Vehicle speed estimation method, device, controller, and vehicle

Abstract

The present disclosure provides a vehicle speed estimation method, device, controller and vehicle. The method comprises: obtaining a driving mode of the vehicle, and determining a target threshold and target slip ratios of wheels of the vehicle according to the driving mode, wherein the target threshold is greater than the minimum value of the target slip ratios and less than the maximum value of the target slip ratios; controlling the driving motor of the corresponding wheel according to the target slip ratio, and determining the slip condition of each wheel according to the target threshold; and estimating the vehicle speed according to the slip condition and the wheel speed of each wheel. The method sets different target slip ratios for different wheels, sets a target threshold between the target slip ratios, and then identifies the steady-state wheel and the non-steady-state wheel according to the target threshold. This identification method is more reliable and can avoid the scenario where all wheels of the vehicle are non-steady-state. Then, the vehicle speed is estimated based on the judgment result, which can improve the robustness and reliability of the vehicle speed estimation.

Description

Technical Field

[0001] This disclosure relates to the field of vehicle technology, and more particularly to a vehicle speed estimation method, apparatus, controller, and vehicle. Background Technology

[0002] In related technologies, the vehicle speed is estimated by distinguishing between steady-state and unsteady-state states through slip ratio and decision time. However, in complex scenarios, such as desert roads, at low speeds, the wheels frequently switch between steady-state and unsteady-state states, and the overall trend is non-convergent. The aforementioned technologies do not easily distinguish between steady-state and unsteady-state states, which can easily lead to distorted vehicle speed estimation. Summary of the Invention

[0003] This disclosure aims to at least partially address one of the technical problems in the related art. Therefore, the purpose of this disclosure is to propose a vehicle speed estimation method, apparatus, controller, and vehicle to make steady-state identification easier and more reliable, and to avoid scenarios where all wheels of the vehicle are in a non-steady state, thereby improving the robustness and reliability of vehicle speed estimation.

[0004] In a first aspect, this disclosure proposes a vehicle speed estimation method, comprising: acquiring a vehicle's driving mode, and determining a target threshold and a target slip ratio for each wheel of the vehicle based on the driving mode, wherein the target threshold is greater than a minimum value among the target slip ratios and less than a maximum value among the target slip ratios; controlling the drive motors of the corresponding wheels based on the target slip ratios, and determining the slip condition of each wheel based on the target threshold; and estimating the vehicle speed based on the slip condition and the wheel speed of each wheel.

[0005] In addition, the vehicle speed estimation method of this disclosure embodiment may also have the following additional technical features:

[0006] According to one embodiment of this disclosure, the method further includes: constraining the output torque of the drive motor to enable the vehicle to drive in a steady state.

[0007] According to one embodiment of this disclosure, determining the target threshold and the target slip ratio of each wheel of the vehicle based on the driving mode includes: if the driving mode is a paved road mode, then determining the target slip ratio of the two front wheels of the vehicle as a first slip ratio and the target slip ratio of the two rear wheels as a second slip ratio, wherein the target threshold is a first threshold, and the first threshold is between the first slip ratio and the second slip ratio.

[0008] According to one embodiment of this disclosure, determining the target threshold and the target slip ratio of each wheel of the vehicle based on the driving mode includes: if the driving mode is an unpaved road mode, determining the target slip ratio of the left front wheel of the vehicle as a third slip ratio, the target slip ratio of the right front wheel as a fourth slip ratio, the target slip ratio of the left rear wheel as a fifth slip ratio, and the target slip ratio of the right rear wheel as a sixth slip ratio, wherein the target threshold is a second threshold, and the second threshold is located between the third slip ratio, the fourth slip ratio, the fifth slip ratio, and the sixth slip ratio.

[0009] According to one embodiment of this disclosure, constraining the output torque of the drive motor includes: if the vehicle is traveling straight on a uniform road surface, constraining the output torque of the drive motor using a first constraint condition, wherein the first constraint condition includes: the output torque of the drive motor corresponding to the left wheel of the vehicle is equal to the output torque of the drive motor corresponding to the right wheel.

[0010] According to one embodiment of this disclosure, constraining the output torque of the drive motor includes: if the vehicle is traveling straight on a split road, constraining the output torque of the drive motor using a second constraint condition, wherein the second constraint condition includes: the output torque of the drive motor corresponding to the wheel on the higher surface contact side is greater than the output torque of the drive motor corresponding to the wheel on the lower surface contact side.

[0011] According to one embodiment of this disclosure, constraining the output torque of the drive motor includes: if the vehicle speed is greater than a preset vehicle speed threshold, then constraining the output torque of the drive motor using a third constraint condition, wherein the third constraint condition includes: the difference between the sum of the output torques of the drive motors corresponding to the two rear wheels and the sum of the output torques of the drive motors corresponding to the two front wheels is less than a preset torque difference threshold.

[0012] Secondly, this disclosure proposes a vehicle speed estimation device, comprising: an acquisition module for acquiring a vehicle's driving mode; a determination module for determining a target threshold and a target slip ratio for each wheel of the vehicle based on the driving mode; a control module for controlling the drive motors of the corresponding wheels based on the target slip ratio and determining the slip condition of each wheel based on the target threshold; and an estimation module for estimating the vehicle speed based on the slip condition and the wheel speed of each wheel.

[0013] Thirdly, this disclosure proposes a controller, including a memory and a processor, wherein the memory stores a computer program, characterized in that, when the computer program is executed by the processor, it implements the vehicle speed estimation method described in the first aspect above.

[0014] Fourthly, this disclosure proposes a vehicle comprising: a plurality of wheels and a plurality of drive motors, and a controller as described in the third aspect above, wherein the plurality of wheels correspond one-to-one with the plurality of drive motors, and the controller is connected to the plurality of drive motors respectively.

[0015] The vehicle speed estimation method, device, controller, and vehicle disclosed in this embodiment firstly set different slip control targets (i.e., target slip rates) for different wheels based on the driving mode and set target thresholds. Then, the steady-state wheels and non-steady-state wheels are determined by combining the target thresholds. This identification method is easier and more reliable, and can avoid the scenario where all wheels of the vehicle are non-steady-state. Then, the vehicle speed is estimated based on the judgment results, which can improve the robustness and reliability of the vehicle speed estimation.

[0016] Additional aspects and advantages of this disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this disclosure. Attached Figure Description

[0017] Figure 1 This is a flowchart of a vehicle speed estimation method according to an embodiment of the present disclosure;

[0018] Figure 2 This is a schematic diagram of a vehicle speed estimation process according to a specific embodiment of this disclosure;

[0019] Figure 3 This is a graph of the slip ratio according to a specific embodiment of this disclosure;

[0020] Figure 4 This is a flowchart of a vehicle speed estimation method according to another embodiment of this disclosure;

[0021] Figure 5 This is a structural block diagram of the vehicle speed estimation device according to an embodiment of the present disclosure;

[0022] Figure 6 This is a structural block diagram of the controller according to an embodiment of the present disclosure;

[0023] Figure 7 This is a structural block diagram of a vehicle according to an embodiment of the present disclosure. Detailed Implementation

[0024] Embodiments of this disclosure are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this disclosure, and should not be construed as limiting this disclosure.

[0025] The vehicle speed estimation method, apparatus, controller, and vehicle of this disclosure are described below with reference to the accompanying drawings.

[0026] Figure 1 This is a flowchart of a vehicle speed estimation method according to an embodiment of the present disclosure.

[0027] like Figure 1 As shown, the vehicle speed estimation methods include:

[0028] S1, obtain the vehicle's driving mode, and determine the target threshold and the target slip ratio of each wheel of the vehicle based on the driving mode. The target threshold is greater than the minimum target slip ratio and less than the maximum target slip ratio.

[0029] Specifically, driving modes can be selected actively by the user, such as through operation on the central control screen; or they can be determined automatically by an intelligent system that enables the vehicle to identify the current road conditions and determine the driving mode accordingly. For example, the vehicle can capture images of the road surface using an onboard camera, identify the road conditions from the images, and then determine the driving mode. Driving modes can include paved road modes and unpaved road modes.

[0030] In some embodiments of this disclosure, determining the target threshold and the target slip ratio of each wheel of the vehicle based on the driving mode includes: if the driving mode is a paved road mode, then determining the target slip ratio of the two front wheels of the vehicle as a first slip ratio, the target slip ratio of the two rear wheels as a second slip ratio, and the target threshold as a first threshold, wherein the first threshold is between the first slip ratio and the second slip ratio.

[0031] Specifically, paved road surface mode refers to the mode in which vehicles drive on the road structure layer. The road structure layer is usually used as the wearing course of a multi-layer asphalt surface, a thin overlay for maintenance, and a road surface for bridge paving. In paved road surface mode, the vehicle wheels are basically in contact with the road surface in most driving scenarios, and the maximum vehicle speed is relatively high.

[0032] Taking four-wheel drive vehicles as an example, such as Figure 2 As shown, after determining the driving mode to be paved road mode, different target slip ratios are set for the front and rear axle wheels of the vehicle. For example, the target slip ratio for the front axle wheels is set to A, and the target slip ratio for the rear axle wheels is set to B. The specific values ​​of A and B can be differentiated based on specific scenarios (such as road surface adhesion coefficient, steering wheel angle, vehicle speed, etc.), meaning that the values ​​of A and B are dynamic. For example, when the vehicle is traveling straight on a single road surface or on two opposing roads, A > B can be set; when the vehicle is traveling straight on connecting roads, the target slip ratio for the wheel corresponding to the high road surface adhesion coefficient can be set to be greater than the target slip ratio for the wheel corresponding to the low road surface adhesion coefficient, and so on. At the same time, a target threshold is set as the first threshold C, which is also dynamic. Assuming A > B, then A > C > B, to facilitate subsequent judgments on steady-state and unsteady-state conditions of the vehicle.

[0033] In some other embodiments of this disclosure, determining the target threshold and the target slip ratio of each wheel of the vehicle based on the driving mode includes: if the driving mode is an unpaved road mode, determining the target slip ratio of the left front wheel of the vehicle as the third slip ratio, the target slip ratio of the right front wheel as the fourth slip ratio, the target slip ratio of the left rear wheel as the fifth slip ratio, and the target slip ratio of the right rear wheel as the sixth slip ratio, and the target threshold as the second threshold, wherein the second threshold is located between the third slip ratio, the fourth slip ratio, the fifth slip ratio, and the sixth slip ratio.

[0034] Specifically, unpaved road mode refers to the mode in which vehicles travel on non-paved structural layers. These non-paved structural layers simply lack paving stones or cement bricks, and may even be dirt roads, gravel roads, etc. In unpaved road mode, the number of wheels in contact with the road surface is dynamically changing (for example, it could be two wheels, three wheels, or four wheels, etc.). Furthermore, the consistency of road surface adhesion is variable, resulting in higher tire resistance. For example, uneven surfaces and numerous road obstacles require frequent deceleration or steering wheel corrections, leading to lower vehicle speeds compared to paved roads, and consequently, a lower maximum speed.

[0035] Taking four-wheel drive vehicles as an example, such as Figure 2 As shown, after determining the driving mode to be unpaved road mode, different target slip ratios are set for each of the vehicle's four wheels. For example, the target slip ratio is set to D for the left front wheel, E for the right front wheel, F for the left rear wheel, and G for the right rear wheel. The specific values ​​of D, E, F, and G can be differentiated based on specific scenarios (such as road adhesion coefficient, steering wheel angle, vehicle speed, etc.), meaning that the values ​​of D, E, F, and G are dynamic. Simultaneously, a second threshold H is set as the target threshold, which is also dynamic. Assuming D > E > F > G, then H lies between E and F, i.e., D > E > H > F > G, to facilitate subsequent determination of the vehicle's steady-state and unsteady-state conditions.

[0036] Optionally, the values ​​of the target thresholds can be randomly determined after each target slip ratio is determined. For example, after A and B are determined, C can be any value between A and B, such as the median value; or, after D, E, F and G are determined, if E and F are between D and G, then H can be any value between E and F, such as the median value.

[0037] S2 controls the drive motors of the corresponding wheels according to the target slip ratio and determines the slippage of each wheel according to the target threshold.

[0038] Specifically, after obtaining the target slip ratio for each wheel, the traction control system (TCS) can control the drive motors of the corresponding wheels based on the target slip ratio. Taking paved road surface mode as an example, the target slip ratio of the front axle wheels is A, the target slip ratio of the rear axle wheels is B, and the target threshold is C. Assuming A > C > B, ... Figure 3 As shown, during control, TCS controls the slip ratio of the front axle wheels to around A (e.g., the absolute value of the difference between the actual slip ratio and A is less than a preset difference threshold, which is a value close to 0), and controls the slip ratio of the rear axle wheels to around B (e.g., the absolute value of the difference between the actual slip ratio and B is less than a preset difference threshold). By setting C, the front axle wheels can be identified as slipping, and their wheel speed can be identified as non-steady-state wheel speed, while the rear axle wheels can be identified as non-slipping, and their wheel speed can be identified as steady-state wheel speed. This avoids the scenario where all wheels of the vehicle are non-steady-state, and can improve the robustness and reliability of subsequent speed estimation.

[0039] Taking the unpaved road surface mode as an example, the target slip ratio of the left front wheel is D, the target slip ratio of the right front wheel is E, the target slip ratio of the left rear wheel is F, and the target slip ratio of the right rear wheel is G. The target threshold is H, assuming D > E > H > F > G. During control, TCS controls the slip ratios of the left and right front wheels to be around D and E, respectively, and the slip ratios of the left and right rear wheels to be around F and G, respectively. By setting H, the front axle wheels can be identified as slipping, and their wheel speeds can be identified as non-steady-state wheel speeds. The rear axle wheels can be identified as not slipping, and their wheel speeds can be identified as steady-state wheel speeds. This avoids the scenario where all wheels of the vehicle are in a non-steady-state state, and improves the robustness and reliability of subsequent speed estimation.

[0040] It should be noted that when determining the slippage of each wheel based on the target threshold, the actual slip rate of each wheel is calculated and compared with the target threshold. If the actual slip rate is greater than the target threshold, the corresponding wheel is determined to be slipping; if the actual slip rate is less than the target threshold, the corresponding wheel is determined not to be slipping. Furthermore, the aforementioned target slip rates are all within the tolerance capacity of the corresponding road surface adhesion, ensuring that the non-steady-state wheel is also within a relatively steady-state range, while maintaining good utilization of longitudinal and lateral adhesion. This makes the method for identifying steady-state and non-steady-state conditions disclosed in this invention easier, more reliable, and more robust.

[0041] S3 estimates the vehicle speed based on slippage and the wheel speeds of each wheel.

[0042] Specifically, when estimating vehicle speed, the wheel speeds of each wheel and signals from inertial measurement units (IMUs) can be acquired. If a wheel is not slipping, its corresponding wheel speed is determined to be reliable; if a wheel is slipping, its corresponding wheel speed is determined to be unreliable. Then, vehicle speed estimation algorithms such as Kalman averaging, integral averaging, and model averaging can be used to estimate the vehicle speed using the wheel speeds of any one or more wheels that are not slipping, based on the weights and number of steady-state wheels (i.e., wheels that are not slipping).

[0043] It should be noted that multiple estimation algorithms can be weighted to obtain the vehicle speed estimation result. Since the integral vehicle speed estimation algorithm depends on time, and the longer the time, the greater the error may be, the integral vehicle speed estimation algorithm can be used for short-time estimation, while Kalman or model estimation algorithms can be used for long-time estimation.

[0044] The vehicle speed estimation method of this disclosure firstly sets different slip control targets (i.e., target slip rates) for different wheels based on the driving mode, and sets target thresholds between the target slip rates. Then, it combines the target thresholds to identify steady-state wheels and unsteady wheels. This identification method is easier and more reliable, and can avoid the scenario where all wheels of the vehicle are unsteady. Then, it estimates the vehicle speed based on the judgment results, which can improve the robustness and reliability of the vehicle speed estimation.

[0045] In some embodiments of this disclosure, such as Figure 4 As shown, vehicle speed estimation methods also include:

[0046] S4 constrains the output torque of the drive motor to ensure steady-state vehicle operation.

[0047] Specifically, in certain special scenarios, different slip rates in the front-to-rear and left-to-right directions of a vehicle may produce significant differentials or unexpected unsteady-state effects, such as understeer and oversteer. Therefore, this disclosure addresses different scenarios by using steady-state vehicle driving (steady-state refers to the ideal vehicle posture, in which the vehicle is neutrally steered, neither fishtailing nor understeer, and can well follow the driver's steering intentions; this can be determined based on the vehicle model) as the control objective. Combined with different input quantities (such as steering wheel angle, vehicle speed, vehicle ensemble parameters, tire lateral stiffness, etc.), torque constraints are added to the output torque of each wheel drive motor (e.g., ... Figure 2 As shown in the figure, this reduces the probability of unexpected yaw or unsteady-state problems, making the technical solution of this disclosure more practical.

[0048] In some examples of this disclosure, the output torque of the drive motor is constrained, including: if the vehicle is traveling straight on a uniform road surface, the output torque of the drive motor is constrained using a first constraint condition, wherein the first constraint condition includes: the output torque of the drive motor corresponding to the left wheel of the vehicle is equal to the output torque of the drive motor corresponding to the right wheel.

[0049] Specifically, a uniform road surface refers to a road surface with a uniform coefficient of friction, where straight-line travel can be determined by steering wheel angle. When a vehicle travels straight on a uniform road surface, torque constraints are applied to both sides of the vehicle to ensure that the sum of the torques on both sides is equal, i.e., T. 左前 +T 左后 =T 右前 +T 右后 This is to prevent the vehicle from veering off course due to differential protection. Among them, T 左前 T 左后 T 右前 T 右后 These represent the output torque of the left front-wheel drive motor, the output torque of the left rear-wheel drive motor, the output torque of the right front-wheel drive motor, and the output torque of the right rear-wheel drive motor, respectively.

[0050] In other examples of this disclosure, the output torque of the drive motor is constrained, including: if the vehicle is traveling straight on a split road, the output torque of the drive motor is constrained using a second constraint condition, wherein the second constraint condition includes: the output torque of the drive motor corresponding to the wheel on the higher surface of the road is greater than the output torque of the drive motor corresponding to the wheel on the lower surface of the road.

[0051] Specifically, a split-road surface refers to a surface where the coefficients of friction on the left and right sides of a vehicle's wheels are different, and straight-line travel can be determined by steering wheel angle. When a vehicle is traveling straight on a split-road surface, to ensure acceleration, the differential can be appropriately released, allowing the output torque of the drive motor on the side with higher friction (i.e., the side with a higher coefficient of friction) to be slightly greater than the output torque of the drive motor on the side with lower friction (i.e., the side with a lower coefficient of friction).

[0052] In some further examples of this disclosure, the output torque of the drive motor is constrained, including: if the vehicle speed is greater than a preset vehicle speed threshold, the output torque of the drive motor is constrained using a third constraint condition, wherein the third constraint condition includes: the difference between the sum of the output torques of the drive motors corresponding to the two rear wheels and the sum of the output torques of the drive motors corresponding to the two front wheels is less than a preset torque difference threshold.

[0053] Specifically, when a vehicle is turning at high speed, it may experience fishtailing. To avoid or reduce this, when the vehicle speed exceeds a preset speed threshold, the torque difference between the rear axle and the front axle can be limited to a preset torque difference threshold to prevent it from becoming too large, thereby avoiding or reducing the problem of rear axle fishtailing at high speeds. The values ​​of the preset speed threshold and the preset torque difference threshold can be calibrated according to actual needs.

[0054] In summary, the vehicle speed estimation method of this disclosure is more reliable and robust at the wheel steady-state identification level, and easier to implement. Estimating vehicle speed based on the results obtained from this identification method improves the robustness of the speed estimation. Furthermore, to prevent unexpected unsteady-state effects from different control objectives, adding torque constraint processing makes this disclosure more practical.

[0055] Figure 5 This is a structural block diagram of a vehicle speed estimation device in one embodiment of the present disclosure.

[0056] like Figure 5 As shown, the vehicle speed estimation device 100 includes: an acquisition module 110, a determination module 120, a control module 130, and an estimation module 140.

[0057] The acquisition module 110 is used to acquire the vehicle's driving mode. The determination module 120 is used to determine a target threshold and a target slip ratio for each wheel of the vehicle based on the driving mode. The control module 130 is used to control the drive motors of the corresponding wheels according to the target slip ratio and to determine the slippage condition of each wheel according to the target threshold. The estimation module 140 is used to estimate the vehicle speed based on the slippage condition and the wheel speed of each wheel.

[0058] In some embodiments of this disclosure, when determining the target threshold and the target slip ratio of each wheel of the vehicle according to the driving mode, the determining module 120 is used to determine the target slip ratio of the two front wheels of the vehicle as a first slip ratio and the target slip ratio of the two rear wheels as a second slip ratio when the driving mode is paved road mode, and the target threshold is the first threshold, wherein the first threshold is between the first slip ratio and the second slip ratio.

[0059] In some embodiments of this disclosure, when determining the target threshold and the target slip ratio of each wheel of the vehicle according to the driving mode, the determining module 120 is used to determine the target slip ratio of the left front wheel of the vehicle as the third slip ratio, the target slip ratio of the right front wheel as the fourth slip ratio, the target slip ratio of the left rear wheel as the fifth slip ratio, and the target slip ratio of the right rear wheel as the sixth slip ratio when the driving mode is the unpaved road mode. The target threshold is a second threshold, wherein the second threshold is located between the third slip ratio, the fourth slip ratio, the fifth slip ratio, and the sixth slip ratio.

[0060] In some embodiments of this disclosure, the control module 130 is also used to constrain the output torque of the drive motor to enable the vehicle to drive in a steady state.

[0061] In some examples of this disclosure, when the control module 130 constrains the output torque of the drive motor, it is used to constrain the output torque of the drive motor by means of a first constraint condition when the vehicle is traveling straight on a uniform road surface. The first constraint condition includes: the output torque of the drive motor corresponding to the left wheel of the vehicle is equal to the output torque of the drive motor corresponding to the right wheel.

[0062] In other examples of this disclosure, when constraining the output torque of the drive motor, the control module 130 is used to constrain the output torque of the drive motor by means of a second constraint condition when the vehicle is traveling straight on a split road surface. The second constraint condition includes: the output torque of the drive motor corresponding to the wheel on the higher surface contact side is greater than the output torque of the drive motor corresponding to the wheel on the lower surface contact side.

[0063] In some further examples of this disclosure, when the control module 130 constrains the output torque of the drive motor, it uses a third constraint condition to constrain the output torque of the drive motor when the vehicle speed is greater than a preset vehicle speed threshold. The third constraint condition includes: the torque difference between the output torques of the drive motors corresponding to the two rear wheels is greater than the torque difference between the output torques of the drive motors corresponding to the two front wheels.

[0064] It should be noted that for other specific implementations of the vehicle speed estimation device of this disclosure, please refer to the specific implementations of the vehicle speed estimation method of the above-described embodiments of this disclosure.

[0065] Figure 6 This is a structural block diagram of the controller according to an embodiment of the present disclosure.

[0066] like Figure 6 As shown, the controller 200 includes a processor 201 and a memory 203. The processor 201 and the memory 203 are connected, for example, via a bus 202. Optionally, the controller 200 may also include a transceiver 204. It should be noted that in practical applications, the transceiver 204 is not limited to one, and the structure of the controller 200 does not constitute a limitation on the embodiments of this disclosure.

[0067] Processor 201 may be a CPU (Central Processing Unit), a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), a FPGA (Field Programmable Gate Array), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It may implement or execute the various exemplary logic blocks, modules, and circuits described in connection with this disclosure. Processor 201 may also be a combination that implements computational functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc.

[0068] Bus 202 may include a pathway for transmitting information between the aforementioned components. Bus 202 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc. Bus 202 can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 6 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0069] The memory 203 stores a computer program corresponding to the vehicle speed estimation method of the above embodiments of this disclosure. This computer program is controlled and executed by the processor 201. The processor 201 executes the computer program stored in the memory 203 to implement the content shown in the foregoing method embodiments.

[0070] The controller 200 includes, but is not limited to, mobile terminals such as mobile phones, laptops, digital radio receivers, PDAs (personal digital assistants), PADs (tablet computers), PMPs (portable multimedia players), and in-vehicle terminals (such as in-vehicle navigation terminals), as well as fixed terminals such as digital TVs and desktop computers. Figure 6 The controller 200 shown is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments disclosed herein.

[0071] Figure 7 This is a structural block diagram of a vehicle according to an embodiment of the present disclosure.

[0072] like Figure 7 As shown, the vehicle 300 includes: a plurality of wheels 310 and a plurality of drive motors 320, as well as the controller 200 of the above embodiment.

[0073] Among them, multiple wheels 310 correspond one-to-one with multiple drive motors 320, and the controller 200 is connected to each of the multiple drive motors 320.

[0074] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0075] It should be understood that various parts of this disclosure can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0076] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0077] In the description of this disclosure, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure.

[0078] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0079] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0080] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0081] Although embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present disclosure.

Claims

1. A method for estimating vehicle speed, characterized in that, include: The vehicle's driving mode is obtained, including paved road mode and unpaved road mode, and a target threshold and a target slip ratio of each wheel of the vehicle are determined based on the driving mode, wherein the target threshold is greater than the minimum value of the target slip ratio and less than the maximum value of the target slip ratio; The drive motors of the corresponding wheels are controlled according to the target slip ratio, and the slippage of each wheel is determined according to the target threshold. The vehicle speed is estimated based on the slippage and the wheel speed of each wheel; The step of determining the target threshold and the target slip ratio of each wheel of the vehicle based on the driving mode includes: If the driving mode is the paved road mode, then the target slip ratio of the two front wheels of the vehicle is determined to be the first slip ratio, and the target slip ratio of the two rear wheels is determined to be the second slip ratio. The target threshold is the first threshold, wherein the first threshold is between the first slip ratio and the second slip ratio.

2. The vehicle speed estimation method according to claim 1, characterized in that, The method further includes: The output torque of the drive motor is constrained to ensure steady-state driving of the vehicle.

3. The vehicle speed estimation method according to claim 1, characterized in that, The step of determining the target threshold and the target slip ratio of each wheel of the vehicle based on the driving mode includes: If the driving mode is the unpaved road mode, then the target slip ratio of the left front wheel of the vehicle is determined to be the third slip ratio, the target slip ratio of the right front wheel to be the fourth slip ratio, the target slip ratio of the left rear wheel to be the fifth slip ratio, and the target slip ratio of the right rear wheel to be the sixth slip ratio. The target threshold is the second threshold, wherein the second threshold is located between the third slip ratio, the fourth slip ratio, the fifth slip ratio, and the sixth slip ratio.

4. The vehicle speed estimation method according to claim 2, characterized in that, The constraint on the output torque of the drive motor includes: If the vehicle is traveling straight on a uniform road surface, the output torque of the drive motor is constrained by a first constraint condition, wherein the first constraint condition includes: the output torque of the drive motor corresponding to the left wheel of the vehicle is equal to the output torque of the drive motor corresponding to the right wheel.

5. The vehicle speed estimation method according to claim 2, characterized in that, The constraint on the output torque of the drive motor includes: If the vehicle is traveling straight on the opposite side of the road, the output torque of the drive motor is constrained by a second constraint condition, wherein the second constraint condition includes: the output torque of the drive motor corresponding to the wheel on the higher surface of the road is greater than the output torque of the drive motor corresponding to the wheel on the lower surface of the road.

6. The vehicle speed estimation method according to claim 2, characterized in that, The constraint on the output torque of the drive motor includes: If the vehicle speed is greater than a preset vehicle speed threshold, the output torque of the drive motor is constrained by a third constraint condition, wherein the third constraint condition includes: the difference between the sum of the output torques of the drive motors corresponding to the two rear wheels and the sum of the output torques of the drive motors corresponding to the two front wheels is less than a preset torque difference threshold.

7. A vehicle speed estimation device, characterized in that, include: The acquisition module is used to acquire the vehicle's driving mode, which includes paved road mode and unpaved road mode. The determining module is used to determine a target threshold and a target slip ratio for each wheel of the vehicle based on the driving mode, wherein the target threshold is greater than the minimum value of the target slip ratio and less than the maximum value of the target slip ratio; The control module is used to control the drive motor of the corresponding wheel according to the target slip ratio, and to determine the slippage status of each wheel according to the target threshold. An estimation module is used to estimate the vehicle speed based on the slippage and the wheel speed of each wheel; The step of determining the target threshold and the target slip ratio of each wheel of the vehicle based on the driving mode includes: If the driving mode is the paved road mode, then the target slip ratio of the two front wheels of the vehicle is determined to be the first slip ratio, and the target slip ratio of the two rear wheels is determined to be the second slip ratio. The target threshold is the first threshold, wherein the first threshold is between the first slip ratio and the second slip ratio.

8. A controller, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the computer program is executed by the processor, it implements the method as described in any one of claims 1-6.

9. A vehicle, characterized in that, include: The system comprises multiple wheels and multiple drive motors, and a controller according to claim 8, wherein each of the multiple wheels corresponds to one of the multiple drive motors, and the controller is connected to each of the multiple drive motors respectively.

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