentiating circuit is used for carrying out differential calculation on the measured yaw rate signal to obtain yaw-rate acceleration information.

In step S702, in a case where the yaw rate information of the vehicle satisfies a preset condition, a current actual torque of the first wheel is obtained.

The preset conditions include that the yaw rate is greater than a first preset value, or/and that the yaw rate acceleration is greater than a second preset value. The first preset value is set according to experiments or experience, and the second preset value is used for representing that the yaw rate is in an acceleration stage. Illustratively, the first preset value is 8 and the second preset value is 0.

In the embodiment of the application, the power consumption of the vehicle can be saved by executing the subsequent torque control step for the high-attached-side wheels under the condition that the yaw rate information meets the preset condition.

Step S703 determines a desired torque of the second wheel based on the current actual torque of the first wheel.

The current actual torque of the second wheel is greater than the desired torque of the second wheel.

Step S704, determining a control duration according to the yaw rate.

The control duration is in positive correlation with the yaw rate. That is, the larger the yaw rate, the longer the control period, and the smaller the yaw rate, the shorter the control period.

In some embodiments, the vehicle looks up a control duration corresponding to the yaw rate in a first map that includes a mapping relationship between the yaw rate and the control duration. The first mapping table may be set empirically or empirically, specifically, in the first experimental stage, the first mapping table is set empirically by a technician, and in the subsequent experimental process, the first mapping table may be iterated according to the experimental result. In other embodiments, the vehicle is determining the control duration from a first functional relationship that characterizes a functional relationship between yaw rate and control duration, which may be fitted from experimental data, and yaw rate.

Step S705, controlling the second wheel to operate according to the desired torque of the second wheel during the control period.

The time length of the control period is the control duration. In the embodiment of the application, the control time length is determined according to the yaw rate, so that the control precision can be improved.

Step S706, after the control period ends, controls the torque of the second wheel to increase.

Wherein the amount of increase in torque per unit time of the second wheel is inversely related to the yaw rate. That is, the larger the yaw rate, the smaller the increase amount per unit time of the torque of the second wheel, and the smaller the yaw rate, the larger the increase amount per unit time of the torque of the second wheel.

In some embodiments, the vehicle looks up an amount of increase per unit time in the torque of the second wheel corresponding to the yaw rate in a second map that includes a mapping between the yaw rate and the amount of increase per unit time in the torque of the second wheel. The second mapping table may be set empirically or empirically, specifically, during the first experimental stage, the second mapping table is set empirically by a technician, and the second mapping table may be iterated according to the experimental results during the subsequent experimental process. In other embodiments, the vehicle determines the amount of increase in torque per unit time of the second wheel from the second functional relationship and the yaw rate, the second functional relationship characterizing the functional relationship between the yaw rate and the amount of increase in torque per unit time of the second wheel, which may be fitted based on experimental data.

By the mode, under the condition of controlling the torque of the wheels on the high side, the torque of the wheels on the high side is allowed to be gradually increased according to the magnitude of the yaw rate, and the requirement of a driver on the acceleration performance of the vehicle is met on the premise of ensuring the running safety of the vehicle.

Step S707 controls the second wheel operation in accordance with the increased torque of the second wheel.

In summary, the technical solution provided in the embodiments of the present application further executes the subsequent torque control step for the high-side wheel under the condition that the yaw rate information satisfies the preset condition, so that the vehicle can be prevented from providing torque control for the high-side wheel under the unnecessary condition, the power consumption of the vehicle is effectively saved, the control accuracy is improved by determining the control duration of the torque for the high-side wheel according to the yaw rate, and the acceleration requirement of the driver on the vehicle is satisfied under the premise of ensuring the running safety of the vehicle by controlling the torque of the high-side wheel according to the yaw rate after the control period is over.

The embodiment of the application provides a torque control scheme for wheels on the high-attachment side aiming at the specified road condition of the vehicle, and in order to improve the control precision, the vehicle is required to be ensured to run under the specified road condition. An embodiment of monitoring whether a vehicle is traveling on a specified road condition is described below.

In some embodiments, the vehicle monitors whether the vehicle is traveling on the split road by obtaining slip rates respectively corresponding to coaxial wheels of the vehicle, the slip rates respectively corresponding to the coaxial wheels including a first slip rate and a second slip rate, and determining that the vehicle is traveling on the split road if an absolute value of a difference between the first slip rate and the second slip rate is greater than a second threshold.

Under the condition that the vehicle is a four-motor driven vehicle, the vehicle can acquire the slip rates corresponding to the front axle wheels respectively, can also acquire the slip rates corresponding to the rear axle wheels respectively, and can also simultaneously acquire the slip rates corresponding to the front axle wheels respectively and the slip rates corresponding to the rear axle wheels respectively. In the case of a three-motor drive vehicle, the vehicle may acquire slip rates corresponding to the rear axle wheels, respectively.

When the wheels generate traction or braking force, relative motion occurs between the wheels and the ground, wherein the slip rate of the wheels is used for representing the proportion of the slip component in the motion of the wheels. The larger the slip ratio of the wheel, the smaller the adhesion coefficient of the road surface on which the wheel runs, and the larger the slip ratio of the wheel, the larger the adhesion coefficient of the road surface on which the wheel runs.

In some embodiments, a wheel speed sensor is provided on a wheel of a vehicle for detecting a wheel speed, and the slip ratio of the wheel is calculated by the following calculation formula after the vehicle acquires the wheel speed and the vehicle speed.

Where u denotes a vehicle speed, u _w denotes a wheel speed, and s denotes a slip ratio.

In other embodiments, an angular velocity sensor is provided on a wheel of a vehicle for detecting an angular velocity of the wheel, and the vehicle calculates a slip ratio of the wheel by the following calculation formula after acquiring the angular velocity and the vehicle speed of the wheel.

Where u represents the vehicle speed, w represents the angular velocity of the wheel, and r represents the radius of the wheel. s represents the slip ratio.

The absolute value of the difference between the slip rates respectively corresponding to the coaxial wheels can be calculated by the following mathematical formula.

y=|y1-y2|。

Wherein y1 represents a first slip ratio among slip ratios respectively corresponding to the coaxial wheels, and y2 represents a second slip ratio among slip ratios respectively corresponding to the coaxial wheels.

The second threshold is set experimentally or empirically, and embodiments of the present application are not limited in this regard. Illustratively, the second threshold is 1. In a specific example, the first slip ratio is 3.6, the second slip ratio is 4.7, and the absolute value of the difference between the first slip ratio and the second slip ratio is 1.1, and the difference is greater than the second threshold value, which indicates that the vehicle is currently running on the split road surface.

In some embodiments, the vehicle obtains slip rates corresponding to the coaxial wheels at preset time intervals to ensure real-time monitoring of the vehicle. The preset time may be set according to experiments or experience, and the embodiment of the present application is not limited thereto. The preset time is, for example, 5 seconds. In other embodiments, the vehicle obtains the slip rates respectively corresponding to the on-axis wheels when the yaw acceleration is detected to be greater than a preset value. The preset value is used to characterize the yaw rate in the acceleration phase. Optionally, the preset value is zero. In general, when a vehicle runs on a specified road condition, the yaw rate will increase, and the yaw rate acceleration is greater than zero at this time, so that when the yaw rate acceleration is greater than zero, the vehicle is indicated to run on a split road surface with a high probability, and whether the vehicle runs on the split road surface is monitored at this time, so that the problem of high power consumption caused by continuous monitoring is avoided.

After determining that the vehicle is traveling on the split road, if the first slip ratio is smaller than the second slip ratio, the wheel having the first slip ratio is determined to be the second wheel, and the wheel having the second slip ratio is determined to be the first wheel, and if the first slip ratio is larger than the second slip ratio, the wheel having the first slip ratio is determined to be the first wheel, and the wheel having the second slip ratio is determined to be the second wheel.

In other embodiments, after the vehicle obtains the slip rates corresponding to the coaxial wheels respectively, the attachment coefficient corresponding to the first slip rate and the attachment coefficient corresponding to the second slip rate are searched in a mapping table between the slip rates and the attachment coefficient, then whether the absolute value of the difference between the slip rates and the attachment coefficient is larger than a first threshold value is detected, if the absolute value of the difference between the slip rates and the attachment coefficient is larger than the first threshold value, the vehicle is indicated to run on the split road, and if the absolute value of the difference between the slip rates and the attachment coefficient is smaller than or equal to the first threshold value, the vehicle is indicated to not run on the split road. The map between the slip ratio and the sticking coefficient may be preset according to experiments or experience, and the embodiment of the present application is not limited thereto.

Referring to fig. 8, a block diagram of a vehicle control apparatus 800 according to an embodiment of the application is shown. The apparatus is applied to a vehicle employing distributed driving, and the vehicle control apparatus 800 includes a torque acquisition module 810, a torque determination module 820, and a control module 830.

The torque obtaining module 810 is configured to obtain a current actual torque of a first wheel among coaxial wheels of the vehicle in a case where the vehicle is monitored to travel on a split road. The torque determination module 820 is configured to determine a desired torque of a second wheel of the coaxial wheels based on a current actual torque of the first wheel, wherein a coefficient of adhesion of a road surface on which the first wheel is traveling is less than a coefficient of adhesion of a road surface on which the second wheel is traveling, and the current actual torque of the second wheel is greater than the desired torque of the second wheel. A control module 830 for controlling the second wheel to operate according to a desired torque of the second wheel.

In some embodiments, the torque determination module 820 is configured to obtain an operating parameter of the first wheel, where the operating parameter of the first wheel includes at least one of angular acceleration information of the first motor, rotational inertia information of the first motor, angular acceleration information of the first wheel, rotational inertia information of the first wheel, and a gear ratio of the first wheel, where the first motor is a motor for controlling the first wheel, determine a loss value based on the operating parameter of the first wheel, obtain a current actual torque of the first wheel, the loss value, and a preset compensation value, and determine a desired torque of the second wheel.

In some embodiments, the torque determination module 820 is configured to determine a product between the angular acceleration information of the first motor and the moment of inertia information of the first motor as a first loss component, determine a product between the angular acceleration information of the first wheel and the moment of inertia information of the first wheel as an intermediate value, determine a gear ratio of the intermediate value to the first wheel as a second loss component, and determine a sum of the first loss component and the second loss component as a loss value.

In some embodiments, the torque obtaining module 810 is configured to obtain yaw rate information of the vehicle when it is monitored that the vehicle is traveling on a specified road condition, where the yaw rate information is used to characterize yaw rate acceleration of the vehicle and yaw rate of the vehicle, and obtain a current actual torque of the first wheel when the yaw rate information of the vehicle meets a preset condition, where the preset condition includes that the yaw rate is greater than a first preset value, or/and the yaw rate acceleration is greater than a second preset value.

In some embodiments, the control module 830 is configured to determine a control duration according to the yaw rate, where the control duration is in a positive correlation with the yaw rate, and control the second wheel to operate according to the desired torque of the second wheel during a control period, where the time duration of the control period is the control duration.

In some embodiments, the torque determination module 820 is further configured to control the torque increase of the second wheel after the control period is over, wherein the amount of increase in torque per unit time of the second wheel is inversely related to the yaw rate. The control module 830 is configured to control operation of the second wheel according to the increased torque of the second wheel.

In some embodiments, the apparatus further comprises a road condition monitoring module (not shown). The road condition monitoring module is used for acquiring the slip rates respectively corresponding to the coaxial wheels of the vehicle, wherein the slip rates respectively corresponding to the coaxial wheels comprise a first slip rate and a second slip rate, and the vehicle is determined to run on the split road surface under the condition that the absolute value of the difference value between the first slip rate and the second slip rate is larger than a second threshold value.

It will be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working process of the apparatus and modules described above may refer to the corresponding process in the foregoing method embodiment, which is not repeated herein.

In several embodiments provided by the present application, the coupling of the modules to each other may be electrical, mechanical, or other.

In addition, each functional module in each embodiment of the present application may be integrated into one processing module, or each module may exist alone physically, or two or more modules may be integrated into one module. The integrated modules may be implemented in hardware or in software functional modules.

As shown in fig. 9, the present example also provides a vehicle 900, the vehicle 900 including a processor 910, a memory 920, and at least one lidar 930. Wherein the memory 920 stores computer program instructions.

Processor 910 may include one or more processing cores. The processor 910 utilizes various interfaces and lines to connect various portions of the overall battery management system, perform various functions of the battery management system, and process data by executing or executing instructions, programs, code sets, or instruction sets stored in the memory 920, and invoking data stored in the memory 920. Alternatively, the processor 910 may be implemented in hardware in at least one of digital signal Processing (DIGITAL SIGNAL Processing, DSP), field-Programmable gate array (Field-Programmable GATE ARRAY, FPGA), programmable logic array (Programmable Logic Array, PLA). The processor 910 may integrate one or a combination of several of a central processor 910 (Central Processing Unit, CPU), an image processor 910 (Graphics Processing Unit, GPU), and a modem, etc. The CPU mainly processes an operating system, a user interface, an application program and the like, the GPU is used for rendering and drawing display contents, and the modem is used for processing wireless communication. It will be appreciated that the modem may not be integrated into the processor 910 and may be implemented solely by a single communication chip.

The Memory 920 may include a random access Memory 920 (Random Access Memory, RAM) or may include a Read-Only Memory 920. Memory 920 may be used to store instructions, programs, code, sets of codes, or instruction sets. The memory 920 may include a stored program area and a stored data area, wherein the stored program area may store instructions for implementing an operating system, instructions for implementing at least one function (such as a touch function, a sound playing function, an image playing function, etc.), instructions for implementing various method examples described below, and the like. The storage data area may also store data created by the vehicle in use (e.g., phonebook, audio-video data, chat-record data), etc.

Referring to fig. 10, an embodiment of the present application is further provided with a computer readable storage medium 1000, where the computer readable storage medium 1000 stores computer program instructions 1010, and the computer program instructions 1010 may be invoked by a processor to perform the method described in the above embodiment.

The computer readable storage medium 1000 may be an electronic memory such as a flash memory, an EEPROM (electrically erasable programmable read only memory), an EPROM, a hard disk, or a ROM. Optionally, computer readable storage medium 1000 includes non-volatile computer readable storage medium (non-transitory computer-readable storage medium). The computer readable storage medium 1000 has storage space for computer program instructions 1010 that perform any of the method steps S described above. The computer program instructions 1010 may be read from or written to one or more computer program products. The computer program instructions 1010 may be compressed in a suitable form.

The foregoing is merely a preferred embodiment of the present application, and the present application is not limited thereto, but the present application has been described in any form by the preferred embodiment, and it should be understood that it is not limited thereto, and that any modification, equivalent change and variation made by the above-described embodiment can be made by those skilled in the art without departing from the scope of the present application.

Claims

1. A vehicle control method, characterized in that the method is applied to a vehicle employing distributed driving, the method comprising:

Under the condition that the vehicle is monitored to run on a split road, acquiring the current actual torque of a first wheel in the coaxial wheels of the vehicle;

Acquiring working parameters of the first wheel, wherein the working parameters of the first wheel comprise at least one of angular acceleration information of a first motor, rotational inertia information of the first motor, angular acceleration information of the first wheel, rotational inertia information of the first wheel and a transmission ratio between the first wheel and the first motor, and the first motor is a motor for controlling the first wheel;

determining a loss value based on an operating parameter of the first wheel;

Acquiring the current actual torque of the first wheel, the loss value and a preset compensation value to determine the expected torque of a second wheel, wherein the attachment coefficient of the road surface driven by the first wheel is smaller than that of the road surface driven by the second wheel, and the current actual torque of the second wheel is larger than the expected torque of the second wheel;

The second wheel is controlled to operate in accordance with a desired torque of the second wheel.

2. The method of claim 1, wherein the determining a loss value based on the operating parameter of the first wheel comprises:

Determining a product between angular acceleration information of the first motor and moment of inertia information of the first motor as a first loss component;

determining a product between the angular acceleration information of the first wheel and the moment of inertia information of the first wheel as an intermediate value, and determining a transmission ratio of the intermediate value and the first wheel as a second loss component;

Determining a sum of the first loss component and the second loss component as the loss value.

3. The method of claim 1, wherein the obtaining the current actual torque of the first of the vehicle's on-axis wheels if the vehicle is monitored to be traveling on a split road surface comprises:

acquiring yaw rate information of the vehicle under the condition that the vehicle is monitored to run on a specified road condition, wherein the yaw rate information is used for representing yaw rate acceleration of the vehicle and yaw rate of the vehicle;

acquiring the current actual torque of the first wheel under the condition that the yaw rate information of the vehicle meets a preset condition;

the preset conditions include that the yaw rate is greater than a first preset value, or/and the yaw acceleration is greater than a second preset value.

4. A method according to claim 3, wherein said controlling said second wheel to operate in accordance with a desired torque of said second wheel comprises:

Determining a control duration according to the yaw rate, wherein the control duration and the yaw rate are in positive correlation;

and controlling the second wheel to work according to the expected torque of the second wheel in a control period, wherein the time length of the control period is the control duration.

5. The method of claim 4, wherein after said controlling said second wheel to operate at a desired torque for said second wheel during a control period, further comprising:

after the control period is finished, controlling the torque of the second wheel to increase, wherein the unit time increment of the torque of the second wheel and the yaw rate are in a negative correlation;

And controlling the second wheel to work according to the increased torque of the second wheel.

6. The method according to any one of claims 1 to 5, further comprising:

Acquiring the slip rates respectively corresponding to the coaxial wheels, wherein the slip rates respectively corresponding to the coaxial wheels comprise a first slip rate and a second slip rate;

and determining that the vehicle is driven on the split road surface when the absolute value of the difference between the first slip rate and the second slip rate is larger than a second threshold value.

7. A vehicle control apparatus, characterized in that the apparatus comprises:

the torque acquisition module is used for acquiring the current actual torque of a first wheel in the coaxial wheels of the vehicle under the condition that the vehicle is monitored to run on a split road surface;

The torque determining module is used for obtaining working parameters of the first wheel, wherein the working parameters of the first wheel comprise at least one of angular acceleration information of a first motor, rotational inertia information of the first motor, angular acceleration information of the first wheel, rotational inertia information of the first wheel and a transmission ratio between the first wheel and the first motor, the first motor is used for controlling the first wheel, loss values are determined based on the working parameters of the first wheel, current actual torque of the first wheel, the loss values and preset compensation values are obtained, and expected torque of a second wheel is determined, wherein the attachment coefficient of a road surface on which the first wheel is driven is smaller than that of the road surface on which the second wheel is driven, and the current actual torque of the second wheel is larger than the expected torque of the second wheel;

and the control module is used for controlling the second wheel to work according to the expected torque of the second wheel.

8. A vehicle comprising a processor, a memory storing computer program instructions that are invoked by the processor to perform the vehicle control method of any one of claims 1-6.

9. A computer-readable storage medium, characterized in that the computer-readable storage medium has stored therein a program code, which is called by a processor to execute the vehicle control method according to any one of claims 1 to 6.