Torque distribution method and device for distributed drive, vehicle and medium

Abstract

The application provides a distributed driving torque distribution method and device, a vehicle and a medium, and relates to the technical field of vehicles.The method comprises the following steps: when the driving mode of the vehicle is a getting-out-of-trouble mode, determining a first target demand torque of a target axle provided with an EDS, a first target torque of each wheel corresponding to the target axle and a maximum allowable driving torque according to an accelerator pedal opening degree and a vehicle state parameter; when a first wheel of the target axle slips, calculating a second target demand torque of the target axle according to the first target demand torque of the target axle and the maximum allowable driving torque of each wheel corresponding to the target axle; and if the second wheel meets a preset condition, transmitting the motor torque capacity of the first wheel to the second wheel, so as to maximize the utilization of power.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicles, in particular to a torque distribution method and device for distributed driving, a vehicle and a medium. BACKGROUND

[0002] With the development of vehicle technology, the driving mode of vehicles is no longer limited to centralized driving. More and more vehicles begin to use distributed driving to achieve vehicle control. Distributed driving is a new power form in which four motors independently drive four wheels. The wheel torque can be arbitrarily distributed according to the actual road conditions and vehicle driving state to realize single wheel drive and brake force control. The control system can achieve this through software, so the off-road mode of four-motor driving type will not cause operation out of control due to the limitations of mechanical structure.

[0003] At present, the driving torque distribution method of the distributed structure electric vehicle usually uses a relatively simple method, such as torque average distribution method, that is, the torque requested by the driver is evenly distributed to the four wheels, and the torque allocated to each wheel is 1 / 4 of the torque requested by the driver.

[0004] However, if any wheel slips, there will be a problem of power waste. SUMMARY

[0005] The present application provides a torque distribution method and device for distributed driving, a vehicle and a medium to solve the problem of power waste in the prior art when the wheels slip.

[0006] In a first aspect, the present application provides a torque distribution method for distributed driving, comprising:

[0007] When the driving mode of the vehicle is the escape mode, the first target demand torque of the target axle provided with the EDS, the first target torque of each wheel corresponding to the target axle, and the allowable maximum drive torque are determined according to the accelerator pedal opening degree and the vehicle state parameters;

[0008] When the first wheel of the target axle slips, the second target demand torque of the target axle is calculated according to the first target demand torque of the target axle and the allowable maximum drive torque of each wheel corresponding to the target axle.

[0009] If the second wheel meets the preset condition, the second target torque of each wheel corresponding to the target axle is calculated according to the second target demand torque of the target axle, the torque capacity of the EDS, the first target torque of each wheel corresponding to the target axle, and the maximum available torque of the motor, the preset condition being related to the second target demand torque of the target axle, and the second wheel being in the target axle.

[0010] For each wheel corresponding to the target axle, a final motor target request torque of the wheel is determined according to a second target torque of the wheel, an initial motor target request torque, a yaw torque, and a motor available torque after power limiting on the wheel, the initial motor target request torque being a motor target request torque obtained after wheel slip control on the wheel.

[0011] In a possible design, the second target demand torque of the target axle is calculated according to the first target demand torque of the target axle and the allowable maximum drive torque of each wheel corresponding to the target axle, and includes the following steps.

[0012] The allowable maximum drive torque of the first wheel and the allowable maximum drive torque of the second wheel are added to obtain an allowable maximum drive torque cumulative sum.

[0013] The minimum value of the first target demand torque of the target axle and the allowable maximum drive torque cumulative sum is determined as the second target demand torque of the target axle.

[0014] In a possible design, the second target torque of each wheel corresponding to the target axle is calculated according to the second target demand torque of the target axle, the torque capacity of the EDS, the first target torque of each wheel corresponding to the target axle, and the motor maximum available torque, and includes the following steps.

[0015] The difference between the second target demand torque of the target axle and the first target torque of the second wheel is determined as the first torque difference of the first wheel.

[0016] The minimum value of the first torque difference of the first wheel, the torque capacity of the EDS, and the motor maximum available torque of the first wheel is determined as the second target torque of the first wheel.

[0017] The difference between the second target demand torque of the target axle and the second target torque of the first wheel is determined as the first torque difference of the second wheel.

[0018] The minimum value of the first torque difference of the second wheel, the torque capacity of the EDS, and the motor maximum available torque of the second wheel is determined as the second target torque of the second wheel.

[0019] In a possible design, the final motor target request torque of each wheel corresponding to the target axle is determined according to the second target torque of the wheel, the initial motor target request torque, the yaw torque, and the motor available torque after power limiting on the wheel, and includes the following steps.

[0020] determining the minimum value among the second target torque of the first wheel, the initial motor target request torque, the yaw torque, and the motor available torque after power limiting of the first wheel as the final motor target request torque of the first wheel;

[0021] determining the minimum value among the second target torque of the second wheel, the initial motor target request torque, the yaw torque, and the motor available torque after power limiting of the second wheel as the final motor target request torque of the second wheel.

[0022] In a possible design, the determining of the first target demand torque of the target axle provided with the EDS, the first target torque of each wheel corresponding to the target axle, and the maximum allowable driving torque according to the accelerator pedal opening degree and the vehicle state parameter includes:

[0023] for each wheel corresponding to the target axle, calculating the utilization adhesion coefficient and the slip rate of the wheel according to the vehicle speed and the wheel speed, the vertical load, and the driving force of the wheel;

[0024] calculating the first target demand torque of the target axle and the first target torque of each wheel corresponding to the target axle according to the accelerator pedal opening degree, the vehicle basic parameter of the vehicle, the input axle load / wheel load parameter, the tire rolling radius of each wheel, the wheel track, the distance from the center of mass to the axle where the wheel is located, and the rotation angle of the wheel;

[0025] determining the maximum allowable driving torque of the wheel according to the road surface type, the utilization adhesion coefficient of the wheel, the slip rate, the preset maximum load, the tire rolling radius, and the safety coefficient, the safety coefficient being determined according to the adhesion coefficient.

[0026] In a possible design, the calculating of the utilization adhesion coefficient and the slip rate of the wheel according to the vehicle speed and the wheel speed, the vertical load, and the driving force of the wheel includes:

[0027] calculating the slip rate of the wheel according to the vehicle speed and the wheel speed of the wheel;

[0028] calculating the utilization adhesion coefficient of the wheel according to the driving force of the wheel and the vertical load of the wheel.

[0029] In a possible design, the calculating of the first target demand torque of the target axle and the first target torque of each wheel corresponding to the target axle according to the accelerator pedal opening degree, the vehicle basic parameter of the vehicle, the input axle load / wheel load parameter, the tire rolling radius of each wheel, the wheel track, the distance from the center of mass to the axle where the wheel is located, and the rotation angle of the wheel includes:

[0030] determining a total target demand torque and a total target yaw torque of the vehicle according to the whole vehicle basic parameters of the vehicle and the accelerator pedal opening;

[0031] calculating a torque distribution ratio of the target axle according to the input axle load / wheel load parameters;

[0032] calculating a yaw torque conversion coefficient of each wheel corresponding to the target axle according to the tire rolling radius of each wheel corresponding to the target axle, the wheel track of each wheel, the distance from the center of mass to the axle where each wheel is located, and the rotation angle of each wheel;

[0033] calculating a first target demand torque of the target axle and a first target torque of each wheel corresponding to the target axle according to the total target demand torque, the total target yaw torque, the torque distribution ratio of the target axle, and the yaw torque conversion coefficient of each wheel corresponding to the target axle.

[0034] In a possible design, the determining the allowable maximum driving torque of the wheel according to the road surface type, the utilization adhesion coefficient of the wheel, the slip ratio, the preset maximum load, the tire rolling radius, and the safety coefficient comprises:

[0035] determining a target slip ratio corresponding to the road surface type, the target slip ratio being a slip ratio corresponding to a maximum utilization adhesion coefficient under the road surface type;

[0036] determining the allowable maximum driving force of the wheel according to the slip ratio of the wheel, the target slip ratio, the utilization adhesion coefficient, and the preset maximum load;

[0037] determining the allowable maximum driving torque of the wheel according to the allowable maximum driving force of the wheel, the tire rolling radius, and the safety coefficient.

[0038] In a possible design, the determining the allowable maximum driving torque of the wheel according to the road surface type, the utilization adhesion coefficient of the wheel, the slip ratio, the preset maximum load, the tire rolling radius, and the safety coefficient comprises:

[0039] determining a target slip ratio corresponding to the road surface type, the target slip ratio being a slip ratio corresponding to a maximum utilization adhesion coefficient under the road surface type;

[0040] determining the allowable maximum driving force of the wheel according to the slip ratio of the wheel, the target slip ratio, the utilization adhesion coefficient, and the preset maximum load;

[0041] The allowable maximum driving torque of the wheel is determined according to the allowable maximum driving force of the wheel, the rolling radius of the tire, and the safety factor.

[0042] In a possible design, the preset condition comprises that the maximum available torque of the motor of the second wheel is less than the second target demand of the target axle, and the second target demand of the target axle is less than the allowable maximum driving torque of the second wheel.

[0043] In a possible design, the method further comprises:

[0044] The driving mode of the vehicle is adjusted to the escape mode in response to a user selecting an escape mode operation through the HMI.

[0045] In a possible design, the method further comprises:

[0046] The control signal is sent to the motor controller of each wheel according to the final motor target request torque of each wheel corresponding to the target axle.

[0047] In a second aspect, an embodiment of the present application provides a torque distribution control device for distributed driving, comprising:

[0048] The first determination module is configured to determine the first target demand torque of the target axle provided with the EDS, the first target torque of each wheel corresponding to the target axle, and the allowable maximum driving torque according to the accelerator pedal opening degree and the vehicle state parameter when the driving mode of the vehicle is the escape mode.

[0049] The first calculation module is configured to calculate the second target demand torque of the target axle according to the first target demand torque of the target axle and the allowable maximum driving torque of each wheel corresponding to the target axle when the first wheel of the target axle slips.

[0050] The second calculation module is configured to calculate the second target torque of each wheel corresponding to the target axle according to the second target demand torque of the target axle, the torque capacity of the EDS, the first target torque of each wheel corresponding to the target axle, and the maximum available torque of the motor if the second wheel meets a preset condition, wherein the preset condition is related to the second target demand torque of the target axle, and the second wheel is in the target axle.

[0051] The second determination module is configured to determine the final motor target request torque of each wheel corresponding to the target axle according to the second target torque of the wheel, the initial motor target request torque, the yaw torque, and the available torque of the motor after power limitation on the wheel, wherein the initial motor target request torque is the motor target request torque obtained after wheel slip control on the wheel.

[0052] In a possible design, the first calculation module is specifically configured to:

[0053] add the allowable maximum driving torque of the first wheel and the allowable maximum driving torque of the second wheel to obtain an allowable maximum driving torque accumulation;

[0054] determine the minimum value of the first target demand torque of the target axle and the allowable maximum driving torque accumulation as the second target demand torque of the target axle.

[0055] In a possible design, the second calculation module is specifically configured to:

[0056] determine the difference between the second target demand torque of the target axle and the second target torque of the first wheel as the first torque difference of the first wheel;

[0057] determine the minimum value of the first torque difference of the first wheel, the torque capacity of the EDS, and the maximum available torque of the motor of the first wheel as the second target torque of the first wheel;

[0058] determine the difference between the second target demand torque of the target axle and the second target torque of the first wheel as the first torque difference of the first wheel;

[0059] determine the minimum value of the first torque difference of the second wheel, the torque capacity of the EDS, and the maximum available torque of the motor of the second wheel as the second target torque of the second wheel.

[0060] In a possible design, the second determination module is specifically configured to:

[0061] determine the minimum value of the second target torque of the first wheel, the initial motor target request torque, the yaw torque, and the available torque of the motor after power limitation on the first wheel as the final motor target request torque of the first wheel;

[0062] determine the minimum value of the second target torque of the second wheel, the initial motor target request torque, the yaw torque, and the available torque of the motor after power limitation on the second wheel as the final motor target request torque of the second wheel.

[0063] In a possible design, the first determination module is specifically configured to:

[0064] for each wheel corresponding to the target axle, calculate the utilization adhesion coefficient and the slip rate of the wheel according to the vehicle speed, the wheel speed, the vertical load, and the driving force of the wheel of the vehicle;

[0065] According to the accelerator pedal opening degree, the whole vehicle basic parameter of the vehicle, the input axle load / wheel load parameter, the tire rolling radius of each wheel, the wheel track of the wheel, the distance from the center of mass to the axle where the wheel is located, and the rotation angle of the wheel, a first target required torque of the target axle and a first target torque of each wheel corresponding to the target axle are calculated.

[0066] According to the road surface type, the utilization adhesion coefficient of the wheel, the slip ratio, the preset maximum load, the tire rolling radius, and the safety coefficient determined according to the adhesion coefficient, the allowable maximum driving torque of the wheel is determined.

[0067] In a possible design, the first determining module is specifically configured to:

[0068] According to the vehicle speed and the wheel speed of the wheel, the slip ratio of the wheel is calculated.

[0069] According to the driving force of the wheel and the vertical load of the wheel, the utilization adhesion coefficient of the wheel is calculated.

[0070] In a possible design, the first determining module is specifically configured to:

[0071] According to the whole vehicle basic parameter of the vehicle and the accelerator pedal opening degree, the total target required torque and the total target yaw torque of the vehicle are determined.

[0072] According to the input axle load / wheel load parameter, the torque distribution ratio of the target axle is calculated.

[0073] According to the tire rolling radius, the wheel track, the distance from the center of mass to the axle where the wheel is located, and the rotation angle of the wheel of each wheel corresponding to the target axle, the yaw torque conversion coefficient of the wheel is calculated.

[0074] According to the total target required torque, the total target yaw torque, the torque distribution ratio of the target axle, and the yaw torque conversion coefficient of each wheel corresponding to the target axle, the first target required torque of the target axle and the first target torque of each wheel corresponding to the target axle are calculated.

[0075] In a possible design, the first determining module is specifically configured to:

[0076] According to the road surface type, the target slip ratio corresponding to the road surface type is determined, the target slip ratio being the slip ratio corresponding to the maximum utilization adhesion coefficient under the road surface type.

[0077] determining the allowable maximum driving force of the wheel according to the slip ratio of the wheel, the target slip ratio, the adhesion coefficient and the preset maximum load;

[0078] determining the allowable maximum driving torque of the wheel according to the allowable maximum driving force of the wheel, the tire rolling radius and the safety coefficient.

[0079] In a possible design, the torque distribution control apparatus for the distributed drive further includes a control module, configured to:

[0080] if the second wheel satisfies the preset condition, controlling the EDS to enter the lock mode;

[0081] if the wheel of the target axle exits the wheel slip control, or the reference speed of the vehicle is greater than a preset speed, or the steering angle of the vehicle is greater than a preset angle, or any motor of the vehicle fails, controlling the EDS to exit the lock mode.

[0082] In a possible design, the preset condition includes that the maximum available torque of the motor of the second wheel is less than the second target demand of the target axle, and the second target demand of the target axle is less than the allowable maximum driving torque of the second wheel.

[0083] In a possible design, the torque distribution control apparatus for the distributed drive further includes an adjustment module, configured to:

[0084] in response to a user selecting an escape mode through the human-machine interface (HMI), adjusting the driving mode of the vehicle to the escape mode.

[0085] In a possible design, the torque distribution control apparatus for the distributed drive further includes a sending module, configured to:

[0086] sending a control signal to the motor controller of each wheel according to the final motor target request torque of each wheel corresponding to the target axle.

[0087] In a third aspect, an embodiment of the present application provides a vehicle, including: a vehicle body, a vehicle controller, a motor of each wheel, a memory, and computer program instructions stored in the memory and executable on the vehicle controller, and the vehicle controller is configured to execute the computer program instructions to implement the method in the first aspect and each possible design.

[0088] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium, and the computer readable storage medium stores computer execution instructions, and the computer execution instructions are configured to be executed by a processor to implement the method in the first aspect and each possible design.

[0089] In a fifth aspect, an embodiment of the present application provides a computer program product, comprising a computer program, which, when executed by a processor, is used to implement the method provided in the first aspect and possible designs.

[0090] The distributed driving torque distribution method, device, vehicle and medium provided by the embodiment of the present application, the method comprises: when the driving mode of the vehicle is a getting-out-of-trouble mode, determining the first target demand torque of a target axle provided with an EDS, the first target torque of each wheel corresponding to the target axle and the allowable maximum driving torque according to an accelerator pedal opening degree and a vehicle state parameter. Then, when the first wheel of the target axle slips, calculating the second target demand torque of the target axle according to the first target demand torque of the target axle and the allowable maximum driving torque of each wheel corresponding to the target axle. If the second wheel meets a preset condition, calculating the second target torque of each wheel corresponding to the target axle according to the second target demand torque of the target axle, the torque capacity of the EDS, the first target torque of each wheel corresponding to the target axle and the maximum available torque of the motor. For each wheel corresponding to the target axle, determining the final motor target request torque of the wheel according to the second target torque of the wheel, the initial motor target request torque, the yaw torque and the available torque of the motor after power limiting on the wheel. The initial motor target request torque is the motor target request torque obtained after wheel slip control on the wheel, the preset condition is related to the second target demand torque of the target axle, and the second wheel is on the target axle. In the technical solution, when the first wheel of the target axle slips and the second wheel meets the preset condition, the EDS is controlled to enter the locking mode, so that the unavailable motor torque capacity of the first wheel is transmitted to the second wheel, thereby ensuring that the power is maximized. BRIEF DESCRIPTION OF DRAWINGS

[0091] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments consistent with the present application and, together with the description, further serve to explain the principles of the application.

[0092] Figure 1 A topology diagram of distributed driving power;

[0093] Figure 2 A flowchart of the torque distribution method for distributed driving provided by the embodiment of the present application;

[0094] Figure 3 Another topology diagram of distributed driving power;

[0095] Figure 4 A position diagram of the EDS in the front-two-rear distributed driving configuration;

[0096] Figure 5A schematic diagram of a scene in which the right rear wheel of the vehicle is stuck;

[0097] Figure 6 A flowchart of a torque distribution method for distributed driving provided by an embodiment of the present application, embodiment two;

[0098] Figure 7 A graph of the relationship between slip rate and the use of the adhesion coefficient provided by an embodiment of the present application;

[0099] Figure 8 A schematic diagram of the structure of a traditional power off-road vehicle;

[0100] Figure 9 A flowchart of a torque distribution method for distributed driving provided by an embodiment of the present application, embodiment three;

[0101] Figure 10 A flowchart of a torque distribution method for distributed driving provided by an embodiment of the present application, embodiment four;

[0102] Figure 11 A schematic diagram of the structure of a torque distribution control device for distributed driving provided by an embodiment of the present application.

[0103] The specific embodiments of the present application have been shown in the above-described drawings, and will be described in more detail hereinafter. These drawings and written descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0104] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0105] Before introducing the embodiments of the present application, the application background of the embodiments of the present application is first explained:

[0106] Figure 1 A schematic diagram of a topology of distributed driving power. As shown in FIG. 1, a distributed driving vehicle is provided with a power battery for supplying power to four electric drive systems. The four electric drive systems independently drive four wheels, so that each wheel has an independent power source, and the wheel torque can be distributed in real time according to the road conditions and the vehicle driving state. Figure 1

[0107] ​The distributed drive vehicle can realize intelligent torque distribution of front and rear axles and left and right wheels, but due to complete decoupling of driving forces of coaxial left and right wheels, when one side wheel slips, the driving torque of the slipping side wheel is limited, and the driving torque of the other wheel does not change. That is, in the above example, if one side wheel of the same axle slips, the distribution relationship of the slipping side wheel and the high adhesion side wheel of the axle is approximately 0:25%. In this case, the maximum capacity of the vehicle driving system is limited, causing power waste.

[0108] Based on the above technical problems, the present application is as follows: in the prior art, the main reason for power waste of the distributed drive vehicle when slipping is that the driving torque of the slipping side wheel can only be limited, and the motor torque cannot be transferred, resulting in waste of the driving torque of the slipping side wheel. Therefore, an electronic limited-slip differential (EDS) can be provided on the axle of the vehicle, and when it is determined that the vehicle is in the escape mode, there is wheel slip, and certain preset conditions are met, the EDS is locked to transfer the motor torque capacity of the slipping side wheel to the high adhesion side wheel of the same axle, maximize the utilization of the same axle driving capacity, thereby solving the problem of power waste and helping the vehicle to escape.

[0109] In the following, the technical solutions of the present application are described in detail through specific embodiments.

[0110] It should be noted that the following specific embodiments can be combined with each other, and the same or similar concepts or processes can not be described in detail in some embodiments.

[0111] Figure 2 The flowchart of the torque distribution method for the distributed drive provided by the embodiment of the present application is shown in Figure Figure 2 As shown in the figure, the torque distribution method for the distributed drive can include the following steps:

[0112] S21, when the driving mode of the vehicle is in the escape mode, the first target demand torque of the target axle provided with the EDS, the first target torque of each wheel corresponding to the target axle, and the allowable maximum driving torque are determined according to the accelerator pedal opening degree and the vehicle state parameters.

[0113] The execution subject of the embodiment of the present application is a vehicle, and the driving form of the vehicle is distributed drive, which can be Figure 1 As shown in the figure, it can also be a front and rear distributed drive configuration as shown in Figure 3 As shown in the figure, it can also be a front and rear distributed drive configuration as shown in

[0114] Figure 3 Another topology diagram of the distributed drive power is shown in FigureFigure 3 As shown, the power battery is arranged in the middle of the distributed drive vehicle, and is used to supply power to the three electric drive systems. One of the drive systems drives the two wheels of the front axle, and the remaining two electric drive systems independently drive the two wheels of the rear axle.

[0115] It should be understood that if the distributed drive is as shown in Figure 1 , one EDS can be arranged on the front axle and the rear axle of the vehicle respectively, i.e., the front axle and the rear axle are both target axles; if the distributed drive is as shown in Figure 3 , one EDS can be arranged on the rear axle, i.e., the rear axle of the vehicle is the target axle.

[0116] Figure 4 The position of the EDS in the front-rear distributed drive configuration is shown in the schematic diagram. As shown in Figure 4 , on the basis of Figure 3 , the rear axle of the vehicle is provided with an EDS.

[0117] In actual application, the driver can operate the human-machine interface (HMI), and then select the driving mode of the vehicle.

[0118] In an optional implementation, in response to the user selecting the escape mode through the HMI, the driving mode of the vehicle is adjusted to the escape mode.

[0119] In a specific implementation, the HMI can display controls corresponding to multiple driving modes for the user. When the driver finds that the vehicle is trapped in a low adhesion condition (shell crater, mud, rock, sand or deep snow), the driver can click the control corresponding to the escape mode in the HMI, and the vehicle adjusts the driving mode of the vehicle to the escape mode in response to the user clicking the control corresponding to the escape mode. It should be understood that the user clicking the control corresponding to the escape mode is the user selecting the escape mode through the HMI.

[0120] Since the escape mode optimizes the injection, ignition and other parameters of the engine to prevent sudden power interruption or fluctuation, in some low adhesion conditions, the vehicle can be adjusted to the most suitable escape mode by interacting with the driver to help the vehicle pass through the complex road section more stably.

[0121] It should be understood that the escape mode includes an intelligent terrain mode ATS (all terrain setting) and a four-wheel drive low-speed mode (4L).

[0122] Among them:

[0123] a) ATS is suitable for all-terrain working conditions, such as rock, mud, sand, etc. The vehicle intelligently judges the current road type through a dynamic fusion algorithm and a visual perception algorithm, and automatically adjusts the power output of the vehicle.

[0124] b) In 4L mode, the vehicle can realize large torque output, and is suitable for complex road conditions and large torque escape needs.

[0125] It should be understood that the first target torque of each wheel corresponding to the target axle is the target torque obtained by the vehicle according to the accelerator pedal opening degree to obtain the total target demand torque of the vehicle, and combined with the first target torque distribution of the left and right motors of the target axle. The first target demand torque of the target axle is the sum of the first target torque of the left and right wheels corresponding to the target axle.

[0126] It should be understood that the wheel corresponding to the target axle is the wheel installed on the target axle.

[0127] It should be understood that the specific implementation process and principles of this step will be specifically explained in the embodiment shown in Figure 6 , and will not be repeated here.

[0128] S22, when the first wheel of the target axle slips, the second target demand torque of the target axle is calculated according to the first target demand torque of the target axle and the allowable maximum driving torque of each wheel corresponding to the target axle.

[0129] It should be understood that the second target demand torque of the target axle is the demand torque of the target axle limited by the allowable maximum driving torque, and the first wheel and the second wheel are in the target axle.

[0130] In one possible implementation, the allowable maximum driving torque of the first wheel and the allowable maximum driving torque of the second wheel are added to obtain the allowable maximum driving torque cumulative sum. Then, the minimum value of the first target demand torque of the target axle and the allowable maximum driving torque cumulative sum is determined as the second target demand torque of the target axle.

[0131] It should be understood that for the target axle, the target demand torque of the target axle needs to be less than the sum of the allowable maximum driving torque of the left and right wheels, and also needs to be less than the first target demand torque allocated to the target axle in the first torque distribution. Therefore, the minimum value between the two can be determined as the second target demand torque of the target axle.

[0132] On the basis of Figure 4 , Figure 5 is a schematic diagram of a vehicle right rear wheel stuck scene. As shown in Figure 5As shown, the right rear wheel of the vehicle is stuck in the pothole, at this time, the first wheel of the vehicle is the right rear wheel, the second wheel is the left rear wheel, and the target axle is the rear axle.

[0133] On the basis of Figure 5 The second target demand torque of the target axle can be calculated by the following formula:

[0134]

[0135] Wherein, The second target demand torque of the rear axle, T Re_TgtDrv is the first target demand torque of the rear axle, is the allowable maximum driving torque of the left rear wheel, is the allowable maximum driving torque of the right rear wheel.

[0136] S23, if the second wheel meets the preset condition, the second target torque of each wheel corresponding to the target axle is calculated according to the second target demand torque of the target axle, the torque capacity of the EDS, the first target torque of each wheel corresponding to the target axle, and the maximum available torque of the motor.

[0137] Wherein, the preset condition is related to the second target demand torque of the target axle.

[0138] For example, the preset condition includes that the maximum available torque of the motor of the second wheel is less than the second target demand of the target axle, and the second target demand of the target axle is less than the allowable maximum driving torque of the second wheel.

[0139] It should be understood that the second target torque of each wheel corresponding to the target axle is the target torque after the difference torque calculation.

[0140] In a possible implementation, the difference between the second target demand torque of the target axle and the first target torque of the second wheel can be determined as the first torque difference of the first wheel. Then, the minimum value of the first torque difference of the first wheel, the torque capacity of the EDS, and the maximum available torque of the motor of the first wheel is determined as the second target torque of the first wheel. Then, the difference between the second target demand torque of the target axle and the second target torque of the first wheel is determined as the first torque difference of the second wheel, and then the minimum value of the first torque difference of the second wheel, the torque capacity of the EDS, and the maximum available torque of the motor of the second wheel is determined as the second target torque of the second wheel.

[0141] In the present solution, the target torque of each wheel needs to be less than the torque capacity of the EDS and the maximum available torque of the motor of the first wheel. Therefore, the difference between the second target demand torque of the target axle and the first target torque of the high adhesion side wheel is calculated for the slipping wheel, and the minimum value of the torque capacity of the EDS and the maximum available torque of the motor of the slipping wheel is determined as the second target torque of the slipping wheel. On this basis, the difference between the second target demand torque of the target axle and the second target torque of the slipping wheel is calculated, and the minimum value of the torque capacity of the EDS and the maximum available torque of the motor of the slipping wheel is determined as the second target torque of the high adhesion side wheel. In this way, the high adhesion side wheel can maximize the use of the torque that the slipping wheel cannot use, improve the utilization rate of power, and also avoid damage and loss of control of the vehicle caused by excessive torque of the vehicle exceeding the torque capacity of the EDS or exceeding the maximum available torque of the motor of the wheel.

[0142] For example, on the basis of the above, Figure 5 Taking the first wheel as the right rear wheel as an example, the second target torque of the first wheel and the second target torque of the second wheel can be calculated by the following formula:

[0143]

[0144]

[0145] wherein T RR_dif is the second target torque of the right rear wheel, is the first target torque of the left rear wheel, T EDS is the torque capacity of the EDS, T RRmax is the maximum available torque of the motor of the right rear wheel, T RL_dif is the second target torque of the left rear wheel, T RLmax is the maximum available torque of the motor of the left rear wheel.

[0146] It should be understood that the torque capacity of the EDS can be calculated according to the differential lock torque model, the temperature model, the state correction model, and the differential lock rotation speed.

[0147] Optionally, if the second wheel meets the preset condition, the EDS enters the locking mode.

[0148] It should be understood that after the EDS enters the locking mode, the torque capacity of the EDS is used to redistribute the power of the two wheels of the target axle, i.e., to determine the final motor target request torque of the two wheels of the target axle.

[0149] S24, for each wheel corresponding to the target axle, determining a final motor target request torque of the wheel according to the second target torque of the wheel, the initial motor target request torque, the yaw torque, and the motor available torque after power limiting of the wheel.

[0150] wherein the initial motor target request torque is a motor target request torque obtained after wheel slip control of the wheel. Specifically, when the first wheel slips is detected, the wheel slip control is activated to limit the torque output of the first wheel to prevent wheel spin, thereby obtaining the initial motor target request torque of the first wheel and the initial motor target request torque of the second wheel.

[0151] In a possible implementation, the minimum value among the second target torque of the first wheel, the initial motor target request torque, the yaw torque, and the motor available torque after power limiting of the first wheel can be determined as the final motor target request torque of the first wheel. The minimum value among the second target torque of the second wheel, the initial motor target request torque, the yaw torque, and the motor available torque after power limiting of the second wheel can be determined as the final motor target request torque of the second wheel.

[0152] In this implementation, the final motor target request torque of the wheel is determined considering the yaw limiting and the system capability limiting (battery power, thermal management, fault state, etc.) to ensure that the vehicle is not damaged and out of control due to excessive torque of the vehicle.

[0153] For example, based on the above, Figure 5 The final motor target request torque of the first wheel and the final motor target request torque of the second wheel can be calculated by the following formula:

[0154] T Req_RL = Min(T RL_dif , T RL_slip , T RL_yaw , T RL_Power )

[0155] T Req_RR = Min(T RR_dif , T RR_slip , T RR_yaw , T RR_Power )

[0156] wherein T Req_RL is the final motor target request torque of the left rear wheel, T RL_slip is the initial motor target request torque of the left rear wheel, T RL_yaw is the yaw torque of the left rear wheel, and T RL_Power is the motor available torque after power limiting of the left rear wheel, TReq_RR final motor target request torque of the right rear wheel, T RR_slip initial motor target request torque of the right rear wheel, T RR_yaw yaw torque of the right rear wheel, T RR_Power motor available torque after power limitation of the right rear wheel.

[0157] The torque distribution method provided by the embodiments of the present application is used for a vehicle with an EDS. When the driving mode of the vehicle is a getting-out-of-trouble mode, a first target demand torque of a target axle provided with the EDS, a first target torque of each wheel corresponding to the target axle, and a maximum allowable driving torque are determined according to an accelerator pedal opening degree and a vehicle state parameter. Then, when a first wheel of the target axle slips, a second target demand torque of the target axle is calculated according to the first target demand torque of the target axle and the maximum allowable driving torque of each wheel corresponding to the target axle. If a second wheel meets a preset condition, a second target torque of each wheel corresponding to the target axle is calculated according to the second target demand torque of the target axle, a torque capacity of the EDS, the first target torque of each wheel corresponding to the target axle, and a maximum available torque of a motor. For each wheel corresponding to the target axle, a final motor target request torque of the wheel is determined according to the second target torque of the wheel, an initial motor target request torque, a yaw torque, and a motor available torque after power limitation of the wheel. The initial motor target request torque is a motor target request torque obtained after wheel slip control of the wheel. The preset condition is related to the second target demand torque of the target axle, and the second wheel is in the target axle. In the technical solution, when the first wheel of the target axle slips and the second wheel meets the preset condition, the EDS is controlled to enter a locking mode, so that the motor torque capacity that cannot be used by the first wheel is transmitted to the second wheel, thereby ensuring that the power is maximally used.

[0158] Optionally, in some embodiments, if the wheel of the target axle exits the wheel slip control, or the reference speed of the vehicle is greater than a preset speed, or the steering angle of the vehicle is greater than a preset angle, or any motor of the vehicle fails, the EDS is controlled to exit the locking mode.

[0159] In the implementation, when the wheel of the target axle exits the wheel slip control, or the reference speed of the vehicle is greater than a preset speed, or the steering angle of the vehicle is greater than a preset angle, it indicates that the vehicle is not in a trapped state at this time, and the locking mode can be exited at this time. Since the control system of the vehicle is designed based on the assumption that all the motors work normally, when a motor fails, the control system of the vehicle can not effectively support the operation of the locking mode. Therefore, when any motor of the vehicle fails, the EDS needs to be controlled to exit the locking mode, so as to ensure that the control system can accurately control the vehicle and ensure normal driving of the vehicle.

[0160] Optionally, in some embodiments, a control signal may be sent to the motor controller of each wheel according to the final motor target requested torque of each wheel corresponding to the target axle.

[0161] After determining the final motor target request torque for each wheel according to each of the above steps, the vehicle controller can send the final motor target request torque for each wheel to the corresponding motor controller to control the motor and complete the torque distribution process and control process.

[0162] Figure 6 This is a flow chart of the second embodiment of the torque distribution method for distributed drive provided in the embodiment of the present application. Figure 6 As shown, S21 can be implemented by the following steps:

[0163] S61 . For each wheel corresponding to the target axle, calculate the utilization adhesion coefficient and slip rate of the wheel according to the vehicle speed and the wheel speed, vertical load, and driving force.

[0164] In one possible implementation, the wheel slip ratio may be calculated based on the vehicle speed and the wheel speed, and then the wheel utilization adhesion coefficient may be calculated based on the wheel driving force and the wheel vertical load.

[0165] In one specific implementation, the wheel speed of each wheel can be collected using a wheel speed sensor. For each wheel corresponding to the target axle, the converted wheel speed is calculated based on the reference vehicle speed. The slip ratio of each wheel is then calculated based on the converted wheel speed and the collected wheel speed. The reference vehicle speed is the vehicle's speed.

[0166] exist Figure 5 Based on this, the slip rate of each wheel corresponding to the target axle can be calculated by the following formula:

[0167]

[0168] V Wl_RL Indicates the wheel speed of the left rear wheel, V Wl_RR Indicates the speed of the right rear wheel, V x is the reference speed, d r Indicates the rear wheel track.

[0169]

[0170] S RL is the slip rate of the left rear wheel, V RL The wheel speed of the left rear wheel collected by the wheel speed sensor; S RR is the slip rate of the right rear wheel, V RRThe wheel speed of the right rear wheel collected by the wheel speed sensor.

[0171] Further, the utilization adhesion coefficient of each wheel corresponding to the target axle is calculated by the following formula:

[0172]

[0173]

[0174] μ RL The utilization adhesion coefficient of the left rear wheel, F x,RL The driving force of the left rear wheel, F z,RL The vertical load of the left rear wheel; μ RR The utilization adhesion coefficient of the right rear wheel, F x,RR The driving force of the right rear wheel, F z,RR The vertical load of the right rear wheel.

[0175] S62, according to the accelerator pedal opening degree, the whole vehicle basic parameters of the vehicle, the input axle load / wheel load parameters, the tire rolling radius of each wheel, the wheel track, the distance from the mass center to the axle where the wheel is located, and the rotation angle of the wheel, the first target demand torque of the target axle and the first target torque of each wheel corresponding to the target axle are calculated.

[0176] In a possible implementation, the following steps A1-A4 can be implemented:

[0177] Step A1, according to the whole vehicle basic parameters of the vehicle and the accelerator pedal opening degree, the total target demand torque and the total target yaw torque of the vehicle are determined.

[0178] In this step, when the torque of the vehicle needs to be distributed, the whole vehicle controller first needs to obtain the whole vehicle basic parameters of the vehicle, and based on these parameters and the accelerator pedal opening degree, the total target demand torque and the total target yaw torque of the vehicle are determined.

[0179] In a specific implementation, the torque distribution of the vehicle can be performed by the vehicle control unit, specifically by the distributed control unit integrated therein. The vehicle control unit (VCU) obtains vehicle basic parameters such as driver demand torque, gear signal, vehicle longitudinal acceleration Ax, vehicle lateral acceleration Ay, vehicle yaw rate YawRate, battery power, and state of charge (SOC), and then estimates a series of state parameters (vehicle speed estimation, axle load estimation, road adhesion coefficient estimation, actual yaw torque estimation, and mass center side slip angle estimation) in a software model environment according to the vehicle basic parameters and the accelerator pedal opening degree. Finally, the total target demand torque and the total target yaw torque are calculated and distributed to the four drive motors, while the actual torque, actual speed, current mode, and fault information of the four drive motors are monitored.

[0180] Step A2, according to the input axle load / wheel load parameter, the torque distribution proportion of the target axle is calculated.

[0181] The axle load / wheel load parameters of the vehicle include front axle load, rear axle load, and total wheel load. The axle load / wheel load parameters can be obtained from the upper module. Specifically, the sum of the wheel loads of the two front wheels of the vehicle is the front axle load, and the sum of the wheel loads of the two rear wheels is the rear axle load.

[0182] In a specific implementation of this step, the ratio of the wheel load corresponding to the target axle of the vehicle to the total wheel load is obtained to obtain the torque distribution proportion of the target axle.

[0183] Step A3, according to the tire rolling radius of each wheel corresponding to the target axle, the wheel track, the distance from the mass center to the axle where the wheel is located, and the wheel rotation angle, the yaw torque conversion coefficient of the wheel is calculated.

[0184] For each wheel, the yaw torque conversion coefficient of the wheel can be calculated according to the characteristics of the wheel itself. The yaw torque conversion coefficient is used to represent the coefficient for converting the driving torque into the yaw torque, and is used to calculate the request torque of each wheel in the torque distribution process.

[0185] On the basis of Figure 5 , the yaw torque conversion coefficient of the first wheel and the yaw torque conversion coefficient of the second wheel can be calculated by the following formula:

[0186] λ RL =[sin(α RL )×l r -cos(μ RL )×d / 2)] / R rolling

[0187] λRR =[sin(α RR )×l r +cos(α RR )×d / 2)] / R rolling

[0188] Among them, λ RL is the yaw torque conversion coefficient of the left rear wheel, α RL is the left rear wheel turning angle, l r is the distance from the center of mass to the rear axle, d is the wheel track, R rolling is the wheel tire rolling radius, α RR is the right rear wheel turning angle, α RR It is the right rear wheel angle.

[0189] Step A4: Calculate the first target required torque of the target axle and the first target torque of each wheel corresponding to the target axle based on the total target required torque, the total target yaw torque, the torque distribution ratio of the target axle, and the yaw torque conversion coefficient of each wheel corresponding to the target axle.

[0190] exist Figure 5 Based on this, the first target required torque of the target axle can be calculated by the following formula:

[0191] T Re_TgtDrv =T TgtDriving ×Rate

[0192] Among them, T TgtDriving is the total target required torque, and Rate is the torque distribution ratio of the rear axle.

[0193] Furthermore, the yaw torque of the target axle can be calculated using the following formula:

[0194] T RE_Yaw =T TgtYaw ×Rate

[0195] Among them, T RE_Yaw is the rear axle yaw torque, T TgtYaw is the total target yaw torque.

[0196] Furthermore, the first target required torque of the target axle and the first target torque of each wheel corresponding to the target axle can be calculated by the following formula:

[0197] T Re_TgtDrv =T RL_raw +T RR_raw ;

[0198] T RL_raw =(T TgtDriving ×λ RR -T RE_Yaw) / (λ RR -λ RL );

[0199] T RR_raw =(T TgtDriving ×λ RL -T RE_Yaw ) / (λ rl -λ RR );

[0200] Among them, T RL_raw is the first target torque of the left rear wheel, T RR_raw is the first target torque of the right rear wheel.

[0201] S63. Determine the maximum allowable driving torque of the wheel based on the road surface type, the utilized adhesion coefficient of the wheel, the slip ratio, the preset maximum load, the tire rolling radius, and the safety factor, where the safety factor is determined based on the adhesion coefficient.

[0202] In a possible implementation, this can be achieved through the following steps B1 to B3:

[0203] Step B1: Determine the target slip rate corresponding to the road surface type.

[0204] Figure 7 The relationship between the slip rate and the adhesion coefficient provided in the embodiment of this application is shown in FIG. Figure 7 As shown in the figure, on different road types (concrete road, dry asphalt road, wet asphalt road, snow and ice), the same slip rate corresponds to different utilization adhesion coefficients, and as the slip rate increases, the utilization adhesion coefficient shows a trend of first increasing and then decreasing.

[0205] Therefore, the target slip rate corresponding to the current road type on which the vehicle is traveling can be determined. The target slip rate is the slip rate corresponding to the maximum utilization adhesion coefficient under the road type. Subsequently, the utilization adhesion coefficient limit of the road surface on which the wheel is located can be determined based on the target slip rate and the slip rate of the wheel.

[0206] Step B2: Determine the maximum allowable driving force of the wheel according to the slip rate of the wheel, the target slip rate, the utilized adhesion coefficient, and the preset maximum load.

[0207] The wheel slip rate and the target slip rate can be compared. If the wheel slip rate is greater than or equal to the target slip rate, the utilization adhesion coefficient corresponding to the target slip rate is determined as the utilization adhesion coefficient limit; if the wheel slip rate is less than the target slip rate, the utilization adhesion coefficient of the wheel is determined as the utilization adhesion coefficient limit.

[0208] exist Figure 5Based on this, the maximum permissible driving force of each wheel corresponding to the target axle can be calculated using the following formula:

[0209]

[0210]

[0211] in, is the maximum permissible driving force of the left rear wheel, is the maximum ground adhesion of the left rear wheel, is the preset maximum load of the left rear wheel, μ RL_max is the utilization adhesion coefficient limit of the left rear wheel, is the maximum permissible driving force of the right rear wheel, is the maximum ground adhesion of the right rear wheel, is the preset maximum load of the right rear wheel, μ RR_max is the utilization adhesion limit of the right rear wheel.

[0212] In practical applications, the maximum ground adhesion of the wheel is generally determined as the maximum allowable driving force.

[0213] Step B3: Determine the maximum allowable driving torque of the wheel according to the maximum allowable driving force of the wheel, the tire rolling radius, and the safety factor.

[0214] exist Figure 5 Based on this, the maximum permissible driving torque of each wheel corresponding to the target axle can be calculated using the following formula:

[0215]

[0216]

[0217] is the maximum permissible driving torque of the left rear wheel, R roll is the tire rolling radius, η μRL is the safety factor of the left rear wheel, is the maximum permissible driving torque of the right rear wheel, η μRR is the safety factor of the right rear wheel.

[0218] It should be understood that the safety factor of each wheel is obtained by looking up the table using the adhesion coefficient limit.

[0219] In the off-road escape mode (escape mode) of the distributed drive system, the vehicle can significantly improve its maneuverability and stability in complex road conditions through intelligent torque distribution strategies. The torque distribution process generally follows the following steps:

[0220] 1) Sensor data processing: Vehicle status and road type are calculated in real time based on on-board sensor signals (including but not limited to wheel speed sensors, accelerometers, and steering angle sensors).

[0221] 2) Target Torque Calculation: Based on the vehicle's basic parameters and current driving conditions, the controller calculates the total target demand torque and total target yaw torque, ensuring that the vehicle not only moves forward but also maintains a stable driving direction.

[0222] 3) Torque Distribution: Based on axle / wheel load parameters and the total target torque demand, the controller determines the specific torque value to be provided to each wheel. For wheels on low-grip surfaces, power output may be reduced or even temporarily cut off to prevent slip. For other wheels with sufficient grip, torque is increased to maintain vehicle power and stability.

[0223] 4) Dynamic Adjustment: Based on vehicle needs and road conditions during driving, the controller continuously monitors and dynamically adjusts the torque distribution to each wheel to cope with changing road conditions and driving demands, dynamically adjusting the torque output of the front and rear axle motors to optimize system efficiency and vehicle stability.

[0224] 5) System optimization: To further improve performance, the distributed drive system may also combine preset constraints and objective functions to achieve more refined control effects through optimization algorithms.

[0225] Through the above process, the distributed drive wheels can demonstrate excellent power, stability and economy in off-road mode, and give full play to their advantages in driving force output and handling stability.

[0226] In existing technologies, traditional off-road vehicles also use differential locks to distribute torque. Next, we will introduce mechanical differential locks and electronic differential locks respectively:

[0227] Mechanical differential lock: Figure 8 The diagram below is a schematic diagram of the structure of a traditional powered off-road vehicle. Figure 8As shown, the traditional power off-road vehicle has only one power source (a longitudinal engine) connected with a transfer case to distribute the power output by the longitudinal engine to different vehicle axles (such as front and rear axles). The mechanical differential lock of the off-road vehicle is arranged on the rear axle, and the function of the mechanical differential lock is to eliminate the speed difference of the left and right drive wheels to obtain the same driving force, and cancel the automatic distribution of driving force relying on rolling resistance after locking. After the front, middle and rear differential locks are all locked, the power is distributed in a fixed ratio of 50%:50% front and rear, 50%:50% left and right, and the vehicle can drive straight at low speed, but the left and right wheels can only be forced to twist and slide when turning, and the steering operation can be realized by relying on manual torque or by adding a special assistance mechanism to compensate for the limitations of the mechanical structure, and the actual driving experience is extremely poor. The off-road vehicle with traditional mechanical four-wheel drive has a high risk of losing control, which is a safety risk. For example, assuming that the total power of the vehicle is 100, and the front axle and the rear axle are each allocated 50 after the three locks are all locked, and the left front wheel, the right front wheel, the left rear wheel and the right rear wheel are each allocated 25. If the wheels on one side of the same shaft slip, the distribution relationship between the wheels on the slipping side of the shaft and the wheels on the high adhesion side is approximately 0:50%.

[0228] Electronic differential lock: automatically lock by judging the speed difference between the left and right wheels. This automatic locking mode is judged by the electronic differential lock itself, and there is no direct interaction with the yaw stability control and anti-slip control of the TVC module, the control target torque deviation is large, or the power loss is caused, and the vehicle driving stability is poor.

[0229] In summary, the traditional electronic differential mechanism does not interact with the wheel anti-slip control, the control target torque deviation is large, and the driving ability and drivability of the vehicle cannot be fully utilized.

[0230] The distributed drive torque distribution method provided by the present application can retain the characteristics of distributed drive torque control, realize intelligent transfer of drive torque, fully utilize the maximum capacity of the drive system, and improve the extreme escape ability of the vehicle in special working conditions.

[0231] Next, the distributed drive torque distribution scheme is explained and described through two specific examples.

[0232] Figure 9 A flowchart of a distributed drive torque distribution method embodiment provided for the embodiments of the present application is shown in FIG. 8. Figure 9 As shown, the distributed drive torque distribution method includes the following steps:

[0233] S901, obtaining a determination operation of a driver through an HMI.

[0234] The determination operation includes a determination operation for an ATS, or a determination operation for a 4L.

[0235] S902, determine the mode determined by the driver according to the determination operation.

[0236] S903, monitor the electric drive system state to obtain the motor mode, actual speed, actual torque, and fault level.

[0237] S904, determine the electric drive system capability according to the motor mode, actual speed, actual torque, and fault level, to output the left rear wheel torque limit and the right rear wheel torque limit.

[0238] S905, determine the vehicle state parameters.

[0239] The vehicle state parameters include actual vehicle speed, actual wheel speed, actual torque, and inertial measurement unit (IMU) sensor parameters.

[0240] S906, calculate the utilization adhesion coefficients of each wheel according to the vehicle state parameters.

[0241] Among them, the left front wheel utilization adhesion coefficient, the left front wheel utilization adhesion coefficient, the right rear wheel utilization adhesion coefficient, and the right rear wheel utilization adhesion coefficient are calculated.

[0242] S907, calculate the target demand torque according to the mode selected by the driver, the left rear wheel torque limit, and the right rear wheel torque limit.

[0243] S908, perform wheel slip rate control according to the left front wheel utilization adhesion coefficient, the left front wheel utilization adhesion coefficient, the right rear wheel utilization adhesion coefficient, and the right rear wheel utilization adhesion coefficient.

[0244] S909, calculate the EDS torque according to the EDS state, the EDS position, and the EDS torque capacity.

[0245] S910, perform PID control torque distribution according to the front axle target torque, the left rear wheel original target torque, the right rear wheel original target torque, the left rear wheel torque reduction request, the right rear wheel torque reduction request, the left rear wheel torque capacity, the right rear wheel torque capacity, and the EDS maximum torque.

[0246] S911, perform torque arbitration, torque limitation, and torque transfer according to the torque limit, the speed limit, the power limit calculated according to the EDS torque, and the yaw torque limit, the steering input limit, the front axle target torque, the left rear wheel target torque, and the right rear wheel target torque obtained by PID control torque distribution, to obtain the arbitrated front axle target torque, the arbitrated right rear wheel target torque, and the arbitrated left rear wheel target torque.

[0247] Figure 10 The flowchart of the fourth embodiment of the distributed drive torque distribution method provided by the embodiments of the present application is shown in FIG. 4.Figure 10 The torque distribution method of the distributed drive shown includes the following steps:

[0248] S1001, HMI input.

[0249] S1002, determine the enable state of the driving mode.

[0250] If ATS is enabled, execute S1003; if 4L is enabled, execute S1010.

[0251] S1003, calculate the first target demand torque according to the terrain mode.

[0252] S1004, determine whether the right rear wheel is slipping.

[0253] If the right rear wheel is slipping, execute S1005; if the right rear wheel is not slipping, execute S1003.

[0254] S1005, whether the maximum available torque of the left rear wheel is less than the second target demand of the rear axle.

[0255] If yes, execute S1006.

[0256] S1006, whether the second target demand of the rear axle is less than the maximum allowable driving torque of the left rear wheel.

[0257] If yes, execute S1007; if no, adjust the state of EDS to open.

[0258] S1007, adjust the state of EDS to slip lock.

[0259] S1008, determine the final motor target request torque of the left rear wheel and the right rear wheel.

[0260] S1009, determine whether EDS is in the enabled state.

[0261] If yes, and EDS is in the slip lock state, execute S1008; if yes, and EDS is in the slip lock state, execute S1010; if no, execute S1002.

[0262] S1010, perform target torque distribution according to 50:50 to determine the motor target request torque of the left rear wheel and the right rear wheel.

[0263] In the technical solution, the vehicle load information and the road condition information of the target vehicle are acquired, in the escape mode, and when the accelerator pedal is stepped on, the target torque of the differential lock is obtained according to the pedal opening degree information, the vehicle load information and the road condition information, and the target position of the differential lock is determined according to the target torque. The transferred torque is the target torque of the EDS, which is dynamically calculated by the vehicle control system according to the current vehicle state, the road condition and the driving demand, aiming to maximize the traction and stability of the vehicle in complex road conditions.

[0264] When the technology solution identifies that a certain wheel is slipping and the calculated target driving force exceeds the single-wheel maximum motor torque capacity, the EDS is controlled to be locked. The torque difference is obtained according to the target driving torque of the target axle and the single-wheel maximum motor torque capacity. The torque transmission capacity of the EDS is controlled according to the calculated torque difference. Whether the vehicle has escaped is judged according to the slip ratio of the slipping wheel, and the slip ratio control is exited. According to the state of judging whether the vehicle has escaped, the EDS is controlled to be opened, and the road driving force of the slipping side wheel is restored. Intelligent distribution: when a wheel is slipping, the required torque > non-slip side motor torque (motor allowable torque, motor torque is limited), and the slipping side motor has no capacity limited fault, the limited slip differential lock is intelligently locked, and the driving torque is compensated.

[0265] The technical effects of the technology solution include:

[0266] 1) The coaxial distributed dual-motor with electronic mechanical limited slip differential lock realizes the left and right motor driving lock.

[0267] 2) The intelligent escape mode judges the opening and closing of the electronic limited slip differential lock and the torque output according to the wheel slip ratio.

[0268] 3) The motor torque capacity of the slipping side wheel is transmitted to the high-attached side wheel, the total driving torque capacity of the coaxial is increased, the coaxial driving capacity is maximized, and the vehicle is helped to escape.

[0269] 4) The electronic differential control and the wheel slipping control (state) interact, the actual required driving torque can be accurately calculated, and the vehicle driving process is more stable.

[0270] The following is an embodiment of the device of the present application, which can be used to execute the method embodiments of the present application. For details not disclosed in the device embodiments of the present application, please refer to the method embodiments of the present application.

[0271] Figure 11 The structure diagram of the torque distribution control device of the distributed drive provided by the embodiment of the present application is shown in FIG. Figure 11 As shown in the figure, the torque distribution control device 110 of the distributed drive includes:

[0272] The first determination module 1101 is configured to determine, when the driving mode of the vehicle is the escape mode, a first target demand torque of a target axle provided with an EDS, a first target torque of each wheel corresponding to the target axle, and a maximum allowable driving torque according to an accelerator pedal opening degree and a vehicle state parameter.

[0273] The first calculation module 1102 is configured to calculate a second target demand torque of the target axle according to the first target demand torque of the target axle and the maximum allowable driving torque of each wheel corresponding to the target axle when a first wheel of the target axle slips.

[0274] The second calculation module 1103 is configured to calculate a second target torque of each wheel corresponding to the target axle according to the second target demand torque of the target axle, a torque capacity of the EDS, the first target torque of each wheel corresponding to the target axle, and a maximum available torque of the motor if a second wheel meets a preset condition, the preset condition being related to the second target demand torque of the target axle, and the second wheel being in the target axle.

[0275] The second determination module 1104 is configured to determine, for each wheel corresponding to the target axle, a final motor target request torque of the wheel according to the second target torque of the wheel, an initial motor target request torque, a yaw torque, and a motor available torque after power limiting of the wheel, the initial motor target request torque being a motor target request torque obtained after wheel slip control of the wheel.

[0276] In a possible design, the first calculation module 1102 is specifically configured to:

[0277] add the maximum allowable driving torque of the first wheel and the maximum allowable driving torque of the second wheel to obtain a maximum allowable driving torque cumulative sum;

[0278] determine, as the second target demand torque of the target axle, a minimum value in the first target demand torque of the target axle and the maximum allowable driving torque cumulative sum.

[0279] In a possible design, the second calculation module 1103 is specifically configured to:

[0280] determine, as a first torque difference of the first wheel, a difference between the second target demand torque of the target axle and the first target torque of the second wheel;

[0281] determine, as the second target torque of the first wheel, a minimum value in the first torque difference of the first wheel, the torque capacity of the EDS, and a maximum available torque of the motor of the first wheel;

[0282] determine, as a first torque difference of the second wheel, a difference between the second target demand torque of the target axle and the second target torque of the first wheel;

[0283] determining the minimum value among the first target torque of the second wheel, the initial motor target request torque, the yaw torque, and the motor available torque after power limiting on the second wheel as the final motor target request torque of the second wheel.

[0284] In a possible design, the second determining module 1104 is specifically configured to:

[0285] determining the minimum value among the second target torque of the first wheel, the initial motor target request torque, the yaw torque, and the motor available torque after power limiting on the first wheel as the final motor target request torque of the first wheel;

[0286] determining the minimum value among the second target torque of the second wheel, the initial motor target request torque, the yaw torque, and the motor available torque after power limiting on the second wheel as the final motor target request torque of the second wheel.

[0287] In a possible design, the first determining module 1101 is specifically configured to:

[0288] calculating the utilization adhesion coefficient and the slip ratio of the wheel according to the vehicle speed, the wheel speed, the vertical load, and the driving force of the wheel;

[0289] calculating the first target demand torque of the target axle and the first target torque of each wheel corresponding to the target axle according to the accelerator pedal opening degree, the vehicle basic parameter, the input axle load / wheel load parameter, the tire rolling radius of each wheel, the wheel track, the distance from the mass center to the axle where the wheel is located, and the wheel rotation angle;

[0290] determining the allowable maximum driving torque of the wheel according to the road type, the utilization adhesion coefficient, the slip ratio, the preset maximum load, the tire rolling radius, and the safety coefficient, the safety coefficient being determined according to the adhesion coefficient.

[0291] In a possible design, the first determining module 1101 is specifically configured to:

[0292] calculating the slip ratio of the wheel according to the vehicle speed and the wheel speed;

[0293] calculating the utilization adhesion coefficient of the wheel according to the driving force of the wheel and the vertical load of the wheel.

[0294] In a possible design, the first determining module 1101 is specifically configured to:

[0295] determining the total target demand torque and the total target yaw torque of the vehicle according to the vehicle basic parameter and the accelerator pedal opening degree;

[0296] According to the input axle load / wheel load parameter, the torque distribution ratio of the target axle is calculated;

[0297] According to the tire rolling radius, wheel track, distance from the mass center to the wheel, and rotation angle of each wheel corresponding to the target axle, the yaw torque conversion coefficient of the wheel is calculated;

[0298] According to the total target demand torque, total target yaw torque, torque distribution ratio of the target axle, and yaw torque conversion coefficient of each wheel corresponding to the target axle, the first target demand torque of the target axle and the first target torque of each wheel corresponding to the target axle are calculated.

[0299] In a possible design, the first determination module 1101 is specifically configured to:

[0300] According to the road type, the target slip ratio corresponding to the road type is determined, and the target slip ratio is the slip ratio corresponding to the maximum utilization adhesion coefficient under the road type;

[0301] According to the slip ratio of the wheel, the target slip ratio, the utilization adhesion coefficient, and the preset maximum load, the allowable maximum driving force of the wheel is determined.

[0302] According to the allowable maximum driving force of the wheel, the tire rolling radius, and the safety coefficient, the allowable maximum driving torque of the wheel is determined.

[0303] In a possible design, the torque distribution control device 110 of the distributed drive further includes a control module, configured to:

[0304] If the second wheel meets the preset condition, the EDS is controlled to enter the locking mode;

[0305] If the wheel of the target axle exits the wheel slip control, or the reference speed of the vehicle is greater than the preset speed, or the steering angle of the vehicle is greater than the preset angle, or any motor of the vehicle fails, the EDS is controlled to exit the locking mode.

[0306] In a possible design, the preset condition includes that the maximum available torque of the motor of the second wheel is less than the second target demand of the target axle, and the second target demand of the target axle is less than the allowable maximum driving torque of the second wheel.

[0307] In a possible design, the torque distribution control device 110 of the distributed drive further includes an adjustment module, configured to:

[0308] In response to the user selecting the escape mode through the human-computer interface HMI, the driving mode of the vehicle is adjusted to the escape mode.

[0309] In a possible design, the distributed drive torque distribution control device 110 further includes a sending module configured to:

[0310] According to the final motor target request torque of each wheel corresponding to the target axle, a control signal is sent to the motor controller of each wheel.

[0311] The distributed drive torque distribution control device provided in the embodiments of the present application can be used to execute the distributed drive torque distribution control method in any of the above-mentioned embodiments, and has similar implementation principles and technical effects, which will not be described here again.

[0312] It should be noted that the division of each module of the above device is only a logical function division, and all or part of the modules can be integrated into one physical entity, or can be physically separated. Moreover, all of the modules can be implemented in the form of software invoked by a processing element, or all of the modules can be implemented in the form of hardware, or part of the modules are implemented in the form of software invoked by a processing element, and part of the modules are implemented in the form of hardware. In addition, all or part of the modules can be integrated together, or can be independently implemented. The processing element mentioned herein can be an integrated circuit having a signal processing capability. In the implementation process, each step of the above method or each module can be completed by an integrated logic circuit of hardware in the processing element or an instruction in the form of software.

[0313] In addition, the present application also provides a vehicle, which includes a vehicle body, a vehicle controller, a motor of each wheel, a memory, and computer program instructions stored in the memory and executable on the vehicle controller, and the vehicle controller is configured to implement the technical solutions of the distributed drive torque distribution method in any of the above-mentioned method embodiments when executing the computer program instructions.

[0314] Optionally, the above-mentioned devices in the vehicle can be connected through a system bus.

[0315] The memory can be a separate storage unit, or can be a storage unit integrated in the vehicle controller.

[0316] Optionally, the vehicle can further include an interface for interacting with other devices, a display for displaying information to a user, and the like.

[0317] It should be understood that the whole vehicle controller can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in the present application can be directly embodied by a hardware processor for execution, or executed by a combination of hardware and software modules in the processor.

[0318] The system bus can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The system bus can be divided into an address bus, a data bus, a control bus, etc. For the sake of representation, only one thick line is used in the figure, but it does not mean that there is only one bus or only one type of bus. The memory can include a random access memory (RAM), and can also include a non-volatile memory (NVM), such as at least one disk memory.

[0319] All or part of the steps of the above-mentioned method embodiments can be completed by program instruction related hardware. The foregoing program can be stored in a readable memory. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the foregoing memory (storage medium) includes a read-only memory (ROM), a RAM.

[0320] The vehicle provided by the embodiments of the present application is used to execute the technical solutions provided by any method embodiment, and has similar implementation principles and technical effects, which will not be described here.

[0321] The embodiments of the present application provide a computer readable storage medium, which stores computer execution instructions, when the computer execution instructions run on the controller of the vehicle, the vehicle executes the distributed driving torque distribution method.

[0322] The above computer readable storage medium can be implemented by any type of volatile or nonvolatile storage devices or a combination thereof, such as static random access memory, electrically erasable programmable read only memory, erasable programmable read only memory, programmable read only memory, read only memory, magnetic storage, flash memory. The readable storage medium can be any available medium that can be accessed by a general purpose or special purpose computer.

[0323] Optionally, the readable storage medium is coupled to the processor so that the processor can read information from, and write information to, the readable storage medium. It is appreciated that the readable storage medium can be a part of the processor. The processor and the readable storage medium can be located in an application specific integrated circuits (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in a variety of devices.

[0324] It is to be understood that the application is not limited to the precise construction that has been described above and shown in the accompanying drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the present application. The scope of the application should only be limited by the appended claims.

Claims

1. A torque distribution method for distributed drive, characterized in that: include: When the vehicle's driving mode is the escape mode, determining, based on the accelerator pedal opening and vehicle state parameters, a first target required torque of a target axle provided with an EDS, a first target torque of each wheel corresponding to the target axle, and an allowable maximum driving torque; When a first wheel of the target axle slips, calculating a second target required torque of the target axle according to the first target required torque of the target axle and the maximum allowable driving torque of each wheel corresponding to the target axle; If the second wheel meets a preset condition, calculating a second target torque for each wheel corresponding to the target axle according to the second target required torque of the target axle, the torque capacity of the EDS, the first target torque of each wheel corresponding to the target axle, and the maximum available torque of the motor, wherein the preset condition is related to the second target required torque of the target axle and the second wheel is on the target axle; For each wheel corresponding to the target axle, the final motor target request torque of the wheel is determined based on the second target torque of the wheel, the initial motor target request torque, the yaw torque, and the motor available torque after power limitation of the wheel. The initial motor target request torque is the motor target request torque obtained after wheel slip control is performed on the wheel.

2. The method according to claim 1, characterized in that Calculating the second target required torque of the target axle according to the first target required torque of the target axle and the maximum allowable driving torque of each wheel corresponding to the target axle includes: adding the maximum permissible driving torque of the first wheel and the maximum permissible driving torque of the second wheel to obtain a cumulative sum of the maximum permissible driving torques; The minimum value of the accumulated sum of the first target required torque of the target axle and the allowable maximum driving torque is determined as the second target required torque of the target axle.

3. The method according to claim 1 or 2, characterized in that The calculating, based on the second target required torque of the target axle, the torque capacity of the EDS, the first target torque of each wheel corresponding to the target axle, and the maximum available torque of the motor, the second target torque of each wheel corresponding to the target axle includes: Determine a difference between the second target required torque of the target axle and the first target torque of the second wheel as a first torque difference of the first wheel; determining a minimum value among a first torque difference of the first wheel, a torque capacity of the EDS, and a maximum available torque of the motor of the first wheel as a second target torque of the first wheel; Determine a difference between the second target required torque of the target axle and the second target torque of the first wheel as a first torque difference of the second wheel; A minimum value among the first torque difference of the second wheel, the torque capacity of the EDS, and the maximum available torque of the motor of the second wheel is determined as the second target torque of the second wheel.

4. The method according to claim 1 or 2, characterized in that The method further comprises determining, for each wheel corresponding to the target axle, a final motor target requested torque for the wheel based on the second target torque of the wheel, the initial motor target requested torque, the yaw torque, and the motor available torque after power limitation is applied to the wheel, including: determining a minimum value among the second target torque of the first wheel, the initial motor target request torque, the yaw torque, and the motor available torque after power limitation is applied to the first wheel as a final motor target request torque for the first wheel; The minimum value among the second target torque of the second wheel, the initial motor target request torque, the yaw torque, and the motor available torque after power limitation is performed on the second wheel is determined as the final motor target request torque of the second wheel.

5. The method according to claim 1 or 2, characterized in that The determining, based on the accelerator pedal opening and the vehicle state parameters, of a first target required torque of a target axle provided with an EDS, a first target torque of each wheel corresponding to the target axle, and an allowable maximum driving torque includes: For each wheel corresponding to the target axle, calculating the utilized adhesion coefficient and slip rate of the wheel according to the vehicle speed and the wheel speed, vertical load, and driving force of the wheel; Calculating a first target required torque for the target axle and a first target torque for each wheel corresponding to the target axle based on the accelerator pedal opening, the basic vehicle parameters of the vehicle, the input axle load / wheel load parameters, the tire rolling radius of each wheel, the wheel track, the distance from the center of mass to the axle where the wheel is located, and the turning angle of the wheel; The maximum allowable driving torque of the wheel is determined according to the road surface type, the utilized adhesion coefficient of the wheel, the slip rate, the preset maximum load, the tire rolling radius and the safety factor, wherein the safety factor is determined according to the adhesion coefficient.

6. The method according to claim 5, characterized in that The calculating the utilization adhesion coefficient and slip rate of the wheel according to the vehicle speed and the wheel speed, vertical load, and driving force of the wheel includes: Calculating the slip rate of the wheel according to the vehicle speed and the wheel speed; The utilization adhesion coefficient of the wheel is calculated according to the driving force of the wheel and the vertical load of the wheel.

7. The method according to claim 5, characterized in that The step of calculating the first target required torque of the target axle and the first target torque of each wheel corresponding to the target axle based on the accelerator pedal opening, the basic vehicle parameters, the input axle load / wheel load parameters, the tire rolling radius of each wheel, the wheel track, the distance from the center of mass to the axle where the wheel is located, and the wheel rotation angle includes: determining a total target required torque and a total target yaw torque of the vehicle according to the basic vehicle parameters and the accelerator pedal opening; Calculate the torque distribution ratio of the target axle based on the input axle load / wheel load parameters; Calculating a yaw torque conversion coefficient of each wheel according to a tire rolling radius, a wheel track, a distance from the center of mass to the axle where the wheel is located, and a rotation angle of the wheel; According to the total target required torque, the total target yaw torque, the torque distribution ratio of the target axle and the yaw torque conversion coefficient of each wheel corresponding to the target axle, the first target required torque of the target axle and the first target torque of each wheel corresponding to the target axle are calculated.

8. A torque distribution control device for distributed drive, characterized in that: include: a first determination module for determining, when the vehicle driving mode is the escape mode, a first target required torque of a target axle provided with an EDS, a first target torque of each wheel corresponding to the target axle, and an allowable maximum driving torque based on an accelerator pedal opening and vehicle state parameters; a first calculation module, configured to calculate a second target required torque of the target axle according to the first target required torque of the target axle and the maximum allowable driving torque of each wheel corresponding to the target axle when the first wheel of the target axle slips; a second calculation module, configured to calculate a second target torque for each wheel corresponding to the target axle based on a second target required torque of the target axle, a torque capacity of the EDS, a first target torque for each wheel corresponding to the target axle, and a maximum available torque of the motor if the second wheel satisfies a preset condition, the preset condition being related to the second target required torque of the target axle and the second wheel being on the target axle; The second determination module is used to determine the final motor target request torque of each wheel corresponding to the target axle according to the second target torque of the wheel, the initial motor target request torque, the yaw torque, and the motor available torque after power limitation of the wheel, wherein the initial motor target request torque is the motor target request torque obtained after wheel slip control is performed on the wheel.

9. A vehicle, characterized in that: include: A vehicle body, a vehicle controller, a motor for each wheel, a memory, and computer program instructions stored in the memory and executable on the vehicle controller. When the vehicle controller executes the computer program instructions, it is used to implement the torque distribution method for distributed drive as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to implement the torque distribution method for distributed drive according to any one of claims 1 to 7.

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