A method, system, computer-readable storage medium, electronic device, and vehicle for estimating vehicle speed in a four-wheel independent drive vehicle.

Abstract

This invention discloses a method, system, computer-readable storage medium, electronic device, and vehicle for estimating the speed of a four-wheel independently driven vehicle. The method includes: identifying a target wheel when all wheels are slipping; applying torque control to the target wheel to bring it into a non-slipping state; and determining the overall vehicle speed based on the torque of the target wheel. The method, system, computer-readable storage medium, electronic device, and vehicle for estimating the speed of a four-wheel independently driven vehicle provided by this invention utilize the advantages of four-motor independent drive to quickly and accurately control the torque of the target wheel, eliminating the need for acceleration sensors with high signal noise and enabling overall vehicle speed estimation solely through stable wheel speed signals.

Description

Technical Field

[0001] This invention relates to the field of vehicle control technology, and more specifically to a method, system, computer-readable storage medium, electronic device, and vehicle for estimating the speed of a four-wheel independently driven vehicle. Background Technology

[0002] In existing technologies, vehicle speed estimation is mainly divided into vehicle speed estimation under steady-state conditions and vehicle speed estimation under unstable conditions. Vehicle speed estimation under steady-state conditions is primarily obtained by converting wheel speeds collected by sensors. However, under unstable conditions, due to significant wheel slippage, the wheel speeds collected by wheel speed sensors no longer accurately reflect the overall vehicle speed. For vehicle speed estimation when all four wheels are slipping, none of the wheel speeds can be used as a reference for estimating the overall vehicle speed. The only way to obtain the current estimated vehicle speed is by integrating the acceleration signal collected by the IMU. This method requires high-quality input acceleration signals; otherwise, the integrated speed will have a significant deviation. Summary of the Invention

[0003] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This summary section is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0004] This invention provides a method for estimating the speed of a four-wheel independently driven vehicle, comprising:

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

[0006] Torque control is applied to the target wheel to keep it in a non-slipping state;

[0007] The vehicle speed is determined based on the torque of the target wheel.

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

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

[0010] The overall vehicle speed is determined based on the pure rolling wheel speed of the target wheel.

[0011] For example, torque control of the target wheel includes:

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

[0013] Apply a reverse torque to the target wheel.

[0014] For example, putting the target wheel in a non-slipping state includes:

[0015] This causes the slip ratio of the target wheel to enter the linear region of the adhesion coefficient-slip ratio curve.

[0016] For example, when all wheels are slipping, a target wheel is determined, including determining the target wheel based on the vehicle body state, wherein:

[0017] When the vehicle is traveling in a straight line, select the diagonal wheel as the target wheel;

[0018] When the vehicle is understeer, select the inner wheel as the target wheel;

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

[0020] For example, determining the pure rolling wheel speed of a target wheel includes:

[0021]

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

[0023] V W This indicates the wheel speed of the target wheel obtained through the wheel speed sensor;

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

[0025] F D This indicates the torque at the drive wheel end after the target wheel's torque is reduced;

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

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

[0028]

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

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

[0031] Indicates the vehicle's yaw rate;

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

[0033] δN This indicates the turning angle of the target wheel.

[0034] Exemplarily, the method further includes:

[0035] Obtain the acceleration of the entire vehicle and the acceleration of each wheel;

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

[0037] For example, determining whether each wheel is slipping based on the overall vehicle acceleration and the acceleration of each wheel includes:

[0038] The difference between the overall vehicle acceleration and the acceleration of each wheel is obtained;

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

[0040] For example, the slip ratio of the target wheel entering the linear region of the adhesion coefficient-slip ratio curve includes:

[0041] The slip ratio of the target wheel falls within 0% to 20% of the adhesion coefficient-slip ratio curve.

[0042] For example, the target wheel may 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] The target wheel determination module is used to determine the target wheel when all wheels are slipping.

[0045] A torque control module is used to control the torque of the target wheel so that the target wheel is in a non-slipping state;

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

[0047] The present invention also provides a computer-readable storage medium storing one or more programs that can be executed by one or more processors to implement the speed estimation method for a four-wheel independently driven vehicle as described in any of the preceding claims.

[0048] The present invention also provides an electronic device including a processor and a memory, wherein the processor is configured to perform the vehicle speed estimation method for a four-wheel independently driven vehicle as described in any of the preceding claims.

[0049] The present invention also provides a vehicle including the electronic equipment described above.

[0050] According to the present invention, a method, system, computer-readable storage medium, electronic device, and vehicle for estimating vehicle speed of a four-wheel independently driven vehicle can determine the target wheel when all four wheels slip simultaneously under non-steady-state conditions. By utilizing the advantage of independent drive of four motors, the torque of the target wheel can be quickly and accurately controlled to keep the target wheel in a non-slipping state. The vehicle speed is obtained based on the torque of the target wheel. This eliminates the need to rely on acceleration sensors with high signal noise, and the vehicle speed can be estimated using only stable wheel speed signals. Attached Figure Description

[0051] The following drawings, which are incorporated herein by reference as part of this invention, are provided for understanding the invention. The drawings illustrate embodiments of the invention and their descriptions, serving to explain the principles of the invention.

[0052] In the attached image:

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

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

[0055] Figure 3 This is a schematic diagram of the adhesion coefficient-slip ratio curve according to an embodiment of the present invention. Detailed Implementation

[0056] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0057] It should be understood that the invention can be embodied in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated. The same reference numerals denote the same elements throughout.

[0058] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0059] To fully understand this invention, detailed steps and structures will be presented in the following description to illustrate the technical solution proposed by this invention. Preferred embodiments of the invention are described in detail below; however, in addition to these detailed descriptions, the invention may have other embodiments.

[0060] To address the problem of simultaneous slippage of all four wheels under unsteady conditions, this invention provides a method for estimating vehicle speed, an electronic device, and a vehicle for four-wheel independently driven vehicles.

[0061] The following is a reference. Figure 1 A schematic diagram depicting the structure of a vehicle 100.

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

[0063] In one embodiment, the vehicle sensing device 110 includes one or more sensors for collecting vehicle information, driving information, and / or environmental information. The vehicle sensing device 110 includes, but is not limited to, speed sensors, pressure sensors, temperature sensors, torque sensors, ABS sensors, and axle position sensors.

[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 one or more application-specific integrated circuits (ASICs), one or more general-purpose integrated circuits, one or more microprocessors, one or more programmable logic devices, or any combination of the foregoing circuits and / or devices, or other suitable circuits or devices. Furthermore, the processor 121 can control other components in the vehicle 100 to perform corresponding steps of the methods described below. The memory 122 can be a flash memory card, solid-state memory, hard disk, etc. It can be volatile memory and / or non-volatile memory, removable memory and / or non-removable memory, etc.

[0065] It should be understood that Figure 1 The components included in the vehicle 100 shown are merely illustrative and may include more or fewer components. This invention is not limited thereto.

[0066] This invention provides a method for estimating the speed of a four-wheel independently driven vehicle, such as... Figure 2 As shown, it includes:

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

[0068] Step S220: Perform torque control on the target wheel to keep the target wheel in a non-slipping state;

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

[0070] For example, before performing step S210, the following steps are also included:

[0071] Obtain the acceleration of the entire vehicle and the acceleration of each wheel;

[0072] Whether each wheel slips is determined based on the overall 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 located 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 vehicle acceleration and the acceleration of each wheel includes: obtaining the difference between the 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 accelerations of each wheel (accelerations a1 for the left front wheel, a2 for the right front wheel, a3 for the left rear wheel, and a4 for the right rear wheel), the differences |a0-a|1, |a0-a2|, |a0-a3|, and |a0-a4| are obtained respectively. These differences are then compared to thresholds. When a difference is greater than the threshold, for example, |a0-a2| > a1, a2, or |a0-a4| is considered a threshold. 阈值 If the difference is less than a threshold, for example, |a0-a3|<a 阈值 If so, it can be determined that the left rear wheel is not slipping (normal).

[0076] In one embodiment, when all four differences are less than a threshold, it indicates that none of the four wheels are slipping, and the vehicle is in a steady-state condition. When one or more of the four differences are greater than the threshold, it indicates that one of the four wheels is slipping, and the vehicle is in a non-steady-state condition. The non-steady-state condition includes a non-four-wheel slipping condition and a four-wheel slipping condition. The non-four-wheel slipping condition involves performing a weighted average of the wheel speeds of one or more non-slipping wheels to obtain the vehicle's overall speed when one or more of the wheels are not slipping. For the four-wheel slipping condition, step S210 is then executed.

[0077] In one embodiment, the threshold is determined based on the current vehicle speed: the higher the current speed, the smaller the threshold range; conversely, the lower the current speed, the larger the threshold range. Specifically, when the vehicle is in a steady-state condition or a non-four-wheel slippage condition, the current speed is the overall vehicle speed obtained from sensors or obtained by weighted averaging of the wheel speeds of the non-slipping wheels. When the vehicle is in a four-wheel slippage condition, the current speed can be the overall vehicle speed at the last moment of the steady-state condition before entering the four-wheel slippage condition or the speed at the end of the non-four-wheel slippage condition. Lower current speeds pose a lower threat to vehicle safety due to wheel slippage, thus a larger threshold range has less impact on vehicle safety. Conversely, higher current speeds make the vehicle more prone to loss of control, and wheel slippage poses a greater threat to vehicle safety; therefore, a smaller threshold range is needed to improve vehicle control safety.

[0078] In step S210, when all wheels slip, determining the target wheel includes determining the target wheel based on the vehicle's state: when the vehicle turns outward, the inner wheel is selected as the target wheel; when the vehicle turns inward, the outer wheel is selected as the target wheel; when the vehicle 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 performed to control the torque of the target wheel so that the target wheel is in a non-slipping state.

[0080] For example, torque control of a target wheel includes: reducing the torque of the target wheel; or, applying a reverse torque to the target wheel. Both of these will be referred to as "torque reduction" below.

[0081] For example, placing the target wheel in a non-slip state includes: causing the slip ratio of the target wheel to enter the linear region of the coefficient of adhesion-slip ratio curve. Specifically, causing the slip ratio of the target wheel to enter the linear region of the coefficient of adhesion-slip ratio curve includes: the slip ratio of the target wheel entering the range of 0% to 20% of the coefficient of adhesion-slip ratio curve.

[0082] Figure 3 The figure illustrates the use of the coefficient of adhesion (COA) versus slip ratio curve. As we can see from the graph, when wheel slippage occurs, increasing the driving torque will further increase the slip ratio; conversely, decreasing the driving torque will decrease the slip ratio. For estimating the pure rolling speed of a slipping wheel, it is necessary to select the wheel with the least impact on vehicle dynamics as the target wheel for torque reduction based on the current road conditions. Torque reduction requires ensuring that the slip ratio remains within the linear region of the COA-Slip ratio curve, which ranges from 0% to 20%. Based on this premise, the COA of the wheel used for torque reduction can be obtained using the following equation.

[0083] μ S =C λ ·λ S (Equation 1)

[0084] Where, μ S The tire in the linear region utilizes the coefficient of friction;

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

[0086] λ S This represents the slip ratio after the target wheel reduces torque to the linear region.

[0087] For the wheel slip ratio, under the condition that the wheel slip is in the linear region of the adhesion coefficient-slip ratio curve, it can be solved by equation (1); for the general working condition, it can be solved by equation (2).

[0088]

[0089] Where λ represents the wheel slip ratio;

[0090] V WThis indicates the wheel speed of the target wheel obtained through the wheel speed sensor;

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

[0092] The wheel-road adhesion coefficient under general working conditions can be calculated using equation (3):

[0093]

[0094] Where μ represents the coefficient of adhesion between the wheel and the road surface;

[0095] F D This indicates the torque at the drive wheel end after the target wheel's torque is reduced;

[0096] F N This indicates the vertical load on the target wheel;

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

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

[0099]

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

[0101] V W This indicates the wheel speed of the target wheel obtained through the wheel speed sensor;

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

[0103] F D This indicates the torque at the drive wheel end after the target wheel's torque is reduced;

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

[0105] It should be noted that controlling the slip ratio of the target wheel within the linear region by reducing torque is a very short process. Therefore, when all four wheels are slipping, it is necessary to continuously select one or two target wheels that have the least impact on the overall vehicle dynamics to reduce torque, repeat the above steps, and continuously obtain the pure rolling wheel speed of the wheel to estimate the overall vehicle speed.

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

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

[0108]

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

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

[0111] Indicates the vehicle's yaw rate;

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

[0113] δ N The angles of rotation of the target wheel are represented by δ1 (left front wheel angle, δ2 (right front wheel angle), δ3 (left rear wheel angle), and δ4 (right rear wheel angle).

[0114] After accurately estimating the vehicle speed, the wheel speeds of the remaining wheels can be derived 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 drive torque of the wheel-side motor;

[0117] i g This indicates the speed ratio between the output end of the wheel-side motor and the wheel end.

[0118]

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

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

[0121] The target wheel determination module is used to determine the target wheel when all wheels are slipping.

[0122] A torque control module is used to control the torque of the target wheel so that the target wheel is in a non-slipping state;

[0123] The vehicle speed determination module is used to determine the overall vehicle speed 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 ratio of the target wheel enters the linear region of the adhesion coefficient-slip ratio 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 overall vehicle speed based on the pure rolling wheel speed of the target wheel.

[0127] Furthermore, according to embodiments of the present invention, a computer-readable storage medium is provided, on which program instructions are stored. When executed by a computer or processor, the program instructions are used to perform corresponding steps of the vehicle speed estimation method for a four-wheel independently driven vehicle according to embodiments of the present invention, and to implement corresponding modules in the vehicle speed estimation system for a four-wheel independently driven vehicle according to embodiments of the present invention. The computer-readable storage medium may, for example, include 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 disc 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 may contain computer-readable program code for randomly generating sequences of action instructions, and another computer-readable storage medium may contain computer-readable program code for controlling crystal growth.

[0128] According to the present invention, a method, system, computer-readable storage medium, electronic device, and vehicle for estimating the speed of a four-wheel independently driven vehicle can determine the target wheel when all four wheels slip simultaneously under non-steady-state conditions. By utilizing the advantage of independent drive of four motors, the torque of the target wheel can be quickly and accurately controlled to keep the target wheel in a non-slipping state. The overall vehicle speed can be obtained based on the target wheel. In this way, there is no need to rely on acceleration sensors with large signal noise, and the overall vehicle speed can be estimated only through stable wheel speed signals.

[0129] Although exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above exemplary embodiments are merely illustrative and are not intended to limit the scope of this application. Various changes and modifications can be made therein by those skilled in the art without departing from the scope and spirit of this application. All such changes and modifications are intended to be included within the scope of this application as claimed in the appended claims.

[0130] Those skilled in the art will recognize that the units and algorithm steps of the various examples 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 implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered 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 merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed.

[0132] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0133] Similarly, it should be understood that, in order to streamline this application and aid in understanding one or more of the various inventive aspects, features of this application may sometimes be grouped together in a single embodiment, figure, or description thereof in the description of exemplary embodiments of this application. However, this approach should not be construed as reflecting an intention that the claimed application requires more features than are expressly recited in each claim. Rather, as reflected in the corresponding claims, its inventive point lies in solving the corresponding technical problem with features fewer than all features of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of this application.

[0134] Those skilled in the art will understand that, apart from the mutual exclusion of features, all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or apparatus so disclosed can be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0135] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features but not others included in other embodiments, combinations of features from different embodiments are intended to be within the scope of this 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 this application can be implemented in hardware, or as software modules running on one or more processors, or a combination thereof. Those skilled in the art will understand that microprocessors or digital signal processors (DSPs) can be used in practice to implement some or all of the functions of some modules according to the embodiments of this application. This application can also be implemented as an apparatus program (e.g., a computer program and computer program product) for performing part or all of the methods described herein. Such an implementation of this application can be stored on a computer-readable medium, or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, provided on a carrier signal, or provided in any other form.

[0137] It should be noted that the above embodiments are illustrative of this application and not limiting of it, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. This application can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

[0138] The above description is merely a specific embodiment or illustration of the embodiments of this application. The scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. The scope of protection of this application shall be determined by the scope of the claims.

Claims

1. A method for estimating vehicle speed in a four-wheel independent drive vehicle, characterized in that, include: When all wheels slip, the target wheel is identified, where: When the vehicle is traveling in a straight line, select the diagonal wheel as the target wheel; When the vehicle is understeer, select the inner wheel as the target wheel; When the vehicle is oversteer, select the outer wheel as the target wheel; Torque control is applied to the target wheel to keep it in a non-slipping state; The vehicle speed is determined based on the torque of the target wheel.

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

3. The vehicle speed estimation method as described in claim 1, characterized in that, Torque control of the target wheel includes: Reduce the torque of the target wheel; or Apply a reverse torque to the target wheel.

4. The vehicle speed estimation method as described in claim 1, characterized in that, Making the target wheel non-slip includes: This causes the slip ratio of the target wheel to enter the linear region of the adhesion coefficient-slip ratio curve.

5. The vehicle speed estimation method as described in claim 2, characterized in that, Determining the pure rolling wheel speed of the target wheel includes: in, This represents the pure rolling wheel speed of the target wheel; This indicates the wheel speed of the target wheel obtained through the wheel speed sensor; Indicates the longitudinal stiffness of the tire; This indicates the torque at the drive wheel end after the target wheel's torque is reduced; This indicates the vertical load on the target wheel.

6. The vehicle speed estimation method as described in claim 2, characterized in that, Determining the vehicle's overall speed based on the pure rolling wheel speed of the target wheel includes: in, Indicates the speed of the entire vehicle; This represents the pure rolling wheel speed of the target wheel; Indicates the vehicle's yaw rate; Indicates the track width of the front or rear axle; This indicates the turning angle of the target wheel.

7. The vehicle speed estimation method as described in claim 1, characterized in that, Also includes: Obtain the acceleration of the entire vehicle and the acceleration of each wheel; Whether each wheel slips is determined based on the overall vehicle acceleration and the acceleration of each wheel.

8. The vehicle speed estimation method as described in claim 7, characterized in that, Determining whether each wheel is slipping based on the overall vehicle acceleration and the acceleration of each wheel includes: The difference between the overall vehicle acceleration and the acceleration of each wheel is obtained; When the difference is greater than a threshold, the wheel is determined to be slipping.

9. The vehicle speed estimation method as described in claim 4, characterized in that, The target wheel's slip ratio enters the linear region of the adhesion coefficient-slip ratio curve, including: The slip ratio of the target wheel falls within 0% to 20% of the adhesion coefficient-slip ratio curve.

10. The vehicle speed estimation method as described in claim 1, characterized in that, The target wheel includes one or two wheels.

11. A speed estimation system for a four-wheel independent drive vehicle, characterized in that, include: The target wheel determination module is used to determine the target wheel when all wheels are slipping, wherein: When the vehicle is traveling in a straight line, select the diagonal wheel as the target wheel; When the vehicle is understeer, select the inner wheel as the target wheel; When the vehicle is oversteer, select the outer wheel as the target wheel; A torque control module is used to control the torque of the target wheel so that the target wheel is in a non-slipping state; The vehicle speed determination module is used to determine the overall vehicle speed based on the torque of the target wheel.

12. A computer-readable storage medium storing one or more programs that can be executed by one or more processors to implement the speed estimation method for a four-wheel independently driven vehicle according to any one of claims 1-10.

13. An electronic device, characterized in that, It includes a processor and a memory, wherein the processor is used to execute the vehicle speed estimation method for a four-wheel independently driven vehicle as described in any one of claims 1-10.

14. A vehicle, characterized in that, Includes the electronic device described in claim 13.

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