Vehicle speed estimation method and system for four-wheel independent drive vehicle, computer readable storage medium, electronic equipment and vehicle

Abstract

The invention discloses a vehicle speed estimation method and system for a four-wheel independent drive vehicle, a computer readable storage medium, electronic equipment and a vehicle, and the method comprises the steps: determining a target wheel when each wheel slips; performing torque control on a target wheel to enable the target wheel to be in a non-slip state; and determining the speed of the whole vehicle based on the torque of the target wheel. According to the vehicle speed estimation method and system for the four-wheel independent drive vehicle, the computer readable storage medium, the electronic equipment and the vehicle provided by the invention, torque control is quickly and accurately performed on the target wheel by utilizing the advantage of four-motor independent drive, dependence on an acceleration sensor with relatively large signal noise is not needed, and the vehicle speed estimation efficiency is improved. And the vehicle speed of the whole vehicle can be estimated only through the stable wheel speed signal.

Description

Technical Field

[0001] The present invention relates to the field of vehicle control technology, and in particular to a vehicle speed estimation method, system, computer-readable storage medium, electronic equipment and vehicle for a four-wheel independent drive vehicle. Background Art

[0002] In the prior art, vehicle speed estimation is mainly divided into vehicle speed estimation under stable conditions and vehicle speed estimation under unstable conditions. The vehicle speed estimation under stable conditions is mainly obtained by converting the wheel speed collected by the sensor. Under unstable conditions, the wheel will produce large slippage, so the wheel speed collected by the wheel speed sensor can no longer accurately reflect the speed of the whole vehicle. For vehicle speed estimation when the four wheels slip, in this case, all wheel speeds cannot be used as a reference for the estimated speed of the whole vehicle. The current estimated speed of the whole vehicle can only be obtained by integrating the acceleration signal collected by the IMU. This method has high requirements on the quality of the input acceleration signal, otherwise the speed obtained by integration will have a large deviation. Summary of the invention

[0003] A series of simplified concepts are introduced in the Summary of the Invention, which will be further described in detail in the Detailed Description of the Invention. The Summary of the Invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0004] The present invention provides a vehicle speed estimation method for a four-wheel independent drive vehicle, comprising:

[0005] When all wheels are slipping, determine the target wheel;

[0006] Performing torque control on a target wheel so that the target wheel is in a non-slip state;

[0007] Based on the torque of the target wheel, the vehicle speed is determined.

[0008] Exemplarily, determining the vehicle speed of the vehicle based on the torque of the target wheel includes:

[0009] Determine the pure rolling wheel speed of the target wheel;

[0010] Based on the pure rolling wheel speed of the target wheel, the vehicle's overall speed is determined.

[0011] Exemplarily, performing torque control on the target wheel includes:

[0012] reducing the torque of the target wheel; or

[0013] A reverse torque is applied to the target wheel.

[0014] Exemplarily, placing the target wheel in a non-slip state includes:

[0015] The slip rate of the target wheel is made to enter a linear region of an adhesion coefficient-slip rate curve.

[0016] Exemplarily, when all wheels are slipping, determining the target wheel includes determining the target wheel based on a vehicle body state, wherein:

[0017] When the vehicle body is moving straight, the diagonal wheel is selected as the target wheel;

[0018] When the vehicle body is in understeer, the inner wheel is selected as the target wheel;

[0019] When the vehicle is in oversteering, the outer wheel is selected as the target wheel.

[0020] Exemplarily, determining the pure rolling wheel speed of the target wheel includes:

[0021]

[0022] Among them, V FW represents the pure rolling wheel speed of the target wheel;

[0023] V W represents the wheel speed of the target wheel obtained by the wheel speed sensor;

[0024] C λ Indicates the longitudinal stiffness of the tire;

[0025] F D Indicates the driving wheel end torque after the target wheel torque is reduced;

[0026] F N Indicates the vertical load on the target wheel.

[0027] Exemplarily, determining the vehicle speed of the vehicle based on the pure rolling wheel speed of the target wheel includes:

[0028]

[0029] Among them, V CoG Indicates the vehicle speed;

[0030] V FW represents the pure rolling wheel speed of the target wheel;

[0031] represents the vehicle yaw rate;

[0032] L f,r Indicates the track width of the front or rear axle;

[0033] δN Indicates the turning angle of the target wheel.

[0034] Exemplarily, the method further includes:

[0035] Get the acceleration of the whole vehicle and each wheel;

[0036] Whether each wheel is slipping is determined based on the whole vehicle acceleration and the acceleration of each wheel.

[0037] Exemplarily, determining whether each wheel is slipping based on the whole vehicle acceleration and the acceleration of each wheel includes:

[0038] Obtaining a difference between the acceleration of the entire vehicle and the acceleration of each wheel;

[0039] When the difference is greater than a threshold, it is determined that the wheel is slipping.

[0040] Exemplarily, the slip rate of the target wheel enters the linear region of the adhesion coefficient-slip rate curve including:

[0041] The slip rate of the target wheel enters 0% to 20% of the adhesion coefficient-slip rate curve.

[0042] Exemplarily, the target wheels include one or two wheels.

[0043] The present invention also provides a vehicle speed estimation system for a four-wheel independent drive vehicle, comprising:

[0044] A target wheel determination module, used to determine the target wheel when all wheels are slipping;

[0045] A torque control module, used for performing torque control on a target wheel so that the target wheel is in a non-slip state;

[0046] The vehicle speed determination module is used to determine the vehicle speed of the vehicle based on the torque of the target wheel.

[0047] The present invention also provides a computer-readable storage medium, which stores one or more programs. The one or more programs can be executed by one or more processors to implement any of the above-described vehicle speed estimation methods for four-wheel independent drive vehicles.

[0048] The present invention also provides an electronic device, comprising a processor and a memory, wherein the processor is used to execute any of the above-mentioned vehicle speed estimation methods for a four-wheel independent drive vehicle.

[0049] The present invention also provides a vehicle, comprising the electronic device as described above.

[0050] According to the vehicle speed estimation method, system, computer-readable storage medium, electronic device and vehicle for a four-wheel independent drive vehicle provided by the present invention, when four wheels slip simultaneously under non-steady-state conditions, a target wheel is determined, and the advantage of the independent drive of four motors is utilized to quickly and accurately perform torque control on the target wheel so that the target wheel is in a non-slip state, and the whole vehicle speed of the vehicle is obtained based on the torque of the target wheel. In this way, there is no need to rely on an acceleration sensor with large signal noise, and the whole vehicle speed estimation can be achieved only by using a stable wheel speed signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The following drawings of the present invention are used to understand the present invention as part of the present invention. The embodiments of the present invention are shown in the drawings and the description thereof is used to explain the principle of the present invention.

[0052] In the attached figure:

[0053] Figure 1 FIG. 4 is a structural block diagram of a vehicle according to an embodiment of the present invention.

[0054] Figure 2 is a flow chart of a vehicle speed estimation method for a four-wheel independent drive vehicle according to an embodiment of the present invention;

[0055] Figure 3 Schematic diagram of an adhesion coefficient-slip rate curve according to an embodiment of the present invention. DETAILED DESCRIPTION

[0056] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is apparent to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features well known in the art are not described.

[0057] It should be understood that the present invention can be implemented in different forms and should not be construed as being limited to the embodiments presented herein. On the contrary, providing these embodiments will make the disclosure thorough and complete and fully convey the scope of the present invention to those skilled in the art. In the accompanying drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. The same reference numerals throughout represent the same elements.

[0058] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present invention. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0059] In order to fully understand the present invention, detailed steps and detailed structures will be presented in the following description to illustrate the technical solution proposed by the present invention. The preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other implementations.

[0060] In order to solve the problem of four-wheel slipping simultaneously under non-steady-state conditions, the present invention provides a vehicle speed estimation method, electronic equipment and vehicle for a four-wheel independent drive vehicle.

[0061] First refer to Figure 1 A schematic structural diagram of a vehicle 100 is described.

[0062] like Figure 1 As shown, vehicle 100 includes vehicle sensor device 110 and electronic device 120 .

[0063] In one embodiment, the vehicle sensing device 110 includes one or more sensors, and the one or more sensors are used to collect vehicle information, driving information and / or environmental information of the vehicle, etc. The vehicle sensing device 110 includes but is not limited to a speed sensor, a pressure sensor, a temperature sensor, a torque sensor, an ABS sensor, an axle position sensor, etc.

[0064] In one embodiment, the electronic device 120 includes a processor 121 and a memory 122. The processor 121 can be implemented as software, hardware, firmware or any combination thereof, and can use a single or multiple application specific integrated circuits (ASIC), a single or multiple general purpose integrated circuits, a single or multiple microprocessors, a single or multiple programmable logic devices, or any combination of the aforementioned circuits and / or devices, or other suitable circuits or devices. In addition, the processor 121 can control other components in the vehicle 100 to perform the corresponding steps of the method described below. The memory 122 can be a flash memory card, a solid state memory, a hard disk, etc. It can be a volatile memory and / or a non-volatile memory, a removable memory and / or a non-removable memory, etc.

[0065] It should be understood that Figure 1 The components included in the vehicle 100 are only exemplary, and the vehicle 100 may include more or fewer components, and the present invention is not limited thereto.

[0066] The present invention provides a vehicle speed estimation method for a four-wheel independent drive vehicle, such as Figure 2 As shown, including:

[0067] Step S210: When all wheels are slipping, determine the target wheel;

[0068] Step S220: performing torque control on the target wheel to put the target wheel in a non-slip state;

[0069] Step S230: Determine the vehicle speed based on the torque of the target wheel.

[0070] Exemplarily, before executing step S210, the following steps are also included:

[0071] Get the acceleration of the whole vehicle and each wheel;

[0072] Whether each wheel is slipping is determined based on the whole vehicle acceleration and the acceleration of each wheel.

[0073] First, the vehicle acceleration a0 is obtained through the vehicle acceleration sensor, and the acceleration of each wheel is obtained through the acceleration sensors arranged at each wheel, including the acceleration a1 of the left front wheel, the acceleration a2 of the right front wheel, the acceleration a3 of the left rear wheel and the acceleration a4 of the right rear wheel.

[0074] Next, determining whether each wheel is slipping based on the whole vehicle acceleration and the acceleration of each wheel includes: obtaining the difference between the whole vehicle acceleration and the acceleration of each wheel; when the difference is greater than a threshold, determining that the wheel is slipping.

[0075] In one embodiment, based on the acquired vehicle acceleration a0 and the acceleration of each wheel (the acceleration a1 of the left front wheel, the acceleration a2 of the right front wheel, the acceleration a3 of the left rear wheel, and the acceleration a4 of the right rear wheel), the difference values ​​|a0-a|1, |a0-a2|, |a0-a3|, |a0-a4| are obtained respectively, and the difference values ​​are compared with the threshold value. When the difference value is greater than the threshold value, for example, |a0-a2|>a 阈值 , it is determined that the right front wheel is slipping. When the difference is less than the threshold, for example, |a0-a3|<a 阈值 , it is determined that the left rear wheel is not slipping (normal).

[0076] In one embodiment, when the four differences are all less than the threshold, it means that the four wheels are not slipping and the vehicle is in a steady state; when one or more of the four differences are greater than the threshold, it means that one of the four wheels is slipping and the vehicle is in a non-steady state; the non-steady state includes a non-four-wheel slip condition and a four-wheel slip condition, wherein the non-four-wheel slip condition includes when one or more of the wheels are not slipping, the wheel speeds of the one or more non-slipping wheels are weighted averaged to obtain the vehicle speed. For the four-wheel slip condition, step S210 is continued.

[0077] In one embodiment, the determination of the threshold is related to the current vehicle speed: the greater the current vehicle speed, the smaller the threshold range; the smaller the current vehicle speed, the larger the threshold range. Among them, when the vehicle is in a steady-state condition or a non-four-wheel slip condition, the current vehicle speed is the vehicle speed obtained by the sensor or the vehicle speed obtained by weighted average processing of the wheel speed of the non-slipping wheels; when the vehicle is in a four-wheel slip condition, the current vehicle speed can be the steady-state condition before the vehicle enters the four-wheel slip condition or the vehicle speed at the last moment of the non-four-wheel slip condition. The smaller the current vehicle speed, the lower the threat of wheel slip to the safety of the whole vehicle, so the larger the threshold range can be, the smaller the impact on vehicle safety, and the larger the current vehicle speed, the easier it is for the vehicle body to lose control, and the threat of wheel slip to the safety of the whole vehicle is greater, so it is necessary to make the threshold range smaller to improve the safety of vehicle control.

[0078] In step S210, when all wheels are slipping, determining the target wheel includes determining the target wheel based on the vehicle body state: when the vehicle body turns outward, the inner wheel is selected as the target wheel; when the vehicle body turns inward, the outer wheel is selected as the target wheel; when the vehicle body is moving straight, the front wheel is selected as the target wheel. It should be noted that the target wheel may include one or two wheels.

[0079] Next, step S220 is executed to perform torque control on the target wheel so that the target wheel is in a non-slip state.

[0080] Exemplarily, performing torque control on the target wheel includes: reducing the torque of the target wheel; or applying a reverse torque to the target wheel. Both of these situations are referred to as "torque reduction" hereinafter.

[0081] Exemplarily, placing the target wheel in a non-slip state includes: placing the slip rate of the target wheel in a linear region of an adhesion coefficient-slip rate curve. Specifically, placing the slip rate of the target wheel in a linear region of an adhesion coefficient-slip rate curve includes: placing the slip rate of the target wheel in a range of 0% to 20% of the adhesion coefficient-slip rate curve.

[0082] Figure 3 The utilization adhesion coefficient-slip ratio curve is shown. From the figure, we can see that when the wheel slips, if the driving torque continues to increase, the slip ratio will continue to increase; if the driving torque is reduced, the slip ratio will decrease. For the pure rolling wheel speed estimation of the slipping wheel, it is necessary to select the wheel with the least impact on the vehicle dynamics as the target wheel for torque reduction according to the current road conditions. Torque reduction requires ensuring that the slip ratio is in the linear region of the adhesion coefficient-slip ratio curve, wherein the linear region range of the adhesion coefficient-slip ratio curve includes 0% to 20%. Based on this premise, the utilization adhesion coefficient of the current torque reduction wheel can be obtained through the following equation.

[0083] μ S =C λ ·λ S (Equation 1)

[0084] Among them, μ S The tire utilization adhesion coefficient represents the linear region;

[0085] C λ Indicates the longitudinal stiffness of the tire;

[0086] λ S Indicates the slip rate of the target wheel after the torque is reduced to the linear area.

[0087] For the wheel slip rate, when the wheel slip is in the linear region of the adhesion coefficient-slip rate curve, it can be solved by equation (1); for general working conditions, it can be solved by equation (2);

[0088]

[0089] Where, λ represents the wheel slip rate;

[0090] V Wrepresents the wheel speed of the target wheel obtained by the wheel speed sensor;

[0091] V FW Indicates the pure rolling wheel speed of the target wheel.

[0092] For the calculation of the wheel-road adhesion coefficient under general working conditions, it can be solved by equation (3):

[0093]

[0094] Among them, μ represents the utilization adhesion coefficient between the wheel and the road surface;

[0095] F D Indicates the driving wheel end torque after the target wheel torque is reduced;

[0096] F N Indicates the vertical load of the target wheel;

[0097] Next, step S230 is executed to determine the vehicle speed based on the torque of the target wheel. Exemplarily, determining the vehicle speed based on the torque of the target wheel includes: determining the pure rolling wheel speed of the target wheel; determining the vehicle speed based on the pure rolling wheel speed of the target wheel.

[0098] In one embodiment, when the wheel slip is in the linear region of the adhesion coefficient-slip rate curve, equations (1), (2), and (3) can be combined to obtain the pure rolling wheel speed of the wheel after torque reduction, as shown in equation (4).

[0099]

[0100] Among them, V FW represents the pure rolling wheel speed of the target wheel;

[0101] V W represents the wheel speed of the target wheel obtained by the wheel speed sensor;

[0102] C λ Indicates the longitudinal stiffness of the tire;

[0103] F D Indicates the driving wheel end torque after the target wheel torque is reduced;

[0104] F N Indicates the vertical load on the target wheel.

[0105] It should be noted that controlling the target wheel slip rate in the linear region by reducing torque is an extremely short process. Therefore, when the four wheels are slipping, it is necessary to continuously select one or two target wheels that have the smallest impact on the dynamics of the vehicle for torque reduction, repeat the above steps, and continuously obtain the pure rolling wheel speed of the wheel to estimate the vehicle speed.

[0106] Next, step S260 is executed to obtain the entire vehicle speed of the vehicle based on the pure rolling wheel speed of the target wheel.

[0107] In one embodiment, after the pure rolling wheel speed of the target wheel is obtained, the wheel speed can be converted to the center of mass of the entire vehicle through equation (5) to obtain the vehicle speed of the entire vehicle.

[0108]

[0109] Among them, V CoG Indicates the vehicle speed;

[0110] V FW represents the pure rolling wheel speed of the target wheel;

[0111] represents the vehicle yaw rate;

[0112] L f,r Indicates the track width of the front or rear axle;

[0113] δ N Indicates the turning angle of the target wheel (δ1 indicates the left front wheel turning angle, δ2 indicates the right front wheel turning angle, δ3 indicates the left rear wheel turning angle, and δ4 indicates the right rear wheel turning angle).

[0114] After estimating the accurate vehicle speed, the wheel speeds of the remaining wheels can be inferred from equation (5) as their pure rolling wheel speeds, and the slip ratios of each wheel can be obtained from equation (2) for slip ratio control. It should be noted that the slip ratio calculated for the target wheel with reduced torque cannot be used for slip ratio control.

[0115]

[0116] Among them, F M Indicates the wheel side motor driving torque;

[0117] i g Indicates the speed ratio from the wheel motor output end to the wheel end.

[0118]

[0119] Wherein, F1, F2, F3, F4 represent the dynamic vertical loads of the left front wheel, right front wheel, left rear wheel and right rear wheel respectively; m represents the curb weight of the vehicle; a and b represent the distances from the front axle and rear axle to the center of mass respectively; h grepresents the height of the center of mass; L represents the wheelbase; L f , L r It indicates the wheelbase between the left and right wheels of the front (rear) axle; g indicates the acceleration due to gravity; a x Indicates the vehicle's longitudinal acceleration; a y Indicates the lateral acceleration of the vehicle.

[0120] The present invention also provides a vehicle speed estimation system for a four-wheel independent drive vehicle, comprising:

[0121] A target wheel determination module, used to determine the target wheel when all wheels are slipping;

[0122] A torque control module, used for performing torque control on a target wheel so that the target wheel is in a non-slip state;

[0123] The vehicle speed determination module is used to determine the vehicle speed of the vehicle based on the torque of the target wheel.

[0124] In an embodiment of the present invention, the target wheel determination module determines the target wheel based on the vehicle body state: when the vehicle body turns outward, the inner wheel is selected as the target wheel; when the vehicle body turns inward, the outer wheel is selected as the target wheel; when the vehicle body is moving straight, the front wheel is selected as the target wheel. It should be noted that the target wheel may include one or two wheels.

[0125] In an embodiment of the present invention, the torque control module reduces the torque of the target wheel or applies a reverse torque to the target wheel, so that the slip rate of the target wheel enters a linear region of an adhesion coefficient-slip rate curve.

[0126] In an embodiment of the present invention, the vehicle speed determination module determines the pure rolling wheel speed of the target wheel, and determines the entire vehicle speed of the vehicle based on the pure rolling wheel speed of the target wheel.

[0127] In addition, according to an embodiment of the present invention, a computer-readable storage medium is also provided, on which program instructions are stored, and when the program instructions are run by a computer or a processor, the corresponding steps of the vehicle speed estimation method for a four-wheel independent drive vehicle according to the embodiment of the present invention are used, and the corresponding modules in the vehicle speed estimation system for a four-wheel independent drive vehicle according to the embodiment of the present invention are implemented. The computer-readable storage medium may include, for example, a storage component of a tablet computer, a hard disk of a personal computer, a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a portable compact disk read-only memory (CD-ROM)), a USB memory, or any combination of the above storage media. The computer-readable storage medium may be any combination of one or more computer-readable storage media, for example, one computer-readable storage medium contains a computer-readable program code for randomly generating a sequence of action instructions, and another computer-readable storage medium contains a computer-readable program code for controlling crystal growth.

[0128] According to the vehicle speed estimation method, system, computer-readable storage medium, electronic device and vehicle for a four-wheel independent drive vehicle provided by the present invention, when four wheels slip simultaneously under non-steady-state conditions, a target wheel is determined, and the advantage of the independent drive of four motors is utilized to quickly and accurately perform torque control on the target wheel so that the target wheel is in a non-slip state, and the whole vehicle speed of the vehicle is obtained based on the target wheel. In this way, there is no need to rely on an acceleration sensor with large signal noise, and the whole vehicle speed estimation can be achieved only by using a stable wheel speed signal.

[0129] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application thereto. Various changes and modifications may be made therein by one of ordinary skill in the art without departing from the scope and spirit of the present application. All such changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0130] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0131] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of the units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed.

[0132] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0133] Similarly, it should be understood that in order to streamline the present application and help understand one or more of the various inventive aspects, in the description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, the method of the present application should not be interpreted as reflecting the following intention: the claimed application requires more features than the features clearly stated in each claim. More specifically, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with features less than all the features of a single disclosed embodiment. Therefore, the claims following the specific embodiment are hereby explicitly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present application.

[0134] It will be understood by those skilled in the art that, except for mutually exclusive features, all features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this specification may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.

[0135] In addition, those skilled in the art will appreciate that, although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the claims, any one of the claimed embodiments can be used in any combination.

[0136] The various component embodiments of the present application can be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. It should be understood by those skilled in the art that a microprocessor or digital signal processor (DSP) can be used in practice to implement some or all functions of some modules according to the embodiments of the present application. The application can also be implemented as a device program (e.g., computer program and computer program product) for executing a part or all of the methods described herein. Such a program implementing the present application can be stored on a computer-readable medium, or can have the form of one or more signals. Such a signal can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

[0137] It should be noted that the above embodiments illustrate rather than limit the present application, and that those skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets should not be constructed as a limitation to the claims. The present application may be implemented by means of hardware including several different elements and by means of a suitably programmed computer. In a unit claim that lists several devices, several of these devices may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words may be interpreted as names.

[0138] The above is only a specific implementation method or an explanation of a specific implementation method of the present application, and the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. The protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A vehicle speed estimation method for a four-wheel independent drive vehicle, characterized in that: include: When all wheels are slipping, determine the target wheel; Performing torque control on a target wheel so that the target wheel is in a non-slip state; Based on the torque of the target wheel, the vehicle speed is determined.

2. The vehicle speed estimation method according to claim 1, characterized in that: Determining the vehicle speed of the vehicle based on the torque of the target wheel includes: Determine the pure rolling wheel speed of the target wheel; Based on the pure rolling wheel speed of the target wheel, the vehicle's overall speed is determined.

3. The vehicle speed estimation method according to claim 1, characterized in that: Torque control of the target wheel includes: reducing the torque of the target wheel; or A reverse torque is applied to the target wheel.

4. The vehicle speed estimation method according to claim 1, characterized in that: Placing the target wheel in a non-slip state comprises: The slip rate of the target wheel is made to enter a linear region of an adhesion coefficient-slip rate curve.

5. The vehicle speed estimation method according to claim 1, characterized in that: When all wheels are slipping, determining a target wheel includes determining the target wheel based on a vehicle body state, wherein: When the vehicle body is moving straight, the diagonal wheel is selected as the target wheel; When the vehicle body is in understeer, the inner wheel is selected as the target wheel; When the vehicle is in oversteering, the outer wheel is selected as the target wheel.

6. The vehicle speed estimation method according to claim 2, characterized in that: Determine the pure rolling wheel speed of the target wheel, including: Among them, V FW represents the pure rolling wheel speed of the target wheel; V W represents the wheel speed of the target wheel obtained by the wheel speed sensor; C λ Indicates the longitudinal stiffness of the tire; F D Indicates the driving wheel end torque after the target wheel torque is reduced; F N Indicates the vertical load on the target wheel.

7. The vehicle speed estimation method according to claim 2, characterized in that: Determining the vehicle speed of the vehicle based on the pure rolling wheel speed of the target wheel includes: Among them, V CoG Indicates the vehicle speed; V FW represents the pure rolling wheel speed of the target wheel; represents the vehicle yaw rate; L f,r Indicates the track width of the front or rear axle; δ N Indicates the turning angle of the target wheel.

8. The vehicle speed estimation method according to claim 1, characterized in that: Also includes: Get the acceleration of the whole vehicle and each wheel; Whether each wheel is slipping is determined based on the whole vehicle acceleration and the acceleration of each wheel.

9. The vehicle speed estimation method according to claim 8, characterized in that: Determining whether each wheel is slipping based on the whole vehicle acceleration and the acceleration of each wheel includes: Obtaining a difference between the acceleration of the entire vehicle and the acceleration of each wheel; When the difference is greater than a threshold, it is determined that the wheel is slipping.

10. The vehicle speed estimation method according to claim 4, characterized in that: The slip rate of the target wheel enters the linear region of the adhesion coefficient-slip rate curve including: The slip rate of the target wheel enters 0% to 20% of the adhesion coefficient-slip rate curve.

11. The vehicle speed estimation method according to claim 1, characterized in that: The target wheels include one or two wheels.

12. A vehicle speed estimation system for a four-wheel independent drive vehicle, characterized in that: include: A target wheel determination module, used to determine the target wheel when all wheels are slipping; A torque control module, used for performing torque control on a target wheel so that the target wheel is in a non-slip state; The vehicle speed determination module is used to determine the vehicle speed of the vehicle based on the torque of the target wheel.

13. A computer-readable storage medium storing one or more programs, wherein the one or more programs can be executed by one or more processors to implement the vehicle speed estimation method for a four-wheel independent drive vehicle according to any one of claims 1 to 11.

14. An electronic device, characterized in that: The invention comprises a processor and a memory, wherein the processor is used to execute the vehicle speed estimation method for a four-wheel independent drive vehicle according to any one of claims 1 to 11.

15. A vehicle, characterized in that: The electronic device comprising the electronic device described in claim 14.

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