Method for determining a vehicle speed and vehicle

Abstract

The application provides a vehicle speed determination method and a vehicle, and relates to the technical field of data processing. The method comprises the following steps: obtaining current running data and historical vehicle speed of the vehicle when it is detected that the vehicle is in a target road condition, wherein the target road condition represents a road condition affecting the vehicle speed, and the historical vehicle speed is the vehicle speed of the vehicle at a previous moment of the current moment; determining a target wheel in a steady state based on the current running data and the historical vehicle speed of the vehicle; determining a target change gradient of the vehicle speed based on the target wheel, the current running data and the historical vehicle speed of the vehicle; and determining the current vehicle speed of the vehicle based on the target change gradient and the historical vehicle speed. According to the above scheme, the accuracy of the vehicle speed determination can be improved.

Description

Technical Field

[0001] This application relates to the field of data processing technology, and more particularly to a method for determining vehicle speed and a vehicle within the field of data processing technology. Background Technology

[0002] Vehicle speed is required for safety warnings and intelligent driving functions. Any deviation in the determined vehicle speed will lead to control errors, potentially reducing vehicle safety.

[0003] Therefore, improving the accuracy of vehicle speed determination is an urgent problem that needs to be solved. Summary of the Invention

[0004] This application provides a method for determining vehicle speed and a vehicle. The method determines a speed change gradient that matches the actual vehicle speed by using the wheels in a steady state, and uses this speed change gradient to determine the true and accurate vehicle speed, thereby improving the accuracy of vehicle speed determination.

[0005] Firstly, this application provides a method for determining vehicle speed, the method comprising: When the vehicle is detected to be in the target road condition, the current operating data and historical speed of the vehicle are obtained. The target road condition refers to the road condition that affects the vehicle speed, and the historical speed is the vehicle speed at the previous moment. Based on the vehicle's current operating data and historical speed, the target wheel in a steady state is determined; Based on the target wheel, the vehicle's current operating data, and historical vehicle speed, determine the target speed change gradient. The current vehicle speed is determined based on the target change gradient and historical vehicle speeds.

[0006] In this embodiment of the application, when a vehicle is detected to be in a road condition that affects the vehicle speed, in order to avoid deviation of the vehicle speed, the target wheel in a steady state can be determined by acquiring the current operating data and historical vehicle speed of the vehicle. The rate of change of the vehicle speed (i.e., the target change gradient) is determined by the target wheel, the current operating data of the vehicle, and the vehicle speed at the previous moment. The current vehicle speed is then determined by the target change gradient and the historical vehicle speed. In contrast, when a vehicle is in road conditions that affect its speed, directly calculating the vehicle speed from wheel speeds can lead to discrepancies between wheel speeds and the actual vehicle speed due to wheel slippage or rotation. This results in inaccurate speed determination. In this embodiment, the target wheel in a steady state is first determined using the vehicle's current operating data and historical speeds. This provides a wheel speed that matches the vehicle's actual speed, ensuring that the target speed gradient determined from the target wheel matches the actual vehicle speed. This makes the speed determination from the target speed gradient more realistic and accurate. Furthermore, the inclusion of current operating data ensures that the target speed gradient aligns with the vehicle's actual operating conditions, resulting in a speed that is consistent with those conditions. Additionally, the inclusion of historical speed data ensures that the target speed gradient conforms to the vehicle's physical inertia, preventing abrupt changes in speed determination. Ultimately, this improves the accuracy of speed determination and enhances vehicle safety.

[0007] In conjunction with the first aspect, in some implementations of the first aspect, the determination of the target wheel in a steady state based on the vehicle's current operating data and historical vehicle speed includes: Based on the vehicle's current operating data and historical speed, determine whether each wheel is rotating stably; Based on the vehicle's current operating data, determine whether the vehicle's steering is stable; The target wheel is determined based on whether each wheel rotates stably and whether the vehicle steers stably.

[0008] In this embodiment, the target wheel is determined by the rotational stability of each wheel and the steering stability of the vehicle. This takes into account the influence of both wheel rotation and vehicle steering on the wheel steady state, which can improve the accuracy of the target wheel determination. Based on the more accurate determination of the target wheel, the accuracy of the vehicle speed determination is further improved.

[0009] In conjunction with the first aspect and the above-described implementations, in some implementations of the first aspect, the current operating data of the vehicle includes the current wheel speed of each wheel, the current yaw rate of the vehicle, and the current longitudinal acceleration of the vehicle collected by the inertial measurement device in the vehicle. The determination of whether each wheel is rotating stably based on the vehicle's current operating data and historical vehicle speed includes: Based on the current wheel speed of each wheel, the current yaw rate of the vehicle, and the wheelbase of the vehicle, determine the center-of-gravity velocity of each wheel. Determine the wheel acceleration of each wheel based on the center-of-mass velocity of each wheel; Based on the center-of-gravity velocity of each wheel, the historical vehicle speed, the wheel acceleration of each wheel, and the current longitudinal acceleration of the vehicle, it is determined whether each wheel is rotating stably.

[0010] In this embodiment, multi-dimensional data (i.e., wheel center-of-gravity velocity, historical vehicle speed, wheel acceleration, and current longitudinal acceleration) are used to jointly determine whether the wheel is rotating stably, rather than solely relying on wheel speed. This avoids potential biases from using the vehicle's own data to measure its own state, thus improving the accuracy of wheel rotation stability determination. Based on this more accurate determination of wheel rotation stability, the accuracy of target wheel determination can be further improved.

[0011] Combining the first aspect and the above implementation methods, in some implementation methods of the first aspect, the determination of whether each wheel is rotating stably based on the center-of-gravity velocity of each wheel, the historical vehicle speed, the wheel acceleration of each wheel, and the current longitudinal acceleration of the vehicle includes: Based on the center-of-gravity velocity and historical vehicle speed of each wheel, determine the current slip ratio of each wheel. The absolute value of the difference between the wheel acceleration of each wheel and the current longitudinal acceleration of the vehicle is determined as the target acceleration deviation. If the current slip ratio of each wheel is within a first preset range, the target acceleration deviation is less than or equal to a first preset threshold, and the wheel acceleration of each wheel is within a second preset range, then the rotation of each wheel is determined to be stable.

[0012] In this embodiment, multi-dimensional data (i.e., the wheel's current slip ratio, wheel acceleration, and vehicle's current longitudinal acceleration) are used to jointly determine whether the wheel is rotating stably, rather than solely relying on wheel speed. This avoids potential biases in using the wheel's own data to measure its own state, thus improving the accuracy of wheel rotation stability determination. Based on this more accurate determination of wheel rotation stability, the accuracy of target wheel determination can be further improved.

[0013] In conjunction with the first aspect and the above implementation methods, in some implementation methods of the first aspect, the current operating data of the vehicle includes the current wheel speed of each wheel, the current yaw rate of the vehicle, the current steering angle and current steering velocity of the steering wheel in the vehicle, and the determination of whether the vehicle is steering stably based on the current operating data of the vehicle includes: Based on the current wheel speed of each wheel, the current yaw rate of the vehicle, and the wheelbase of the vehicle, determine the center-of-gravity velocity of each wheel. Based on the center-of-gravity velocity of each wheel, the current steering angle and current angular velocity of the steering wheel, it is determined whether the vehicle is steering stably.

[0014] In this embodiment, multi-dimensional data (i.e., the wheel's center of gravity velocity, the current steering wheel angle, and the current angular velocity) are used to jointly determine whether the vehicle is steering stably, rather than solely relying on steering wheel angle data. This avoids the limitations of using single-object data to determine vehicle steering stability and improves the accuracy of vehicle steering stability determination. Based on this more accurate vehicle steering stability determination, the accuracy of target wheel identification can also be improved.

[0015] Combining the first aspect and the above implementation methods, in some implementation methods of the first aspect, the determination of whether the vehicle is steering stably based on the center-of-gravity velocity of each wheel, the current steering angle of the steering wheel, and the current angular velocity includes: Based on the center-of-gravity velocities of each wheel, the difference in rotational speed between the front and rear wheels, the first center-of-gravity velocity, and the second center-of-gravity velocity are determined. The first center-of-gravity velocity represents the maximum center-of-gravity velocity between the left front wheel and the right front wheel, and the second center-of-gravity velocity represents the minimum center-of-gravity velocity between the left rear wheel and the right rear wheel. The vehicle is determined to be stable in steering if the absolute value of the current steering wheel angle is greater than or equal to the second preset threshold, the absolute value of the current steering wheel speed is less than or equal to the third preset threshold, the difference in speed between the front and rear wheels is greater than or equal to the fourth preset threshold, and the second center of gravity speed is greater than or equal to the first center of gravity speed.

[0016] In this embodiment, vehicle steering stability is determined using multi-dimensional data (i.e., the difference in rotational speed between the front and rear wheels, the maximum center-of-gravity velocity between the left and right front wheels, and the minimum center-of-gravity velocity between the left and right rear wheels) rather than solely relying on steering wheel angle data. This avoids the limitations of using single-object data to determine vehicle steering stability and improves the accuracy of steering stability determination. Furthermore, the increased accuracy in determining vehicle steering stability can enhance the accuracy of target wheel identification.

[0017] Combining the first aspect and the above implementation methods, in some implementation methods of the first aspect, the determination of the target wheel based on whether each wheel rotates stably and whether the vehicle steers stably includes: Determine the first rotating wheel that is stable among multiple wheels; Once the vehicle is stable in steering, the first wheel is identified as the target wheel.

[0018] In this embodiment, the wheel with stable rotation is identified as the target wheel only when the vehicle is in a stable steering position. This avoids the problem of the wheel being out of balance due to the instability of the vehicle's steering, thus improving the accuracy of the target wheel determination. Based on the more accurate target wheel determination, the accuracy of the vehicle speed determination is further improved.

[0019] Combining the first aspect and the above implementation methods, in some implementation methods of the first aspect, the current operating data of the vehicle includes the current accelerator pedal opening and the current braking pressure of the vehicle. The determination of the target speed change gradient based on the target wheel, the current operating data of the vehicle, and historical vehicle speed includes: Determine whether the vehicle is operating stably based on at least one of the following: the current accelerator pedal opening, the current braking pressure, and whether each wheel is rotating stably. Under stable vehicle operation conditions, the vehicle's first initial speed is determined based on the number of target wheels and the vehicle's current operating data. Based on the initial vehicle speed and the historical vehicle speed, determine the first gradient of vehicle speed change. The first gradient change is subjected to a limit, resulting in a target gradient change that is within a first preset range.

[0020] In this embodiment, vehicle stability is determined by using multiple data points (i.e., the vehicle's current accelerator pedal opening, current braking pressure, and whether each wheel is rotating stably). This avoids the limitations of using data from a single object to determine vehicle stability, thus improving the accuracy of vehicle stability determination. Furthermore, the target gradient is determined only when the vehicle is stable, avoiding deviations caused by determining the target gradient when the vehicle is unstable, thus improving the accuracy of the target gradient. Additionally, the target gradient is kept within a preset range by limiting its value, preventing it from being too large or too small, further improving its accuracy. Based on the improved accuracy of the target gradient, the accuracy of vehicle speed determination is further enhanced.

[0021] Combining the first aspect and the above implementation methods, in some implementation methods of the first aspect, the current operating data of the vehicle includes the current steering angle and current angular velocity of the steering wheel in the vehicle. Based on the number of target wheels and the current operating data of the vehicle, the first initial speed of the vehicle is determined, including: If the number of target wheels is greater than or equal to the preset number, the current steering angle of the vehicle is determined based on the current steering wheel angle and the current steering wheel angular velocity. The first initial vehicle speed is determined based on the vehicle's current steering angle, the vehicle's current accelerator pedal opening, and the center-of-gravity speed of each wheel. If the number of target wheels is less than the preset number, the first initial vehicle speed is determined based on the center-of-gravity velocity of each wheel.

[0022] In this embodiment of the application, by selecting the corresponding vehicle speed (first initial speed) based on the number of target wheels, the determined vehicle speed can be made to conform to the actual operating conditions of the vehicle, thereby improving the accuracy of vehicle speed determination.

[0023] In conjunction with the first aspect and the above implementation methods, in some implementations of the first aspect, the method further includes: When the vehicle is running unstablely, the second initial speed of the vehicle is determined based on the center-of-gravity speed of each wheel. Based on the second initial vehicle speed and the historical vehicle speed, determine the second gradient of vehicle speed change; The second gradient change is subjected to limit processing to obtain the target gradient change within a second preset range, wherein the second preset range is determined by the vehicle's current longitudinal acceleration.

[0024] In this embodiment, the target gradient is determined only when the vehicle's stability control function is triggered. This avoids deviations caused by determining the target gradient when the stability control function is not triggered, thus improving the accuracy of the target gradient. Furthermore, the target gradient is within a preset range when the limit is reached, preventing it from being too large or too small, which also improves its accuracy. Based on the improved accuracy of the target gradient, the accuracy of vehicle speed determination is further enhanced.

[0025] In conjunction with the first aspect and the above implementation methods, in some implementation methods of the first aspect, the determination of the vehicle's second initial speed based on the center-of-gravity velocity of each wheel includes: When the vehicle's traction function is detected to be triggered, a second initial vehicle speed is determined based on the third center of gravity speed and the fourth center of gravity speed, wherein the third center of gravity speed represents the minimum center of gravity speed between the left front wheel and the right rear wheel, and the fourth center of gravity speed represents the minimum center of gravity speed between the left rear wheel and the right front wheel. If the vehicle's anti-lock braking system and / or dynamic control function are detected to be triggered, a second initial vehicle speed is determined based on the maximum center-of-gravity speed among the center-of-gravity speeds of each wheel.

[0026] In this embodiment of the application, when the vehicle's traction function is triggered, or the vehicle's anti-lock braking function and / or dynamic control function is triggered, selecting the corresponding vehicle speed (second initial speed) determination method can make the determined vehicle speed conform to the actual operating conditions of the vehicle, thereby improving the accuracy of vehicle speed determination.

[0027] Secondly, this application provides a vehicle speed determination device, the device comprising: The acquisition module is used to acquire the vehicle's current operating data and historical speed when the vehicle is detected to be in the target road condition. The target road condition refers to the road condition that affects the vehicle's speed, and the historical speed is the vehicle's speed in the previous moment at the current moment. The processing module is used to determine the target wheel in a steady state based on the vehicle's current operating data and historical vehicle speed; to determine the target speed change gradient of the vehicle based on the target wheel, the vehicle's current operating data, and historical vehicle speed; and to determine the vehicle's current speed based on the target speed change gradient and historical vehicle speed.

[0028] Thirdly, this application provides a controller, including a storage module and a processing module. The storage module is used to store executable program code, and the processing module is used to call and run the executable program code from the storage module, causing the controller to execute the methods in the first aspect or any possible implementation of the first aspect.

[0029] Fourthly, this application provides a vehicle including a memory and a processor. The memory is used to store executable program code, and the processor is used to call and run the executable program code from the memory, causing the vehicle to perform the methods described in the first aspect or any possible implementation thereof.

[0030] Fifthly, this application provides a computer program product comprising: computer program code, which, when run on a computer, causes the computer to perform the method described in the first aspect or any possible implementation thereof.

[0031] Sixthly, this application provides a computer-readable storage medium storing computer program code that, when executed on a computer, causes the computer to perform the methods described in the first aspect or any possible implementation thereof. Attached Figure Description

[0032] Figure 1 This is a schematic diagram illustrating a scenario of the vehicle speed determination method provided in an embodiment of this application. Figure 2 This is a flowchart illustrating a method for determining vehicle speed provided in an embodiment of this application; Figure 3 This is another flowchart illustrating a method for determining vehicle speed provided in an embodiment of this application; Figure 4 This is a schematic diagram of the vehicle speed determination device provided in the embodiments of this application; Figure 5 This is a schematic diagram of the controller provided in an embodiment of this application; Figure 6 This is a schematic diagram of the vehicle structure provided in the embodiments of this application. Detailed Implementation

[0033] The technical solutions in this application will be clearly and thoroughly described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B. "And / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more than two.

[0034] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0035] Vehicle speed (also known as "longitudinal speed") is required for safety warnings and intelligent driving. If the calculated vehicle speed deviates from the actual speed, it will lead to control deviations, potentially reducing vehicle safety. For example, when a vehicle travels on uneven surfaces, the wheels may slip or spin, causing a discrepancy between the calculated speed and the actual speed. Furthermore, when calculating speed using acceleration integrals collected by the vehicle's Inertial Measurement Unit (IMU), the vehicle's longitudinal acceleration and gravitational acceleration must first be separated before calculating the speed through longitudinal acceleration integration. During this calculation, integral drift may occur over time, causing the speed deviation to increase and the accuracy of the determined speed to decrease. Uneven surfaces can include at least one of the following: uneven surfaces, separated surfaces, joined surfaces, sloping surfaces, and bumpy surfaces. High / low adhesion road surfaces refer to road surfaces with excessively high or low coefficients of adhesion; separated road surfaces indicate that the vehicle's wheels have different coefficients of adhesion, for example, the left front wheel driving on a flooded road while the right rear wheel is driving on a gravel road; mating road surfaces indicate road surfaces with different materials and / or heights that are rigidly joined together, for example, asphalt and concrete road surfaces joined together, or smooth road surfaces joined together; sloping road surfaces indicate road surfaces with a gradient, such as downhill roads or roads sloping to the left or right. Additionally, slip indicates a wheel speed greater than the vehicle's actual speed, while drift indicates a wheel speed less than the vehicle's actual speed. Furthermore, the IMU can be used to measure a vehicle's longitudinal acceleration (which can be denoted as "y-axis acceleration"), lateral acceleration (which can be denoted as "x-axis acceleration"), vertical acceleration (which can be denoted as "z-axis acceleration"), and yaw rate.

[0036] Figure 1 This is a schematic diagram illustrating a scenario of the vehicle speed determination method provided in this application embodiment.

[0037] For example, such as Figure 1 As shown, Figure 1 The system includes a vehicle 101 and a bumpy road surface 102. The vehicle 101 is equipped with an IMU (Integrated Measurement Unit). When the vehicle 101 travels on the bumpy road surface 102, it may slip, causing the wheel speed to exceed the vehicle's actual speed. This results in a discrepancy between the calculated speed based on the wheel speed and the actual vehicle speed, leading to a deviation in the calculated speed.

[0038] Based on this, the technical solution provided in this application addresses the following issues when a vehicle is traveling on road conditions that significantly affect its speed: Firstly, by using wheels in a steady state to determine the vehicle's speed change gradient (i.e., the target speed change gradient below), the deviation of the non-steady-state wheels on the speed change gradient can be avoided. Secondly, by using the vehicle's current operating data to determine the speed change gradient, the determined speed change gradient can be ensured to remain within the vehicle's actual operating conditions. Using the vehicle's historical speeds to determine the speed change gradient can prevent abrupt changes in the speed change gradient. Upon obtaining the speed change gradient, the vehicle speed is determined based on it. Through multi-dimensional constraints and fusion, the accuracy of the speed change gradient is maximized, thereby effectively improving the accuracy of the vehicle speed determined from the speed change gradient, given its already relatively accurate gradient.

[0039] The following is combined with Figures 2 to 3 The method for determining vehicle speed provided in the embodiments of this application will be described in detail.

[0040] Figure 2 This is a flowchart illustrating a method for determining vehicle speed according to an embodiment of this application. The method can be implemented by a vehicle (e.g., Figure 1 The vehicle 101 in the vehicle executes the command, or the controller in the vehicle executes the command.

[0041] For example, such as Figure 2 As shown, the method 200 includes the following implementation process: S210, when the vehicle is detected to be in the target road condition, obtains the vehicle's current operating data and historical speed.

[0042] The target road condition refers to road conditions that affect vehicle speed. Driving on the target road condition will cause a deviation in vehicle speed, reducing the accuracy of the vehicle speed reading. In other words, the target road condition represents road conditions that reduce the accuracy of vehicle speed readings, such as the aforementioned uneven road surface. The historical speed is the vehicle's speed at the previous time point. For example, if the current time is time t, then the historical speed is the speed at time t-1. The historical speed is stored in the vehicle's storage device or in a cloud server connected to the vehicle for easy retrieval.

[0043] For example, when a vehicle is detected to be powered on, in order to determine a more accurate vehicle speed, the vehicle's current operating data and historical speeds can be obtained first.

[0044] The vehicle's current operating data may include at least one of the following: the current wheel speed of each wheel, the current yaw rate of the vehicle, the current longitudinal acceleration of the vehicle collected by the inertial measurement unit (IMU) in the vehicle, the current steering wheel angle and current angular velocity, the current accelerator pedal opening (also known as "accelerator pedal opening"), and the current braking pressure. Furthermore, the vehicle's current operating data can be acquired in real time by multiple sensors within the vehicle. For example, the current wheel speed of each wheel can be acquired in real time by wheel speed sensors, the current yaw rate and current longitudinal acceleration can be acquired in real time by the inertial measurement unit, the current steering wheel angle and current angular velocity can be acquired in real time by a steering wheel angle sensor, the current accelerator pedal opening can be acquired in real time by an accelerator pedal position sensor, and the current braking pressure can be acquired in real time by a brake pressure sensor.

[0045] S220 determines the target wheel in a steady state based on the vehicle's current operating data and historical speed.

[0046] For example, when the vehicle is detected to be powered on, it's also possible to check if the vehicle's stability program (ESP) is activated. This is because when ESP is activated, the vehicle is generally already on the verge of loss of control and extremely unstable, so there are virtually no wheels in a steady state. Therefore, it's unnecessary to determine which wheel is in a steady state among the vehicle's multiple wheels, as the wheel speeds of multiple wheels are unreliable. However, when ESP is not activated, the vehicle is not on the verge of loss of control and is relatively stable, making it highly likely that there are wheels in a steady state. Therefore, when ESP is not activated, the wheels in a steady state (which can be called "target wheels") can be determined based on the vehicle's current operating data and historical speeds. Furthermore, it's not impossible that there are no wheels in a steady state when ESP is not activated. A steady-state wheel is one whose rotational state matches the overall driving state of the vehicle, with no slippage or drift. The wheel speed of a steady-state wheel is essentially the same as the vehicle's actual speed; that is, the wheel speed of a steady-state wheel is equal to the vehicle's actual speed, and the wheel speed of a steady-state wheel is reliable and without abnormal fluctuations. Multiple wheels refer to all the wheels in the vehicle, such as the left front wheel, right front wheel, left rear wheel, and right rear wheel. In this application embodiment, whether a function is triggered can also be understood as "whether a function is activated". The vehicle stability function refers to the function that can be achieved through the vehicle's Electronic Stability Program (ESP), denoted as "ESP function".

[0047] Optionally, when acquiring the vehicle's current operating data and historical speed, the vehicle's track width can also be acquired. If the ESP function is not detected to be triggered, the target wheel in a steady state can be determined based on the vehicle's current operating data, historical speed, and track width.

[0048] The vehicle's track width can include the front track width and the rear track width. The front track width represents the horizontal straight-line distance between the contact points of the left and right front wheels on the front axle, while the rear track width represents the horizontal straight-line distance between the contact points of the left and right rear wheels on the rear axle. It should be understood that the vehicle's track width is generally calibrated when the vehicle rolls off the production line and rarely changes. The calibrated track width can be stored in the vehicle's storage unit or in a cloud server connected to the vehicle for easy retrieval at any time.

[0049] S230 determines the target speed change gradient of the vehicle based on the target wheels, the vehicle's current operating data, and historical vehicle speeds.

[0050] For example, the rate of change of vehicle speed between the current moment and the previous moment is determined by using the number of target wheels, the vehicle's current operating data, and historical vehicle speed; this is known as the target speed change gradient. In other words, the speed change gradient represents the rate of change of vehicle speed between the current moment and the previous moment. The number of target wheels can be any number from 0 to the total number of wheels on the vehicle, for example, 0, 1, 2, 3, or 4.

[0051] For example, the target speed change gradient of the vehicle can be determined by using the wheel speed of the target wheel, the vehicle's current operating data, and historical vehicle speed.

[0052] For example, the target speed change gradient of a vehicle can be determined by the wheel speed and number of target wheels, the vehicle's current operating data, and historical vehicle speeds.

[0053] S240 determines the vehicle's current speed based on the target change gradient and historical vehicle speeds.

[0054] For example, the vehicle's historical speed is adjusted based on the target change gradient to obtain the adjusted speed. This adjusted speed is then determined as the vehicle's current speed. The sum of the target change gradient and the vehicle's historical speed is then used to determine the vehicle's current speed.

[0055] In such Figure 2In the method 200 shown, when the vehicle is detected to be in a road condition that affects the vehicle speed, in order to avoid deviation of the vehicle speed, the target wheel in a steady state can be determined by acquiring the current running data and historical vehicle speed of the vehicle. The rate of change of the vehicle speed (i.e., the target change gradient) is determined by the target wheel, the current running data of the vehicle, and the vehicle speed at the previous moment. The current vehicle speed is then determined by the target change gradient and the historical vehicle speed. In contrast, when a vehicle is in road conditions that affect its speed, directly calculating the vehicle speed from wheel speeds can lead to discrepancies between wheel speeds and the actual vehicle speed due to wheel slippage or rotation. This results in inaccurate speed determination. In this embodiment, the target wheel in a steady state is first determined using the vehicle's current operating data and historical speeds. This provides a wheel speed that matches the vehicle's actual speed, ensuring that the target speed gradient determined from the target wheel matches the actual vehicle speed. This makes the speed determination from the target speed gradient more realistic and accurate. Furthermore, the inclusion of current operating data ensures that the target speed gradient aligns with the vehicle's actual operating conditions, resulting in a speed that is consistent with those conditions. Additionally, the inclusion of historical speed data ensures that the target speed gradient conforms to the vehicle's physical inertia, preventing abrupt changes in speed determination. Ultimately, this improves the accuracy of speed determination and enhances vehicle safety.

[0056] Furthermore, in this embodiment, the use of the Kalman fusion algorithm to calculate wheel speed under target road conditions can be avoided, which may lead to abrupt changes in the calculated vehicle speed. This results in a smoother and more realistic vehicle speed, thereby improving the accuracy of vehicle speed determination.

[0057] It should be noted that S210~S240 above is a simplified description of the vehicle speed determination method provided in the embodiments of this application. The following will further explain... Figure 2 The specific implementation methods shown in the embodiments are described in detail below: When executing S210, the above-mentioned determination of the target wheel in a steady state based on the vehicle's current operating data and historical vehicle speed includes: determining whether each wheel is rotating stably based on the vehicle's current operating data and historical vehicle speed; determining whether the vehicle is steering stably based on the vehicle's current operating data; and determining the target wheel based on whether each wheel is rotating stably and whether the vehicle is steering stably.

[0058] For example, the stability of each wheel's rotation is determined by using the vehicle's current operating data, historical speed, and wheelbase. Specifically, the stability of each wheel's rotation is determined by using the current wheel speed, current yaw rate, current longitudinal acceleration, historical speed, and wheelbase. Stable wheel rotation means that the wheel's rotational speed changes linearly with the vehicle speed; the wheel rotates only on its own, without being affected by slippage or drift, and the wheel's rotational speed does not change abruptly. Unstable wheel rotation means that the wheel's rotational speed does not change linearly with the vehicle speed; it is affected by slippage or drift, and the wheel's rotational speed changes abruptly.

[0059] For example, vehicle steering stability can be determined using the vehicle's current operating data and wheelbase. Specifically, vehicle steering stability is determined using the current wheel speeds of each wheel, the vehicle's current yaw rate, the vehicle's current longitudinal acceleration, and the vehicle's wheelbase. Steering stability indicates that when turning, the vehicle's actual trajectory and the theoretical trajectory corresponding to the steering wheel angle are essentially the same, with no excessive lateral deviation, sideslip, fishtailing, or understeer, and no oversteer or understeer occurs. Conversely, unstable steering indicates that when turning, there is a significant deviation between the vehicle's actual trajectory and the theoretical trajectory corresponding to the steering wheel angle, with excessive lateral deviation, sideslip, fishtailing, and / or understeer, leading to oversteer or understeer.

[0060] In this embodiment, the target wheel is determined by the rotational stability of each wheel and the steering stability of the vehicle. This takes into account the influence of both wheel rotation and vehicle steering on the wheel steady state, which can improve the accuracy of the target wheel determination. Based on the more accurate determination of the target wheel, the accuracy of the vehicle speed determination is further improved.

[0061] In one implementation, determining the target wheel based on whether each wheel rotates stably and whether the vehicle is steerably stable includes: determining a first wheel that rotates stably among multiple wheels; and determining the first wheel as the target wheel when the vehicle is steerably stable.

[0062] For example, when determining whether each wheel is rotating stably, the wheel with stable rotation can be identified from among multiple wheels and designated as the first wheel to filter out the wheels with stable rotation. Simultaneously, when the vehicle's steering is stable, it indicates that the wheels are not affected by the vehicle's steering and will not experience wheel speed deviations due to steering. Therefore, when the vehicle's steering is stable, the first wheel can be designated as the target wheel.

[0063] Alternatively, the first wheel that is stable in rotation can be identified among multiple wheels. When the vehicle is traveling in a straight line and not turning, the wheels will not be affected by the vehicle's turning. Therefore, when the vehicle is traveling in a straight line, the first wheel can also be identified as the target wheel.

[0064] In this embodiment, the wheel with stable rotation is identified as the target wheel only when the vehicle is in a stable steering position. This avoids the problem of the wheel being out of balance due to the instability of the vehicle's steering, thus improving the accuracy of the target wheel determination. Based on the more accurate target wheel determination, the accuracy of the vehicle speed determination is further improved.

[0065] In one implementation, determining whether each wheel is rotating stably based on the vehicle's current operating data and historical vehicle speed includes: determining the center-of-gravity velocity of each wheel based on the current wheel speed, the vehicle's current yaw rate, and the vehicle's track width; determining the wheel acceleration of each wheel based on the center-of-gravity velocity of each wheel; and determining whether each wheel is rotating stably based on the center-of-gravity velocity of each wheel, historical vehicle speed, wheel acceleration of each wheel, and the vehicle's current longitudinal acceleration.

[0066] For example, the center-of-gravity velocity of the front wheels is calculated using the wheel speed of the front wheels, the current yaw rate of the vehicle, and the front track width of the vehicle. Similarly, the center-of-gravity velocity of the rear wheels is calculated using the wheel speed of the rear wheels, the current yaw rate of the vehicle, and the rear track width of the vehicle. Refer to formulas (1) to (12) below for details, which will not be elaborated upon here. Furthermore, when obtaining the center-of-gravity velocity of each wheel, the center-of-gravity velocity of each wheel can be differentiated to obtain the wheel acceleration corresponding to the center-of-gravity velocity of each wheel, i.e., the wheel acceleration of each wheel.

[0067] Furthermore, by measuring the center-of-gravity velocity of each wheel, the wheel acceleration of each wheel, the historical vehicle speed, and the current longitudinal acceleration of the vehicle, it can be determined whether each wheel is rotating stably.

[0068] The wheel's center-of-gravity velocity represents the absolute velocity of the wheel's own geometric center (i.e., the hub center). It is the resultant velocity obtained by superimposing the wheel's velocity due to the vehicle's overall traction velocity and the wheel's rotational rolling velocity around its own axle. The traction velocity represents the additional velocity generated by the wheel itself, which is not actively moving but is driven by the vehicle's yaw motion around its center of gravity. Furthermore, the front wheels can include the left front wheel and the right front wheel, and the rear wheels can include the left rear wheel and the right rear wheel.

[0069] In this embodiment, multi-dimensional data (i.e., wheel center-of-gravity velocity, historical vehicle speed, wheel acceleration, and current longitudinal acceleration) are used to jointly determine whether the wheel is rotating stably, rather than solely relying on wheel speed. This avoids potential biases from using the vehicle's own data to measure its own state, thus improving the accuracy of wheel rotation stability determination. Based on this more accurate determination of wheel rotation stability, the accuracy of target wheel determination can be further improved.

[0070] Furthermore, the determination of whether each wheel is rotating stably based on the center-of-gravity velocity, historical vehicle speed, wheel acceleration, and current longitudinal acceleration of each wheel includes: determining the current slip ratio of each wheel based on the center-of-gravity velocity and historical vehicle speed; determining the absolute value of the difference between the wheel acceleration of each wheel and the current longitudinal acceleration of the vehicle as the target acceleration deviation; and determining that each wheel is rotating stably when the current slip ratio of each wheel is within a first preset range, the target acceleration deviation is less than or equal to a first preset threshold, and the wheel acceleration of each wheel is within a second preset range.

[0071] For example, the speed difference between the center-of-gravity speed of each wheel and the historical vehicle speed is determined, and the ratio of this speed difference to the historical vehicle speed is determined as the current slip ratio of each wheel. That is, the current slip ratio of each wheel = Furthermore, determine the absolute value of the difference between the wheel acceleration of each wheel and the current longitudinal acceleration of the vehicle, and define this absolute value as the target acceleration deviation, i.e., target acceleration deviation = Then, by using the current slip ratio, target acceleration deviation, and wheel acceleration of each wheel, it is determined whether each wheel is rotating stably.

[0072] If the current slip ratio of each wheel is within the first preset range, the target acceleration deviation is less than or equal to the first preset threshold, and the wheel acceleration of each wheel is within the second preset range, it indicates that the stability of the wheel's running state is high, and it can be determined that the rotation of each wheel is stable.

[0073] If the current slip ratio of each wheel is not within the first preset range, and / or the target acceleration deviation is greater than the first preset threshold, and / or the wheel acceleration of each wheel is not within the second preset range, it indicates that the stability of the wheel's running state is poor, and it is determined that the rotation of each wheel is unstable.

[0074] It should be understood that the first preset range, the first preset threshold, and the second preset range can all be obtained through actual vehicle calibration, and this application embodiment does not limit this.

[0075] In this embodiment, multi-dimensional data (i.e., the wheel's current slip ratio, wheel acceleration, and vehicle's current longitudinal acceleration) are used to jointly determine whether the wheel is rotating stably, rather than solely relying on wheel speed. This avoids potential biases in using the wheel's own data to measure its own state, thus improving the accuracy of wheel rotation stability determination. Based on this more accurate determination of wheel rotation stability, the accuracy of target wheel determination can be further improved.

[0076] In one implementation, determining whether the vehicle is steering stably based on the vehicle's current operating data includes: determining the center-of-gravity velocity of each wheel based on the current wheel speed, the vehicle's current yaw rate, and the vehicle's track width; and determining whether the vehicle is steering stably based on the center-of-gravity velocity of each wheel, the current steering angle of the steering wheel, and the current steering angular velocity.

[0077] For example, the center-of-gravity velocity of the front wheels is calculated using the wheel speed of the front wheels, the current yaw rate of the vehicle, and the front track width. Similarly, the center-of-gravity velocity of the rear wheels is calculated using the wheel speed of the rear wheels, the current yaw rate of the vehicle, and the rear track width. Furthermore, the vehicle's steering stability is determined using the center-of-gravity velocities of each wheel, the current steering angle of the steering wheel, and the current steering angular velocity.

[0078] In this embodiment, multi-dimensional data (i.e., the wheel's center of gravity velocity, the current steering wheel angle, and the current angular velocity) are used to jointly determine whether the vehicle is steering stably, rather than solely relying on steering wheel angle data. This avoids the limitations of using single-object data to determine vehicle steering stability and improves the accuracy of vehicle steering stability determination. Based on this more accurate vehicle steering stability determination, the accuracy of target wheel identification can also be improved.

[0079] Furthermore, the above-mentioned determination of whether the vehicle is steering stably based on the center-of-gravity velocity of each wheel, the current steering angle and the current angular velocity of the steering wheel includes: determining the front-to-rear wheel speed difference, the first center-of-gravity velocity, and the second center-of-gravity velocity based on the center-of-gravity velocity of each wheel; determining vehicle steering stability when the absolute value of the current steering angle is greater than or equal to a second preset threshold, and the absolute value of the current angular velocity of the steering wheel is less than or equal to a third preset threshold, and the front-to-rear wheel speed difference is greater than or equal to a fourth preset threshold, and the second center-of-gravity velocity is greater than or equal to the first center-of-gravity velocity.

[0080] Wherein, the first center of gravity velocity represents the maximum center of gravity velocity between the left front wheel and the right front wheel, and the second center of gravity velocity represents the minimum center of gravity velocity between the left rear wheel and the right rear wheel.

[0081] For example, the center-of-gravity velocity of the front wheels is determined using the center-of-gravity velocities of the left and right front wheels. Specifically, the sum of the center-of-gravity velocities of the left and right front wheels is determined as the center-of-gravity velocity of the front wheels, i.e., the center-of-gravity velocity of the front wheels = the center-of-gravity velocity of the left front wheel + the center-of-gravity velocity of the right front wheel. Similarly, the center-of-gravity velocity of the rear wheels is determined using the center-of-gravity velocities of the left and right rear wheels. Specifically, the sum of the center-of-gravity velocities of the left and right rear wheels is determined as the center-of-gravity velocity of the rear wheels, i.e., the center-of-gravity velocity of the rear wheels = the center-of-gravity velocity of the left rear wheel - the center-of-gravity velocity of the right rear wheel. The difference between the center-of-gravity velocities of the rear wheels and the front wheels is then determined as the front-to-rear wheel speed difference, i.e., the front-to-rear wheel speed difference = the center-of-gravity velocity of the rear wheels - the center-of-gravity velocity of the front wheels. Furthermore, the maximum center-of-gravity velocity between the left front wheel and the right front wheel is determined as the first center-of-gravity velocity, and the minimum center-of-gravity velocity between the left rear wheel and the right rear wheel is determined as the second center-of-gravity velocity.

[0082] Then, by using the difference in speed between the front and rear wheels, the first center of gravity velocity, the second center of gravity velocity, the current steering angle, and the current angular velocity of the steering wheel, the stability of the vehicle's steering is determined. Specifically, first, the absolute value of the current steering angle and the absolute value of the current angular velocity of the steering wheel are determined, and then the stability of the vehicle's steering is determined by using the difference in speed between the front and rear wheels, the first center of gravity velocity, the second center of gravity velocity, the absolute value of the current steering angle, and the absolute value of the current angular velocity of the steering wheel.

[0083] If the absolute value of the current steering wheel angle is greater than or equal to the second preset threshold, and the absolute value of the current steering wheel speed is less than or equal to the third preset threshold, and the difference in speed between the front and rear wheels is greater than or equal to the fourth preset threshold, and the second center of gravity speed is greater than or equal to the first center of gravity speed, it indicates that the vehicle is steering smoothly and the vehicle steering is stable.

[0084] If the absolute value of the current steering wheel angle is less than the second preset threshold, and / or if the difference in speed between the front and rear wheels of the vehicle is less than the fourth preset threshold, it indicates that the vehicle may not be turning, but is traveling in a straight line, and it can be determined that the vehicle is not turning.

[0085] If the absolute value of the current angular velocity of the steering wheel is greater than the third preset threshold, and / or the second center of gravity velocity is less than the first center of gravity velocity, it indicates that the vehicle is turning but not smoothly, and it can be determined that the vehicle is turning unstably.

[0086] It should be understood that the second, third, and fourth preset thresholds can all be obtained through actual vehicle calibration, and this application embodiment does not limit this.

[0087] In this embodiment, vehicle steering stability is determined using multi-dimensional data (i.e., the difference in rotational speed between the front and rear wheels, the maximum center-of-gravity velocity between the left and right front wheels, and the minimum center-of-gravity velocity between the left and right rear wheels) rather than solely relying on steering wheel angle data. This avoids the limitations of using single-object data to determine vehicle steering stability and improves the accuracy of steering stability determination. Furthermore, the increased accuracy in determining vehicle steering stability can enhance the accuracy of target wheel identification.

[0088] In one implementation, determining the target speed change gradient of the vehicle based on the target wheels, the vehicle's current operating data, and historical vehicle speed includes: determining whether the vehicle is operating stably based on at least one of the vehicle's current accelerator pedal opening, the vehicle's current braking pressure, and whether each wheel is rotating stably; if the vehicle is operating stably, determining the vehicle's first initial speed based on the number of target wheels and the vehicle's current operating data; determining the first speed change gradient of the vehicle based on the first initial speed and historical vehicle speed; and applying a limit to the first speed change gradient to obtain a target speed change gradient within a first preset range.

[0089] For example, vehicle stability can be determined using current operating data. This includes the current accelerator pedal opening, current brake pressure, and / or the stability of wheel rotation. Stable vehicle operation means that the vehicle operates stably without sudden acceleration, sudden braking, or vehicle drift. Unstable vehicle operation means that the vehicle may experience sudden acceleration, sudden braking, or vehicle drift, and therefore cannot operate stably.

[0090] Specifically, vehicle stability is determined by judging whether the current accelerator pedal opening is less than or equal to an eighth preset threshold, whether the current braking pressure is less than or equal to a ninth preset threshold, and whether each wheel rotates stably. If the current accelerator pedal opening is less than or equal to the eighth preset threshold, the current braking pressure is less than or equal to the ninth preset threshold, and at least one wheel rotates stably, it indicates that the vehicle is not experiencing sudden acceleration or braking, and there are wheels with stable rotation; therefore, the vehicle is operating stably overall, and its operation is considered stable. Conversely, if the current accelerator pedal opening is greater than the eighth preset threshold, and / or the current braking pressure is greater than the ninth preset threshold, and / or no wheel rotates stably, it indicates that the vehicle may be experiencing sudden acceleration or braking, and there are no wheels with stable rotation; therefore, the vehicle is not operating stably overall, and its operation is considered unstable.

[0091] Alternatively, vehicle stability can be determined by checking the stability of each wheel's rotation. Specifically, vehicle stability is determined by assessing the stability of each wheel's rotation. If at least two wheels are rotating stably, and these at least two wheels include either the left or right front wheel, it indicates that multiple wheels are rotating stably and the vehicle's steering is stable, meaning the vehicle is operating stably overall. In this case, vehicle stability can be determined. Conversely, if at most one wheel is rotating stably, it means that only one wheel is rotating stably, and the vehicle is likely not operating stably overall. In this case, vehicle instability can be determined.

[0092] If the vehicle is running stably, it indicates that the EPS (Electronic Power Surgery) is generally not triggered. The initial vehicle speed can be determined based on the number of target wheels, the current steering wheel angle, and the current steering velocity. Then, the speed difference between the initial speed and the historical speed is determined, and this speed difference is defined as the first speed change gradient. This first speed change gradient is then subject to limit processing to obtain a target speed change gradient within a first preset range; that is, the target speed change gradient is greater than or equal to the lower limit of the first preset range and less than or equal to the upper limit of the first preset range.

[0093] It should be understood that the eighth preset threshold, the ninth preset threshold, and the first preset range can all be obtained through actual vehicle calibration, and this application embodiment does not limit this.

[0094] In this embodiment, vehicle stability is determined by using multiple data points (i.e., the vehicle's current accelerator pedal opening, current braking pressure, and whether each wheel is rotating stably). This avoids the limitations of using data from a single object to determine vehicle stability, thus improving the accuracy of vehicle stability determination. Furthermore, the target gradient is determined only when the vehicle is stable, avoiding deviations caused by determining the target gradient when the vehicle is unstable, thus improving the accuracy of the target gradient. Additionally, the target gradient is kept within a preset range by limiting its value, preventing it from being too large or too small, further improving its accuracy. Based on the improved accuracy of the target gradient, the accuracy of vehicle speed determination is further enhanced.

[0095] In one implementation, determining the first initial vehicle speed based on the number of target wheels and the vehicle's current operating data includes: when the number of target wheels is greater than or equal to a preset number, determining the current steering angle of the vehicle based on the current steering wheel angle and the current steering wheel angular velocity; determining the first initial vehicle speed based on the current steering angle of the vehicle, the current accelerator pedal opening of the vehicle, and the center-of-gravity velocity of each wheel; and when the number of target wheels is less than the preset number, determining the first initial vehicle speed based on the center-of-gravity velocity of each wheel.

[0096] If the number of target wheels is greater than or equal to the preset number, the current steering angle of the vehicle is determined by the absolute value of the current steering wheel angle and the absolute value of the current steering wheel angular velocity. Then, the first initial vehicle speed is determined by the current steering angle of the vehicle, the current accelerator pedal opening, and the center-of-gravity velocity of each wheel.

[0097] Specifically, the current steering angle of the vehicle is determined by judging whether the absolute value of the current steering wheel angle is greater than or equal to a fifth preset threshold, and / or whether the absolute value of the current steering wheel angular velocity is greater than or equal to a seventh preset threshold. When the absolute value of the current steering wheel angle is greater than or equal to the fifth preset threshold, and / or the absolute value of the current steering wheel angular velocity is greater than or equal to the seventh preset threshold, it indicates that the current steering angle of the vehicle is large, and the vehicle is in a large steering state. Conversely, when the absolute value of the current steering wheel angle is less than the fifth preset threshold, and the absolute value of the current steering wheel angular velocity is less than the seventh preset threshold, it indicates that the current steering angle of the vehicle is small, and the vehicle is not in a large steering state.

[0098] If the number of target wheels is less than the preset number, the first initial vehicle speed is determined by the center-of-gravity velocity of each wheel.

[0099] The preset quantity is greater than or equal to 2, for example, 2, 3, 4.

[0100] It should be understood that the fifth and seventh preset thresholds can be obtained through actual vehicle calibration, and this application embodiment does not limit this.

[0101] In this embodiment of the application, by selecting the corresponding vehicle speed (first initial speed) based on the number of target wheels, the determined vehicle speed can be made to conform to the actual operating conditions of the vehicle, thereby improving the accuracy of vehicle speed determination.

[0102] In one implementation, when the vehicle is running unstablely, a second initial vehicle speed is determined based on the centroid speed of each wheel; a second speed change gradient is determined based on the second initial vehicle speed and the historical vehicle speed; and the second speed change gradient is subjected to limit processing to obtain a target speed change gradient within a second preset range.

[0103] The second preset range is determined by the vehicle's current longitudinal acceleration.

[0104] For example, in a situation where the vehicle is running unstable, EPS is triggered. The second initial vehicle speed is determined by measuring the center-of-gravity speed of each wheel. The speed difference between the second initial speed and the historical speed is then determined and defined as the second speed change gradient. This second speed change gradient is then subject to limit processing to obtain a target speed change gradient within a second preset range; that is, the target speed change gradient is greater than or equal to the lower limit of the second preset range and less than or equal to the upper limit of the second preset range.

[0105] For example, a negative value of the vehicle's current longitudinal acceleration is determined, a minimum acceleration between the vehicle's current longitudinal acceleration and the negative value of the vehicle's current longitudinal acceleration is determined, and a lower limit of a second preset range is determined based on the minimum acceleration; and a maximum acceleration between the vehicle's current longitudinal acceleration and the negative value of the vehicle's current longitudinal acceleration is determined, and an upper limit of the second preset range is determined based on the maximum acceleration.

[0106] Optionally, in cases of unstable vehicle operation, the first preset range can also be determined based on the vehicle's current longitudinal acceleration. The lower limit of the first preset range is determined based on the minimum acceleration, and the upper limit of the first preset range is determined based on the maximum acceleration.

[0107] In this embodiment, the target gradient is determined only when the vehicle's stability control function is triggered. This avoids deviations caused by determining the target gradient when the stability control function is not triggered, thus improving the accuracy of the target gradient. Furthermore, by limiting the target gradient to a preset range, it avoids the target gradient being too large or too small, further improving its accuracy. Based on the improved accuracy of the target gradient, the accuracy of vehicle speed determination is further enhanced. In addition, determining a second preset range for limiting the target gradient using the vehicle's current longitudinal acceleration avoids the integral drift problem inherent in IMU integration, further improving the accuracy of vehicle speed determination.

[0108] In one implementation, determining the second initial vehicle speed based on the center-of-gravity velocities of each wheel includes: determining the second initial vehicle speed based on a third and a fourth center-of-gravity velocities when the vehicle's traction function is detected to be triggered; and determining the second initial vehicle speed based on the maximum center-of-gravity velocities among the wheel's center-of-gravity velocities when the vehicle's anti-lock braking system and / or dynamic control function are detected to be triggered.

[0109] Among them, the third center-of-gravity velocity represents the minimum center-of-gravity velocity between the left front wheel and the right rear wheel, and the fourth center-of-gravity velocity represents the minimum center-of-gravity velocity between the left rear wheel and the right front wheel.

[0110] For example, in cases of unstable vehicle operation, it is also possible to detect whether at least one of the following functions, such as traction control, anti-lock braking, and dynamic control, has been triggered.

[0111] When the PCT function is detected to be triggered, the vehicle's second initial speed is determined by the minimum center-of-gravity speed between the left front wheel and the right rear wheel (referred to as the "third center-of-gravity speed"), and the minimum center-of-gravity speed between the left rear wheel and the right front wheel (referred to as the "fourth center-of-gravity speed"). Specifically, the maximum center-of-gravity speed between the third and fourth center-of-gravity speeds is determined as the vehicle's second initial speed.

[0112] When the ABS function and / or VDC function are detected to be triggered, the second initial vehicle speed is determined by the maximum center-of-gravity speed among the center-of-gravity speeds of each wheel. Specifically, the maximum center-of-gravity speed among the multiple wheel center-of-gravity speeds is determined as the second initial vehicle speed.

[0113] When the ESP function is triggered, but the PTC, ABS, and VDC functions are not triggered, the second initial vehicle speed is determined by averaging the center-of-gravity velocities of multiple wheels. Specifically, the average center-of-gravity velocities of multiple wheels are used to determine the vehicle's second initial speed.

[0114] Among them, traction function refers to the function that can be achieved through the vehicle's traction control system (PTC), denoted as "PTC function". Anti-lock braking function refers to the function that can be achieved through the vehicle's anti-lock braking system (ABS), denoted as "ABS function". Dynamic control function refers to the function that can be achieved through the vehicle's vehicle dynamic control system (VDC), denoted as "VDC function".

[0115] In this embodiment of the application, when the vehicle's traction function is triggered, or the vehicle's anti-lock braking function and / or dynamic control function is triggered, selecting the corresponding vehicle speed (second initial speed) determination method can make the determined vehicle speed conform to the actual operating conditions of the vehicle, thereby improving the accuracy of vehicle speed determination.

[0116] Figure 3 This is another flowchart illustrating a method for determining vehicle speed provided in this application. This method can be implemented using a vehicle (e.g., Figure 1 The vehicle 101 in the vehicle executes the command, or the controller in the vehicle executes the command.

[0117] For example, such as Figure 3As shown, the method 300 includes the following implementation process: S1, acquires the wheel speed, vehicle yaw rate, longitudinal acceleration measured by IMU, vehicle accelerator pedal opening, vehicle braking pressure, vehicle steering wheel angle, vehicle steering wheel angular velocity, and the vehicle speed at the previous moment, as well as the vehicle's front track and rear track.

[0118] For example, when the vehicle is detected to be powered on, in order to determine a more accurate vehicle speed, the following vehicle operation data can be acquired in real time: wheel speed (i.e., the current wheel speed of each wheel), yaw rate (i.e., the current yaw rate of the vehicle), longitudinal acceleration measured by the IMU (i.e., the current longitudinal acceleration of the vehicle), accelerator pedal opening (i.e., the current accelerator pedal opening of the vehicle), braking pressure (i.e., the current braking pressure of the vehicle), steering wheel angle (i.e., the current steering wheel angle), steering wheel angular velocity (i.e., the current steering wheel angular velocity), and the vehicle speed at the previous moment (i.e., the historical vehicle speed). Additionally, the front track and rear track (i.e., the wheelbase of the vehicle) can be acquired. Here, "wheel" refers to any wheel in the vehicle, such as the left front wheel, right front wheel, left rear wheel, and right rear wheel.

[0119] S2 calculates the wheel's center of gravity velocity using the wheel speed, vehicle yaw rate, front and rear track widths, and steering wheel angle.

[0120] For example, the center-of-gravity velocity of the front wheels is calculated using the wheel speed of the front wheels, the current yaw rate of the vehicle, and the front track width of the vehicle. Similarly, the center-of-gravity velocity of the rear wheels is calculated using the wheel speed of the rear wheels, the current yaw rate of the vehicle, and the rear track width of the vehicle; thus, the current center-of-gravity velocity of each wheel (which can be referred to as the "equivalent center-of-gravity wheel speed") is obtained.

[0121] Specifically, when calculating the center-of-gravity velocity of the front wheel using the wheel speed of the front wheel and the front track width of the vehicle, the product of half the front track width and the yaw rate can be calculated, and the sum of this product and the wheel speed of the front wheel is determined as the center-of-gravity velocity of the front wheel. Half the front track width is used because the left and right front wheels are generally symmetrically mounted and have the same distance from the center of the front axle. Similarly, when calculating the center-of-gravity velocity of the rear wheel using the wheel speed of the rear wheel and the rear track width of the vehicle, the product of half the rear track width and the yaw rate can be calculated, and the sum of this product and the wheel speed of the rear wheel is determined as the center-of-gravity velocity of the rear wheel. Half the rear track width is used because the left and right rear wheels are generally symmetrically mounted and have the same distance from the center of the rear axle. Examples are provided using formulas (1) to (4):

[0122] In formula (1), VCGfl represents the center of gravity velocity of the left front wheel, Vfl represents the wheel speed of the left front wheel, r represents the yaw rate of the vehicle, and Tf represents the front track width.

[0123] In formula (2), VCGfr represents the center of gravity velocity of the right front wheel, Vfr represents the wheel speed of the right front wheel, r represents the yaw rate of the vehicle, and Tf represents the front track width.

[0124] In formula (3), VCGrl represents the center-of-gravity velocity of the left rear wheel, Vrl represents the wheel speed of the left rear wheel, r represents the yaw rate of the vehicle, and Tr represents the rear track width.

[0125] In formula (4), VCGrr represents the center of gravity velocity of the right rear wheel, Vrr represents the wheel speed of the right rear wheel, r represents the yaw rate of the vehicle, and Tr represents the rear track width.

[0126] Furthermore, the vehicle's steering angle is determined by the steering wheel angle. The sign of the product of the wheelbase and yaw rate is determined by the vehicle's steering angle. When the vehicle turns left, the product of the wheelbase and yaw rate corresponding to the left wheel is generally positive, while the product of the wheelbase and yaw rate corresponding to the right wheel is generally negative. This is because when the vehicle turns left, the left wheel has a drag velocity in the same direction as the vehicle's forward movement, while the right wheel has a drag velocity in the opposite direction. The left wheel can include the left front wheel and the left rear wheel, and the right wheel can include the right front wheel and the right rear wheel. The following is an illustrative example using formulas (5) to (8):

[0127] Alternatively, when a vehicle turns right, the product of the track width and yaw rate of the left wheel is generally negative, while the product of the track width and yaw rate of the right wheel is generally positive. This is because when a vehicle turns right, the left wheel has a drag velocity opposite to the direction of travel, while the right wheel has a drag velocity in the same direction as the direction of travel. This is illustrated by formulas (9) to (12):

[0128] S3, differentiate the velocity of the wheel's center of mass to obtain the wheel acceleration.

[0129] For example, the wheel acceleration corresponding to the center-of-mass velocity of the wheel can be obtained by taking the first derivative of the wheel's center-of-mass velocity over time.

[0130] For example, by taking the first-order time derivative of VCGfl, VCGfr, VCGrl, and VCGrr respectively, we can obtain the wheel acceleration corresponding to VCGfl (which can be denoted as "VCGfl"). The wheel acceleration corresponding to VCGfr (which can be denoted as "VCGfr") The wheel acceleration corresponding to VCGrl (which can be denoted as "VCGrl") The wheel acceleration corresponding to VCGrr (which can be denoted as "VCGrr") (”).

[0131] S4 determines the steady-state flag position of the wheel by using the wheel's center of mass velocity, wheel acceleration, longitudinal acceleration measured by the IMU, and vehicle speed at the current moment and the previous moment.

[0132] For example, the velocity difference between the wheel's center of mass velocity and the vehicle speed at the current moment is calculated, and the velocity ratio between this difference and the vehicle speed at the current moment (i.e., the current slip ratio of each wheel) is calculated. Additionally, the absolute value of the acceleration difference between the wheel's wheel acceleration and the longitudinal acceleration measured by the IMU is calculated.

[0133] Furthermore, it is determined whether the speed ratio, the absolute value of the acceleration difference, and the wheel acceleration satisfy a first set of preset conditions, i.e., whether each wheel is rotating stably. When all preset conditions in the first set of preset conditions are met, it indicates that the wheel's operating state is more stable, the wheel's center-of-gravity velocity is more reliable, and the accuracy of the vehicle speed determined by the wheel's center-of-gravity velocity is higher. In this case, the wheel's steady-state flag can be activated, and its value is set to "1". The value of the wheel's steady-state flag represents the confidence level of the wheel's rotation. When the value of the wheel's steady-state flag is 1, it indicates that the wheel's center-of-gravity velocity is reliable. However, when at least one preset condition in the first set of preset conditions is not met, it indicates that the wheel's operating state may be stable, the wheel's center-of-gravity velocity is not very reliable, and the accuracy of the vehicle speed determined by the wheel's rotation is lower. In this case, the wheel's steady-state flag can be deactivated, and its value is set to "0". In this embodiment, the wheel's steady-state flag is denoted as "W".

[0134] The first set of preset conditions may include: determining whether the speed ratio is within a first preset range, determining whether the absolute value of the acceleration difference is less than or equal to a first preset threshold (denoted as "threshold 3"), and determining whether the wheel acceleration is within a second preset range. By determining whether the speed ratio is within the first preset range, it can be determined whether the wheel's center of gravity speed is affected by slippage or displacement, thus ensuring a match between the wheel's center of gravity speed and the vehicle's speed. If the speed ratio is not within the first preset range, it indicates that the wheel's center of gravity speed is affected by slippage or displacement, and the wheel acceleration and vehicle speed are mismatched, which is highly likely to be unreliable. Conversely, if the speed ratio is within the first preset range, it indicates that the wheel's center of gravity speed is not affected by slippage or displacement, and the wheel's center of gravity speed and vehicle speed are matched, which is reliable. Furthermore, by determining whether the absolute value of the acceleration difference is less than or equal to a first preset threshold, it can be determined whether the wheel's center of gravity velocity is caused by the wheel's abnormal rotation. If the absolute value of the acceleration difference is less than or equal to the first preset threshold, it indicates that the wheel's center of gravity velocity is the speed at which the wheel moves with the entire vehicle body, rather than the speed caused by the wheel's abnormal rotation, and is therefore reliable. However, if the absolute value of the acceleration difference is greater than the preset threshold, it indicates that the wheel's rotation speed is not the speed at which the wheel moves with the entire vehicle body, but rather the speed caused by the wheel's abnormal rotation, which is likely unreliable. For example, if the driver suddenly presses the accelerator pedal, causing the wheel to spin freely, the wheel's rotation speed will suddenly increase, but the longitudinal acceleration measured by the IMU will not change. Furthermore, by determining whether the wheel acceleration is within the second preset range, it can be determined whether the wheel's center of gravity velocity has changed abruptly. If the wheel acceleration is within the second preset range, it means that the wheel's center of gravity velocity is continuous and smooth, without any abrupt change, and is reliable. However, if the wheel acceleration is not within the second preset range, it means that the wheel may be subjected to a momentary impact (e.g., road bumps, noise interference, etc.), which may cause a sudden change in the wheel's center of gravity velocity, and is likely unreliable.

[0135] It should be noted that the first preset range is the range of wheel slip ratio, the first preset threshold is the center of mass velocity threshold, and the second preset range is the range of wheel acceleration. The lower boundary of the first preset range can be denoted as "threshold 1", the upper boundary of the first preset range can be denoted as "threshold 2", the lower boundary of the second preset range can be denoted as "threshold 4", and the upper boundary of the second preset range can be denoted as "threshold 5".

[0136] If the speed ratio is within the first preset range, the absolute value of the acceleration difference is less than or equal to the preset threshold, and the wheel acceleration is within the second preset range, it indicates that the stability of the wheel's running state is high, the corresponding steady-state flag value of the wheel is 1, and the wheel's center of mass speed is reliable.

[0137] Alternatively, if the speed ratio is not within the first preset range, and / or the absolute value of the acceleration difference is greater than the preset threshold, and / or the wheel acceleration is not within the second preset range, it indicates that the stability of the wheel's running state is poor, the corresponding steady-state flag value of the wheel is 0, and the wheel's center of gravity speed is unreliable.

[0138] The steady-state flag value of the left front wheel can be calculated under the following conditions: threshold 1 ≤ speed ratio ≤ threshold 2, and |VCGfl –Axm|≤threshold 3, and threshold 4≤VCGfl When the threshold value is ≤ 5, the steady-state flag value of the left front wheel can be set to "1"; otherwise, the steady-state flag value of the left front wheel can be set to "0". The steady-state flag value of the right front wheel can be calculated under the following conditions: when threshold 1 ≤ speed ratio ≤ threshold 2, and |VCGfr –Axm|≤threshold 3, and threshold 4≤VCGfr When the speed ratio is less than or equal to threshold 5, the steady-state flag value of the right front wheel can be set to "1"; otherwise, the steady-state flag value of the right front wheel can be set to "0". The steady-state flag value of the left rear wheel can be calculated under the following conditions: when threshold 1 ≤ speed ratio ≤ threshold 2, and |VCGrl –Axm|≤threshold 3, and threshold 4≤VCGrl When the speed ratio is less than or equal to threshold 5, the steady-state flag value of the left rear wheel can be set to "1"; otherwise, the steady-state flag value of the left rear wheel can be set to "0". The steady-state flag value of the right rear wheel can be calculated under the following conditions: when threshold 1 ≤ speed ratio ≤ threshold 2, and |VCGrr –Axm|≤threshold 3, and threshold 4≤VCGrr When the value is less than or equal to the threshold of 5, the steady-state flag of the right rear wheel can be set to "1"; otherwise, the steady-state flag of the right rear wheel can be set to "0".

[0139] Where Axm represents the longitudinal acceleration measured by the IMU, |VCGfr –Axm| represents the absolute value of the acceleration difference, i.e., the target acceleration deviation mentioned above.

[0140] S5. Determine the steady-state status of the vehicle by using at least one of the following: the accelerator pedal opening, the braking pressure, and the steady-state status of the wheel.

[0141] For example, since the more stable the vehicle's operating state, the more reliable the wheel's center of gravity velocity, it is necessary to determine the vehicle's stable operating state, i.e., whether the vehicle is operating stably, by using at least one of the following: accelerator pedal opening, braking pressure, and wheel steady-state indicator values. When the vehicle's operating state is unstable, the wheel's center of gravity velocity is unreliable. In this case, the vehicle speed can be determined by measuring the longitudinal acceleration using an IMU (Integrated Device Unit).

[0142] Specifically, it is determined whether the accelerator pedal opening, braking pressure (which can be referred to as "brake master cylinder pressure"), and the steady-state flag of the wheel satisfy a fourth set of preset conditions. If at least one preset condition in the fourth set of preset conditions is satisfied, it indicates that the vehicle's operating state is stable and the wheel's center-of-gravity velocity is reliable. In this case, the vehicle's steady-state flag can be activated, and its value can be set to "1". Conversely, if the accelerator pedal opening, braking pressure, or the wheel's steady-state flag does not satisfy any of the preset conditions in the fourth set of preset conditions, it indicates that the vehicle's operating state is unstable and the wheel's center-of-gravity velocity is unreliable. In this case, the vehicle's steady-state flag can be deactivated, and its value can be set to "0". In this embodiment, the vehicle's steady-state flag is denoted as "VS".

[0143] The fourth set of preset conditions may include: determining whether the accelerator pedal opening is less than or equal to the eighth preset threshold (which can be denoted as "threshold 12") and whether the braking pressure is less than or equal to the ninth preset threshold (which can be denoted as "threshold 13") and whether there is at least one wheel's steady-state flag activated among the wheel's steady-state flags, and / or whether there are multiple wheels' steady-state flags activated among the wheel's steady-state flags and whether the multiple wheels' steady-state flags include the steady-state flag of the left front wheel or the steady-state flag of the right front wheel. By determining whether the accelerator pedal opening is less than or equal to the eighth preset threshold, whether the braking pressure is less than or equal to the ninth preset threshold, and whether at least one wheel's steady-state flag is activated, it can be determined whether the vehicle is undergoing rapid acceleration and braking without losing control. If the accelerator pedal opening is less than or equal to the eighth preset threshold, the braking pressure is less than or equal to the ninth preset threshold, and at least one wheel's steady-state flag is activated, it indicates that the vehicle's acceleration and braking amplitudes are small, and the vehicle is not undergoing rapid acceleration and braking, indicating that the vehicle's operating state is stable and the wheel's center of gravity speed is reliable. Conversely, if the accelerator pedal opening is greater than the eighth preset threshold and / or the braking pressure is greater than the ninth preset threshold and / or no wheel's steady-state flag is activated, it indicates that the vehicle's acceleration and / or braking amplitudes are large, and the vehicle may be undergoing rapid acceleration and / or braking under conditions of loss of control, indicating that the vehicle's operating state is unstable and the wheel's center of gravity speed is unreliable. Furthermore, by checking whether multiple wheel steady-state markers are activated, including either the left or right front wheel steady-state marker, the stability of the multiple wheel rotations and the vehicle steering can be determined. When multiple wheel steady-state markers are activated, including either the left or right front wheel steady-state marker, the multiple wheels rotate stably and the vehicle steering is stable, indicating that the vehicle's operating state is stable and the wheel center-of-gravity velocity is reliable. Conversely, when no wheel steady-state marker is activated, the wheel rotation is unstable, making the vehicle's operating state unstable and the wheel center-of-gravity velocity unreliable. Furthermore, using the steady-state indicator position of the left front wheel or the steady-state indicator position of the right front wheel as the preset condition, instead of using the steady-state indicator positions of the left front wheel and the right front wheel as the preset condition, is to avoid the problem that the vehicle's steady-state indicator position cannot be activated when the steady-state indicator position of the left front wheel or the right front wheel is not activated, thus ensuring the normal activation of the vehicle's steady-state indicator position.

[0144] It should be noted that the eighth preset threshold is the braking pressure threshold and the ninth preset threshold is the accelerator pedal opening threshold. Both the eighth and ninth preset thresholds can be obtained through actual vehicle calibration, and this application embodiment does not limit them.

[0145] When the accelerator pedal opening is less than or equal to threshold 12 and the braking pressure is less than or equal to threshold 13, and at least one wheel's steady-state flag is active, and / or two or more wheels' steady-state flags are active, including either the left front wheel's or the right front wheel's steady-state flag, the vehicle's steady-state flag can be activated and its flag value set to "1". Conversely, when the accelerator pedal opening is greater than threshold 12 and / or the braking pressure is greater than threshold 13, and / or no wheel's steady-state flag is active, the vehicle's steady-state flag can be deactivated and its flag value set to "0". The calculation of the vehicle's steady-state flag can be performed under the following conditions: when PmsPacc < threshold 12 and Pms < threshold 13, and at least one wheel's steady-state flag is active, and / or, two or more wheels' steady-state flags are active, and the active wheel's steady-state flag includes either the left front wheel's steady-state flag or the right front wheel's steady-state flag, the flag value of the vehicle's steady-state flag can be set to "1". Otherwise, the flag value of the vehicle's steady-state flag is set to "0". Here, Pacc represents the accelerator pedal opening, and Pms represents the brake pressure.

[0146] S6 determines the steady-state large steering mark position of the vehicle by measuring the steering wheel angle, the steering wheel angular velocity, and the wheel center of gravity velocity.

[0147] For example, the vehicle's steady-state large steering flag is activated by first measuring the vehicle's steering wheel angle, steering wheel angular velocity, and wheel center of gravity velocity, thus determining whether the vehicle's steering is stable.

[0148] Specifically, the absolute value of the steering wheel angle and the absolute value of the steering wheel angular velocity are determined; the difference in rotational speed between the front and rear wheels is calculated using the center-of-gravity velocities of the front and rear wheels, and this difference is defined as the front-to-rear wheel rotational speed difference. The sum of the center-of-gravity velocities of the left and right front wheels is defined as the center-of-gravity velocity of the front wheel, i.e., front wheel center-of-gravity velocity = VCGfl + VCGfr; and the sum of the center-of-gravity velocities of the left and right rear wheels is defined as the center-of-gravity velocity of the rear wheel, i.e., rear wheel center-of-gravity velocity = VCGrl + VCGrr; the difference between the center-of-gravity velocities of the rear and front wheels is defined as the front-to-rear wheel rotational speed difference, i.e., front-to-rear wheel rotational speed difference = rear wheel center-of-gravity velocity - front wheel center-of-gravity velocity = (VCGrl + VCGrr) - (VCGfl + VCGfr). In addition, determine the minimum center-of-gravity velocity between the left rear wheel and the right rear wheel, i.e., min(VCGrl,VCGrr); and determine the maximum center-of-gravity velocity between the left front wheel and the right front wheel, i.e., max(VCGfl,VCGfr).

[0149] Furthermore, it is determined whether the absolute value of the steering angle, the absolute value of the steering velocity, the difference in speed between the front and rear wheels, the minimum center of gravity velocity, and the maximum center of gravity velocity satisfy the second preset condition set. If all preset conditions in the second preset condition are satisfied, it indicates that the vehicle is in a stable large steering state. In this case, the steady-state large steering flag can be activated, and its value can be set to "1". If the difference in speed between the front and rear wheels and / or the absolute value of the steering angle do not satisfy the preset conditions in the second preset condition, it indicates that the vehicle is not in a stable large steering state. In this case, the steady-state large steering flag can be deactivated, and its value can be set to "0". If the difference in speed between the front and rear wheels and / or the absolute value of the steering angle satisfy the preset conditions in the second preset condition, but the absolute value of the steering velocity, the minimum center of gravity velocity, and the maximum center of gravity velocity do not satisfy the preset conditions in the second preset condition, the steady-state large steering flag of the previous moment can be obtained and used as the steady-state large steering flag of the current moment. In this embodiment, the steady-state large steering flag is denoted as "P".

[0150] The second set of preset conditions may include: determining whether the absolute value of the turning angle is greater than or equal to a second preset threshold (denoted as "threshold 6"), determining whether the absolute value of the turning velocity is less than or equal to a third preset threshold (denoted as "threshold 7"), determining whether the difference in speed between the front and rear wheels is greater than or equal to a fourth preset threshold (denoted as "threshold 8"), and determining whether the minimum center of gravity velocity is greater than or equal to the maximum center of gravity velocity. By determining whether the absolute value of the turning angle is greater than or equal to the second preset threshold, it can be determined whether the vehicle is making a large-angle turn (e.g., a sharp turn). When the absolute value of the turning angle is less than or equal to the second preset threshold, it indicates that the vehicle's turning angle is small and the vehicle is not making a large turn; while when the absolute value of the turning angle is greater than the second preset threshold, it indicates that the vehicle's turning angle is large and the vehicle is making a large turn. Furthermore, by determining whether the absolute value of the angular velocity is less than or equal to a third preset threshold, it can be determined whether the vehicle's steering angle is too large. When the absolute value of the angular velocity is greater than or equal to the third preset threshold, it indicates that the vehicle's steering angle is too large, indicating a sharp turn (e.g., an emergency lane change), and the vehicle is not steering stably. Conversely, when the absolute value of the angular velocity is less than the third preset threshold, it indicates that the vehicle's steering angle is small, and the vehicle is steering stably. Also, by determining whether the difference in speed between the front and rear wheels is greater than or equal to a fourth preset threshold, it can be determined whether the vehicle is steering. When the difference in speed between the front and rear wheels is greater than or equal to the fourth preset threshold, it indicates that the difference in wheel speed is large, and the vehicle may be steering. Conversely, when the difference in speed between the front and rear wheels is less than the fourth preset threshold, it indicates that the difference in wheel speed is small, and the vehicle may not be steering. Furthermore, by determining whether the minimum center of gravity speed is greater than or equal to the maximum center of gravity speed, it can be determined whether the center of gravity speed of the front wheels is greater than that of the rear wheels. When the minimum center of gravity speed is greater than or equal to the maximum center of gravity speed, it indicates that the difference in speed between the front and rear wheels exists as a whole in the vehicle, and the vehicle is turning. However, when the minimum center of gravity speed is less than the maximum center of gravity speed, it indicates that the difference in speed between the front and rear wheels does not exist as a whole in the vehicle, and may be caused by abnormal rotation of a certain wheel, and the vehicle may not be turning.

[0151] It should be noted that the second preset threshold is a turning angle threshold, the third preset threshold is a turning acceleration threshold, and the fourth preset threshold is a wheel speed threshold. The second, third, and fourth preset thresholds can all be obtained through actual vehicle calibration, and this application embodiment does not limit them.

[0152] When the absolute value of the turning angle is greater than or equal to threshold 6, and the absolute value of the angular velocity is less than or equal to threshold 7, and the difference in speed between the front and rear wheels is greater than or equal to threshold 8, and the minimum center of gravity velocity is greater than or equal to the maximum center of gravity velocity, it indicates that the vehicle is smoothly performing a large turn and is in a stable large turn state. In this case, the steady-state large turn flag can be activated and its value set to "1". Conversely, when the absolute value of the turning angle is less than threshold 6 and / or the difference in speed between the front and rear wheels is greater than threshold 8, it indicates that the vehicle is not turning. In this case, the steady-state large turn flag can be left unactivated and its value set to "0". When the absolute value of the angular velocity is greater than or equal to threshold 7 and / or the minimum center of gravity velocity is less than the maximum center of gravity velocity, it indicates that the vehicle may be performing a large turn but is unstable. In this case, the steady-state large turn flag from the previous moment can be used as the steady-state large turn flag for the current moment. The calculation for activating the steady-state large turn flag can be performed under the following conditions: when |δ| ≥ threshold 6, and |δ When |δ| ≤ threshold 7, and (VCGrl + VCGrr) - (VCGfl + VCGfr) ≥ threshold 8, and min(VCGrl + VCGrr) > max(VCGfl + VCGfr), the steady-state large steering flag can be activated and its value set to "1". The steady-state large steering flag can be deactivated under the following conditions: when |δ| < threshold 6, and / or (VCGrl + VCGrr) - (VCGfl + VCGfr) < threshold 8, the steady-state large steering flag is not activated and its value is set to "0". Here, |δ| represents the absolute value of the steering angle, |δ | represents the absolute value of the angular velocity.

[0153] S7 determines the vehicle's large steering mark position by measuring the vehicle's steering wheel angle and steering wheel angular velocity.

[0154] For example, first determine whether the vehicle is in a large steering state (i.e., determine the current steering range) by the vehicle's steering wheel angle and steering wheel angular velocity. When the vehicle is in a large steering state, the value of the large steering mark can be determined by the vehicle's steering wheel angle and steering wheel angular velocity.

[0155] Specifically, the absolute value of the vehicle's steering wheel angle and the absolute value of the vehicle's steering wheel angular velocity are determined. It is then determined whether the absolute values ​​of the angle and angular velocity satisfy a third set of preset conditions. If at least one preset condition in the third set of preset conditions is satisfied, it indicates that the vehicle is in a large steering state. In this case, the large steering flag can be activated, and its value is set to "1". If at least one preset condition in the third set of preset conditions is not satisfied, it indicates that the vehicle is not in a large steering state. In this case, the large steering flag can be deactivated, and its value is set to "0". In this embodiment, the large steering flag is denoted as "Ls".

[0156] The third set of preset conditions may include: determining whether the absolute value of the turning angle is greater than or equal to a fifth preset threshold (denoted as "threshold 9"), and / or determining whether the absolute value of the turning angle is greater than or equal to a sixth preset threshold (denoted as "threshold 10") and whether the absolute value of the angular velocity is greater than or equal to a seventh preset threshold (denoted as "threshold 11"); the fifth preset threshold is greater than the sixth preset threshold. By determining whether the absolute value of the turning angle is greater than or equal to the fifth preset threshold, it can be determined whether the vehicle is making a large-angle turn. When the absolute value of the turning angle is greater than or equal to the fifth preset threshold, it indicates that the vehicle's turning angle is large and it is in a large-angle turn state; while when the absolute value of the turning angle is less than the fifth preset threshold, it indicates that the vehicle's turning angle is small and the vehicle is not in a large-angle turn state. Furthermore, by determining whether the absolute value of the turning angle is greater than or equal to the sixth preset threshold and whether the absolute value of the turning velocity is greater than or equal to the seventh preset threshold, it can be determined whether the vehicle's steering angle is too large. When the absolute value of the turning angle is greater than or equal to the sixth preset threshold and the absolute value of the turning velocity is greater than or equal to the seventh preset threshold, although the vehicle's turning angle is small, the vehicle's steering angle is too large, and the vehicle is in a large steering state. When the absolute value of the turning angle is less than or equal to the sixth preset threshold and the absolute value of the turning velocity is less than the seventh preset threshold, the vehicle's turning angle is small and the vehicle's steering angle is also small, and it is not in a large steering state.

[0157] It should be noted that the fifth preset threshold is a turning angle threshold, the sixth preset threshold is a turning angle threshold, and the seventh preset threshold is a turning speed threshold. The fifth, sixth, and seventh preset thresholds can be obtained through actual vehicle calibration, and this application embodiment does not limit them.

[0158] When the absolute value of the turning angle is greater than or equal to threshold 9, and / or when the absolute value of the turning angle is greater than or equal to threshold 10 and the absolute value of the angular velocity is greater than or equal to threshold 11, the vehicle is in a large turn, and the value of the large turn indicator can be set to "1". When the absolute value of the turning angle is less than threshold 9, and / or when the absolute value of the turning angle is less than or equal to threshold 10 and the absolute value of the angular velocity is less than threshold 11, the vehicle is not in a large turn, and the value of the large turn indicator can be set to "0". The value of the large turn indicator can be calculated under the following conditions: when |δ| ≥ threshold 9, and / or |δ| ≥ threshold 10 and |δ| ≥ threshold 11, the vehicle is not in a large turn, and the value of the large turn indicator can be set to "0". When the threshold value is ≥11, the value of the large steering flag can be set to "1"; otherwise, the value of the large steering flag can be set to "0".

[0159] S8, when the vehicle's steady-state indicator indicates the vehicle's steady state, determines the number of wheel speed steady states by using the wheel's steady-state indicator and the vehicle's steady-state large steering indicator.

[0160] For example, when the vehicle's steady-state indicator is obtained, it can be first determined whether the vehicle's steady-state indicator indicates a steady state. If the vehicle's steady-state indicator indicates a steady state, the number of wheel speeds in steady-state condition can be determined by the values ​​of the steady-state indicator values ​​for each wheel and the value of the vehicle's steady-state large steering indicator. It should be understood that when the vehicle's steady-state indicator indicates a steady state, the ESP function is generally not triggered; at this time, the vehicle's steady-state indicator is activated. Since vehicle steering is generally controlled by the front wheels, it can be first determined whether the vehicle's steady-state large steering indicator is activated (i.e., whether the vehicle is performing a large steering maneuver). If the vehicle's steady-state large steering indicator is not activated, the sum of the values ​​of the steady-state indicator values ​​for the front wheels and the vehicle's steady-state large steering indicator can be calculated, and then this sum can be added to the values ​​of the steady-state indicator values ​​for the rear wheels to obtain the number of wheel speeds in steady-state condition. Specifically, the steady-state indicator value of the left front wheel is added to the sum of the steady-state steering indicator value of the vehicle, the steady-state indicator value of the right front wheel is added to the sum of the steady-state steering indicator value of the vehicle, the steady-state indicator value of the left rear wheel, and the steady-state indicator value of the right rear wheel to obtain the number of steady-state wheel speeds. Furthermore, since the steady-state steering indicator value is "0" when the vehicle's steady-state steering indicator value is not activated, the actual number of steady-state wheel speeds is the sum of the steady-state indicator values ​​of the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel. When the vehicle's steady-state steering indicator value is activated, the steady-state indicator values ​​of the left rear wheel and the right rear wheel can be added to obtain the number of steady-state wheel speeds. This is illustrated by formulas (13) and (14).

[0161] In formula (12), the steady-state large steering flag position (i.e., P) of the vehicle is not activated, and the corresponding flag value is "0", that is, VSum=WFlgfl+WFlgfr+WFlgrl+WFlgrr. VSum represents the number of steady-state wheel speeds. VSum is less than or equal to the number of steady-state wheel speeds. For example, in a four-wheeled vehicle, VSum can be any of 0, 1, 2, 3, or 4. WFlgfl represents the flag value of the steady-state flag position of the left front wheel, WFlgfr represents the flag value of the steady-state flag position of the right front wheel, WFlgrl represents the flag value of the steady-state flag position of the left rear wheel, and WFlgrr represents the flag value of the steady-state flag position of the right rear wheel.

[0162] For example, if the steady-state large steering flag of the vehicle is not activated, and the flag values ​​of WFlgfl, WFlgfr, WFlgrl, and WFlgrr are 1, then VSum can be obtained as 4 by formula (13).

[0163] For example, if the steady-state large steering flag of the vehicle is not activated, and the flag values ​​of WFlgfl are 1, WFlgfr are 0, WFlgrl are 1, and WFlgrr are 1, then VSum can be obtained as 3 by formula (13).

[0164] For example, if the steady-state large steering flag of the vehicle is not activated, and the flag values ​​of WFlgfl are 1, WFlgfr are 0, WFlgrl are 0, and WFlgrr are 1, then VSum can be obtained as 2 by formula (13).

[0165] For example, if the steady-state large steering flag of the vehicle is not activated, and the flag values ​​of WFlgfl are 1, WFlgfr are 0, WFlgrl are 0, and WFlgrr are 0, then VSum can be obtained as 1 by formula (13).

[0166] For example, if the steady-state large steering flag of the vehicle is not activated, and the flag values ​​of WFlgfl, WFlgfr, WFlgrl, and WFlgrr are 0, then VSum can be obtained as 0 by formula (13).

[0167] For example, if the steady-state large steering flag of the vehicle is activated, and the flag value of WFlgrl is 1 and the flag value of WFlgrr is 1, then VSum can be obtained as 2 by formula (14).

[0168] For example, if the steady-state large steering flag of the vehicle is activated, and the flag value of WFlgrl is 1 and the flag value of WFlgrr is 0, then VSum can be obtained as 1 by formula (14).

[0169] For example, if the steady-state large steering flag of the vehicle is activated, and the flag values ​​of WFlgrl and WFlgrr are both 0, then VSum can be obtained as 0 using formula (14).

[0170] It should be noted that when VSum is 4, it means the center-of-gravity velocities of all wheels are reliable. When VSum is 3, it means the center-of-gravity velocities of all three wheels are reliable, and the center-of-gravity velocity of one wheel is unreliable. When VSum is 2, it means the center-of-gravity velocities of two wheels are reliable, and the center-of-gravity velocities of the other two wheels are unreliable. When VSum is 1, it means the center-of-gravity velocity of one wheel is reliable, and the center-of-gravity velocities of all three wheels are unreliable. When VSum is 0, it means the center-of-gravity velocities of all wheels are unreliable.

[0171] S9 calculates the vehicle's first initial speed using at least one of the following: the number of steady-state wheel speeds, the vehicle's large steering indicator position, and the wheel's center of gravity speed.

[0172] For example, the vehicle speed is calculated by determining the number of steady-state wheel speeds (i.e., the number of target wheels), and the vehicle's first initial speed is calculated using this method. In this embodiment, the vehicle's first initial speed is denoted as "Vx1".

[0173] (1) The number of steady-state wheel speeds is 4: For example, when the number of steady-state wheel speeds is 4, the vehicle speed is calculated by combining the activation state of the large steering indicator and the accelerator pedal opening. When the large steering indicator is activated and the accelerator pedal opening is less than or equal to the threshold of 12, the front wheels generally experience braking slippage due to steering, reducing the reliability of their center-of-gravity speed. At this time, although the center-of-gravity speed of the front wheels is still reliable, its reliability is lower than that of the rear wheels. Therefore, the first initial vehicle speed can be determined by the center-of-gravity speed of the rear wheels. Specifically, the average center-of-gravity speed of the left and right rear wheels is determined as the first initial vehicle speed, i.e., Vx1 = .

[0174] When the large steering indicator is not activated, if the accelerator pedal opening is greater than the threshold 12, the vehicle is under heavy throttle, and the wheels may slip (also known as "longitudinal slip"), causing the wheel's center of gravity velocity to be greater than the vehicle's actual speed. At this time, although the wheel's center of gravity velocity is still reliable, its reliability will be slightly weaker. Since the minimum center of gravity velocity of a wheel during slippage is generally closer to the vehicle's actual speed, and to avoid deviations in the center of gravity velocity of a single wheel, the average wheel speeds of the front and rear wheels can be determined first. Then, the minimum wheel speed among the average wheel speeds of the front and rear wheels is determined as the first initial speed. Specifically, the minimum wheel speed among the average wheel speeds of the left and right front wheels and the average wheel speeds of the left and right rear wheels is determined as the first initial speed, i.e., Vx1 = Min ( ).in, This indicates the average wheel speed of the front wheels. This indicates the average wheel speed of the rear wheels.

[0175] When the vehicle's large steering indicator is activated and the accelerator pedal opening is greater than the threshold 12, the vehicle is in a state of high throttle and large steering. At this time, wheel slippage will intensify. To improve the accuracy of vehicle speed, the minimum wheel speed among the average wheel speeds of the left and right front wheel centers of gravity and the average wheel speeds of the left and right rear wheel centers of gravity can be determined as the first initial vehicle speed, i.e., Vx1 = Min ( ).

[0176] When the vehicle's large steering indicator is not activated and the accelerator pedal opening is less than or equal to the threshold of 12, it indicates that the reliability of the wheel center-of-gravity velocities is relatively high. Therefore, the average wheel speed of the center-of-gravity velocities of multiple vehicles can be determined as the first initial vehicle speed. Specifically, the average wheel speed of the center-of-gravity velocities of the left front wheel, right front wheel, left rear wheel, and right rear wheel is determined as the first initial vehicle speed, i.e., Vx1 = .

[0177] (2) The number of steady-state wheel speeds is 3: For example, when there are 3 steady-state wheel speeds, the vehicle speed is calculated by combining the activation state of the large steering indicator and the accelerator pedal opening. The presence of 3 steady-state wheel speeds indicates the existence of one unreliable wheel's center-of-gravity velocity, which needs to be filtered out. By filtering out this unreliable wheel's center-of-gravity velocity using the wheel's center-of-gravity velocity and steady-state wheel indicator, the reliable average wheel speeds of the front and rear wheels are obtained; these are the filtered average wheel speeds of the front and rear wheels. Specifically, first calculate the product of the center-of-gravity velocity of the left front wheel and the steady-state indicator value (which can be denoted as "product 1"), the product of the center-of-gravity velocity of the right front wheel and the steady-state indicator value (which can be denoted as "product 2"), and the sum of the steady-state indicator values ​​of the left and right front wheels (which can be denoted as "sum 1"). Then calculate the sum of product 1 and product 2. The ratio of the sum of product 1 and product 2 to sum 1 is determined as the average wheel speed of the filtered front wheels, and the average wheel speed of the filtered front wheels is denoted as "VAf"; that is, VAf = First, calculate the product of the center-of-gravity velocity of the left rear wheel and the steady-state indicator value (which can be denoted as "product 3"), the product of the center-of-gravity velocity of the right rear wheel and the steady-state indicator value (which can be denoted as "product 4"), and the sum of the steady-state indicator values ​​of the left and right rear wheels (which can be denoted as "sum 2"). Then, calculate the sum of product 3 and product 4. The ratio of the sum of product 3 and product 4 to sum 2 is determined as the average wheel speed of the filtered rear wheels, and the average wheel speed of the filtered rear wheels is denoted as "VAr"; that is, VAr = .

[0178] When the vehicle's large steering indicator is activated and the accelerator pedal opening is less than or equal to the threshold 12, the reliability of the front wheels' center of gravity velocity is reduced due to braking slippage caused by steering. Although the front wheels' center of gravity velocity is still reliable, its reliability is lower than that of the rear wheels. Therefore, the vehicle's initial speed can be determined using the rear wheels' center of gravity velocity. Specifically, the average wheel speed of the filtered rear wheels is determined as the first initial speed, i.e., Vx1 = Var.

[0179] When the vehicle's large steering indicator is not activated, if the accelerator pedal opening is greater than the threshold 12, the vehicle is under heavy throttle, and the wheels may slip, causing the wheel's center of gravity velocity to be greater than the vehicle's actual speed. In this case, although the wheel's center of gravity velocity is still reliable, its reliability will be slightly weaker. Since the center of gravity velocity of the wheel with the smallest slippage is generally closer to the vehicle's actual speed, and to avoid deviations in the center of gravity velocity of a single wheel, the minimum wheel speed among the filtered average wheel speeds of the front wheels and the filtered average wheel speeds of the rear wheels can be determined as the first initial vehicle speed, i.e., Vx1 = Min(VAf, VAr).

[0180] When the vehicle's large steering indicator is activated and the accelerator pedal opening is greater than the threshold 12, the vehicle is in a state of large throttle and large steering. At this time, the wheel slippage will be aggravated. In order to improve the accuracy of vehicle speed, the minimum wheel speed among the average wheel speed of the filtered front wheel and the average wheel speed of the filtered rear wheel can be determined as the first initial vehicle speed, i.e., Vx1=Min(VAf,VAr).

[0181] When the vehicle's large steering indicator is not activated and the accelerator pedal opening is less than or equal to the threshold of 12, it indicates that the reliability of the filtered average wheel speeds of the front and rear wheels is relatively high. Therefore, the filtered average wheel speeds of the front and rear wheels can be determined as the first initial vehicle speed, i.e., Vx1. .

[0182] (3) The number of steady-state wheel speeds is 2: For example, when there are two steady-state wheel speeds, the vehicle speed is calculated by combining the activation state of the large steering indicator and the accelerator pedal opening. The presence of two steady-state wheel speeds indicates the existence of two unreliable wheel center-of-gravity velocities, which need to be filtered out. By filtering out these two unreliable wheel center-of-gravity velocities using the wheel center-of-gravity velocities and their steady-state indicator values, reliable wheel center-of-gravity velocities are obtained—the filtered wheel center-of-gravity velocities. Specifically, the product of the wheel center-of-gravity velocities and the steady-state indicator value is calculated, and this product is determined as the filtered wheel center-of-gravity velocities. For example, the product of the left front wheel's center-of-gravity velocities and the steady-state indicator value is the filtered left front wheel center-of-gravity velocities: Vxinfl = VCGfl × WFlgfl. Vxinfl represents the filtered left front wheel center-of-gravity velocities. Furthermore, the product of the center-of-gravity velocity of the right front wheel and the steady-state flag value is the filtered center-of-gravity velocity of the right front wheel, Vxinfr = VCGfr × WFlgfr. Vxinfr represents the filtered center-of-gravity velocity of the right front wheel. Similarly, the product of the center-of-gravity velocity of the left rear wheel and the steady-state flag value is the filtered center-of-gravity velocity of the left rear wheel, Vxinrl = VCGrl × WFlgrl. Vxinrl represents the filtered center-of-gravity velocity of the left rear wheel. Likewise, the product of the center-of-gravity velocity of the right rear wheel and the steady-state flag value is the filtered center-of-gravity velocity of the right rear wheel, Vxinrr = VCGrr × WFlgrr. Vxinrr represents the filtered center-of-gravity velocity of the right rear wheel.

[0183] When the vehicle's large steering indicator is activated and the accelerator pedal opening is less than or equal to the threshold 12, although the front wheels will generally brake and slip due to steering, reducing the reliability of their own center of gravity velocity, the center of gravity velocity of the front wheels is still reliable. Furthermore, to avoid the problem that the center of gravity velocities of the two unreliable wheels are both the center of gravity velocities of the rear wheels, which would lead to a large deviation in the vehicle speed determined solely by the center of gravity velocities of the left and right rear wheels, and to avoid the problem that vehicle steering will cause the center of gravity velocities of the wheels to be less than the actual vehicle speed, the center of gravity velocity of the largest wheel is generally closer to the actual vehicle speed. Therefore, the largest center of gravity velocity among the filtered wheel center of gravity velocities can be determined as the first initial vehicle speed, i.e., Vx1 = Max(Vxinfl, Vxinfr, Vxinrl, Vxinrr).

[0184] When the large steering indicator of the vehicle is not activated, if the accelerator pedal opening is greater than the threshold 12, and the stability indicator of the left front wheel and the indicator of the right front wheel are activated, or the stability indicator of the left rear wheel and the indicator of the right rear wheel are activated, the minimum center of gravity speed of the filtered left front wheel and the minimum center of gravity speed of the filtered right front wheel can be determined first, i.e., the minimum front wheel speed; and the minimum center of gravity speed of the filtered left rear wheel and the minimum center of gravity speed of the filtered right rear wheel can be determined, i.e., the minimum rear wheel speed; then the maximum wheel speed of the minimum front wheel speed and the minimum rear wheel speed is determined as the first initial vehicle speed, i.e., Vx1=Max(Min(Vxinfl,Vxinfr),Min(Vxinrl,Vxinrr)). This is because the activation of the stability flags for both the left and right front wheels indicates front axle stability, making the center-of-gravity velocities of the left and right front wheels reliable. However, the center-of-gravity velocities of the two unreliable wheels are those of the left and right rear wheels, which are filtered out, resulting in Vxinrl and Vxinrr being 0. Therefore, the maximum wheel speed between the minimum front and rear wheel speeds needs to be determined as the first initial vehicle speed. Furthermore, since wheel slippage may occur when the vehicle is under heavy throttle, the minimum center-of-gravity velocity of the wheel is generally closer to the actual vehicle speed. Therefore, the minimum center-of-gravity velocity between the filtered left and right front wheel speeds is determined. Alternatively, when the stability flags for both the left and right rear wheels are activated, it indicates that the rear axle is stable, and the center-of-gravity velocities of the left and right rear wheels are reliable. The center-of-gravity velocities of the two unreliable wheels are those of the left and right front wheels, which are filtered out, resulting in Vxinfl and Vxinfr being 0. Therefore, the maximum wheel speed between the minimum front wheel speed and the minimum rear wheel speed needs to be determined as the first initial vehicle speed. Furthermore, because the wheels may slip under heavy throttle, the minimum center-of-gravity velocity of the wheel is generally closer to the actual vehicle speed. Therefore, the minimum center-of-gravity velocity between the filtered left and right rear wheel speeds needs to be determined.

[0185] When the large steering indicator of the vehicle is not activated, if the accelerator pedal opening is greater than the threshold 12, and the stability indicator of the left front wheel is not activated and / or the indicator of the right front wheel is not activated, or the stability indicator of the left rear wheel is not activated and / or the indicator of the right rear wheel is not activated, the maximum center of gravity speed among the filtered center of gravity speeds of the left front wheel and the right front wheel can be determined first, i.e., the maximum front wheel speed; and the maximum center of gravity speed among the filtered center of gravity speeds of the left rear wheel and the right rear wheel can be determined, i.e., the maximum rear wheel speed; then the minimum wheel speed among the maximum front wheel speed and the maximum rear wheel speed is determined as the first initial vehicle speed, i.e., Vx1=Min(Max(Vxinfl,Vxinfr),Max(Vxinrl,Vxinrr)). This is because when the stability indicator for the left front wheel is not activated and / or the indicator for the right front wheel is not activated, it indicates that the front axle is unstable. The center-of-gravity velocities of the left and / or right front wheels are unreliable and need to be filtered out. Therefore, the maximum center-of-gravity velocity among the filtered left and right front wheel velocities is determined. Similarly, when the stability indicator for the left rear wheel is not activated and / or the indicator for the right rear wheel is not activated, it indicates that the rear axle is unstable. The center-of-gravity velocities of the left and / or right rear wheels are unreliable and need to be filtered out. Therefore, the maximum center-of-gravity velocity among the filtered left and right rear wheel velocities is determined. Furthermore, because the wheels may slip when the vehicle is under heavy throttle, the minimum center-of-gravity velocity of the wheel is generally closer to the actual vehicle speed. Therefore, the minimum wheel speed among the maximum front wheel speed and the maximum rear wheel speed is determined as the first initial vehicle speed.

[0186] When the large steering flag of the vehicle is activated and the accelerator pedal opening is greater than the threshold 12, the stability flag of each wheel can be used to determine the use of Vx1=Max(Min(Vxinfl,Vxinfr),Min(Vxinrl,Vxinrr)), or Vx1=Min(Max(Vxinfl,Vxinfr),Max(Vxinrl,Vxinrr)).

[0187] When the vehicle's large steering indicator is not activated and the accelerator pedal opening is less than or equal to the threshold of 12, it indicates that the reliability of the filtered wheel center-of-gravity velocities is weak. Therefore, the average wheel speed of the filtered wheels can be determined as the first initial vehicle speed, i.e., Vx1 = .

[0188] (4) The number of steady-state wheel speeds is 1: For example, when the number of steady-state wheel speeds is 1, it indicates the existence of 3 unreliable wheel center-of-gravity velocities, which need to be filtered out. By filtering out the 3 unreliable wheel center-of-gravity velocities using the wheel's center-of-gravity velocity and steady-state flag, the reliable wheel center-of-gravity velocities are obtained, i.e., the filtered wheel center-of-gravity velocities, such as Vxinfl, Vxinfr, Vxinrl, and Vxinrr. The maximum center-of-gravity velocity among the filtered wheel center-of-gravity velocities is then determined as the first initial vehicle speed, i.e., Vx1 = max(Vxinfl, Vxinfr, Vxinrl, Vxinrr). This is because after filtering out the 3 unreliable wheel center-of-gravity velocities, a non-zero center-of-gravity velocity remains; therefore, the maximum center-of-gravity velocity among the filtered wheel center-of-gravity velocities is determined as the first initial vehicle speed.

[0189] (5) The number of steady-state wheel speeds is 0: For example, when the number of steady-state wheel velocities is 0, it indicates the existence of 4 unreliable wheel center-of-gravity velocities. Filtering out these 4 unreliable wheel center-of-gravity velocities would result in all wheel center-of-gravity velocities being filtered out, making it impossible to calculate the vehicle speed. Therefore, when the reliability of the wheel center-of-gravity velocities is weak, the average wheel speed of multiple vehicle center-of-gravity velocities can be determined as the first initial vehicle speed, i.e., Vx1 = .

[0190] S10: Determine the target gradient by using the first initial vehicle speed and the preset gradient.

[0191] For example, when the first initial vehicle speed is obtained, the vehicle speed change gradient can be determined by the activation state of the vehicle's steady-state flag. Specifically, when the vehicle's steady-state flag is activated, the product of the preset gradient limit value and the preset duration can be determined as the vehicle speed change gradient. The preset gradient limit value can include the maximum and minimum limits of the preset gradient. The preset duration can be the data acquisition cycle in the vehicle, such as the running cycle of the data processing software, for example, 10 seconds or 20 seconds, etc., and this embodiment does not limit this.

[0192] The minimum gradient of vehicle speed is the product of the minimum limit of the preset gradient and the preset duration, and the maximum gradient of vehicle speed is the product of the maximum limit of the preset gradient and the preset duration. ΔAx(1) = T1 × t, ΔAx(2) = T2 × t, which can be rearranged as: ΔAx = [T1, T2] T×t. Where ΔAx(1) represents the maximum gradient of vehicle speed change, T1 represents the maximum limit of the preset gradient of change (i.e., the upper limit of the first preset range mentioned above), t represents the preset duration, ΔAx(2) represents the minimum gradient of vehicle speed change (i.e., the lower limit of the first preset range mentioned above), and T2 represents the minimum limit of the preset gradient of change.

[0193] S11, based on the target change gradient and the vehicle speed of the previous moment at the current moment, determine the final longitudinal vehicle speed.

[0194] For example, the final longitudinal speed (i.e., the current speed of the vehicle) is determined by the sum of the target change gradient and the vehicle speed at the previous time (i.e., the historical vehicle speed mentioned above).

[0195] S12, when the vehicle's steady-state indicator shows that the vehicle is in an unsteady state, calculate the vehicle's second initial speed using the wheel's center of mass velocity.

[0196] For example, when the vehicle's steady-state indicator shows an unstable state, i.e., the vehicle is instable, it is detected whether any of ABS, PTC, or VDC is triggered. It should be understood that PTC is generally triggered when the vehicle is moving forward, and ABS or VDC is generally triggered when the vehicle is braking. Furthermore, when the vehicle's steady-state indicator shows an unstable state, the ESP function is generally triggered, and at this time, the vehicle's steady-state indicator is not activated. In this embodiment, the vehicle's second initial speed is denoted as "Vx2".

[0197] When the PCT function is triggered, it indicates that the vehicle's driving torque is too high, which may cause the driving wheels to slip, making the center-of-gravity speed of the driving wheels greater than the actual vehicle speed. The non-driving wheels generally do not slip and are driven to rotate by the driving wheels, making the center-of-gravity speed of the non-driving wheels reliable. By determining the minimum center-of-gravity speed between the left front wheel and the right rear wheel, and the minimum center-of-gravity speed between the left rear wheel and the right front wheel, these two minimum center-of-gravity speeds are used as the center-of-gravity speeds of the non-driving wheels. In order to avoid the problem of abnormal vehicle speed caused by a single non-driving wheel failure, the maximum center-of-gravity speed between the two minimum center-of-gravity speeds can be determined as the second initial vehicle speed. The smaller center-of-gravity speed of the non-driving wheel is more reliable, i.e., Vx2=Max(Min(VCGfl,VCGrr),Min(VCGfr,VCGrl)).

[0198] When the ABS function is triggered and / or the VDC function is triggered, it indicates that the vehicle's braking torque is too large, which may cause the wheels to sideslip, making the wheel center of gravity speed less than the actual vehicle speed. The wheel center of gravity speed of the largest wheel is generally closer to the actual vehicle speed. Therefore, the largest center of gravity speed among multiple wheel center of gravity speeds can be determined as the second initial vehicle speed. The larger center of gravity speed is more reliable, i.e., Vx2=Max(VCGfl, VCGfr, VCGrl, VCGrr).

[0199] When the PTC, ABS, and VDC functions are not detected to be triggered, it indicates that the reliability of the wheel's center of gravity velocity is relatively high. Therefore, the average wheel speed of multiple vehicles' center of gravity velocities can be determined as the second initial vehicle speed, i.e., Vx2 = .

[0200] S13: Determine the target change gradient using the second initial vehicle speed and the longitudinal acceleration measured by the IMU. Then execute S11.

[0201] For example, when the second initial vehicle speed is obtained, the vehicle speed change gradient can be determined by the activation state of the vehicle's steady-state flag. Specifically, when the vehicle's steady-state flag is not activated, in order to improve the accuracy of the vehicle speed, the vehicle speed change gradient can be determined by the longitudinal acceleration measured in real time by the IMU. The minimum and maximum accelerations among the longitudinal accelerations measured by the IMU and the negative values ​​of the longitudinal accelerations measured by the IMU are determined. The product of the minimum acceleration and a preset duration is determined as the minimum speed change gradient (i.e., the lower limit of the second preset range mentioned above), and the product of the maximum acceleration and the preset duration is determined as the maximum speed change gradient (i.e., the upper limit of the second preset range mentioned above). ΔAx(1)=Axm×t, ΔAx(2)=-Axm×t, which can be rearranged as: ΔAx=[Axm, -Axm] T ×t.

[0202] When obtaining the minimum and maximum speed gradients, we can first calculate the speed difference (first or second gradient) between the target initial speed and the previous speed, and determine whether this speed difference is between the minimum and maximum speed gradients. When the speed difference (which can be denoted as "VxN") is between the minimum and maximum speed gradients, i.e., ΔAx(2)≤VxN≤ΔAx(1), the speed difference can be determined as the target speed gradient. However, when the speed difference is not between the minimum and maximum speed gradients, i.e., ΔAx(2)>VxN, or VxN>Ax(1), we need to limit the speed difference using the minimum and maximum speed gradients to obtain the limited speed difference, and then determine the limited speed difference as the target speed gradient. Then execute S11.

[0203] For example, when ΔAx(2) > VxN, the speed difference can be limited to ΔAx(2), that is, the target change gradient is ΔAx(2); or, when VxN > Ax(1), the speed difference can be limited to ΔAx(1), that is, the target change gradient is ΔAx(1).

[0204] It should be noted that, Figure 3 All steps are in Figure 2 The corresponding embodiments are described in detail, and will not be repeated here.

[0205] It should be understood that the above examples are provided to help those skilled in the art understand the embodiments of this application, and are not intended to limit the embodiments of this application to the specific values ​​or scenarios exemplified. Those skilled in the art can obviously make various equivalent modifications or variations based on the above examples, and such modifications or variations also fall within the scope of the embodiments of this application.

[0206] The above text combined Figures 1 to 3 The method for determining vehicle speed provided in the embodiments of this application is described in detail below; the following will be combined with Figure 4 and Figure 6 The apparatus embodiments of this application are described in detail below. It should be understood that the apparatus in the embodiments of this application can perform the various methods described in the foregoing embodiments of this application, that is, the specific working processes of the various products described below can be referred to the corresponding processes in the foregoing method embodiments.

[0207] Figure 4 This is a schematic diagram of the vehicle speed determination device provided in the embodiments of this application.

[0208] For example, such as Figure 4 As shown, the device 400 includes: The acquisition module 410 is used to acquire the vehicle's current operating data and historical speed when the vehicle is detected to be in the target road condition. The target road condition refers to the road condition that affects the vehicle speed, and the historical speed is the vehicle speed at the previous moment at the current moment. The processing module 420 is used to determine the target wheel in a steady state based on the vehicle's current operating data and historical vehicle speed; to determine the target speed change gradient of the vehicle based on the target wheel, the vehicle's current operating data and historical vehicle speed; and to determine the vehicle's current speed based on the target speed change gradient and historical vehicle speed.

[0209] In one possible implementation, the processing module 420 is used for: Based on the vehicle's current operating data and historical speed, determine whether each wheel is rotating stably; Based on the vehicle's current operating data, determine whether the vehicle's steering is stable; The target wheel is determined based on whether each wheel rotates stably and whether the vehicle steers stably.

[0210] In one possible implementation, the processing module 420 is used for: Based on the current wheel speed of each wheel, the current yaw rate of the vehicle, and the wheelbase of the vehicle, determine the center-of-gravity velocity of each wheel. Determine the wheel acceleration of each wheel based on the center-of-mass velocity of each wheel; Based on the center-of-gravity velocity of each wheel, the historical vehicle speed, the wheel acceleration of each wheel, and the current longitudinal acceleration of the vehicle, it is determined whether each wheel is rotating stably.

[0211] In one possible implementation, the processing module 420 is used for: Based on the center-of-gravity velocity and historical vehicle speed of each wheel, determine the current slip ratio of each wheel. The absolute value of the difference between the wheel acceleration of each wheel and the current longitudinal acceleration of the vehicle is determined as the target acceleration deviation. If the current slip ratio of each wheel is within a first preset range, the target acceleration deviation is less than or equal to a first preset threshold, and the wheel acceleration of each wheel is within a second preset range, then the rotation of each wheel is determined to be stable.

[0212] In one possible implementation, the processing module 420 is used for: Based on the current wheel speed of each wheel, the current yaw rate of the vehicle, and the wheelbase of the vehicle, determine the center-of-gravity velocity of each wheel. Based on the center-of-gravity velocity of each wheel, the current steering angle and current angular velocity of the steering wheel, it is determined whether the vehicle is steering stably.

[0213] In one possible implementation, the processing module 420 is used for: Based on the center-of-gravity velocities of each wheel, the difference in rotational speed between the front and rear wheels, the first center-of-gravity velocity, and the second center-of-gravity velocity are determined. The first center-of-gravity velocity represents the maximum center-of-gravity velocity between the left front wheel and the right front wheel, and the second center-of-gravity velocity represents the minimum center-of-gravity velocity between the left rear wheel and the right rear wheel. The vehicle is determined to be stable in steering if the absolute value of the current steering wheel angle is greater than or equal to the second preset threshold, the absolute value of the current steering wheel speed is less than or equal to the third preset threshold, the difference in speed between the front and rear wheels is greater than or equal to the fourth preset threshold, and the second center of gravity speed is greater than or equal to the first center of gravity speed.

[0214] In one possible implementation, the processing module 420 is used for: Determine the first rotating wheel that is stable among multiple wheels; Once the vehicle is stable in steering, the first wheel is identified as the target wheel.

[0215] In one possible implementation, the processing module 420 is used for: Determine whether the vehicle is operating stably based on at least one of the following: the current accelerator pedal opening, the current braking pressure, and whether each wheel is rotating stably. Under stable vehicle operation conditions, the vehicle's first initial speed is determined based on the number of target wheels and the vehicle's current operating data. Based on the initial vehicle speed and the historical vehicle speed, determine the first gradient of vehicle speed change. The first gradient change is subjected to a limit, resulting in a target gradient change that is within a first preset range.

[0216] In one possible implementation, the processing module 420 is used for: If the number of target wheels is greater than or equal to the preset number, the current steering angle of the vehicle is determined based on the current steering wheel angle and the current steering wheel angular velocity. The first initial vehicle speed is determined based on the vehicle's current steering angle, the vehicle's current accelerator pedal opening, and the center-of-gravity speed of each wheel. If the number of target wheels is less than the preset number, the first initial vehicle speed is determined based on the center-of-gravity velocity of each wheel.

[0217] In one possible implementation, the processing module 420 is used for: When the vehicle is running unstablely, the second initial speed of the vehicle is determined based on the center-of-gravity speed of each wheel. Based on the second initial vehicle speed and the historical vehicle speed, determine the second gradient of vehicle speed change; The second gradient change is subjected to limit processing to obtain the target gradient change within a second preset range, wherein the second preset range is determined by the vehicle's current longitudinal acceleration.

[0218] In one possible implementation, the processing module 420 is used for: When the vehicle's traction function is detected to be triggered, a second initial vehicle speed is determined based on the third center of gravity speed and the fourth center of gravity speed, wherein the third center of gravity speed represents the minimum center of gravity speed between the left front wheel and the right rear wheel, and the fourth center of gravity speed represents the minimum center of gravity speed between the left rear wheel and the right front wheel. If the vehicle's anti-lock braking system and / or dynamic control function are detected to be triggered, a second initial vehicle speed is determined based on the maximum center-of-gravity speed among the center-of-gravity speeds of each wheel.

[0219] It should be noted that the aforementioned device 400 is embodied in the form of a functional module. The term "module" here can be implemented in software and / or hardware, without specific limitations.

[0220] For example, a "module" can be a software program, hardware circuit, or a combination of both that implements the above functions. Hardware circuits may include application-specific integrated circuits (ASICs), electronic circuits, processors (e.g., shared processors, proprietary processors, or combined processors) and memory for executing one or more software or firmware programs, combined logic circuits, and / or other suitable components that support the described functions.

[0221] Therefore, the modules of the various examples described in the embodiments of this application can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0222] Figure 5 This is a schematic diagram of the controller provided in the embodiments of this application.

[0223] For example, such as Figure 5 As shown, the vehicle includes a controller 500, which includes a storage module 510 and a processing module 520. The storage module 510 stores executable program code 5101, and the processing module 520 is used to call and execute the executable program code 5101 to perform a method for determining the vehicle speed.

[0224] Figure 6 This is a schematic diagram of the vehicle structure provided in the embodiments of this application.

[0225] For example, such as Figure 6 As shown, the vehicle 600 includes a memory 610 and a processor 620. The memory 610 stores executable program code 6101, and the processor 620 is used to call and execute the executable program code 6101 to perform a method for determining vehicle speed.

[0226] This application can divide the vehicle into functional modules based on the above method example. For example, each module can correspond to a separate function module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware. It should be noted that the module division in this embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods.

[0227] When each functional module is divided according to its corresponding function, the vehicle may include: an acquisition module and a processing module, etc. It should be noted that all relevant content of each step involved in the above method embodiments can be referenced from the functional description of the corresponding functional module, and will not be repeated here.

[0228] The vehicle provided in this application is used to perform the above-described method for determining vehicle speed, and thus can achieve the same effect as the above-described implementation method.

[0229] When using integrated units, the vehicle may include a processing module and a storage module. The processing module is used to control and manage the vehicle's movements. The storage module is used to support the vehicle in executing relevant program code and data.

[0230] The processing module may be a processor or a controller, which can implement or execute various exemplary logic blocks, modules, and circuits shown in conjunction with the disclosure of this application. The processor may also be a combination of functions that implement computing capabilities, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and microprocessors, etc., and the storage module may be a memory.

[0231] This application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the methods described in the foregoing embodiments. The computer-readable storage medium may include, but is not limited to, any type of disk, including floppy disks, optical disks, DVDs (Digital Video Discs), CD-ROMs (Compact Disc Read-Only Memory), microdrives, magneto-optical disks, ROMs (Read-Only Memory), RAMs (Random Access Memory), EPROMs (Erasable Programmable Read-Only Memory), EEPROMs (Electrically Erasable Programmable Read Only Memory), DRAMs (Dynamic Random Access Memory), VRAMs (Video Random Access Memory), flash memory devices, magnetic cards or optical cards, nanosystems (including molecular memory ICs), or any type of medium or device suitable for storing instructions and / or data.

[0232] This application also provides a computer program product that, when run on a computer, causes the computer to perform the aforementioned steps to implement a method for determining vehicle speed in the above embodiments.

[0233] In addition, the vehicle provided in the embodiments of this application may specifically be a chip, component or module. The vehicle may include a connected processor and a memory. The memory is used to store instructions. When the vehicle is running, the processor may call and execute the instructions to make the chip execute a method for determining the vehicle speed in the above embodiments.

[0234] The vehicle, computer-readable storage medium, computer program product or chip provided in this application are all used to execute the corresponding methods provided above. Therefore, the beneficial effects that can be achieved can be referred to the beneficial effects of the corresponding methods provided above, and will not be repeated here.

[0235] Through the above description of the embodiments, those skilled in the art will understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0236] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0237] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for determining vehicle speed, characterized in that, The method includes: When the vehicle is detected to be in the target road condition, the current operating data and historical speed of the vehicle are obtained, wherein the target road condition refers to the road condition that affects the vehicle speed, and the historical speed is the vehicle speed of the vehicle in the previous moment at the current moment. Based on the vehicle's current operating data and historical vehicle speed, the target wheel in a steady state is determined; Based on the target wheel, the vehicle's current operating data, and the historical vehicle speed, determine the target change gradient of the vehicle speed; The current speed of the vehicle is determined based on the target change gradient and the historical vehicle speed.

2. The method according to claim 1, characterized in that, The step of determining the target wheel in a steady state based on the vehicle's current operating data and historical vehicle speed includes: Based on the vehicle's current operating data and historical vehicle speed, determine whether each wheel rotates stably; Based on the vehicle's current operating data, determine whether the vehicle's steering is stable; The target wheel is determined based on whether each wheel rotates stably and whether the vehicle steers stably.

3. The method according to claim 2, characterized in that, The vehicle's current operating data includes the current wheel speed of each wheel, the vehicle's current yaw rate, and the vehicle's current longitudinal acceleration collected by the inertial measurement unit. Determining whether each wheel is rotating stably based on the vehicle's current operating data and the historical vehicle speed includes: The center-of-gravity velocity of each wheel is determined based on the current wheel speed of each wheel, the current yaw rate of the vehicle, and the wheelbase of the vehicle. Based on the center-of-mass velocity of each wheel, the wheel acceleration of each wheel is determined; Based on the center-of-gravity velocity of each wheel, the historical vehicle speed, the wheel acceleration of each wheel, and the current longitudinal acceleration of the vehicle, it is determined whether each wheel is rotating stably.

4. The method according to claim 3, characterized in that, The determination of whether each wheel is rotating stably based on the center-of-gravity velocity of each wheel, the historical vehicle speed, the wheel acceleration of each wheel, and the current longitudinal acceleration of the vehicle includes: Based on the center-of-gravity velocity of each wheel and the historical vehicle speed, the current slip ratio of each wheel is determined. The absolute value of the difference between the wheel acceleration of each wheel and the current longitudinal acceleration of the vehicle is determined as the target acceleration deviation; When the current slip ratio of each wheel is within a first preset range, the target acceleration deviation is less than or equal to a first preset threshold, and the wheel acceleration of each wheel is within a second preset range, it is determined that the rotation of each wheel is stable.

5. The method according to claim 2, characterized in that, The vehicle's current operating data includes the current wheel speed of each wheel, the vehicle's current yaw rate, the current steering angle and current steering velocity of the steering wheel. Determining whether the vehicle is steering stably based on the vehicle's current operating data includes: The center-of-gravity velocity of each wheel is determined based on the current wheel speed of each wheel, the current yaw rate of the vehicle, and the wheelbase of the vehicle. Based on the center-of-gravity velocity of each wheel, the current steering angle of the steering wheel, and the current angular velocity, it is determined whether the vehicle is steering stably.

6. The method according to claim 5, characterized in that, Determining whether the vehicle is stable in steering based on the center-of-gravity velocity of each wheel, the current steering angle of the steering wheel, and the current angular velocity includes: Based on the center-of-gravity velocities of each wheel, the front-to-rear wheel speed difference, the first center-of-gravity velocity, and the second center-of-gravity velocity of the vehicle are determined. The first center-of-gravity velocity represents the maximum center-of-gravity velocity between the left front wheel and the right front wheel, and the second center-of-gravity velocity represents the minimum center-of-gravity velocity between the left rear wheel and the right rear wheel. If the absolute value of the current steering angle of the steering wheel is greater than or equal to a second preset threshold, and the absolute value of the current steering speed of the steering wheel is less than or equal to a third preset threshold, and the difference in speed between the front and rear wheels of the vehicle is greater than or equal to a fourth preset threshold, and the second center of gravity speed is greater than or equal to the first center of gravity speed, then the vehicle is determined to be steering stable.

7. The method according to any one of claims 2 to 6, characterized in that, The determination of the target wheel based on whether each of the wheels rotates stably and whether the vehicle is steering stably includes: Among the plurality of wheels, determine the first wheel that is rotationally stable; When the vehicle is stable in steering, the first wheel is identified as the target wheel.

8. The method according to claim 3, characterized in that, The vehicle's current operating data includes the vehicle's current accelerator pedal opening and the vehicle's current braking pressure. Determining the target speed change gradient of the vehicle based on the target wheel, the vehicle's current operating data, and the historical vehicle speed includes: Whether the vehicle is operating stably is determined based on at least one of the following: the current accelerator pedal opening of the vehicle, the current braking pressure of the vehicle, and whether each of the wheels is rotating stably. When the vehicle is running stably, the first initial speed of the vehicle is determined based on the number of target wheels and the current operating data of the vehicle. Based on the first initial vehicle speed and the historical vehicle speed, a first gradient of change in the vehicle speed is determined; The first gradient change is subjected to a limit process to obtain the target gradient change that is within a first preset range.

9. The method according to claim 8, characterized in that, The vehicle's current operating data includes the current steering wheel angle and current angular velocity. Determining the vehicle's first initial speed based on the number of target wheels and the vehicle's current operating data includes: If the number of target wheels is greater than or equal to a preset number, the current steering angle of the vehicle is determined based on the current steering angle and the current steering speed of the steering wheel. The first initial vehicle speed is determined based on the vehicle's current steering angle, the vehicle's current accelerator pedal opening, and the center-of-gravity velocity of each wheel. If the number of target wheels is less than a preset number, the first initial vehicle speed is determined based on the center-of-gravity velocity of each wheel.

10. The method according to claim 8, characterized in that, The method further includes: In the case of unstable vehicle operation, a second initial vehicle speed is determined based on the center-of-gravity velocity of each wheel; Based on the second initial vehicle speed and the historical vehicle speed, a second gradient of change in the vehicle speed is determined; The second gradient change is subjected to a limit process to obtain the target gradient change within a second preset range, wherein the second preset range is determined by the current longitudinal acceleration of the vehicle.

11. The method according to claim 10, characterized in that, Determining the second initial vehicle speed based on the center-of-gravity velocity of each of the wheels includes: When the traction function of the vehicle is detected to be triggered, the second initial vehicle speed is determined based on the third center of gravity speed and the fourth center of gravity speed, wherein the third center of gravity speed represents the minimum center of gravity speed between the left front wheel and the right rear wheel, and the fourth center of gravity speed represents the minimum center of gravity speed between the left rear wheel and the right front wheel. If the anti-lock braking function and / or dynamic control function of the vehicle are detected to be triggered, the second initial vehicle speed is determined based on the maximum center-of-gravity speed among the center-of-gravity speeds of each wheel.

12. A vehicle, characterized in that, The vehicles include: Memory, used to store executable program code; A processor for calling and running the executable program code from the memory, causing the vehicle to perform the method as described in any one of claims 1 to 11.

Images