Vehicle speed calculation methods, devices and vehicles

Abstract

This disclosure relates to a vehicle speed calculation method, apparatus, and vehicle, and pertains to the field of vehicle speed calculation technology. The vehicle speed calculation method includes: obtaining the acceleration of each wheel based on the acquired wheel speed of each wheel; obtaining a reliable value for each wheel speed based on the acceleration of each wheel and the acquired longitudinal acceleration of the entire vehicle, wherein the reliable value includes a first reliable value characterizing the reliability of the wheel speed and a second reliable value characterizing the unreliability of the wheel speed; determining a vehicle speed calculation method based on the reliable value, the longitudinal acceleration of the entire vehicle, the acquired required torque of the entire vehicle, and the steering wheel angle; and outputting a target vehicle speed based on the vehicle speed calculation method; wherein the vehicle speed calculation method includes a first calculation method using integral calculation and a second calculation method using equivalent calculation.

Description

Technical Field

[0001] This application relates to the field of vehicle speed calculation technology, and more specifically, to vehicle speed calculation methods, devices, and vehicles. Background Technology

[0002] During the operation of a pure electric vehicle, the current vehicle speed is usually used as a very important parameter for vehicle drive control. The motor output torque can be controlled according to the vehicle speed to ensure smooth driving of the electric vehicle and guarantee the performance of vehicle drive control.

[0003] Currently, vehicle speed is calculated by measuring wheel speed using wheel speed sensors. However, when a vehicle skids or brakes suddenly, the wheel speed of the drive wheels is extremely inaccurate and cannot reflect the actual vehicle speed. Using wheel speed to calculate vehicle speed in such situations will inevitably cause a large degree of error. Simply calculating vehicle speed based on wheel speed cannot accurately reflect the actual vehicle speed, resulting in low reliability of wheel speed calculations, which in turn affects the performance of vehicle drive control. Summary of the Invention

[0004] One objective of this application is to provide a new technical solution for a vehicle speed calculation method, device, and vehicle.

[0005] According to a first aspect of this disclosure, a vehicle speed calculation method is provided, comprising: obtaining the acceleration of each wheel based on the acquired wheel speed of each wheel; obtaining a reliable value for each wheel speed based on the acceleration of each wheel and the acquired longitudinal acceleration of the entire vehicle, the reliable value including a first reliable value characterizing the reliability of the wheel speed and a second reliable value characterizing the unreliability of the wheel speed; determining a vehicle speed calculation method based on the reliable value, the longitudinal acceleration of the entire vehicle, the acquired required torque of the entire vehicle, and the steering wheel angle; and outputting a target vehicle speed based on the vehicle speed calculation method; wherein the vehicle speed calculation method includes a first calculation method using integral calculation and a second calculation method using equivalent calculation.

[0006] Optionally, determining the reliable value of the wheel speed based on the acceleration of each wheel and the obtained longitudinal acceleration of the whole vehicle includes: obtaining the first reliable value when the difference between the acceleration of the wheel and the longitudinal acceleration of the whole vehicle is less than a first preset threshold; and obtaining the second reliable value when the difference between the acceleration of the wheel and the longitudinal acceleration of the whole vehicle is greater than the first preset threshold.

[0007] Optionally, the method for determining vehicle speed based on the confidence value, the longitudinal acceleration of the vehicle, the obtained required torque of the vehicle, and the steering wheel angle includes: at least one wheel speed having a confidence value as a first confidence value; the steering wheel angle being less than a second preset threshold; the required torque of the vehicle being greater than a third preset threshold; and the longitudinal acceleration of the vehicle being greater than a fourth preset threshold. If all of the above conditions are met, the vehicle speed calculation method is determined to be a first calculation method; if any of the above conditions are not met, the vehicle speed calculation method is determined to be a second calculation method.

[0008] Optionally, after determining that the vehicle speed calculation method is the first calculation method, the method further includes: when the steering wheel angle is greater than a second preset threshold; or when the vehicle's required torque is less than a third preset threshold and continues for a first time; determining that the vehicle speed calculation method is the second calculation method.

[0009] Optionally, the vehicle speed calculation method is a first calculation method, and the step of outputting the target vehicle speed according to the vehicle speed calculation method includes: obtaining an initial integral vehicle speed based on the minimum value of the reliable wheel speed, wherein the reliable wheel speed is the wheel speed with a reliable value of the first reliable value; taking the product of the integral value of the longitudinal acceleration of the whole vehicle in the second time period and the sampling period as a first value; obtaining a first vehicle speed based on the sum of the first value and the initial integral vehicle speed, and outputting the first vehicle speed as the target vehicle speed.

[0010] Optionally, after obtaining the initial integral vehicle speed, the method includes updating the initial integral vehicle speed when it is determined that the first vehicle speed meets a preset condition. The updating method includes: when the vehicle speed calculation method is a first calculation method, if the first vehicle speed meets the preset condition, then the initial integral vehicle speed is the minimum value among the current reliable wheel speeds.

[0011] Optionally, determining that the first vehicle speed meets the preset conditions includes: determining that the first vehicle speed meets the preset conditions when the absolute value of the difference between the first vehicle speed at the current moment and the initial integral vehicle speed is greater than or equal to a fifth preset threshold, and the absolute value of the difference between the first vehicle speed and the minimum value of the credible wheel speed at the current moment is less than a sixth preset threshold.

[0012] Optionally, the vehicle speed calculation method is a second calculation method, wherein outputting the target vehicle speed according to the vehicle speed calculation method includes: obtaining the turning radius at the vehicle's center of gravity and the turning radius of each wheel based on the acquired vehicle data; obtaining the equivalent wheel speed of each wheel based on the turning radius at the vehicle's center of gravity, the turning radius of each wheel, and the wheel speed of each wheel; and outputting a second vehicle speed as the target vehicle speed based on the equivalent wheel speed.

[0013] Optionally, outputting a second vehicle speed as the target vehicle speed based on the equivalent wheel speeds of the wheels includes: when any wheel speed of the vehicle is a reliable wheel speed, outputting a second vehicle speed based on the average value of the equivalent wheel speeds of the reliable wheel speeds; when all wheel speeds of the vehicle are unreliable wheel speeds, taking the minimum value among the equivalent wheel speeds of each wheel as the second vehicle speed, wherein the unreliable wheel speed is the wheel speed whose reliable value is the second reliable value.

[0014] According to a second aspect of this disclosure, a vehicle speed calculation device is also provided, comprising: an acceleration calculation module for obtaining the acceleration of each wheel based on the acquired wheel speed of each wheel; a confidence value judgment module for obtaining a confidence value of each wheel speed based on the acceleration of each wheel and the acquired longitudinal acceleration of the entire vehicle, wherein the confidence value includes a first confidence value characterizing the confidence of the wheel speed and a second confidence value characterizing the unconfidence of the wheel speed; a processing module for determining a vehicle speed calculation method based on the confidence value, the longitudinal acceleration of the entire vehicle, the acquired required torque of the entire vehicle, and the steering wheel angle; and a vehicle speed calculation module for outputting a target vehicle speed according to the vehicle speed calculation method; wherein the vehicle speed calculation method includes a first calculation method using integral calculation and a second calculation method using equivalent calculation.

[0015] According to a third aspect of this disclosure, a vehicle is also provided, including a memory and a processor, the memory being used to store a computer program; the processor being used to execute the computer program to implement the method according to a first aspect of this disclosure.

[0016] One beneficial effect of this application is that this embodiment obtains wheel acceleration based on wheel speed, compares the wheel acceleration with the vehicle's longitudinal acceleration to obtain a reliable value for the current wheel speed, and then determines the vehicle speed calculation method based on the reliable wheel speed value, the vehicle's longitudinal acceleration, the vehicle's required torque, and the steering wheel angle. The vehicle speed calculation method can be divided into two types: a first calculation method using integral calculation and a second calculation method using equivalent calculation. This can address the problem of inaccurate vehicle speed calculation caused by wheel slippage on wet or icy roads, thereby improving the accuracy of vehicle speed calculation when wheels are slipping.

[0017] Other features and advantages of the embodiments of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the present disclosure and, together with their description, serve to explain the principles of the embodiments of the present disclosure.

[0019] Figure 1 This is a flowchart illustrating the vehicle speed calculation method in this embodiment;

[0020] Figure 2 This is a block diagram of a vehicle speed calculation device according to one embodiment;

[0021] Figure 3 This is a structural schematic diagram of a vehicle according to one embodiment. Detailed Implementation

[0022] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0023] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0024] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0025] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0026] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0027] It should be noted that all actions involving the acquisition of signals, information, or data in this application are carried out in compliance with the relevant data protection laws and policies of the country where the application is located, and with the authorization granted by the owner of the relevant device.

[0028] Hereinafter, various embodiments and examples according to the present invention will be described with reference to the accompanying drawings.

[0029] Figure 1 This is a flowchart illustrating a vehicle speed calculation method according to one embodiment.

[0030] like Figure 1 As shown, the vehicle speed calculation method of this embodiment may include the following steps S101~S104: Step S101, obtain the acceleration of each wheel based on the obtained wheel speed of each wheel.

[0031] In one example, the vehicle speed calculation method of this embodiment is applied to a vehicle, which can be an electric vehicle. The electric vehicle has four wheels: a left front wheel, a right front wheel, a left rear wheel, and a right rear wheel. The wheel speed of each wheel can be obtained through sensors. The wheel speed can be the rotational speed of the wheel, and the wheel speeds of the four wheels are V. FL V FR V RL and V RR Then it can be based on the wheel speed V of the four wheels FL V FR V RL and V RR Find the four-wheel acceleration A FL A FR A RL and A RR Specifically, acceleration can be obtained from the relationship between velocity and time.

[0032] Step S102: Based on the acceleration of each wheel and the obtained longitudinal acceleration of the whole vehicle, obtain the reliable value of each wheel speed.

[0033] In this embodiment, the confidence value includes a first confidence value representing the confidence of the wheel speed and a second confidence value representing the unconfidence of the wheel speed. For example, a first confidence value of 1 indicates that the current wheel speed is a reliable wheel speed, and a second confidence value of 0 indicates that the current wheel speed is unconfidential.

[0034] In one example, the wheel speed V of the four wheels can be... FL V FR V RL V RR And the longitudinal acceleration A of the whole vehicle x Filtering the signal can improve data accuracy. Then, the wheel accelerations corresponding to the wheel speeds of the four wheels are obtained using the least squares method, thus obtaining the four-wheel acceleration A. FL A FR A RL and A RR .

[0035] In this embodiment, the longitudinal acceleration of the vehicle is the acceleration along the vehicle's direction of travel. By comparing the acceleration of each wheel with the obtained longitudinal acceleration of the entire vehicle, it can be determined whether the wheel acceleration deviates too much from the longitudinal acceleration of the entire vehicle. If the deviation is too large, it indicates that the wheel speed of that wheel is affected by uncontrollable factors such as slippage. Therefore, in this embodiment, a reliable value of the wheel speed is obtained based on the acceleration of each wheel and the obtained longitudinal acceleration of the entire vehicle.

[0036] In one embodiment, determining the reliability value of the wheel speed based on the acceleration of each wheel and the obtained longitudinal acceleration of the entire vehicle may include: obtaining a first reliability value when the difference between the wheel acceleration and the longitudinal acceleration of the entire vehicle is less than a first preset threshold; and obtaining a second reliability value when the difference between the wheel acceleration and the longitudinal acceleration of the entire vehicle is greater than the first preset threshold.

[0037] In this embodiment, the acceleration A of each wheel is... FL A FR A RL and A RR And the longitudinal acceleration A of the whole vehicle x By comparing the acceleration of each wheel with the longitudinal acceleration of the entire vehicle, the difference can be obtained. If the difference is less than a first preset threshold, it indicates that the deviation between the wheel's acceleration and the vehicle's longitudinal acceleration is within a controllable range, and the wheel speed of that wheel is reliable. If the difference is greater than the first preset threshold, it indicates that the deviation between the wheel's acceleration and the vehicle's longitudinal acceleration is large, and the wheel speed of that wheel is unreliable. This approach improves the accuracy of wheel speed selection and the performance of vehicle drive control. Furthermore, the reliable wheel speed value can be used to select a vehicle speed calculation method corresponding to the current vehicle condition, improving the accuracy of vehicle speed calculation under different driving conditions. A more accurate vehicle speed can be obtained using the speed calculation method provided in this application, thereby enabling better vehicle control.

[0038] Step S103: Determine the vehicle speed calculation method based on the confidence value, the longitudinal acceleration of the whole vehicle, the obtained vehicle required torque, and the steering wheel angle.

[0039] In this embodiment, the vehicle speed calculation method includes a first calculation method using integral calculation and a second calculation method using equivalent calculation. Both methods are applicable to vehicle speed calculation in skidding and non-skidding states, respectively.

[0040] In one embodiment, the method for determining vehicle speed based on confidence values, vehicle longitudinal acceleration, obtained vehicle required torque, and steering wheel angle may include determining whether the following four conditions are met:

[0041] Condition 1: The confidence value of at least one wheel speed is the first confidence value.

[0042] Condition 2: The steering wheel angle is less than the second preset threshold.

[0043] Condition 3: The required torque of the whole vehicle is greater than the third preset threshold.

[0044] Condition 4: The longitudinal acceleration of the whole vehicle is greater than the fourth preset threshold.

[0045] Understandably, when the steering wheel angle is too small, it indicates that the vehicle may be in a sharp turn. When the torque demanded by the vehicle is too large, it means that the vehicle may need a large control force in a certain direction to keep it moving in the correct direction. When the longitudinal acceleration of the vehicle is too large, it means that the vehicle may be in a state of rapid acceleration and slippage may occur. Therefore, when all four conditions are met, in order to solve the problem of inaccurate vehicle speed calculation caused by wheel slippage during straight-line acceleration, improve the performance of vehicle drive control, and ensure smooth operation, the vehicle speed calculation method is determined to be the first calculation method. The first calculation method is to use the integral calculation method, which can improve the accuracy of vehicle speed calculation.

[0046] When the first calculation method is the integral calculation method, an integral vehicle speed calculation strategy flag V can be generated. SpdEst_Flag The V symbol SpdEst_Flag If V is 1, and any one of the above four conditions is not met, then V... SpdEst_Flag If the value is 0, then the second calculation method is determined to be the vehicle speed calculation method.

[0047] In this embodiment, once the vehicle speed calculation method is determined to be the first calculation method, the first calculation method will be used to calculate the vehicle speed until the steering wheel angle and the required torque of the whole vehicle change. At this time, there may be a situation where the vehicle is turning or going around a corner. The first calculation method is not suitable for the problem of calculating vehicle speed when going around a corner. Therefore, it is necessary to change the vehicle speed calculation method.

[0048] Therefore, after determining the vehicle speed calculation method as the first calculation method, this embodiment further includes: when the steering wheel angle is greater than a second preset threshold; or when the vehicle's required torque is less than a third preset threshold and this condition persists for a first time; determining the vehicle speed calculation method as the second calculation method can solve the problem of inaccurate vehicle speed calculation caused by the speed deviation between the inner and outer sides of the wheels when driving in a curve, and the problem that the first vehicle speed calculation method is not applicable to cornering speed calculation. The first time can be a preset value.

[0049] For example, in this embodiment, when at least one wheel speed has a first reliable value; the steering wheel angle is less than a second preset threshold; the vehicle's required torque is greater than a third preset threshold; and the vehicle's longitudinal acceleration is greater than a fourth preset threshold, V... SpdEst_Flag Change from 0 to 1, while maintaining V SpdEst_Flag If the current speed is 1, the first vehicle speed calculation method is used to calculate the current vehicle speed. This continues until the steering wheel angle exceeds the second preset threshold; or the vehicle's required torque is less than the third preset threshold, and this condition persists for a given period of time. In this case, V... SpdEst_Flag When the speed changes from 1 to 0, the second speed calculation method is used to calculate the current speed.

[0050] Step S104: Output the target vehicle speed according to the vehicle speed calculation method.

[0051] The vehicle speed calculation method in this embodiment includes a first calculation method using integral calculation or a second calculation method using equivalent calculation.

[0052] In one embodiment, when the vehicle speed calculation method is the first calculation method, the target vehicle speed is output according to the vehicle speed calculation method, including: obtaining the initial integral vehicle speed based on the minimum value of the reliable wheel speed; taking the product of the integral value of the longitudinal acceleration of the whole vehicle in the second time period and the sampling period as the first value; obtaining the first vehicle speed based on the sum of the first value and the initial integral vehicle speed, and outputting the first vehicle speed as the target vehicle speed.

[0053] In this embodiment, the reliable wheel speed is the wheel speed with a reliable value of the first reliable value, and the difference between the acceleration of the reliable wheel speed and the longitudinal acceleration of the whole vehicle is less than the first preset threshold.

[0054] It should be noted that the minimum wheel speed among the four wheels is assumed to be V. whl_min In calculating the initial integral vehicle speed and the average wheel speed V of the four wheels aver At this time, unreliable wheel speeds need to be removed. For example, the left front wheel speed V FL When unreliable, V whl_min and V aver The calculation formula is as follows:

[0055]

[0056] In this embodiment, the initial integral vehicle speed V ini The minimum reliable wheel speed V for four wheels when using the first vehicle speed calculation method. whl_min V SpdEst_Flag Minimum reliable wheel speed V of the four wheels at the moment when it changes from 0 to 1 whl_min In this embodiment, the first vehicle speed V interg The initial integral vehicle speed is the sum of the initial integral vehicle speed and the first value, where the first value is the product of the integral value of the vehicle's longitudinal acceleration during the second time interval and the sampling period. Therefore, the first vehicle speed V... interg The specific calculation formula is as follows:

[0057]

[0058] Among them, V ini The initial integral speed, The first value is T, and the second time T is the cumulative time from the start of determining the first vehicle speed calculation method to the current time or the cumulative time after the initial integral vehicle speed is updated. Let T be the longitudinal acceleration of the entire vehicle at each sampling moment within the second time period T. s The sampling period is T, representing the longitudinal acceleration of the entire vehicle.s That is, every T s The longitudinal acceleration of the vehicle is sampled once and can be considered constant. In one example, assuming that a total of 5 samples are taken within the second time period T, the longitudinal accelerations of the vehicle obtained from these 5 samples are as follows: , , , , ,but:

[0059] = ( + + + + )

[0060] When using the first calculation method, in order to eliminate the cumulative error of the integral, the initial integral vehicle speed needs to be updated periodically. When it is necessary to update the initial integral vehicle speed, the initial integral vehicle speed is updated to the minimum speed of the four reliable wheel speeds at the current moment.

[0061] In this embodiment, after obtaining the initial integral vehicle speed, the method further includes updating the initial integral vehicle speed when it is determined that the first vehicle speed meets the preset conditions. Determining that the first vehicle speed meets the preset conditions includes: when the absolute value of the difference between the first vehicle speed at the current time and the initial integral vehicle speed is greater than or equal to a fifth preset threshold, and the absolute value of the difference between the first vehicle speed and the minimum value of the credible wheel speed at the current time is less than a sixth preset threshold, the first vehicle speed is determined to meet the preset conditions, and the initial integral vehicle speed is updated.

[0062] In this embodiment, the first vehicle speed V at the current moment interg With the initial integral speed V ini The absolute value of the difference is greater than or equal to the fifth preset threshold, for example, the initial integral vehicle speed V. ini The speed is 50 km / h, based on the first vehicle speed V. interg After calculating the vehicle speed using the formula for a period of time, V interg Too rapid growth, first speed V interg With the initial integral speed V ini The difference is too large. In order to eliminate the cumulative error of integration, it is necessary to adjust the initial integration speed V. ini Update the system, and simultaneously, when the first vehicle speed V... interg The minimum value V of the reliable wheel speed at the current moment whl_min If the absolute value of the difference is less than the sixth preset threshold, it indicates that the minimum value V of the reliable wheel speed at the current moment is... whl_min To be relatively accurate, the initial integral speed V needs to be calculated. iniThe system is updated to improve the accuracy of vehicle speed calculations.

[0063] In this embodiment, after obtaining the initial integral vehicle speed, updating the initial integral vehicle speed includes: if the vehicle speed calculation method is the first calculation method, and the first vehicle speed meets the preset conditions, then the initial integral vehicle speed is the minimum value among the current reliable wheel speeds.

[0064] The minimum value among the current reliable wheel speeds is the minimum reliable wheel speed among the four wheel speeds at the current moment. That is, if the absolute value of the difference between the first vehicle speed at the current moment and the initial integral vehicle speed is greater than or equal to the fifth preset threshold, and the absolute value of the difference between the first vehicle speed and the minimum reliable wheel speed at the current moment is less than the sixth preset threshold, the initial integral vehicle speed at the current moment is set to the minimum value among the current reliable wheel speeds.

[0065] If the first vehicle speed does not meet the preset conditions, the initial integral vehicle speed remains the same as the initial integral vehicle speed at the previous moment.

[0066] Specifically, the formula for updating the initial integral speed is:

[0067]

[0068] Among them, V whl_min V is the minimum value among the reliable wheel speeds. ini_delay V is the initial integral speed of the vehicle at the previous moment. IntUpdate_Flag V is the initial vehicle speed update identifier. IntUpdate_Flag =1 indicates that the initial vehicle speed needs to be updated, V IntUpdate_Flag =0 indicates that the initial vehicle speed does not need to be updated, V SpdEst_Flag =1 indicates that the first calculation method, integration, is used at this time.

[0069] In this embodiment, when the vehicle speed calculation method is the second calculation method, the target vehicle speed is output according to the vehicle speed calculation method, including: obtaining the turning radius at the vehicle's center of gravity and the turning radius of each wheel based on the acquired vehicle data; obtaining the equivalent wheel speed of each wheel based on the turning radius at the vehicle's center of gravity, the turning radius of each wheel, and the wheel speed of each wheel; and outputting the second vehicle speed as the target vehicle speed based on the equivalent wheel speed.

[0070] In this embodiment, the acquired vehicle data may include the vehicle's longitudinal velocity Vx and the vehicle's yaw rate. The vehicle's wheelbase L, the distance from the center of gravity to the rear axle b, and the track width w.

[0071] Among them, the turning radius R at the vehicle's center of gravity cen The formula is:

[0072]

[0073] The turning radius of each wheel is R, which is the turning radius of the left front wheel. FL Right front wheel turning radius R FR Left rear wheel turning radius R RL and the turning radius R of the right rear wheel RR ,in:

[0074]

[0075] Based on the turning radius at the vehicle's center of gravity, the turning radius of each wheel, and the wheel speed of each wheel, the equivalent wheel speed of each wheel is obtained. The equivalent wheel speed of each wheel includes: the equivalent wheel speed V of the left front wheel. Equ_FL Equivalent wheel speed V of the right front wheel Equ_FR The equivalent wheel speed V of the left rear wheel Equ_RL Equivalent wheel speed V of the right rear wheel Equ_RR Among them, the equivalent wheel speed V of the left front wheel Equ_FL Equivalent wheel speed V of the right front wheel Equ_FR The equivalent wheel speed V of the left rear wheel Equ_RL Equivalent wheel speed V of the right rear wheel Equ_RR The calculation formula is as follows:

[0076]

[0077] In this embodiment, the second vehicle speed is output as the target vehicle speed based on the equivalent wheel speed, including:

[0078] Given any wheel speed of the vehicle that is a reliable wheel speed, the second vehicle speed V is output based on the average value of the equivalent wheel speeds of the reliable wheel speeds. inequ For example, in the four-wheel wheel speed V FL V FR V RL V RR If all are credible,

[0079]

[0080] In this embodiment, when all wheel speeds of the vehicle are unreliable wheel speeds, the minimum value among the equivalent wheel speeds of each wheel is taken as the second vehicle speed V. inequ Wherein, the unreliable wheel speed is the wheel speed whose reliability value is the second reliable value. In this case, the formula for calculating the second wheel speed is:

[0081]

[0082] This embodiment obtains the four-wheel acceleration based on the four-wheel speeds, compares the four-wheel accelerations with the vehicle's longitudinal acceleration to obtain the current reliable values ​​of the four-wheel speeds, and then determines the vehicle speed calculation method based on the reliable values ​​of the four-wheel speeds, the vehicle's longitudinal acceleration, the vehicle's required torque, and the steering wheel angle. The vehicle speed calculation method can be divided into two types: a first calculation method using integral calculation and a second calculation method using equivalent calculation. This can address the problem of inaccurate vehicle speed calculation caused by wheel slippage on wet, slippery, or icy roads, thereby improving the accuracy of vehicle speed calculation when wheels are slipping.

[0083] <Equipment Example>

[0084] Figure 2 This is a schematic diagram of a vehicle speed calculation device according to one embodiment. Figure 2 As shown, the vehicle speed calculation device 200 may include:

[0085] The acceleration calculation module 201 is used to obtain the acceleration of each wheel based on the wheel speed of each wheel.

[0086] The confidence value judgment module 202 is used to obtain a confidence value for each wheel speed based on the acceleration of each wheel and the obtained longitudinal acceleration of the whole vehicle. The confidence value includes a first confidence value that characterizes the confidence of the wheel speed and a second confidence value that characterizes the unconfidence of the wheel speed.

[0087] The processing module 203 is used to determine the vehicle speed calculation method based on the confidence value, the longitudinal acceleration of the whole vehicle, the obtained vehicle required torque and steering wheel angle.

[0088] The vehicle speed calculation module 204 is used to output a target vehicle speed according to the vehicle speed calculation method; wherein, the vehicle speed calculation method includes a first calculation method using integral calculation and a second calculation method using equivalent calculation.

[0089] In one example, the confidence value determination module 202 is used to obtain a first confidence value when the difference between the acceleration of the wheel and the longitudinal acceleration of the whole vehicle is less than a first preset threshold; and to obtain a second confidence value when the difference between the acceleration of the wheel and the longitudinal acceleration of the whole vehicle is greater than the first preset threshold.

[0090] In one example, the processing module 203 is used to determine a vehicle speed calculation method based on the confidence value, the vehicle longitudinal acceleration, the obtained vehicle required torque, and the steering wheel angle, including: the confidence value of at least one wheel speed is a first confidence value; the steering wheel angle is less than a second preset threshold; the vehicle required torque is greater than a third preset threshold; the vehicle longitudinal acceleration is greater than a fourth preset threshold; if all the above conditions are met, the vehicle speed calculation method is determined to be a first calculation method; if any of the above conditions are not met, the vehicle speed calculation method is determined to be a second calculation method.

[0091] In one example, the processing module 203 determines the vehicle speed calculation method as the second calculation method when the steering wheel angle is greater than a second preset threshold, or when the vehicle's required torque is less than a third preset threshold and this continues for a first time.

[0092] In one example, the vehicle speed calculation module 204 is used to obtain an initial integral vehicle speed based on the minimum value of the reliable wheel speed, wherein the reliable wheel speed is the wheel speed with a reliable value of the first reliable value; the product of the integral value of the longitudinal acceleration of the whole vehicle in the second time period and the sampling period is used as a first value; the first vehicle speed is obtained based on the sum of the first value and the initial integral vehicle speed, and the first vehicle speed is output as the target vehicle speed.

[0093] In one example, the vehicle speed calculation module 204 is used to determine the initial integral vehicle speed as the minimum value among the current reliable wheel speeds if the first vehicle speed meets the preset conditions when the vehicle speed calculation method is the first calculation method.

[0094] In one example, the vehicle speed calculation module 204 is used to determine that the first vehicle speed meets the preset conditions when the absolute value of the difference between the first vehicle speed at the current moment and the initial integral vehicle speed is greater than or equal to a fifth preset threshold, and the absolute value of the difference between the first vehicle speed and the minimum value of the credible wheel speed at the current moment is less than a sixth preset threshold.

[0095] In one example, the vehicle speed calculation module 204 is used to obtain the turning radius at the vehicle's center of gravity and the turning radius of each wheel based on the acquired vehicle data; to obtain the equivalent wheel speed of each wheel based on the turning radius at the vehicle's center of gravity, the turning radius of each wheel, and the wheel speed of each wheel; and to output a second vehicle speed as the target vehicle speed based on the equivalent wheel speed.

[0096] In one example, the vehicle speed calculation module 204 is used to output a second vehicle speed based on the average value of the equivalent wheel speeds of the reliable wheel speeds when any wheel speed of the vehicle is a reliable wheel speed; and when all wheel speeds of the vehicle are unreliable wheel speeds, the minimum value among the equivalent wheel speeds of each wheel is taken as the second vehicle speed, wherein the unreliable wheel speed is the wheel speed whose reliable value is the second reliable value.

[0097] This embodiment obtains the four-wheel acceleration based on the four-wheel speeds, compares the four-wheel accelerations with the vehicle's longitudinal acceleration to obtain the current reliable values ​​of the four-wheel speeds, and then determines the vehicle speed calculation method based on the reliable values ​​of the four-wheel speeds, the vehicle's longitudinal acceleration, the vehicle's required torque, and the steering wheel angle. The vehicle speed calculation method can be divided into two types: a first calculation method using integral calculation and a second calculation method using equivalent calculation. This can address the problem of inaccurate vehicle speed calculation caused by wheel slippage on wet, slippery, or icy roads, thereby improving the accuracy of vehicle speed calculation when wheels are slipping.

[0098] Figure 3 This is a schematic diagram of the hardware structure of a vehicle according to another embodiment.

[0099] like Figure 3 As shown, the vehicle 300 includes a processor 310 and a memory 320, the memory 320 being used to store an executable computer program, and the processor 310 being used to execute methods as described in any of the above method embodiments under the control of the computer program.

[0100] Each module of the vehicle 300 described above can be implemented by the processor 310 in this embodiment executing the computer program stored in the memory 320, or it can be implemented by other circuit structures, which are not limited here.

[0101] This invention can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of the invention.

[0102] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0103] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0104] The computer program instructions used to perform the operations of this invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing state information from the computer-readable program instructions. This electronic circuitry can execute the computer-readable program instructions to implement various aspects of the invention.

[0105] Various aspects of the present invention are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0106] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that, when executed by the processor of the computer or other programmable data processing apparatus, they create means for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium that causes a computer, programmable data processing apparatus, and / or other device to operate in a particular manner; thus, the computer-readable medium storing the instructions comprises an article of manufacture that includes instructions for implementing aspects of the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0107] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0108] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions. It will be known to those skilled in the art that implementation in hardware, implementation in software, and implementation using a combination of software and hardware are equivalent.

[0109] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, and are not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein. The scope of the invention is defined by the appended claims.

Claims

1. A method for calculating vehicle speed, characterized in that, The vehicle speed calculation method includes: Based on the obtained wheel speed of each wheel, the acceleration of each wheel is obtained; Based on the acceleration of each wheel and the obtained longitudinal acceleration of the whole vehicle, a reliable value for each wheel speed is obtained. The reliable value includes a first reliable value that characterizes the reliability of the wheel speed and a second reliable value that characterizes the unreliability of the wheel speed. The vehicle speed calculation method is determined based on the confidence value, the longitudinal acceleration of the vehicle, the obtained required torque of the vehicle, and the steering wheel angle. Output the target vehicle speed based on the vehicle speed calculation method described above; The vehicle speed calculation method includes a first calculation method using integral calculation and a second calculation method using equivalent calculation; The method for determining vehicle speed based on the reliable value, the longitudinal acceleration of the vehicle, the obtained required torque of the vehicle, and the steering wheel angle includes: At least one wheel speed has a confidence value that is the first confidence value; The steering wheel angle is less than the second preset threshold; The required torque of the entire vehicle is greater than a third preset threshold. The longitudinal acceleration of the vehicle is greater than a fourth preset threshold. If all the above conditions are met, the vehicle speed calculation method is determined to be the first calculation method; if any of the above conditions are not met, the vehicle speed calculation method is determined to be the second calculation method.

2. The vehicle speed calculation method according to claim 1, characterized in that, The step of determining the reliable value of the wheel speed based on the acceleration of each wheel and the obtained longitudinal acceleration of the entire vehicle includes: The first reliable value is obtained when the difference between the acceleration of the wheel and the longitudinal acceleration of the whole vehicle is less than or equal to a first preset threshold. If the difference between the acceleration of the wheel and the longitudinal acceleration of the whole vehicle is greater than the first preset threshold, the second reliable value is obtained.

3. The vehicle speed calculation method according to claim 1, characterized in that, After determining that the vehicle speed calculation method is the first calculation method, the method further includes: When the steering wheel angle is greater than the second preset threshold; or When the required torque of the entire vehicle is less than the third preset threshold and this condition persists for a certain period of time; The vehicle speed calculation method is determined to be the second calculation method.

4. The vehicle speed calculation method according to claim 1, characterized in that, The vehicle speed calculation method is a first calculation method, and the step of outputting the target vehicle speed according to the vehicle speed calculation method includes: The initial integral vehicle speed is obtained based on the minimum value of the credible wheel speed, where the credible wheel speed is the wheel speed with a credible value of the first credible value. The product of the integral value of the longitudinal acceleration of the whole vehicle in the second time interval and the sampling period is used as the first value; The first vehicle speed is obtained by summing the first value and the initial integral vehicle speed, and the first vehicle speed is output as the target vehicle speed.

5. The vehicle speed calculation method according to claim 4, characterized in that, After obtaining the initial integral vehicle speed, the method includes updating the initial integral vehicle speed when it is determined that the first vehicle speed meets a preset condition, the updating method including: When the vehicle speed calculation method is the first calculation method, if the first vehicle speed meets the preset conditions, then the initial integral vehicle speed is the minimum value among the current reliable wheel speeds.

6. The vehicle speed calculation method according to claim 5, characterized in that, Determining that the first vehicle speed meets preset conditions includes: If the absolute value of the difference between the first vehicle speed at the current moment and the initial integral vehicle speed is greater than or equal to a fifth preset threshold, and the absolute value of the difference between the first vehicle speed and the minimum value of the credible wheel speed at the current moment is less than a sixth preset threshold, then the first vehicle speed is determined to meet the preset conditions.

7. The vehicle speed calculation method according to claim 1, characterized in that, The vehicle speed calculation method is a second calculation method, and the step of outputting the target vehicle speed according to the vehicle speed calculation method includes: Based on the acquired vehicle data, the turning radius at the vehicle's center of gravity and the turning radius of each wheel are obtained. Based on the turning radius at the vehicle's center of gravity, the turning radius of each wheel, and the wheel speed of each wheel, the equivalent wheel speed of each wheel is obtained. Based on the equivalent wheel speed of the wheels, the second vehicle speed is output as the target vehicle speed.

8. The vehicle speed calculation method according to claim 7, characterized in that, Based on the equivalent wheel speed of the wheels, a second vehicle speed is output as the target vehicle speed, including: Given that any wheel speed of the vehicle is a reliable wheel speed, the second vehicle speed is output based on the average value of the equivalent wheel speeds of the reliable wheel speeds. When all wheel speeds of the vehicle are unreliable wheel speeds, the minimum value among the equivalent wheel speeds of each wheel is taken as the second vehicle speed, where the unreliable wheel speed is the wheel speed whose reliable value is the second reliable value.

9. A vehicle speed calculation device, characterized in that, include: The acceleration calculation module is used to obtain the acceleration of each wheel based on the wheel speed of each wheel. The confidence value judgment module is used to obtain the confidence value of each wheel speed based on the acceleration of each wheel and the obtained longitudinal acceleration of the whole vehicle. The confidence value includes a first confidence value that represents the confidence of the wheel speed and a second confidence value that represents the unconfidence of the wheel speed. The processing module is used to determine the vehicle speed calculation method based on the confidence value, the longitudinal acceleration of the vehicle, the obtained vehicle required torque, and the steering wheel angle. The vehicle speed calculation module is used to output a target vehicle speed according to the vehicle speed calculation method; wherein, the vehicle speed calculation method includes a first calculation method using integral calculation and a second calculation method using equivalent calculation; At least one wheel speed has a confidence value that is the first confidence value; The steering wheel angle is less than the second preset threshold; The required torque of the entire vehicle is greater than a third preset threshold. The longitudinal acceleration of the vehicle is greater than a fourth preset threshold. The processing module is further configured to determine the vehicle speed calculation method as the first calculation method if all the above conditions are met, and to determine the vehicle speed calculation method as the second calculation method if any of the above conditions are not met.

10. A vehicle comprising a memory and a processor, the memory for storing a computer program; the processor for executing the computer program to implement the method according to any one of claims 1-8.

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