CN117656863A

CN117656863A - Differential control method, device, equipment and storage medium for vehicle

Info

Publication number: CN117656863A
Application number: CN202311692613.1A
Authority: CN
Inventors: 李立; 邹绵意; 王振锁; 郜业猛; 叶子
Original assignee: Xiaomi Automobile Technology Co Ltd
Current assignee: Xiaomi Automobile Technology Co Ltd
Priority date: 2023-12-11
Filing date: 2023-12-11
Publication date: 2024-03-08

Abstract

The application provides a differential control method, device and equipment for a vehicle and a storage medium, and relates to the technical field of motor driving. The method comprises the following steps: acquiring the current actual yaw rate and the actual slip rate of the vehicle; determining a target yaw torque according to the actual yaw rate and the reference yaw rate; distributing a first rear wheel torque of the vehicle based on the target yaw torque; determining a second rear wheel torque of the vehicle based on the actual slip rate and a reference slip rate; the vehicle is differentially controlled based on the first rear wheel torque and the second rear wheel torque. Therefore, in the turning process of the vehicle, the tire slip rate can be reduced while the turning radius is reduced, the requirements of yaw rate and tire slip rate are met, the driving fun is met, the safety performance is improved, and the running stability and safety of the vehicle are improved.

Description

Differential control method, device, equipment and storage medium for vehicle

Technical Field

The present disclosure relates to the field of motor driving technologies, and in particular, to a differential control method, device, apparatus, and storage medium for a vehicle.

Background

The current electric vehicle mainly drives by a single motor and a double motor, and has the accelerating popularization trend although the three-motor topology and the four-motor topology are fewer. In the case of a three-motor or four-motor vehicle architecture, it is desirable to provide differential control of the rear wheels while the vehicle is cornering.

In the related art, a slide film controller is generally adopted, and only the reduction of the tire slip ratio is targeted, it is difficult to provide a user with good driving pleasure, and it is easy to cause insufficient stability when the vehicle turns.

Disclosure of Invention

The application provides a differential control method, a differential control device, differential control equipment and a storage medium of a vehicle, and aims to solve one of the technical problems in the related technology at least to a certain extent.

In a first aspect, the present application provides a differential control method of a vehicle, including:

acquiring the current actual yaw rate and the actual slip rate of the vehicle;

determining a target yaw torque according to the actual yaw rate and the reference yaw rate;

distributing a first rear wheel torque of the vehicle based on the target yaw torque;

determining a second rear wheel torque of the vehicle based on the actual slip rate and a reference slip rate;

the vehicle is differentially controlled based on the first rear wheel torque and the second rear wheel torque.

In a second aspect, the present application provides a differential control device of a vehicle, including:

the first acquisition module is used for acquiring the current actual yaw rate and the actual slip rate of the vehicle;

a first determining module, configured to determine a target yaw torque according to the actual yaw rate and a reference yaw rate;

a distribution module for distributing a first rear wheel torque of the vehicle based on the target yaw torque;

a second determination module for determining a second rear wheel torque of the vehicle based on the actual slip rate and a reference slip rate;

and the control module is used for performing differential control on the vehicle based on the first rear wheel torque and the second rear wheel torque.

In a third aspect, the present application provides an electronic device, comprising: a processor; a memory for storing processor-executable instructions; wherein the processor is configured to execute instructions to implement a differential control method of the vehicle.

In a fourth aspect, the present application provides a computer-readable storage medium, which when executed by a processor of an electronic device, enables the electronic device to perform a differential control method of a vehicle.

In a fifth aspect, the present application provides a computer program product comprising a computer program for executing a method of differential control of a vehicle by a processor.

In the embodiment of the application, the current actual yaw rate and the actual slip rate of the vehicle are firstly obtained, then the target yaw torque is determined according to the actual yaw rate and the reference yaw rate, then the first rear wheel torque of the vehicle is distributed based on the target yaw torque, then the second rear wheel torque of the vehicle is determined based on the actual slip rate and the reference slip rate, and finally the differential control is performed on the vehicle based on the first rear wheel torque and the second rear wheel torque. Therefore, in the turning process of the vehicle, the tire slip rate can be reduced while the turning radius is reduced, the requirements of yaw rate and tire slip rate are met, the driving fun is met, the safety performance is improved, and the running stability and safety of the vehicle are improved.

Additional aspects and advantages of the disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the disclosure.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, serve to explain the principles of the application.

Fig. 1 is a flow chart diagram of a differential control method of a vehicle according to a first embodiment of the present application;

FIG. 2 is an application scenario diagram of a differential control method of a vehicle according to the present application;

FIG. 3 is a schematic illustration of a differential control of the vehicle;

fig. 4 is a flow chart diagram of a differential control method of a vehicle according to a second embodiment of the present application;

fig. 5 is a flow chart illustrating a differential control method of a vehicle according to a third embodiment of the present application;

fig. 6 is a further flowchart of a differential control method of a vehicle according to a third embodiment of the present application;

fig. 7 is a block diagram of a differential control device of a vehicle according to the present application;

fig. 8 illustrates a block diagram of an exemplary electronic device suitable for use in implementing embodiments of the present application.

Specific embodiments thereof have been shown by way of example in the drawings and will herein be described in more detail. These drawings and the written description are not intended to limit the scope of the inventive concepts in any way, but to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments.

Detailed Description

Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application. On the contrary, the embodiments of the present application include all alternatives, modifications, and equivalents as may be included within the spirit and scope of the appended claims.

The main body of the differential control method of the vehicle according to the present embodiment may be a differential control device of the vehicle, for example, a control system of a vehicle, which may be implemented by software and/or hardware, without limitation.

Fig. 1 is a flow chart of a differential control method of a vehicle according to a first embodiment of the present application, as shown in fig. 1, the method includes:

s101: the current actual yaw rate and the actual slip rate of the vehicle are obtained.

The Yaw Rate (Yaw Rate) refers to an angular velocity at which the vehicle rotates about a vertical axis, that is, an angular velocity at which the vehicle moves laterally. The actual yaw rate may be the yaw rate actually measured at the present time.

The Slip Ratio (Slip Ratio) refers to the relative Slip degree between the vehicle tire and the ground during running, and may be calculated by comparing the difference between the actual rotational speed of the vehicle tire and the actual forward speed of the vehicle. The actual yaw rate may be the current actual measured vehicle tire slip rate.

The actual slip rate may include a slip rate of a left rear wheel of the vehicle and a slip rate of a right rear wheel of the vehicle.

Wherein the actual slip rate may be measured by a vehicle dynamics sensor, such as a wheel speed sensor. Alternatively, the slip ratio of the left and right rear wheels may be calculated by a chassis ESP (Electronic Stability Program ) system of the vehicle. The ESP system may monitor various parameters of the vehicle, including wheel speed, steering angular velocity, yaw rate, etc., through sensors and then calculate and control based on these data to improve the stability and safety of the vehicle.

In an ESP system, the actual rotational speed of each wheel may be obtained by monitoring the wheel speed sensor of the vehicle, which is then used to calculate the slip ratio. By comparing the actual rotational speed of the wheel with the desired rotational speed, the actual slip rate of the wheel can be determined.

The actual yaw rate may be measured by a vehicle dynamics sensor (such as a gyroscope or an inclination sensor), and is not limited herein.

S102: the target yaw torque is determined based on the actual yaw rate and the reference yaw rate.

Wherein the reference yaw rate may characterize a desired yaw rate of the vehicle and be compared to the actual yaw rate to calculate a yaw torque or other control signal. The reference yaw rate may be calibrated in advance, and may be determined, for example, by driver intent, vehicle control system, or other control strategy, without limitation.

Wherein, the yaw torque acts on the vehicle lateral movement part for realizing the moment of lateral stability control, adjusting the lateral stability and handling performance of the vehicle.

The determination of the target yaw moment is calculated based on the difference between the actual yaw rate and the reference yaw rate. The target yaw torque may be used to correct the vehicle lateral motion and return it to the value of the reference yaw rate.

For example, a vehicle stability control system may be used to calculate the target yaw torque, which may be calculated and adjusted based on the vehicle dynamics model and sensor data. First, the two values of the actual yaw rate and the reference yaw rate may be compared to obtain a difference therebetween. Next, the magnitude and direction of the target yaw torque can be calculated from the magnitude and direction of the difference. The vehicle dynamics control system calculates a required yaw torque based on the difference, and performs yaw control of the vehicle through a braking system, an engine output, a steering system, and the like of the vehicle, so that the vehicle generates a restorative moment toward the reference yaw rate direction, to reduce the difference between the actual yaw rate and the reference yaw rate.

The target yaw torque may be used, among other things, to translate into actual vehicle control operations, such as adjusting the braking force distribution, torque distribution, or tire force distribution of the vehicle to achieve control of the lateral stability of the vehicle, without limitation.

Alternatively, the yaw rate deviation may be determined first from the actual yaw rate and the reference yaw rate, and then proportional integral adjustment may be performed based on the yaw rate deviation to obtain the target yaw torque.

For example, if the actual yaw rate is w1 and the reference yaw rate is w2, the yaw rate deviation err1 between the actual yaw rate and the reference yaw rate may be determined. Wherein yaw rate deviation err1=w1-w 2.

Further, the calculation target yaw torque Mz1 may be calculated by the following formula:

Mz1＝Kp1*err1+∑Ki1*err1

where Kp1 is a proportional gain, ki1 is an integral gain, err1 is a yaw rate deviation. The specific values of the proportional gain and the integral gain are set empirically by taking into account the actual running situation of the vehicle, and are not limited herein.

S103: the first rear wheel torque of the vehicle is distributed based on the target yaw torque.

Wherein the first rear wheel torque may be the torque that is distributed to the two rear wheels of the vehicle.

Wherein the first rear wheel torque includes a first left rear wheel torque and a first right rear wheel torque.

The first left rear wheel torque may be a torque to which the left rear wheel of the vehicle is assigned, and the first right rear wheel torque may be a torque to which the right rear wheel of the vehicle is assigned.

Alternatively, the torque adjustment value may be first determined according to the target yaw torque, and the track and roll radius of the vehicle, and then the first left rear wheel torque and the first right rear wheel torque of the vehicle may be allocated based on the target rear wheel torque and the torque adjustment value.

Alternatively, the torque adjustment value Δtr may be calculated by:

the track of the vehicle is Cr, the roll radius is Rr, and the target yaw torque is Mz1.

The target rear wheel torque may be a requested torque of the whole vehicle to the rear drive. The request torque of the whole vehicle for the rear drive refers to the torque generated by the rear wheels in the whole vehicle transmission system, which is required by a driver or a vehicle control system. In the rear drive vehicle type, power generated by an engine is transmitted to rear wheels through a transmission system, and traction and propulsion are provided by the rear wheels, thereby achieving movement and manipulation of the vehicle.

Alternatively, the first left rear wheel torque and the first right rear wheel torque may be distributed by the following formulas:

Where Δtr is the torque adjustment value, tr is the target rear wheel torque. T (T) _RL 1 is the torque of the first left rear wheel, T _RR 1 is the first right rear wheel torque. Alternatively, the assignment may be made by the following formula:

alternatively, the braking torque may be adjusted if the torque adjustment value is greater than a preset torque limit value.

The torque limit value may be a maximum limit torque.

When the torque adjustment value of the vehicle exceeds the preset maximum limit torque, the steering control can be realized by adjusting the braking torque, so that the stability and the control performance of the vehicle can be maintained under the limit condition. In this case, when the vehicle detects that the torque adjustment value exceeds the maximum limit (torque limit value), the control system may realize steering control by adjusting the individual wheel braking forces to suppress sideslip or oversteer of the vehicle. Such braking force adjustment may be achieved by ABS (antilock brake system), ESC (electronic stability control system) or other brake control devices of the vehicle. By adjusting the independent braking force of the wheels, the vehicle can realize active control of lateral movement, so that the stability and safety of the vehicle under the limit control condition are improved, and the overall control performance and safety performance of the vehicle are effectively improved.

S104: a second rear wheel torque of the vehicle is determined based on the actual slip ratio and the reference slip ratio.

The second rear wheel torque may be the torque of the two rear wheels of the vehicle calculated based on the actual slip ratio and the reference slip ratio.

The reference slip rate can be obtained by calibrating the vehicle speed, the steering wheel angle and the yaw rate in advance and combining the parameters of the whole vehicle. Wherein the reference slip ratio is lower than the set upper limit value, so that the vehicle can be prevented from losing stability due to an excessive slip ratio.

The left rear wheel and the right rear wheel of the vehicle have corresponding reference slip ratio and actual slip ratio, respectively, and corresponding second rear wheel torque.

As one possible implementation, the difference between the actual slip ratio and the reference slip ratio may be compared first, if the actual slip ratio is less than the reference slip ratio, indicating that the wheel traction is too great, the torque output of the rear wheels needs to be reduced, and if the actual slip ratio is greater than the reference slip ratio, indicating that the wheel traction is insufficient, the torque output of the rear wheels needs to be increased. The specific method of adjusting the torque of the rear wheels of the vehicle can be realized by an electronic stability control system or other vehicle control systems.

It should be noted that the specific vehicle dynamics model and control strategy may vary from model to model and manufacturer to manufacturer, so the exact calculation method may vary. The above examples are illustrative only and are not intended to limit the disclosed embodiments.

S105: the differential control is performed on the vehicle based on the first rear wheel torque and the second rear wheel torque.

Alternatively, a minimum value may be taken as the target left rear wheel torque between the second left rear wheel torque and the first left rear wheel torque, and a minimum value may be taken as the target right rear wheel torque between the second right rear wheel torque and the first right rear wheel torque.

The second rear wheel torque includes a second left rear wheel torque and a second right rear wheel torque, the second left rear wheel torque may be a second rear wheel torque corresponding to the left rear wheel, and the second right rear wheel torque may be a second rear wheel torque corresponding to the right rear wheel.

Specifically, the calculation can be made with reference to the following formula:

T _RL 3＝MIN{T _RL 2，T _RL 1}，T _RR 3＝MIN{T _RR 2，T _RR 1}

wherein T is _RL 3 is the target left rear wheel torque, T _RR 3 is the target right rear wheel torque, T _RL 1 is the torque of the first left rear wheel, T _RL 2 is the torque of the second left rear wheel, T _RR 1 is the torque of the first right rear wheel, T _RR And 2 is the second right rear wheel torque.

Finally, the differential control of the vehicle may be performed based on the target left rear wheel torque and the target right rear wheel torque.

The target left rear wheel torque may be a torque for controlling behavior of the left rear wheel of the vehicle, and the target right rear wheel torque may be a torque for controlling behavior of the right rear wheel of the vehicle.

The steering control and the stability control of the vehicle are realized by adjusting the torque distribution of the left and right rear wheels of the vehicle. When differential control is performed, the power transmission system of the vehicle can be correspondingly adjusted according to the set values of the target left rear wheel torque and the target right rear wheel torque so as to realize the expected steering behavior of the vehicle.

Specifically, if it is desired to steer the vehicle to the left, the torque output of the right rear wheel may be increased or the torque output of the left rear wheel may be decreased, whereas if it is desired to steer the vehicle to the right, the torque output of the left rear wheel may be increased or the torque output of the right rear wheel may be decreased. In particular, this may be achieved by a differential of the vehicle, a limited slip differential, or by a left and right rear drive motor system of the vehicle.

In practical applications, differential control is typically used in conjunction with a stability control system (e.g., ESC) of a vehicle, and by monitoring the lateral motion state of the vehicle and the steering command of the driver in real time, the torque distribution of the left and right rear wheels is automatically adjusted to achieve the best balance of vehicle stability and steering performance.

In general, differential control is performed based on the target left rear wheel torque and the target right rear wheel torque, which can help the vehicle to better control sideslip and maintain stability while steering, and improve the handling performance and safety performance of the vehicle.

Fig. 2 is an application scenario diagram of a differential control method of a vehicle, which can be applied to a three-electric drive vehicle architecture or a four-electric drive vehicle architecture, so that when the vehicle turns, the rear wheels realize differential control, the slip rate of the wheels is kept at the same level, and tire wear and wear imbalance are reduced.

FIG. 3 is a schematic diagram of a differential control of the vehicle, as shown in FIG. 3, with the vehicle steering to the left and the target left rear wheel torque being less than the target right rear wheel torque.

Fig. 4 is a flow chart illustrating a differential control method of a vehicle according to a second embodiment of the present application, as shown in fig. 4, the method including:

s201: the current actual yaw rate and the actual slip rate of the vehicle are obtained.

It should be noted that, the specific implementation manner of step S201 may refer to the above embodiment, and will not be described herein.

S202: the friction coefficient of the road surface on which the vehicle is currently traveling and the current driving mode of the vehicle are determined.

Wherein different road surface friction coefficients will affect the stability and handling properties of the vehicle. Generally, high coefficient of friction pavements (e.g., dry asphalt pavements) provide better grip while low coefficient of friction pavements (e.g., wet or snow covered pavements) are prone to slip.

The differential control also needs to consider the current driving mode of the vehicle, such as a normal driving mode, a sport mode, a special road condition mode, and the like. Different driving modes may have an impact on aspects of the response speed, torque distribution strategy, etc. of the differential control system, such as left-hand and right-hand turning driving.

S203: and acquiring a mapping relation table associated with the friction coefficient and the driving mode based on a preset mapping relation.

The mapping relation table comprises yaw rates corresponding to different vehicle speeds and steering angles.

It should be noted that, each friction coefficient and driving mode correspond to one mapping relationship table, for example, friction coefficient A1 and driving mode B1 correspond to one mapping relationship table 1, friction coefficient A1 and driving mode B2 correspond to one mapping relationship table 2, friction coefficient A2 and driving mode B1 correspond to one mapping relationship table 3, and friction coefficient A2 and driving mode B2 correspond to one mapping relationship table 4, which is not limited herein.

S204: an actual vehicle speed and an actual steering angle of the vehicle are determined.

It should be noted that the actual vehicle speed can help the system to determine the current running state of the vehicle, including acceleration, uniform speed or deceleration, so as to adjust the differential control system to adapt to different dynamic conditions. The actual steering angle can then help the system to understand the current steering demand of the vehicle, thereby adjusting the torque distribution of the left and right rear wheels according to the steering angle to achieve the desired steering behavior of the vehicle. The steering angle of the vehicle is monitored in real time, and the differential control system can more accurately respond to the steering instruction of a driver and perform corresponding torque adjustment so as to improve the steering performance and stability of the vehicle.

S205: based on the map table, a reference yaw rate corresponding to the actual vehicle speed and the actual steering angle is determined.

Specifically, the tire lateral force test can be performed at different vehicle speeds and steering angles to obtain corresponding lateral force coefficients. Then, the theoretical relationship between the tire side force and the yaw rate is calculated from the vehicle dynamics model, and stored in the form of a map. In actual control, the corresponding reference yaw rate can be obtained by reading the vehicle speed and steering angle information and searching the mapping relation table.

It should be noted that the establishment of the map is based on the vehicle dynamics model and the actual test data to ensure accuracy and reliability.

S206: the first rear wheel torque of the vehicle is distributed based on the target yaw torque.

It should be noted that, the specific implementation manner of step S206 may refer to the above embodiment, and will not be described herein.

S207: the actual slip ratio of the left rear wheel and the reference slip ratio of the left rear wheel are compared to determine a first slip ratio deviation.

Wherein the actual slip ratio includes an actual slip ratio of the left rear wheel and an actual slip ratio of the right rear wheel.

Wherein the reference slip ratio includes a reference slip ratio of the left rear wheel and a reference slip ratio of the right rear wheel.

Wherein the second rear wheel torque includes a second left rear wheel torque and a second right rear wheel torque.

Wherein the first slip ratio deviation is a deviation between an actual slip ratio of the left rear wheel and a reference slip ratio of the left rear wheel.

For example, if the actual slip ratio of the left rear wheel is M1 and the reference slip ratio of the left rear wheel is M2, the first slip ratio deviation err2=m1-M2 may be determined.

S208: the actual slip ratio of the right rear wheel and the reference slip ratio of the right rear wheel are compared to determine a second slip ratio deviation.

Wherein the second slip ratio deviation is a deviation between the actual slip ratio of the right rear wheel and the reference slip ratio of the right rear wheel.

For example, if the actual slip ratio of the right rear wheel is N1 and the reference slip ratio of the right rear wheel is N2, the second slip ratio deviation err3=n1-N2 may be determined.

S209: based on the first slip ratio deviation, a second left rear wheel torque corresponding to the left rear wheel is determined. Wherein the second left rear wheel torque T corresponding to the left rear wheel _RL 2 can be calculated by the following formula:

T _RL 2＝Kp2*err2+∑Ki2*err2

where err2 is the first slip ratio deviation, kp2 is the proportional gain, and Ki2 is the integral gain. The specific values of the proportional gain and the integral gain are set empirically by taking into account the actual running situation of the vehicle, and are not limited herein.

S210: based on the second slip ratio deviation, a second right rear wheel torque corresponding to the right rear wheel is determined. Wherein the second right rear wheel torque T corresponding to the right rear wheel _RR 2 can be calculated by the following formula:

T _RR 2＝Kp3*err3+∑Ki3*err3

where err3 is the second slip ratio deviation, kp3 is the proportional gain, and Ki3 is the integral gain. The specific values of the proportional gain and the integral gain are set empirically by taking into account the actual running situation of the vehicle, and are not limited herein.

S211: the differential control is performed on the vehicle based on the first rear wheel torque and the second rear wheel torque.

It should be noted that, the specific implementation manner of step S211 may refer to the above embodiment, and will not be described herein.

In the embodiment of the disclosure, a current actual yaw rate and an actual slip rate of a vehicle are firstly obtained, then a friction coefficient of a road surface on which the vehicle is currently driven and a current driving mode of the vehicle are determined, then a mapping relation table related to the friction coefficient and the driving mode is obtained based on a preset mapping relation, wherein the mapping relation table comprises yaw rates corresponding to different vehicle speeds and steering angles, then the actual vehicle speed and the actual steering angle of the vehicle are determined, then the reference yaw rate corresponding to the actual vehicle speed and the actual steering angle is determined based on the mapping relation table, then a first rear wheel torque of the vehicle is distributed based on a target yaw torque, then the actual slip rate of the left rear wheel and the reference slip rate of the left rear wheel are compared to determine a first slip rate deviation, then the actual slip rate of the right rear wheel and the reference slip rate of the right rear wheel are compared to determine a second slip rate deviation, then a second left rear wheel corresponding to the left rear wheel and the right rear wheel are determined based on the first slip rate deviation, then the second rear wheel torque is controlled based on the second rear wheel torque deviation, and the second rear wheel torque is controlled based on the second rear wheel torque deviation. Therefore, by acquiring information such as the actual yaw rate, the actual slip rate, the road friction coefficient, the driving mode and the like and combining a preset mapping relation table, the system can calculate the reference yaw rate and further perform differential control so as to optimize the steering performance and stability of the vehicle. The vehicle control system has the advantages that the vehicle control system can be dynamically adjusted according to the actual vehicle state and road surface conditions, so that the vehicle can keep good control performance under different driving modes and road surface friction coefficients. Through carrying out accurate distribution to the moment of torsion of every wheel, the system can restrain sideslip and oversteer effectively, improves the stability and the operability of vehicle, also can promote the security performance of vehicle simultaneously, can make the vehicle in the course of turning, when reducing turning radius, also can reduce the tire slip rate, compromise the demand of yaw rate and tire slip rate. In general, the beneficial effects of such differential control include improving the handling performance of the vehicle, enhancing the driving stability, reducing the sideslip and oversteering phenomena, and improving the adaptability of the vehicle under different road conditions, thereby improving the driving safety.

Fig. 5 is a flow chart of a differential control method of a vehicle according to a third embodiment of the present application, as shown in fig. 5, the method includes:

s301: the current actual yaw rate and the actual slip rate of the vehicle are obtained.

It should be noted that, the specific implementation manner of step S301 may refer to the above embodiment, and will not be described herein.

S302: an actual centroid offset angle and a reference centroid offset angle of the vehicle are obtained.

The actual centroid offset angle of the vehicle refers to an included angle between the current centroid position of the vehicle and the center line of the vehicle. The information such as the lateral acceleration and the angular velocity of the vehicle can be obtained through the vehicle sensor, and then the current actual centroid offset angle of the vehicle is calculated by combining the vehicle dynamics model.

The reference centroid offset angle refers to a preset centroid offset angle of the vehicle under different driving modes and road conditions. Generally, the reference centroid offset angle is preset according to factors such as the type of vehicle, the speed of the vehicle, the steering angle, and the road friction coefficient. Can be calculated by a pre-established mapping relation table or an empirical formula.

The specific acquisition mode of the reference centroid offset angle may refer to the acquisition mode of the reference yaw rate in the above steps S202 to S205.

S303: a centroid offset angle deviation between the actual centroid offset angle and the reference centroid offset angle is determined.

For example, if the actual centroid offset angle is P1 and the reference centroid offset angle is P2, the centroid offset angle deviation err4 between the actual centroid offset angle and the reference centroid offset angle may be determined. Here, the yaw rate deviation err4=p1-P2 is not limited here.

S304: a yaw-rate deviation between the actual yaw-rate and the reference yaw-rate is determined.

For example, if the actual yaw rate is w1 and the reference yaw rate is w2, the yaw rate deviation err1 between the actual yaw rate and the reference yaw rate may be determined. Here, the yaw rate deviation err1=w1-w 2 is not limited here.

S305: the target yaw torque is determined based on the yaw-rate deviation and the centroid-offset-angle deviation.

Specifically, the output value of the yaw rate controller may be calculated first according to the actual yaw rate deviation of the vehicle and a preset yaw rate controller gain coefficient. Then, according to the actual centroid offset angle deviation of the vehicle and a preset centroid offset angle controller gain coefficient, calculating an output value of the centroid offset angle controller. And finally, carrying out weighted sum on the output values of the two controllers to obtain the final target yaw torque.

It should be noted that, the calculation result of the target yaw torque is affected by different gain coefficients and weighting manners of the controller, so that appropriate adjustment and optimization are required according to factors such as the type of the vehicle, the driving mode, the road surface condition, and the like, so as to ensure that the steering performance and the stability of the vehicle reach the optimal state.

S306: the first rear wheel torque of the vehicle is distributed based on the target yaw torque.

S307: a second rear wheel torque of the vehicle is determined based on the actual slip ratio and the reference slip ratio.

S308: the differential control is performed on the vehicle based on the first rear wheel torque and the second rear wheel torque.

It should be noted that, the specific implementation manner of steps S306-S308 may refer to the above embodiment, and will not be described herein.

In the embodiment of the disclosure, the current actual yaw rate and the actual slip rate of the vehicle are firstly obtained, then the actual centroid offset angle and the reference centroid offset angle of the vehicle are obtained, then the centroid offset angle deviation between the actual centroid offset angle and the reference centroid offset angle is determined, then the yaw rate deviation between the actual yaw rate and the reference yaw rate is determined, then the target yaw torque is determined based on the yaw rate deviation and the centroid offset angle deviation, then the first rear wheel torque of the vehicle is distributed based on the target yaw torque, then the second rear wheel torque of the vehicle is determined based on the actual slip rate and the reference slip rate, and finally the differential control is performed on the vehicle based on the first rear wheel torque and the second rear wheel torque. In summary, by analyzing the actual yaw rate deviation and the centroid deviation angle deviation, determining the target yaw torque, and performing distribution and differential control on the rear wheel torque of the vehicle, the steering performance can be improved, and by determining the target yaw torque according to the deviation of the actual yaw rate and the centroid deviation angle, the vehicle can better respond to the steering instruction of the driver, and the steering accuracy and flexibility can be improved. By differential control and rear wheel torque distribution, the sideslip angle and the slip rate of the vehicle can be adjusted, so that the vehicle is kept in a safe and stable range, and the risk of sideslip and out-of-control is reduced. The transverse dynamic stability control can help a driver to keep the stability of the vehicle under an emergency, reduce the occurrence of accidents such as sideslip, out-of-control, rolling and the like, and improve the driving safety.

As shown in fig. 6, fig. 6 is a flowchart of a differential control method of a vehicle shown in the present application, in which a yaw-rate request and a centroid offset-angle request are first calculated based on a reference-quantity generator (Reference generator) from a steering angle, a vehicle speed and a tire-path friction coefficient, and then a yaw-torque calculation is performed, and the yaw-rate request and the centroid offset-angle request, an actual yaw-rate value and a centroid offset-angle observed value are combined to calculate a yaw torque. Further, torque distribution can be performed to obtain rear axle left wheel torque and rear axle right wheel torque, and then drive anti-slip control can be performed to obtain final rear axle left wheel torque and rear axle right wheel torque, which are input into a vehicle, wherein a centroid offset angle can be observed by a centroid offset angle observer.

Wherein Reference generator is a module in a control system for generating a desired input signal. It typically calculates the desired control quantity signal based on the desired system response characteristics and a description of the reference input signal to effect control of the system.

Fig. 7 is a block diagram of a differential control device of a vehicle according to the present application, and as shown in fig. 7, a differential control device 700 of the vehicle includes:

A first obtaining module 710, configured to obtain a current actual yaw rate and an actual slip rate of the vehicle;

a first determining module 720, configured to determine a target yaw torque according to the actual yaw rate and the reference yaw rate;

a distribution module 730 for distributing a first rear wheel torque of the vehicle based on the target yaw torque;

a second determination module 740 for determining a second rear wheel torque of the vehicle based on the actual slip rate and a reference slip rate;

a control module 750 for performing differential control of the vehicle based on the first rear wheel torque and the second rear wheel torque.

Optionally, the first determining module is further configured to:

determining a friction coefficient of a road surface on which the vehicle is currently running and a current driving mode of the vehicle;

acquiring a mapping relation table associated with the friction coefficient and the driving mode based on a preset mapping relation, wherein the mapping relation table comprises yaw rates corresponding to different vehicle speeds and steering angles;

determining an actual vehicle speed and an actual steering angle of the vehicle;

and determining the reference yaw rate corresponding to the actual vehicle speed and the actual steering angle based on the map.

Optionally, the first determining module is specifically configured to:

determining a yaw rate deviation from the actual yaw rate and a reference yaw rate;

and performing proportional integral adjustment based on the yaw rate deviation to obtain the target yaw torque.

Optionally, the first rear wheel torque includes a first left rear wheel torque and a first right rear wheel torque, and the distribution module is specifically configured to:

determining a torque adjustment value according to the target yaw torque, and the track and rolling radius of the vehicle;

a first left rear wheel torque and a first right rear wheel torque of the vehicle are distributed based on the target rear wheel torque and the torque adjustment value.

Optionally, the allocation module is further configured to:

and adjusting the braking torque under the condition that the torque adjustment value is larger than a preset torque limit value.

Optionally, the actual slip ratio includes an actual slip ratio of the left rear wheel and an actual slip ratio of the right rear wheel,

the reference slip ratio includes a reference slip ratio of the left rear wheel and a reference slip ratio of the right rear wheel,

the second rear wheel torque includes a second left rear wheel torque and a second right rear wheel torque,

a second determination module, in particular for

Comparing the actual slip rate of the left rear wheel with a reference slip rate of the left rear wheel to determine a first slip rate deviation;

Comparing the actual slip ratio of the right rear wheel with the reference slip ratio of the right rear wheel to determine a second slip ratio deviation;

determining a second left rear wheel torque corresponding to the left rear wheel based on the first slip ratio deviation;

and determining a second right rear wheel torque corresponding to the right rear wheel based on the second slip ratio deviation.

Optionally, the control module is specifically configured to:

taking a minimum value between the second left rear wheel torque and the first left rear wheel torque as a target left rear wheel torque;

taking a minimum value between the second right rear wheel torque and the first right rear wheel torque as a target right rear wheel torque;

and performing differential control on the vehicle based on the target left rear wheel torque and the target right rear wheel torque.

Optionally, the device further includes:

the second acquisition module is used for acquiring an actual centroid offset angle and a reference centroid offset angle of the vehicle;

a third determining module for determining a centroid offset angle deviation between the actual centroid offset angle and a reference centroid offset angle;

a fourth determination module configured to determine a yaw rate deviation between the actual yaw rate and a reference yaw rate;

And a fifth determination module for determining the target yaw torque based on the yaw-rate deviation and the centroid deviation.

According to embodiments of the present application, there is also provided an electronic device, a readable storage medium and a computer program product.

Fig. 8 illustrates a block diagram of an exemplary electronic device suitable for use in implementing embodiments of the present disclosure. The electronic device 12 shown in fig. 8 is merely an example and should not be construed to limit the functionality and scope of use of embodiments of the present disclosure in any way.

As shown in fig. 8, the electronic device 12 is in the form of a general purpose computing device. Components of the electronic device 12 may include, but are not limited to: one or more processors or processing units 16, a memory 28, and a bus 18 that connects the various system components, including the memory 28 and the processing unit 16.

Bus 18 represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processor, and a local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include industry Standard architecture (Industry Standard Architecture; hereinafter ISA) bus, micro channel architecture (Micro Channel Architecture; hereinafter MAC) bus, enhanced ISA bus, video electronics standards Association (Video Electronics Standards Association; hereinafter VESA) local bus, and peripheral component interconnect (Peripheral Component Interconnection; hereinafter PCI) bus.

Electronic device 12 typically includes a variety of computer system readable media. Such media can be any available media that is accessible by electronic device 12 and includes both volatile and nonvolatile media, removable and non-removable media.

Memory 28 may include computer system readable media in the form of volatile memory, such as random access memory (Random Access Memory; hereinafter: RAM) 30 and/or cache memory 32. The electronic device 12 may further include other removable/non-removable, volatile/nonvolatile computer system storage media. By way of example only, storage system 34 may be used to read from or write to non-removable, nonvolatile magnetic media (not shown in FIG. 8, commonly referred to as a "hard disk drive"). Although not shown in fig. 8, a magnetic disk drive for reading from and writing to a removable non-volatile magnetic disk (e.g., a "floppy disk"), and an optical disk drive for reading from or writing to a removable non-volatile optical disk (e.g., a compact disk read only memory (Compact Disc Read Only Memory; hereinafter CD-ROM), digital versatile read only optical disk (Digital Video Disc Read Only Memory; hereinafter DVD-ROM), or other optical media) may be provided. In such cases, each drive may be coupled to bus 18 through one or more data medium interfaces. Memory 28 may include at least one program product having a set (e.g., at least one) of program modules configured to carry out the functions of the various embodiments of the disclosure.

A program/utility 40 having a set (at least one) of program modules 42 may be stored in, for example, memory 28, such program modules 42 including, but not limited to, an operating system, one or more application programs, other program modules, and program data, each or some combination of which may include an implementation of a network environment. Program modules 42 generally perform the functions and/or methods in the embodiments described in this disclosure.

The electronic device 12 may also communicate with one or more external devices 14 (e.g., keyboard, pointing device, display 24, etc.), one or more devices that enable a user to interact with the electronic device 12, and/or any devices (e.g., network card, modem, etc.) that enable the electronic device 12 to communicate with one or more other computing devices. Such communication may occur through an input/output (I/O) interface 22. Also, the electronic device 12 may communicate with one or more networks, such as a local area network (Local Area Network; hereinafter: LAN), a wide area network (Wide Area Network; hereinafter: WAN) and/or a public network, such as the Internet, via the network adapter 20. As shown, the network adapter 20 communicates with other modules of the electronic device 12 over the bus 18. It should be appreciated that although not shown, other hardware and/or software modules may be used in connection with electronic device 12, including, but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, data backup storage systems, and the like.

The processing unit 16 executes various functional applications and data processing by running programs stored in the memory 28, for example, implementing the methods mentioned in the foregoing embodiments.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present disclosure, the meaning of "a plurality" is at least two, such as two, three, etc., unless explicitly specified otherwise.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and additional implementations are included within the scope of the preferred embodiment of the present disclosure in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the embodiments of the present disclosure.

Logic and/or steps represented in the flowcharts or otherwise described herein, e.g., a ordered listing of executable instructions for implementing logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). In addition, the computer readable medium may even be paper or other suitable medium on which the program is printed, as the program may be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory.

It should be understood that portions of the present disclosure may be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, the various steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. As with the other embodiments, if implemented in hardware, may be implemented using any one or combination of the following techniques, as is well known in the art: discrete logic circuits having logic gates for implementing logic functions on data signals, application specific integrated circuits having suitable combinational logic gates, programmable Gate Arrays (PGAs), field Programmable Gate Arrays (FPGAs), and the like.

Those of ordinary skill in the art will appreciate that all or a portion of the steps carried out in the method of the above-described embodiments may be implemented by a program to instruct related hardware, where the program may be stored in a computer readable storage medium, and where the program, when executed, includes one or a combination of the steps of the method embodiments.

Furthermore, each functional unit in the embodiments of the present disclosure may be integrated in one processing module, or each unit may exist alone physically, or two or more units may be integrated in one module. The integrated modules may be implemented in hardware or in software functional modules. The integrated modules may also be stored in a computer readable storage medium if implemented in the form of software functional modules and sold or used as a stand-alone product.

The above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, or the like. Although embodiments of the present disclosure have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the present disclosure, and that variations, modifications, alternatives, and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the present disclosure.

Claims

1. A differential control method of a vehicle, characterized by comprising:

acquiring the current actual yaw rate and the actual slip rate of the vehicle;

2. The method according to claim 1, characterized by further comprising, before said determining a target yaw torque from said actual yaw rate and a reference yaw rate:

3. The method of claim 1, wherein the determining the target yaw torque from the actual yaw rate and the reference yaw rate comprises:

4. The method of claim 1, wherein the first rear wheel torque comprises a first left rear wheel torque and a first right rear wheel torque, the distributing the first rear wheel torque of the vehicle based on the target yaw torque comprising:

5. The method of claim 4, further comprising, after said determining a torque adjustment value based on said target yaw torque, and a track and a roll radius of said vehicle:

6. The method of claim 4, wherein the step of adding the at least one additional agent to the at least one additional agent,

the actual slip ratio includes an actual slip ratio of the left rear wheel and an actual slip ratio of the right rear wheel,

the determining a second rear wheel torque of the vehicle based on the actual slip rate and a reference slip rate includes:

7. The method of claim 6, wherein the differentially controlling the vehicle based on the first rear wheel torque and the second rear wheel torque comprises:

8. The method as recited in claim 1, further comprising:

acquiring an actual centroid offset angle and a reference centroid offset angle of the vehicle;

determining a centroid offset angle deviation between the actual centroid offset angle and a reference centroid offset angle;

determining a yaw rate deviation between the actual yaw rate and a reference yaw rate;

the target yaw torque is determined based on the yaw-rate deviation and the centroid offset-angle deviation.

9. A differential control device of a vehicle, characterized by comprising:

10. An electronic device, comprising: a processor, and a memory communicatively coupled to the processor;

the memory stores computer-executable instructions;

the processor executes computer-executable instructions stored in the memory to implement the method of any one of claims 1-8.

11. A computer readable storage medium having stored therein computer executable instructions which when executed by a processor are adapted to carry out the method of any one of claims 1-8.