Distributed driving torque distribution method and device, vehicle and medium

Abstract

The invention provides a torque distribution method and device for distributed driving, a vehicle and a medium, and relates to the technical field of vehicles. The method comprises the steps that when the driving mode of the vehicle is an out-of-trap mode, according to the opening degree of an accelerator pedal and state parameters of the whole vehicle, torque distribution is conducted; determining 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 an allowable maximum driving torque; and when the 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 allowable maximum driving torque of each wheel corresponding to the target axle. And if the second wheel meets the preset condition, the motor torque capacity of the first wheel is transmitted to the second wheel, and therefore it is guaranteed that power is utilized to the maximum extent.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a torque distribution method, device, vehicle and medium for distributed drive. Background Art

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

[0003] At present, the driving torque distribution method of distributed structure electric vehicles usually adopts a relatively simple method, such as the 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 of the invention

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

[0006] In a first aspect, an embodiment of the present application provides a torque distribution method for a distributed drive, comprising:

[0007] When the driving mode of the vehicle is the escape mode, determining the first target required 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 and the vehicle state parameters;

[0008] 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 allowable maximum driving torque of each wheel corresponding to the target axle;

[0009] If the second wheel meets a preset condition, the second target torque of each wheel corresponding to the target axle is calculated 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, the preset condition is related to the second target required torque of the target axle, and the second wheel is at the target axle;

[0010] For each wheel corresponding to the target axle, the final motor target request torque of the wheel 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 limitation is performed on the wheel. The initial motor target request torque is the motor target request torque obtained after wheel slip control is performed on the wheel.

[0011] In a possible design, calculating the second target required torque of the target axle according to the first target required torque of the target axle and the allowable maximum driving torque of each wheel corresponding to the target axle includes:

[0012] adding the maximum permissible driving torque of the first wheel and the maximum permissible driving torque of the second wheel to obtain an accumulated sum of the maximum permissible driving torques;

[0013] 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.

[0014] In a possible design, calculating the second target torque of 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 includes:

[0015] Determine a difference between a second target required torque of the target axle and a first target torque of the second wheel as a first torque difference of the first wheel;

[0016] 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;

[0017] 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;

[0018] The 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.

[0019] In a possible design, 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 limitation is performed on the wheel, includes:

[0020] Determine 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 performed on the first wheel as the final motor target request torque of the first wheel;

[0021] 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.

[0022] In a possible design, determining the first target required 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 and the vehicle state parameters includes:

[0023] For each wheel corresponding to the target axle, 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;

[0024] Calculate the first target required torque of the target axle and the first target torque of each wheel corresponding to the target axle according to the accelerator pedal opening, the 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 center of mass to the axle where the wheel is located, and the turning angle of the wheel;

[0025] The maximum allowable driving torque of the wheel is determined 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 factor, and the safety factor is determined according to the adhesion coefficient.

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

[0029] In a possible design, the first target required torque of the target axle and the first target torque of each wheel corresponding to the target axle are calculated according to the accelerator pedal opening, the 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 center of mass to the axle where the wheel is located, and the turning angle of the wheel, including:

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

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

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

[0033] 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.

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

[0035] Determining, according to the road surface type, a target slip rate corresponding to the road surface type, wherein the target slip rate is a slip rate corresponding to a maximum utilized adhesion coefficient under the road surface type;

[0036] determining 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;

[0037] The maximum allowable driving torque of the wheel is determined according to the maximum allowable driving force of the wheel, the tire rolling radius, and the safety factor.

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

[0039] Determining, according to the road surface type, a target slip rate corresponding to the road surface type, wherein the target slip rate is a slip rate corresponding to a maximum utilized adhesion coefficient under the road surface type;

[0040] determining 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;

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

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

[0043] In one possible design, the method further includes:

[0044] In response to a user's escape mode selection operation performed through the HMI, the driving mode of the vehicle is adjusted to the escape mode.

[0045] In one possible design, the method further includes:

[0046] A control signal is sent to a motor controller of each wheel according to a final motor target requested 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 a distributed drive, comprising:

[0048] A first determination module is used to determine, when the driving mode of the vehicle is an 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 according to an accelerator pedal opening and a vehicle state parameter;

[0049] a first calculation module, configured to calculate a second target required torque of the target axle according to a first target required torque of the target axle and an allowable maximum driving torque of each wheel corresponding to the target axle when a first wheel of the target axle slips;

[0050] a second calculation module, configured to calculate a second target torque of each wheel corresponding to the target axle according to a second target required torque of the target axle, a torque capacity of the EDS, a first target torque of each wheel corresponding to the target axle, and a maximum available torque of the motor if the second wheel meets 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;

[0051] 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.

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

[0053] adding the maximum permissible driving torque of the first wheel and the maximum permissible driving torque of the second wheel to obtain an accumulated sum of the maximum permissible driving torques;

[0054] 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.

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

[0056] Determine a difference between a second target required torque of the target axle and a first target torque of the second wheel as a first torque difference of the first wheel;

[0057] 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;

[0058] 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;

[0059] The 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.

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

[0061] Determine 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 performed on the first wheel as the final motor target request torque of the first wheel;

[0062] 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.

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

[0064] For each wheel corresponding to the target axle, 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;

[0065] Calculate the first target required torque of the target axle and the first target torque of each wheel corresponding to the target axle according to the accelerator pedal opening, the 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 center of mass to the axle where the wheel is located, and the turning angle of the wheel;

[0066] The maximum allowable driving torque of the wheel is determined 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 factor, and the safety factor is determined according to the adhesion coefficient.

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

[0068] Calculating the slip rate of the wheel according to the vehicle speed and the wheel speed of the wheel;

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

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

[0071] Determining a total target required torque and a total target yaw torque of the vehicle according to the vehicle basic parameters and the accelerator pedal opening;

[0072] Calculate the torque distribution ratio of the target axle according to the input axle load / wheel load parameters;

[0073] Calculate the yaw torque conversion coefficient of each wheel according to the tire rolling radius, wheel track, distance from the center of mass to the axle where the wheel is located, and the turning angle of the wheel of each wheel corresponding to the target axle;

[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] Determining, according to the road surface type, a target slip rate corresponding to the road surface type, wherein the target slip rate is a slip rate corresponding to a maximum utilized adhesion coefficient under the road surface type;

[0077] determining 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;

[0078] The maximum allowable driving torque of the wheel is determined according to the maximum allowable driving force of the wheel, the tire rolling radius, and the safety factor.

[0079] In a possible design, the torque distribution control device of the distributed drive further includes a control module, which is used to:

[0080] If the second wheel meets the preset condition, controlling the EDS to enter a locking 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, the EDS is controlled to exit the locking mode.

[0082] In one possible design, the preset condition includes that the maximum available torque of the motor of the second wheel is less than the second target requirement of the target axle, and the second target requirement 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 device for distributed drive further includes an adjustment module, which is used to:

[0084] In response to a user's escape mode selection operation through a human-machine interface (HMI), the driving mode of the vehicle is adjusted to the escape mode.

[0085] In a possible design, the torque distribution control device for distributed drive further includes a sending module, which is used to:

[0086] A control signal is sent to a motor controller of each wheel according to a final motor target requested torque of each wheel corresponding to the target axle.

[0087] In the third aspect, an embodiment of the present application provides a vehicle, comprising: 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, wherein the vehicle controller is used to implement the first aspect and the methods provided by various possible designs when executing the computer program instructions.

[0088] In a fourth aspect, an embodiment of the present application may provide a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the first aspect and the methods provided by various possible designs.

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

[0090] The torque distribution method, device, vehicle and medium of the distributed drive provided by the embodiment of the present application include: when the driving mode of the vehicle is the escape mode, the first target demand torque of the target axle provided with EDS, the first target torque of each wheel corresponding to the target axle and the maximum allowable driving torque are determined according to the accelerator pedal opening and the vehicle state parameters. Afterwards, 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 maximum allowable driving torque of each wheel corresponding to the target axle. If the second wheel meets the preset conditions, 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. For each wheel corresponding to the target axle, the final motor target request torque of the wheel 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 the wheel is power-limited. The initial motor target request torque is the motor target request torque obtained after the wheel slip control is performed on the wheel, and 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 this 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 unusable motor torque capacity of the first wheel is transmitted to the second wheel, thereby ensuring that the power is maximized. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0092] Figure 1 A topological diagram of a distributed drive power;

[0093] Figure 2 A schematic diagram of a process flow of a first embodiment of a torque distribution method for a distributed drive provided in an embodiment of the present application;

[0094] Figure 3 Another topological diagram of distributed drive power;

[0095] Figure 4 Schematic diagram of the position of EDS in the distributed drive configuration of one in front and two in the back;

[0096] Figure 5This is a schematic diagram of a scenario where the right rear wheel of a vehicle is trapped;

[0097] Figure 6 A schematic diagram of a flow chart of a second embodiment of a torque distribution method for a distributed drive provided in an embodiment of the present application;

[0098] Figure 7 A curve diagram showing the relationship between the slip rate and the utilized adhesion coefficient provided in the embodiment of the present application;

[0099] Figure 8 It is a schematic diagram of the structure of a conventionally powered off-road vehicle;

[0100] Fig. 9 A schematic diagram of a process flow of a third embodiment of a torque distribution method for a distributed drive provided in an embodiment of the present application;

[0101] Fig.10 A schematic diagram of a flow chart of a fourth embodiment of a torque distribution method for a distributed drive provided in an embodiment of the present application;

[0102] Fig.11 A schematic diagram of the structure of a torque distribution control device for a distributed drive provided in an embodiment of the present application.

[0103] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope 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] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this 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 Figure 1 is a topological diagram of distributed drive power. Figure 1 As shown, the distributed drive vehicle is provided with a power battery for powering 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 vehicle driving status.

[0107] Distributed drive vehicles can achieve intelligent torque distribution between the front and rear axles and the left and right wheels. However, since the driving force of the left and right wheels on the same axis is completely decoupled, when one wheel slips, the driving torque of the wheel on the slipping side will be limited, while the driving torque of other wheels will not change. In other words, in the above example, if the wheel on one side of the same axis slips, the distribution relationship between the wheel on the slipping side and the wheel on the high attachment side of the axis is approximately 0:25%. In this case, the maximum capacity of the vehicle drive system is limited, resulting in power waste.

[0108] Based on the above technical problems, the invention concept of the present application is as follows: In the prior art, the main reason for the power waste of distributed drive vehicles when they slip is that the driving torque of the wheels on the slipping side can only be limited, and the motor torque cannot be transferred, resulting in the waste of the driving torque of the wheels on the slipping side. Therefore, an electronic limited-slip differential (EDS) can be set on the axle of the vehicle. When it is determined that the vehicle is in an escape mode, there is wheel slippage and certain preset conditions are met, the EDS is controlled to lock so that the motor torque capacity of the slipping side wheel is transferred to the coaxial high-addition side wheel, maximizing the use of the coaxial drive capacity, thereby solving the problem of power waste and helping the vehicle escape.

[0109] The technical solution of the present application is described in detail below through specific embodiments.

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

[0111] Figure 2 This is a flow chart of a first embodiment of a torque distribution method for distributed drive provided in an embodiment of the present application. Figure 2 As shown, the torque distribution method of the distributed drive may include the following steps:

[0112] S21. When the vehicle driving mode is the escape mode, determine the first target required torque of the target axle provided with 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 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 a distributed drive, which can be Figure 1 As shown, it can also be Figure 3 The distributed drive configuration of one in front and two in the back shown can also be a distributed drive configuration of two in front and one in the back.

[0114] Figure 3 Another topological diagram of distributed drive power is shown in Figure 2. Figure 3 As shown, a power battery is arranged in the middle of the distributed drive vehicle to power 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 Figure 1 As shown, an EDS can be set on the front axle and the rear axle of the vehicle respectively, that is, the front axle and the rear axle are both target axles; if the distributed drive is as follows Figure 3 As shown, an EDS can be set at the rear axle, that is, the rear axle of the vehicle is the target axle.

[0116] Figure 4 Figure 1 is a schematic diagram of the position of EDS in the distributed drive configuration with one EDS in front and two EDS in the back. Figure 4 As shown, in Figure 3 On the basis of the vehicle, the rear axle is provided with an EDS.

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

[0118] In an optional implementation, in response to the user performing an escape mode selection operation 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 pit, 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 vehicle's driving mode to the escape mode in response to the user's click operation on the control corresponding to the escape mode. It should be understood that the user's click operation on the control corresponding to the escape mode is the user's escape mode selection operation performed through the HMI.

[0120] Since the escape mode optimizes the engine's injection, ignition and other parameters to prevent sudden power interruption or fluctuation, it can interact with the driver in some low-adhesion conditions to adjust the vehicle to the most suitable escape mode to help the vehicle pass through complex roads more stably.

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

[0122] in:

[0123] a) ATS is suitable for all-terrain conditions, such as rock, mud, sand, etc. The vehicle uses dynamic fusion algorithms and visual perception algorithms to intelligently determine the current road type and automatically adjust the vehicle's power output.

[0124] b) In 4L mode, the vehicle can achieve high torque output, which is suitable for the high torque escape requirements in complex road conditions.

[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 obtaining the total target required torque of the vehicle according to the accelerator pedal opening after the driver steps on the accelerator pedal, and performing the first target axle motor torque distribution on the left and right motors in combination with the basic parameters of the vehicle. The first target required torque of the target axle is the sum of the first target torques 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 principle of this step will be Figure 6 The specific explanation is given in the illustrated embodiment and will not be repeated here.

[0128] S22. When a first wheel of the target axle slips, a second target required torque of the target axle is calculated 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.

[0129] It should be understood that the second target required torque of the target axle is the required torque of the target axle subject to the allowable maximum drive torque limit, and the first wheel and the second wheel are located at the target axle.

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

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

[0132] exist Figure 4 On the basis of Figure 5 The following is a schematic diagram of a scenario where the right rear wheel of a vehicle is trapped. Figure 5As shown, the right rear wheel of the vehicle is trapped in a mud pit. 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] exist Figure 5 Based on this, the second target required torque of the target axle can be calculated by the following formula:

[0134]

[0135] in, The second target torque required by the rear axle, T Re_TgtDrv is the first target required torque of the rear axle, is the maximum permissible driving torque of the left rear wheel, is the maximum permissible drive torque for the right rear wheel.

[0136] S23. If the second wheel meets the preset conditions, the second target torque of each wheel corresponding to the target axle is calculated 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.

[0137] The preset condition is related to the second target required torque of the target axle.

[0138] Exemplarily, 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 differential torque calculation.

[0140] In a possible implementation, the difference between the second target required 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. Afterwards, the minimum value among 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 required 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 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.

[0141] In this solution, since the target torque of each wheel needs to be less than the torque capacity of the EDS and less than the maximum available torque of the motor of the first wheel. Therefore, the difference between the second target required torque of the target axle and the first target torque of the high-attachment wheel can be calculated for the slipping wheel, and the difference is compared with the torque capacity of the EDS and the maximum available torque of the motor of the slipping wheel, and the minimum value is determined as the second target torque of the slipping wheel. On this basis, the difference between the second target required torque of the target axle and the second target torque of the slipping wheel is calculated, and the difference is compared with the torque capacity of the EDS and the maximum available torque of the motor of the slipping wheel, and the minimum value is determined as the second target torque of the high-attachment wheel. In this way, it can ensure that the high-attachment wheel can maximize the use of the torque that the slipping wheel cannot use, improve the utilization rate of power, and avoid excessive torque of the vehicle, which exceeds the torque capacity of the EDS or exceeds the maximum available torque of the motor of the wheel, resulting in vehicle damage and loss of control.

[0142] For example, in Figure 5 On this basis, the explanation is continued by taking the first wheel as the right rear wheel as an example, and 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] Among them, 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 EDS, T RRmax is the maximum available torque of the motor on 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 for the left rear wheel.

[0146] It should be understood that the torque capacity of the EDS may be calculated based on a differential lock torque model, a temperature model, a state correction model, and a differential lock speed.

[0147] Optionally, if the second wheel meets a preset condition, the EDS is controlled to enter a locking mode.

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

[0149] S24. For each wheel corresponding to the target axle, determine 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 limitation is performed on the wheel.

[0150] The initial motor target torque is the motor target torque obtained after the wheel slip control is performed on the wheel. Specifically, when the first wheel slip is detected, the wheel slip control is activated to limit the torque output of the first wheel to prevent the wheel from spinning, thereby obtaining the initial motor target torque of the first wheel and the initial motor target 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 limitation is performed on 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 limitation is performed on the second wheel can also be determined as the final motor target request torque of the second wheel.

[0152] In this implementation, the final motor target torque requested by the wheel is determined comprehensively by taking into account the yaw limit and system capability limit (battery power, thermal management, fault status, etc.) to ensure that the vehicle is not damaged or out of control due to excessive torque.

[0153] For example, in Figure 5 Based on this, the explanation is continued by taking the first wheel as the right rear wheel as an example. 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] Among them, T Req_RL is the final motor target torque request for the left rear wheel, T RL_slip is the initial motor target torque request for the left rear wheel, T RL_yaw is the yaw torque of the left rear wheel, T RL_Power is the available torque of the motor after power limitation on the left rear wheel, TReq_RR is the final motor target torque request for the right rear wheel, T RR_slip is the initial motor target torque request for the right rear wheel, T RR_yaw is the yaw torque of the right rear wheel, T RR_Power The motor's available torque after power limitation to the right rear wheel.

[0157] The torque distribution method of the distributed drive provided in the embodiment of the present application, when the driving mode of the vehicle is the escape mode, determines the first target demand torque of the target axle with 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 and the vehicle state parameters. Afterwards, 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 maximum allowable driving torque of each wheel corresponding to the target axle. 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. For each wheel corresponding to the target axle, the final motor target request torque of the wheel 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 the wheel is power-limited. Among them, the initial motor target request torque is the motor target request torque obtained after the wheel is subjected to wheel slip control, 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 this technical solution, when the first wheel of the target axle slips and the second wheel meets the preset conditions, the EDS is controlled to enter the locking mode to transfer the unusable motor torque capacity of the first wheel to the second wheel, thereby ensuring that the power is maximized.

[0158] Optionally, in some embodiments, if the wheels of the target axle exit 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 this implementation, when the wheels of the target axle exit 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, it means 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 motors are working normally, when a motor fails, the control system of the vehicle may not be able to effectively support the operation of the locking mode. Therefore, when any motor of the vehicle fails, it is necessary to control the EDS to exit the locking mode to ensure that the control system can accurately control the vehicle and ensure the normal driving of the vehicle.

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

[0161] After the final motor target request torque of each wheel is determined according to each of the above steps, the vehicle controller can send the final motor target request torque of 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 a second embodiment of a torque distribution method for distributed drive provided in an 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 a possible implementation, the slip rate of the wheel can be calculated according to the vehicle speed and the wheel speed, and then the utilization adhesion coefficient of the wheel can be calculated according to the driving force of the wheel and the vertical load of the wheel.

[0165] In a specific implementation, the wheel speed of each wheel can be collected by a wheel speed sensor. For each wheel corresponding to the target axle, the converted wheel speed of the wheel is calculated according to the reference vehicle speed, and then the slip rate of the wheel is calculated based on the converted wheel speed of the wheel and the collected wheel speed of the wheel. The reference vehicle speed is the vehicle 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] Furthermore, the utilization adhesion coefficient of each wheel corresponding to the target axle is calculated by the following formula:

[0172]

[0173]

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

[0175] S62. Calculate the first target required torque of the target axle and the first target torque of each wheel corresponding to the target axle according to 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 wheel axis, and the wheel turning angle.

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

[0177] Step A1: Determine the total target required torque and the total target yaw torque of the vehicle according to the basic parameters of the vehicle and the accelerator pedal opening.

[0178] In this step, when the vehicle controller needs to distribute the vehicle's torque, it first needs to obtain the vehicle's basic parameters, and determine the vehicle's total target required torque and total target yaw torque based on these parameters and the accelerator pedal opening.

[0179] In a specific implementation, the torque distribution of the vehicle can be executed by the vehicle controller, specifically, it can be processed by the integrated distributed control unit, and the basic parameters of the vehicle are obtained from the vehicle controller (VCU), such as the driver's required torque, gear signal, vehicle longitudinal acceleration Ax, vehicle lateral acceleration Ay, vehicle yaw angular velocity YawRate, battery power, battery state of charge (state of charge, SOC), and then a series of state parameters are estimated in the software model environment according to the basic parameters of the vehicle and the accelerator pedal opening (vehicle speed estimation, axle load estimation, road adhesion coefficient estimation, actual yaw torque estimation, center of mass sideslip angle estimation, etc.), and finally the total target required torque and total target yaw torque are calculated and distributed to the four drive motors, and the actual torque, actual speed, current mode, fault information and other states of the four drive motors are monitored at the same time.

[0180] Step A2: Calculate the torque distribution ratio of the target axle according to the input axle load / wheel load parameters.

[0181] The axle load / wheel load parameters of the vehicle include the front axle wheel load, the rear axle wheel load, and the 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 wheel load, and the sum of the wheel loads of the two rear wheels is the rear axle wheel load.

[0182] In the specific implementation of this step, the torque distribution ratio of the target axle may be obtained by taking the ratio of the wheel load corresponding to the target axle of the vehicle to the total wheel load.

[0183] Step A3: Calculate the yaw torque conversion coefficient of each wheel according to the tire rolling radius, wheel track, distance from the center of mass to the wheel axis, and the wheel turning angle of each wheel corresponding to the target axle.

[0184] For each wheel, the yaw torque conversion coefficient of the wheel can be calculated in combination with 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 requested torque of each wheel during the torque distribution process.

[0185] exist Figure 5 Based on this, 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 turning angle.

[0189] Step A4, calculating the first target required torque of the target axle and the first target torque of each wheel corresponding to the target axle 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.

[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 by 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 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 factor, where the safety factor is determined according to the adhesion coefficient.

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

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

[0204] Figure 7 The relationship between the slip rate and the adhesion coefficient provided in the embodiment of the present 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 utilization adhesion coefficient corresponding to the same slip rate is different, 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 can be determined according to the current road type on which the vehicle is traveling. 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 according to the target slip rate and the slip rate of the wheel.

[0206] Step B2: determining 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 by 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 It is the utilization adhesion coefficient 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: determining the maximum allowable driving torque of the wheel according to the maximum allowable driving force of the wheel, the rolling radius of the tire 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 by 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 distributed drive, the vehicle can significantly improve its passability and stability under complex road conditions through intelligent torque distribution strategy. The torque distribution process usually follows the following steps:

[0220] 1) Sensor data processing: The vehicle status and road type are calculated in real time based on the 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 basic parameters of the vehicle and the current driving conditions, the controller calculates the total target demand torque and the total target yaw torque, ensuring that the vehicle can not only move forward but also maintain a stable driving direction.

[0222] 3) Torque distribution: Based on the axle load / wheel load parameters and the total target torque requirement, the controller will determine the specific torque value that each wheel should obtain. For wheels on low-grip roads, the power output may be reduced or even temporarily cut off to avoid slipping; while for other wheels with sufficient grip, the torque supply is increased to maintain the power and stability of the vehicle.

[0223] 4) Dynamic Adjustment: Based on vehicle needs and road conditions during driving, the controller continuously monitors and dynamically adjusts the torque distribution of each wheel to cope with changing road conditions and driving needs, and dynamically adjusts 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 sophisticated 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 the prior art, traditional off-road vehicles also use differential locks to distribute torque. Next, the mechanical differential lock and the electronic differential lock are introduced respectively:

[0227] Mechanical differential lock: Figure 8 The figure is a schematic diagram of the structure of a traditional off-road vehicle. Figure 8As shown, the traditional off-road vehicle has only one power source (longitudinal engine), which is connected to the transfer case to distribute the power output by the longitudinal engine to different axles of the vehicle (such as the front axle and the rear axle). The mechanical differential lock of this off-road vehicle is set on the rear axle. The function of the mechanical differential lock is to eliminate the wheel speed difference between the left and right driving wheels to obtain the same driving force. After locking, the automatic distribution of driving force based on rolling resistance is cancelled. After the front, middle and rear differential locks are all locked, the power will be distributed in a fixed ratio of 50%:50% front and rear and 50%:50% left and right. The vehicle can drive straight at low speed, but when turning, the left and right wheels can only twist and slide forcibly. The steering operation can only be achieved by relying on hand torque steering or adding a special power-assisting mechanism, and experience is used to compensate for the limitations of the mechanical structure. The actual driving experience is extremely poor. The off-road loss rate of traditional mechanical four-wheel drive is very high, which poses a safety risk. For example: Assuming the total vehicle power is 100, after all three locks are locked, the front axle is 50, the rear axle is 50, the left front wheel is 25, the right front wheel is 25, the left rear wheel is 25, and the right rear wheel is 25. If the wheels on one side of the same axis slip, the distribution relationship between the wheels on the slipping side and the wheels on the high attachment side of the axle is approximately 0:50%.

[0228] Electronic differential lock: Automatically locks the vehicle by judging the speed difference between the left and right wheels. This automatic locking method is determined by the electronic differential lock itself and has no direct interaction with the yaw stability control and anti-skid control of the TVC module. The control target torque deviation is large, or power loss is caused, resulting in poor vehicle driving stability.

[0229] In summary, the traditional electronic differential mechanism has no interaction with the wheel anti-slip control, the control target torque deviation is large, and the vehicle's driving ability and drivability cannot be brought into full play.

[0230] The distributed drive torque distribution method provided in the present application retains the characteristics of distributed drive torque control, realizes the intelligent transfer of drive torque, can fully utilize the maximum capacity of the drive system, and improve the vehicle's ultimate escape capability under special working conditions.

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

[0232] Fig. 9 This is a flow chart of the third embodiment of the torque distribution method for distributed drive provided in the embodiment of the present application. Fig. 9 As shown, the torque distribution method of the distributed drive includes the following steps:

[0233] S901: Acquire the driver's confirmation operation through the HMI.

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

[0235] S902: Determine the mode determined by the driver according to the determination operation.

[0236] S903: Monitor the status of the electric drive system to obtain the motor mode, actual speed, actual torque, and fault level.

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

[0238] S905: Determine vehicle status parameters.

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

[0240] S906: Calculate the utilization adhesion coefficient of each wheel according to the vehicle state parameters.

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

[0242] S907 : Calculate the target required 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 adhesion coefficient, the left front wheel adhesion coefficient, the right rear wheel adhesion coefficient, and the right rear wheel adhesion coefficient.

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

[0245] S910, performing PID controlled 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 based on the torque limit, speed limit, power limit calculated by EDS torque and the yaw torque limit, steering input limit, front axle target torque, left rear wheel target torque and right rear wheel target torque obtained by torque distribution controlled by PID, and obtain the arbitrated front axle target torque, arbitrated right rear wheel target torque and arbitrated right and left wheel target torque.

[0247] Fig.10 This is a flow chart of a fourth embodiment of a torque distribution method for distributed drive provided in an embodiment of the present application. Fig.10 As shown, the torque distribution method of the distributed drive includes the following steps:

[0248] S1001, HMI input.

[0249] S1002: Determine the enabling status of the driving mode.

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

[0251] S1003. Calculate a first target required torque according to the terrain mode.

[0252] S1004: Determine whether the right rear wheel is slipping.

[0253] If the right rear wheel slips, execute S1005; if the right rear wheel does not slip, execute S1003.

[0254] S1005: Is the maximum available torque of the motor of the left rear wheel less than the second target requirement of the rear axle?

[0255] If yes, execute S1006.

[0256] S1006: Is the second target demand of the rear axle less than the allowable maximum 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 EDS status to Sliplock

[0259] S1008: Determine final motor target requested torques for the left rear wheel and the right rear wheel.

[0260] S1009: Determine whether EDS is in an enabled state.

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

[0262] S1010 , distribute the target torque in a 50:50 ratio, and determine the motor target request torques of the left rear wheel and the right rear wheel.

[0263] In the above technical solution, by obtaining the vehicle load information of the vehicle and the road condition information of the road where the target vehicle is located, 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 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 amount of torque transferred is the "target torque of EDS", which is dynamically calculated by the vehicle control system according to the current vehicle state, road conditions and driving requirements, and is intended to maximize the traction and stability of the vehicle under complex road conditions.

[0264] This technical solution controls the EDS to lock when it is identified that a wheel is slipping and the calculated target driving force exceeds the maximum motor torque capacity of a single wheel. The torque difference is obtained based on the target driving torque of the target axle and the maximum motor torque capacity of a single wheel. Based on the calculated torque difference, the torque transmission capacity of the EDS is controlled. Based on the slip rate of the slipping wheel, it is determined whether the vehicle has escaped and the slip rate control is exited. Based on the state of the vehicle's escape, the EDS is controlled to open and the road driving force of the wheel on the slipping side is restored. Intelligent distribution: When one side of the wheel slips and the required torque is greater than the motor torque on the non-slipping side (the motor's allowable torque, the motor torque is limited), and the motor on the slipping side has no capacity limitation fault, the limited slip differential lock is intelligently locked to compensate for the driving torque.

[0265] The technical effects of this technical solution include:

[0266] 1) Coaxial distributed dual motors with electronic mechanical limited slip differential lock to achieve left and right side motor drive locking.

[0267] 2) The intelligent escape mode determines the opening and closing of the electronic limited slip differential lock and the torque output based on the wheel slip rate.

[0268] 3) The motor torque capacity of the slipping side wheel is transferred to the high-attachment side wheel, increasing the total coaxial driving torque capacity, maximizing the use of the coaxial driving capacity, and helping the vehicle to get out of trouble.

[0269] 4) The electronic differential control interacts with the wheel slip control (status) to accurately calculate the actual required driving torque, making the vehicle driving more stable.

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

[0271] Fig.11 This is a schematic diagram of the structure of the torque distribution control device for distributed drive provided in the embodiment of the present application. Fig.11 As shown, the torque distribution control device 110 of the distributed drive includes:

[0272] The first determination module 1101 is used to determine, when the driving mode of the vehicle 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 according to an accelerator pedal opening and a vehicle state parameter;

[0273] A first calculation module 1102 is used to calculate a second target required torque of the target axle according to a first target required torque of the target axle and an allowable maximum driving torque of each wheel corresponding to the target axle when a first wheel of the target axle slips;

[0274] A second calculation module 1103 is used to calculate the second target torque of 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 if the second wheel meets the preset condition, the preset condition is related to the second target required torque of the target axle, and the second wheel is on the target axle;

[0275] The second determination module 1104 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 limiting 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.

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

[0277] 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;

[0278] 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.

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

[0280] Determine the difference between the second target required torque of the target axle and the first target torque of the second wheel as the first torque difference of the first wheel;

[0281] Determine 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;

[0282] Determine the difference between the second target required torque of the target axle and the second target torque of the first wheel as the first torque difference of the second wheel;

[0283] The 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.

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

[0285] Determine 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 performed on the first wheel as the final motor target request torque of the first wheel;

[0286] 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.

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

[0288] For each wheel corresponding to the target axle, the utilization adhesion coefficient and slip rate of the wheel are calculated according to the vehicle speed and the wheel speed, vertical load and driving force;

[0289] Calculate the first target required torque of the target axle and the first target torque of each wheel corresponding to the target axle according to the accelerator pedal opening, the 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 center of mass to the axle where the wheel is located, and the turning angle of the wheel;

[0290] The maximum permissible driving torque of the wheel is determined based on the road surface type, the wheel's utilized adhesion coefficient, the slip rate, the preset maximum load, the tire rolling radius and the safety factor. The safety factor is determined based on the adhesion coefficient.

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

[0292] Calculate the wheel slip rate according to the vehicle speed and the wheel speed;

[0293] The wheel's utilization adhesion coefficient is calculated based on the wheel's driving force and the wheel's vertical load.

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

[0295] Determine the total target required torque and total target yaw torque of the vehicle according to the basic parameters of the vehicle and the accelerator pedal opening;

[0296] Calculate the torque distribution ratio of the target axle according to the input axle load / wheel load parameters;

[0297] Calculate the wheel yaw torque conversion coefficient according to the tire rolling radius, wheel track, distance from the center of mass to the wheel axis, and the wheel turning angle of each wheel corresponding to the target axle;

[0298] 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.

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

[0300] According to the road surface type, a target slip rate corresponding to the road surface type is determined, and the target slip rate is the slip rate corresponding to the maximum utilized adhesion coefficient under the road surface type;

[0301] Determine the maximum permissible 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;

[0302] The maximum allowable driving torque of the wheel is determined based on the maximum allowable driving force of the wheel, the tire rolling radius and the safety factor.

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

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

[0305] If the wheels of the target axle exit 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 one possible design, the preset condition includes that the maximum available torque of the motor of the second wheel is less than the second target requirement of the target axle, and the second target requirement 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 for:

[0308] In response to the user's escape mode selection operation performed through the human-machine interface HMI, the driving mode of the vehicle is adjusted to the escape mode.

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

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

[0311] The torque distribution control device for distributed drive provided in the embodiment of the present application can be used to execute the torque distribution control method for distributed drive in any of the above embodiments. Its implementation principle and technical effects are similar and will not be repeated here.

[0312] It should be noted that it should be understood that the division of the various modules of the above device is only a division of logical functions. In actual implementation, they can be fully or partially integrated into one physical entity, or they can be physically separated. And these modules can all be implemented in the form of software calling through processing elements; they can also be all implemented in the form of hardware; some modules can also be implemented in the form of software calling through processing elements, and some modules can be implemented in the form of hardware. In addition, all or part of these modules can be integrated together, or they can be implemented independently. The processing element described here can be an integrated circuit with signal processing capabilities. In the implementation process, each step of the above method or each module above can be completed by an integrated logic circuit of hardware in the processor element or instructions 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 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 technical solution of the torque distribution method of the distributed drive in any of the aforementioned method embodiments.

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

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

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

[0317] It should be understood that the vehicle controller can be a central processing unit (CPU), or 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 as being executed by a hardware processor, or executed by a combination of hardware and software modules in the processor.

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

[0319] All or part of the steps of the above-mentioned method embodiments can be completed by hardware related to program instructions. The above-mentioned 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 above-mentioned memory (storage medium) includes: read-only memory (ROM), RAM.

[0320] The vehicle provided in the embodiment of the present application is used to execute the technical solution provided in any method embodiment, and its implementation principle and technical effect are similar, which will not be repeated here.

[0321] An embodiment of the present application provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed on a controller of a vehicle, the vehicle executes the above-mentioned torque distribution method of distributed drive.

[0322] The computer-readable storage medium mentioned above can be implemented by any type of volatile or non-volatile storage device 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 memory, flash memory. The readable storage medium can be any available medium that can be accessed by a general or special-purpose computer.

[0323] Optionally, a readable storage medium is coupled to a processor so that the processor can read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (ASIC). Of course, the processor and the readable storage medium can also exist in the device as discrete components.

[0324] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A torque distribution method for distributed drive, characterized in that: include: When the driving mode of the vehicle is the escape mode, determining the first target required 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 and the vehicle state parameters; 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 allowable maximum driving torque of each wheel corresponding to the target axle; If the second wheel meets a preset condition, the second target torque of each wheel corresponding to the target axle is calculated 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, the preset condition is related to the second target required torque of the target axle, and the second wheel is at the target axle; For each wheel corresponding to the target axle, the final motor target request torque of the wheel 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 limitation is performed on 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 The calculating the second target required torque of the target axle according to the first target required torque of the target axle and the allowable maximum 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 an accumulated 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 the second target torque of 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 includes: Determine a difference between a second target required torque of the target axle and a 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; The 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 of determining, 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, the initial motor target request torque, the yaw torque, and the motor available torque after power limitation is performed on the wheel, comprises: Determine 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 performed on the first wheel 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 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 method of determining, according to the accelerator pedal opening and the vehicle state parameter, 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 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; Calculate the first target required torque of the target axle and the first target torque of each wheel corresponding to the target axle according to the accelerator pedal opening, the 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 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 utilization adhesion coefficient of the wheel, the slip rate, the preset maximum load, the tire rolling radius and the safety factor, and 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 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: Calculating the slip rate of the wheel according to the vehicle speed and the wheel speed of the wheel; 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 first target required torque of the target axle and the first target torque of each wheel corresponding to the target axle are calculated according to the accelerator pedal opening, the vehicle basic 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 turning angle of the wheel, including: Determining a total target required torque and a total target yaw torque of the vehicle according to the vehicle basic parameters and the accelerator pedal opening; Calculate the torque distribution ratio of the target axle according to the input axle load / wheel load parameters; Calculate the yaw torque conversion coefficient of each wheel according to the tire rolling radius, wheel track, distance from the center of mass to the axle where the wheel is located, and the turning angle of the wheel of each wheel corresponding to the target axle; 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 is used to determine, when the driving mode of the vehicle is an 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 according to an accelerator pedal opening and a vehicle state parameter; a first calculation module, configured to calculate a second target required torque of the target axle according to a first target required torque of the target axle and an allowable maximum driving torque of each wheel corresponding to the target axle when a first wheel of the target axle slips; a second calculation module, configured to calculate a second target torque of each wheel corresponding to the target axle according to a second target required torque of the target axle, a torque capacity of the EDS, a first target torque of each wheel corresponding to the target axle, and a maximum available torque of the motor if the second wheel meets 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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