Vehicle speed estimation method and device, controller, storage medium and vehicle

Abstract

The invention provides a vehicle speed estimation method and device, a controller, a storage medium and a vehicle. The method comprises the steps that whether a front axle and a rear axle of a vehicle are in a slipping state at the current moment is judged; if the front axle and the rear axle of the vehicle are both in the slipping state at the current moment, a first vehicle speed estimated value is calculated based on the vehicle speed before the slipping state and the current vehicle body acceleration; if the front axle or the rear axle of the vehicle is in the slipping state at the current moment and the difference value of the front axle speed and the rear axle speed is larger than the preset threshold value, a second vehicle speed estimated value is calculated based on the front axle speed, the rear axle speed and the vehicle body acceleration; the smaller value of the front axle speed and the rear axle speed of the vehicle at the current moment is selected as a third vehicle speed estimated value; and determining a reference vehicle speed according to the first vehicle speed estimation value, the second vehicle speed estimation value and the third vehicle speed estimation value. The method can distinguish vehicle speed separation slip and double-axle slip scenes, avoids the problem that a traditional estimation method cannot deal with complex working conditions, and improves the vehicle speed estimation accuracy.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle control, and particularly to a vehicle speed estimation method, device, controller, storage medium, and vehicle. Background Art

[0002] In modern automotive active safety control systems, the Traction Control System (TCS) plays a key role in ensuring the driving stability of vehicles on low-traction road surfaces by adjusting the output torque of the driving wheels to suppress wheel slip. The core control parameter of this system is the slip ratio, and its calculation formula is: where v w is the wheel speed, and v r is the body reference vehicle speed. Accurately obtaining the body reference vehicle speed is a prerequisite for achieving precise control of the slip ratio.

[0003] However, limited by the cost of sensor arrangement and technical feasibility, the body reference vehicle speed usually cannot be obtained by direct measurement and needs to be indirectly estimated based on wheel speed signals, longitudinal acceleration, etc. Currently, the mainstream vehicle speed estimation methods include:

[0004] Extreme wheel speed method: Select the maximum or minimum value of the wheel speeds of each driving wheel as the reference vehicle speed. Although this method is simple to calculate, in the case of multiple wheels slipping simultaneously, the extreme wheel speed deviates significantly from the true vehicle speed.

[0005] Mean filtering method: Process the wheel speed data of multiple wheels through weighted average or low-pass filtering. When 3 or 4 wheels slip synchronously, the filtered data will deviate significantly from the actual vehicle speed.

[0006] Dynamic model method: Estimation is carried out based on models of the whole vehicle, tires, etc. Affected by the accuracy of the models used, its adaptability to different road surfaces is poor.

[0007] It can be seen that the existing vehicle speed estimation methods all have problems of poor estimation accuracy and inaccurate reference vehicle speed estimation. Summary of the Invention

[0008] The present application provides a vehicle speed estimation method, device, controller, storage medium, and vehicle to solve the problem of poor accuracy of vehicle speed estimation in the prior art.

[0009] In a first aspect, the present application provides a vehicle speed estimation method, including:

[0010] Determine whether the front axle and the rear axle of the vehicle are in a slipping state at the current moment;

[0011] If both the front axle and the rear axle of the vehicle are in a slipping state at the current moment, calculate a first vehicle speed estimation value based on the vehicle speed before the slipping state and the current body acceleration;

[0012] If the front axle or the rear axle of the vehicle is in a skidding state at the current moment, and the difference between the front axle vehicle speed and the rear axle vehicle speed is greater than a preset threshold, then calculate a second vehicle speed estimation value based on the front axle vehicle speed, the rear axle vehicle speed, and the vehicle body acceleration;

[0013] Select the smaller value of the front axle vehicle speed and the rear axle vehicle speed of the vehicle at the current moment as the third vehicle speed estimation value;

[0014] Determine the reference vehicle speed of the vehicle at the current moment according to the first vehicle speed estimation value, the second vehicle speed estimation value, and the third vehicle speed estimation value.

[0015] The above method can distinguish between the vehicle speed separation skidding and the double-bridge skidding scenarios, select different calculation rules to estimate the vehicle speed in different skidding scenarios, avoid the problems that traditional extreme value methods, average value methods, etc. cannot handle complex working conditions, and at the same time introduce acceleration integration to correct the vehicle speed change during skidding, reduce the problem of overestimation or underestimation of the wheel speed caused by skidding, and improve the accuracy of vehicle speed estimation.

[0016] In a possible implementation manner, the determining whether the front axle and the rear axle of the vehicle are in a skidding state at the current moment includes:

[0017] Obtain the front axle vehicle speed at the current moment, and take the derivative of the front axle vehicle speed at the current moment to obtain the front axle acceleration;

[0018] Obtain the rear axle vehicle speed at the current moment, and take the derivative of the rear axle vehicle speed at the current moment to obtain the rear axle acceleration;

[0019] If the front axle acceleration is greater than the acceleration calibration value, it is determined that the front axle is in a skidding state;

[0020] If the rear axle acceleration is greater than the acceleration calibration value, it is determined that the rear axle is in a skidding state.

[0021] It can be seen from the above embodiments that compared with the vehicle speed-based threshold judgment method, the acceleration-based skidding judgment method provided in this embodiment can capture the skidding timing more accurately, thereby improving the accuracy of vehicle speed estimation.

[0022] In a possible implementation manner, the calculating the first vehicle speed estimation value based on the vehicle speed before the skidding state and the current vehicle body acceleration includes:

[0023] Use the front axle vehicle speed at the previous moment when it is simultaneously monitored that both the front axle and the rear axle enter the skidding state as the current front axle vehicle speed;

[0024] Use the rear axle vehicle speed at the previous moment when it is simultaneously monitored that both the front axle and the rear axle enter the skidding state as the current rear axle vehicle speed;

[0025] Select the smaller value of the current front axle vehicle speed and the current rear axle vehicle speed as the target vehicle speed;

[0026] Integrate the current vehicle body acceleration for a first preset duration to obtain the cumulative change speed; the first preset duration is the time interval between the current moment and the moment when both the front axle and the rear axle are detected to enter the skidding state;

[0027] Add the target vehicle speed and the cumulative change speed to obtain a first estimated vehicle speed value.

[0028] As can be seen from the above embodiments, since the stable wheel speed before skidding is closer to the true vehicle speed, in this embodiment, the front axle vehicle speed and the rear axle vehicle speed at the previous moment are locked at the moment when it is determined that both the front axle and the rear axle are in the skidding state, avoiding the problem of large deviation in vehicle speed estimation caused by selecting the skidding overestimated wheel speed. At the same time, the integration of the current vehicle body acceleration can adjust the vehicle speed in real time during the skidding state, further improving the accuracy of vehicle speed estimation.

[0029] In a possible implementation manner, calculating a second estimated vehicle speed value based on the front axle vehicle speed, the rear axle vehicle speed, and the vehicle body acceleration includes:

[0030] Use the front axle vehicle speed at the previous moment when the vehicle enters the vehicle speed separation skidding condition as the current front axle vehicle speed; the vehicle speed separation skidding condition is a condition where the front axle or the rear axle of the vehicle is in the skidding state at the current moment, and the difference between the front axle vehicle speed and the rear axle vehicle speed is greater than a preset threshold;

[0031] Use the rear axle vehicle speed at the previous moment when the vehicle enters the vehicle speed separation skidding condition as the current rear axle vehicle speed;

[0032] Average the current front axle vehicle speed and the current rear axle vehicle speed to obtain the current average vehicle speed;

[0033] Integrate the current vehicle body acceleration for a second preset duration to obtain the cumulative change speed; the second preset duration is the time interval between the current moment and the moment when the front axle or the rear axle is detected to enter the skidding state;

[0034] Add the current average vehicle speed and the cumulative change speed to obtain a second estimated vehicle speed value.

[0035] As can be seen from the above embodiments, for the working condition where the vehicle speed is separated and slipping occurs, at the moment when it is determined that at least one of the front and rear axles is in a slipping state, the vehicle speeds of the front axle and the rear axle at the previous moment are locked, avoiding the problem of large deviation in vehicle speed estimation caused by selecting the falsely high wheel speed after slipping. At the same time, since the vehicle speed separation occurs under this working condition, the extreme value deviation caused by the vehicle speed separation and slipping is eliminated by the average vehicle speed in this embodiment; the vehicle speed is adjusted in real time by integrating the current vehicle body acceleration under the slipping state, further improving the accuracy of vehicle speed estimation.

[0036] In a possible implementation manner, if the front axle and the rear axle of the vehicle are both in a slipping state at the current moment, calculating a first vehicle speed estimation value based on the vehicle speed before the slipping state and the current vehicle body acceleration includes:

[0037] If the front axle and the rear axle of the vehicle are both in a slipping state at the current moment, calculate a first vehicle speed estimation value based on the vehicle speed before the slipping state and the current vehicle body acceleration; otherwise, use a first preset speed as the first vehicle speed estimation value; the first preset speed is greater than the vehicle speed upper limit value of the vehicle;

[0038] If the front axle or the rear axle of the vehicle is in a slipping state at the current moment, and the difference between the front axle vehicle speed and the rear axle vehicle speed is greater than a preset threshold, calculating a second vehicle speed estimation value based on the front axle vehicle speed, the rear axle vehicle speed, and the vehicle body acceleration includes:

[0039] If the front axle or the rear axle of the vehicle is in a slipping state at the current moment, and the difference between the front axle vehicle speed and the rear axle vehicle speed is greater than a preset threshold, calculate a second vehicle speed estimation value based on the front axle vehicle speed, the rear axle vehicle speed, and the vehicle body acceleration; otherwise, use a first preset speed as the second vehicle speed estimation value; the first preset speed is greater than the vehicle speed upper limit value of the vehicle.

[0040] The above embodiments provide a protection mechanism for the double-bridge and vehicle speed separation and slipping working conditions. When the working condition requirements are not met, the corresponding estimation value is set to an invalid value, avoiding the incorrect application of the compensation algorithm under non-slipping working conditions. At the same time, setting it to an invalid value can avoid conflicts with the real wheel speed, effectively improving the system reliability and reducing the accident risk caused by algorithm failure.

[0041] In a possible implementation manner, determining the reference vehicle speed of the vehicle at the current moment according to the first vehicle speed estimation value, the second vehicle speed estimation value, and the third vehicle speed estimation value includes:

[0042] Select the minimum value among the first vehicle speed estimation value, the second vehicle speed estimation value, and the third vehicle speed estimation value as the reference vehicle speed of the vehicle at the current moment.

[0043] As can be seen from the above embodiments, in order to meet the safety - first strategy of TCS, the minimum value of the three estimation results is finally taken as the vehicle speed estimation value in this embodiment, avoiding the distortion of the slip ratio calculation caused by over - estimating the vehicle speed and enhancing the system safety.

[0044] In a second aspect, the present application provides a vehicle speed estimation device, which includes:

[0045] A slip - state judgment module, configured to judge whether the front axle and the rear axle of the vehicle are in a slip state at the current moment;

[0046] A first vehicle speed estimation module, configured to calculate a first vehicle speed estimation value based on the vehicle speed before the slip state and the current vehicle body acceleration if both the front axle and the rear axle of the vehicle are in a slip state at the current moment;

[0047] A second vehicle speed estimation module, configured to calculate a second vehicle speed estimation value based on the front axle speed, the rear axle speed, and the vehicle body acceleration if either the front axle or the rear axle of the vehicle is in a slip state at the current moment and the difference between the front axle speed and the rear axle speed is greater than a preset threshold;

[0048] A third vehicle speed estimation module, configured to select the smaller value of the front axle speed and the rear axle speed of the vehicle at the current moment as the third vehicle speed estimation value;

[0049] A reference vehicle speed determination module, configured to determine the reference vehicle speed of the vehicle at the current moment according to the first vehicle speed estimation value, the second vehicle speed estimation value, and the third vehicle speed estimation value.

[0050] In a possible implementation manner, the slip - state judgment module includes:

[0051] Obtain the front axle speed at the current moment, and take the derivative of the front axle speed at the current moment to obtain the front axle acceleration;

[0052] Obtain the rear axle speed at the current moment, and take the derivative of the rear axle speed at the current moment to obtain the rear axle acceleration;

[0053] If the front axle acceleration is greater than the acceleration calibration value, it is determined that the front axle is in a slip state;

[0054] If the rear axle acceleration is greater than the acceleration calibration value, it is determined that the rear axle is in a slip state.

[0055] In a possible implementation manner, the first vehicle speed estimation module includes:

[0056] Take the front axle speed at the previous moment when it is simultaneously monitored that both the front axle and the rear axle enter the slip state as the current front axle speed;

[0057] Take the rear axle vehicle speed at the moment immediately before both the front axle and the rear axle are simultaneously detected to enter the skidding state as the current rear axle vehicle speed;

[0058] Select the smaller value of the current front axle vehicle speed and the current rear axle vehicle speed as the target vehicle speed;

[0059] Integrate the current vehicle body acceleration for a first preset duration to obtain the cumulative change speed; the first preset duration is the time interval between the current moment and the moment when both the front axle and the rear axle are simultaneously detected to enter the skidding state;

[0060] Add the target vehicle speed and the cumulative change speed to obtain a first vehicle speed estimation value.

[0061] In a possible implementation, the second vehicle speed estimation module includes:

[0062] Take the front axle vehicle speed at the moment immediately before the vehicle enters the vehicle speed separation skidding condition as the current front axle vehicle speed; the vehicle speed separation skidding condition is a condition where either the front axle or the rear axle of the vehicle is in a skidding state at the current moment, and the difference between the front axle vehicle speed and the rear axle vehicle speed is greater than a preset threshold;

[0063] Take the rear axle vehicle speed at the moment immediately before the vehicle enters the vehicle speed separation skidding condition as the current rear axle vehicle speed;

[0064] Calculate the average of the current front axle vehicle speed and the current rear axle vehicle speed to obtain the current average vehicle speed;

[0065] Integrate the current vehicle body acceleration for a second preset duration to obtain the cumulative change speed; the second preset duration is the time interval between the current moment and the moment when the front axle or the rear axle is detected to enter the skidding state;

[0066] Add the current average vehicle speed and the cumulative change speed to obtain a second vehicle speed estimation value.

[0067] In a possible implementation, the first vehicle speed estimation module includes:

[0068] If both the front axle and the rear axle of the vehicle are in a skidding state at the current moment, calculate the first vehicle speed estimation value based on the vehicle speed before the skidding state and the current vehicle body acceleration, otherwise take the first preset speed as the first vehicle speed estimation value; the first preset speed is greater than the vehicle speed upper limit value;

[0069] The second vehicle speed estimation module includes:

[0070] If the front axle or the rear axle of the vehicle is in a skidding state at the current moment, and the difference between the front axle vehicle speed and the rear axle vehicle speed is greater than a preset threshold, then calculate a second vehicle speed estimation value based on the front axle vehicle speed, the rear axle vehicle speed, and the vehicle body acceleration; otherwise, use a first preset speed as the second vehicle speed estimation value; the first preset speed is greater than the vehicle speed upper limit value of the vehicle.

[0071] In a possible implementation manner, the reference vehicle speed determination module includes:

[0072] Select the minimum value among the first vehicle speed estimation value, the second vehicle speed estimation value, and the third vehicle speed estimation value as the reference vehicle speed of the vehicle at the current moment.

[0073] In a third aspect, the present application provides a controller, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method in the possible implementation manner of the first aspect as above are implemented.

[0074] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method in any possible implementation manner of the first aspect as above are implemented.

[0075] In a fifth aspect, an embodiment of the present application provides a vehicle, which includes the controller described in the third aspect as above. Description of the Drawings

[0076] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0077] Figure 1 is the implementation flowchart of the vehicle speed estimation method provided by the embodiment of the present application;

[0078] Figure 2 is the structural schematic diagram of the vehicle speed estimation device provided by the embodiment of the present application;

[0079] Figure 3 is the schematic diagram of the controller provided by the embodiment of the present application. Detailed Embodiments

[0080] In the following description, specific details such as specific system architectures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present application. However, those skilled in the art should clearly understand that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from hindering the description of the present application.

[0081] To make the objectives, technical solutions, and advantages of the present application clearer, the following will be described through specific embodiments in conjunction with the accompanying drawings.

[0082] The slip ratio is an important parameter for measuring the degree of tire slip during movement, and is usually used to describe the interaction between the tire and the road surface when the vehicle brakes or accelerates. When accelerating, a larger slip ratio indicates that the wheels are slipping, and when braking, a smaller slip ratio indicates that the wheels are locked. Correspondingly, TCS will suppress wheel slip or lock by adjusting the output torque of the drive wheels, which plays a key role in ensuring the driving stability of the vehicle on low-adhesion road surfaces.

[0083] To ensure accurate calculation of the slip ratio and avoid the problem of the TCS misadjusting the output torque due to inaccurate slip ratio, resulting in a decline in vehicle driving performance, it is necessary to accurately estimate the body reference vehicle speed. However, the body reference vehicle speed is usually indirectly estimated based on wheel speed signals. For example, the extreme value wheel speed method and the mean filtering method. However, there are various wheel slip conditions, and when there is simultaneous slip or speed separation slip, there will be serious deviations in the above estimation results.

[0084] In view of the above problems, this embodiment provides a vehicle speed estimation method, which sets different vehicle speed estimation rules for speed separation slip, double-bridge slip, and non-slip conditions respectively, avoiding the problem that traditional methods such as the extreme value method and the mean method cannot handle complex conditions, so as to improve the accuracy of vehicle speed estimation.

[0085] See Figure 1 , which shows the implementation flowchart of the vehicle speed estimation method provided by the embodiment of the present application, and is described in detail as follows:

[0086] S101: Determine whether the front axle and rear axle of the vehicle are in a slipping state at the current moment.

[0087] The execution subject of this embodiment is a controller, which can be an in-vehicle controller or an out-of-vehicle controller, or a combination of an in-vehicle controller and an out-of-vehicle controller, and can be specifically determined according to the situation. Here, the execution subject is an in-vehicle controller, such as a motor controller.

[0088] Specifically, the specific implementation process for determining whether the front axle of the vehicle is in a slipping state at the current moment includes: obtaining the reference vehicle speed at the previous moment; obtaining the front axle vehicle speed at the current moment; if the difference between the reference vehicle speed at the previous moment and the front axle vehicle speed at the current moment is greater than a preset difference, it is determined that the front axle is in a slipping state.

[0089] Among them, the front axle vehicle speed can be obtained by converting based on the motor speed, or by obtaining the left wheel speed and the right wheel speed from the wheel speed sensors of the left and right wheels of the front axle, averaging the left wheel speed and the right wheel speed, and converting the average value of the left and right wheel speeds of the front axle to the average value of the left and right wheel vehicle speeds to obtain the front axle vehicle speed.

[0090] Specifically, the specific implementation process for determining whether the rear axle of the vehicle is in a slipping state at the current moment includes: obtaining the reference vehicle speed at the previous moment; obtaining the rear axle vehicle speed at the current moment; if the difference between the reference vehicle speed at the previous moment and the rear axle vehicle speed at the current moment is greater than a preset difference, it is determined that the rear axle is in a slipping state.

[0091] Among them, the rear axle vehicle speed can be obtained by converting based on the rear axle motor speed, or by obtaining the left wheel speed and the right wheel speed from the wheel speed sensors of the left and right wheels of the rear axle, averaging the left wheel speed and the right wheel speed, and converting the average value of the left and right wheel speeds of the rear axle to the average value of the left and right wheel vehicle speeds to obtain the rear axle vehicle speed.

[0092] In this embodiment, in order to avoid the interference of accidental acquisition errors of the sensors on the subsequent determination process of the slipping state, this embodiment can finally determine that the front and rear axles are in a slipping state and modify the vehicle speed estimation working condition to a double-bridge slipping working condition when it is detected that both the front and rear axles are in a slipping state at N consecutive moments. The value range of N can be 2 to 4.

[0093] S102: If both the front axle and the rear axle of the vehicle are in a slipping state at the current moment, calculate a first vehicle speed estimation value based on the vehicle speed before the slipping state and the current vehicle body acceleration.

[0094] In this embodiment, when both the front axle and the rear axle of the wheels are in a slipping state, the vehicle speed calculated based on the wheel speed is deceptively high and not credible. Therefore, during the period when both the front and rear axles are in a slipping state, the motor controller can freeze the reference vehicle speed at the previous moment before entering the double-bridge slipping working condition, and then obtain the vehicle body acceleration collected by the acceleration sensor sent by the Electronic Stability Control (ESC); perform real-time integration on the vehicle body acceleration starting from the moment of entering the double-bridge slipping working condition, and the integration formula is: Δv = ∫a(t)dt, and then add the reference vehicle speed at the previous moment before entering the double-bridge slipping working condition to the integration of the vehicle body acceleration to obtain the first vehicle speed estimation value.

[0095] This method can avoid the problem of large deviation in vehicle speed estimation caused by selecting slipping and falsely high wheel speeds. At the same time, integrating the current vehicle body acceleration can adjust the vehicle speed in real time under the slipping state, further improving the accuracy of vehicle speed estimation. Among them, a represents the vehicle body acceleration, and Δv represents the cumulative change speed value after entering the slipping state.

[0096] Specifically, after obtaining the vehicle body acceleration signal collected by the acceleration sensor sent by the ESC, it is necessary to perform low-pass filtering on the acceleration signal.

[0097] S103: If the front axle or rear axle of the vehicle is in a slipping state at the current moment, and the difference between the front axle vehicle speed and the rear axle vehicle speed is greater than a preset threshold, then calculate a second vehicle speed estimation value based on the front axle vehicle speed, the rear axle vehicle speed, and the vehicle body acceleration.

[0098] In this embodiment, when the front axle or rear axle of the wheel is in a slipping state and there is a speed separation between the front and rear axles, using the extreme value rule will cause the vehicle speed to deviate from the true value. Therefore, when the front axle or rear axle is in a slipping state and the difference between the front and rear axle vehicle speeds is greater than a preset threshold, it is determined that the wheel enters the vehicle speed separation and slipping working condition. The motor controller can freeze the reference vehicle speed at the previous moment before entering the vehicle speed separation and slipping working condition, and then obtain the vehicle body acceleration collected by the acceleration sensor sent by the electronic stability system; starting from the moment of entering the vehicle speed separation and slipping working condition, perform real-time integration on the vehicle body acceleration, and the integration formula is: Δv = ∫a(t)dt, and then based on the front axle vehicle speed, the rear axle vehicle speed, and the cumulative change speed value, obtain a first vehicle speed estimation value. This method can avoid the vehicle speed error when using the extreme value method to estimate the vehicle speed for the vehicle speed separation and slipping working condition, and further improve the accuracy of vehicle speed estimation. Among them, a represents the vehicle body acceleration, and Δv represents the cumulative change speed value after entering the slipping state.

[0099] In addition, the above vehicle speed separation and slipping working condition can avoid the problem that when the double bridges slip and the vehicle speeds are separated, the final second vehicle speed estimation value is too low when using the extreme value method to calculate the reference vehicle speed at the previous moment before slipping as the initial reference vehicle speed for entering the vehicle speed separation and slipping working condition, thereby improving the accuracy of vehicle speed estimation.

[0100] S104: Select the smaller value of the front axle vehicle speed and the rear axle vehicle speed of the vehicle at the current moment as the third vehicle speed estimation value.

[0101] When no wheel is in a slipping state, or when a single-bridge wheel is in a slipping state but there is no vehicle speed separation, using the extreme value method to determine the reference vehicle speed can accurately reflect the true vehicle speed. Therefore, while the motor controller executes the above two vehicle speed estimation processes, it will continuously execute a third vehicle speed estimation path, that is, use the extreme value method to calculate the vehicle speed, so that the motor controller outputs the third vehicle speed estimation value as the reference vehicle speed when a single bridge slips and there is no vehicle speed separation or when both double bridges do not slip.

[0102] S105: Determine a reference vehicle speed of the vehicle at the current moment according to the first vehicle speed estimation value, the second vehicle speed estimation value, and the third vehicle speed estimation value.

[0103] Specifically, for each vehicle speed estimation path, when the judgment condition of the vehicle speed estimation path is not triggered, no result is output, and the motor controller directly uses the vehicle speed estimation value of the path that can output a result as the reference vehicle speed of the vehicle at the current moment. At the same time, to avoid the problem of multiple results being output due to multiple paths being in the triggered state simultaneously, in combination with the working conditions targeted by each path, in this embodiment, three levels of priority for the estimation paths can be set, such that the priority of the second vehicle speed estimation value path is greater than the priority of the first vehicle speed estimation value path, and the priority of the first vehicle speed estimation value path is greater than the priority of the third vehicle speed estimation value path, thereby improving the accuracy of vehicle speed estimation under different slipping working conditions.

[0104] The above method can distinguish between the vehicle speed separation slipping and double-bridge slipping scenarios, select different calculation rules to estimate the vehicle speed under different slipping scenarios, avoid problems where traditional extreme value methods, average value methods, etc. cannot handle complex working conditions, and at the same time introduce acceleration integration to correct the vehicle speed change during slipping, reducing the problem of wheel speed being falsely high or underestimated due to slipping, and improving the accuracy of vehicle speed estimation.

[0105] In a possible implementation manner, the specific implementation process of S101 includes:

[0106] Obtain the front axle vehicle speed at the current moment, and take the derivative of the front axle vehicle speed at the current moment to obtain the front axle acceleration;

[0107] Obtain the rear axle vehicle speed at the current moment, and take the derivative of the rear axle vehicle speed at the current moment to obtain the rear axle acceleration;

[0108] If the front axle acceleration is greater than the acceleration calibration value, it is determined that the front axle is in a slipping state;

[0109] If the rear axle acceleration is greater than the acceleration calibration value, it is determined that the rear axle is in a slipping state.

[0110] In this embodiment, the front axle vehicle speed can be obtained based on the foregoing specific method of S101, and the rear axle vehicle speed can be obtained based on the foregoing specific method of S102, which will not be elaborated here. After obtaining the front axle acceleration and the rear axle acceleration, the motor controller can also determine the acceleration calibration value according to the road surface type, and the acceleration calibration values for different road surface types are different. For example, the acceleration calibration value for an ice and snow road surface is smaller than the acceleration calibration value for a cement road surface.

[0111] Specifically, for the determination of the road surface type, in this embodiment, the road surface texture image of the road surface where the vehicle is to travel can be obtained through an in-vehicle camera, and then the road surface texture image is subjected to image recognition to obtain the road surface type. Further, while using the road surface texture image for road surface type recognition in this embodiment, the road surface type recognition can also be assisted based on the wheel speed fluctuation characteristics.

[0112] As can be seen from the above embodiments, compared with the threshold judgment method based on vehicle speed, the method for judging wheel slip by acceleration provided in this embodiment can capture the wheel slip timing more accurately, thereby improving the accuracy of vehicle speed estimation.

[0113] In a possible implementation manner, the specific implementation process of S102 includes:

[0114] Taking the front axle vehicle speed at the previous moment when it is simultaneously monitored that both the front axle and the rear axle enter the wheel slip state as the current front axle vehicle speed;

[0115] Taking the rear axle vehicle speed at the previous moment when it is simultaneously monitored that both the front axle and the rear axle enter the wheel slip state as the current rear axle vehicle speed;

[0116] Selecting the smaller value of the current front axle vehicle speed and the current rear axle vehicle speed as the target vehicle speed;

[0117] Integrating the current vehicle body acceleration for a first preset duration to obtain the cumulative change speed; the first preset duration is the time interval between the current moment and the moment when it is simultaneously monitored that both the front axle and the rear axle enter the wheel slip state;

[0118] Adding the target vehicle speed and the cumulative change speed to obtain the first vehicle speed estimation value.

[0119] In this embodiment, in the case of dual-bridge wheel slip, after calculating the cumulative change speed at the current time, if the wheel slip duration exceeds the preset time threshold, the acceleration integration is corrected based on the attenuation function to suppress the long-time integration drift.

[0120] Specifically, the calculation formula for the cumulative change speed value after entering the dual-bridge wheel slip state is:

[0121]

[0122] where t 0 represents the preset time threshold, and Δt represents the duration in the dual-bridge wheel slip state. Among them, the preset time threshold can be 5 - 10s.

[0123] After calculating the cumulative change speed value, adding the cumulative change speed value to the reference vehicle speed at the previous moment before entering the dual-bridge wheel slip working condition to obtain the first vehicle speed estimation value.

[0124] Similarly, to avoid calculation deviation, when the absolute value of the vehicle body acceleration is detected to be less than a preset acceleration threshold, it is considered that the vehicle is in a uniform speed or low acceleration state. At this time, the reference vehicle speed before slipping is directly used as the estimated value of the current vehicle speed. Exemplarily, the preset acceleration threshold can be 0.1 m / s 2 。

[0125] As another specific embodiment, the specific implementation process of the above S102 includes:

[0126] Taking the front axle vehicle speed at the previous moment when it is simultaneously detected that both the front axle and the rear axle enter the slipping state as the current front axle vehicle speed;

[0127] Taking the rear axle vehicle speed at the previous moment when it is simultaneously detected that both the front axle and the rear axle enter the slipping state as the current rear axle vehicle speed;

[0128] Selecting the smaller value of the current front axle vehicle speed and the current rear axle vehicle speed as the target vehicle speed;

[0129] Integrating the current vehicle body acceleration for a first preset duration to obtain a cumulative change speed; the first preset duration is the time interval between the current moment and the moment when it is simultaneously detected that both the front axle and the rear axle enter the slipping state;

[0130] If the absolute value of the current vehicle body acceleration is greater than a first acceleration threshold, taking a first value as the first weight; if the absolute value of the current vehicle body acceleration is less than a second acceleration threshold, taking a second value as the first weight; multiplying the first weight by the cumulative change speed to obtain a corrected cumulative change speed;

[0131] Adding the target vehicle speed and the corrected cumulative change speed to obtain a first vehicle speed estimation value.

[0132] Specifically, the vehicle body acceleration sensor has zero bias error, dynamic response delay and high-frequency noise. In the case of a large acceleration value, the traditional pure integration method will have a large cumulative error. Therefore, in this embodiment, when the absolute value of the current vehicle body acceleration is greater than the first acceleration threshold, the first value can be used to correct the cumulative change speed to reduce the over-high cumulative change speed. When the absolute value of the current vehicle body acceleration is less than the second acceleration threshold, it indicates that the vehicle is close to the steady state at this time. Therefore, the second value can be directly set to zero. Among them, the first acceleration threshold can be 0.3g, and the second acceleration threshold can be 0.1g. The first value can be 0.7 to 0.9, and preferably, it can be 0.8. When the absolute value of the current vehicle body acceleration is greater than or equal to the second acceleration threshold and less than or equal to the first acceleration threshold, the value of its first weight is set to 1.

[0133] In a possible implementation, the specific implementation process of integrating the current vehicle body acceleration for a first preset duration to obtain the cumulative change speed in S102 includes:

[0134] If it is detected that the vehicle is in a steering condition, the cumulative change speed at the previous moment is frozen. Among them, the steering condition can be determined based on the steering angle of the steering wheel. When the steering angle of the steering wheel is greater than the preset angle or the change rate of the steering angle of the steering wheel is greater than the preset angle change rate, it is determined that the vehicle is in a steering condition at this time.

[0135] Specifically, when the vehicle is in a steering condition, the vehicle longitudinal acceleration collected by the vehicle body acceleration sensor includes the real vehicle longitudinal acceleration and the projection of the vehicle lateral acceleration on the vehicle longitudinal direction, resulting in an overestimated vehicle longitudinal acceleration collected by the vehicle body acceleration sensor. At the same time, the increase in the lateral force received by the wheels during steering will cause the available upper limit of the longitudinal force to decrease. At this time, if the vehicle speed is still estimated based on the integration of the longitudinal acceleration, the actual driving force / braking force will be overestimated. Therefore, in order to avoid the large error caused by the vehicle body acceleration during the steering condition, in this embodiment, the cumulative change speed is frozen during the steering condition until the steering is completed.

[0136] As can be seen from the above embodiments, since the stable wheel speed before slipping is closer to the real vehicle speed, in this embodiment, the front axle vehicle speed and the rear axle vehicle speed at the previous moment are locked at the moment when it is determined that both the front axle and the rear axle are in a slipping state, avoiding the problem of large deviation in vehicle speed estimation caused by selecting the overestimated slipping wheel speed. At the same time, the integration of the current vehicle body acceleration can adjust the vehicle speed in real time during the slipping state, further improving the accuracy of vehicle speed estimation.

[0137] In a possible implementation manner, the specific implementation process of S103 includes:

[0138] Take the front axle vehicle speed at the previous moment when the vehicle enters the vehicle speed separation and slipping condition as the current front axle vehicle speed; the vehicle speed separation and slipping condition is a condition where the front axle or the rear axle of the vehicle is in a slipping state at the current moment, and the difference between the front axle vehicle speed and the rear axle vehicle speed is greater than the preset threshold;

[0139] Take the rear axle vehicle speed at the previous moment when the vehicle enters the vehicle speed separation and slipping condition as the current rear axle vehicle speed;

[0140] Average the current front axle vehicle speed and the current rear axle vehicle speed to obtain the current average vehicle speed;

[0141] Integrate the current vehicle body acceleration for a second preset duration to obtain the cumulative change speed; the second preset duration is the time interval between the current moment and the moment when it is detected that the front axle or the rear axle enters the slipping state;

[0142] Add the current average vehicle speed and the cumulative change speed to obtain a second estimated vehicle speed value.

[0143] In this embodiment, for the load distribution characteristics of front-wheel drive vehicles and rear-wheel drive vehicles, after obtaining the current front axle vehicle speed and the current rear axle vehicle speed, this embodiment performs a weighted sum of the current front axle vehicle speed and the current rear axle vehicle speed to obtain the current average vehicle speed; and the sum of the weights of the current front axle vehicle speed and the current rear axle vehicle speed is 1; the weight ratio of the current front axle vehicle speed and the current rear axle vehicle speed is determined based on the driving mode of the vehicle.

[0144] Specifically, when a front-wheel drive vehicle is accelerating, the center of gravity moves backward, resulting in a decrease in the adhesion of the front wheels, but the driving torque is mainly transmitted by the front wheels. Therefore, the correlation coefficient between the front wheel speed and the actual vehicle speed is high, and the correlation coefficient between the rear wheel speed and the actual vehicle speed is low. Therefore, when the vehicle is a front-wheel drive vehicle, this embodiment sets the weight of the current front axle vehicle speed to be greater than the weight of the current rear axle vehicle speed; when the vehicle is a rear-wheel drive vehicle, this embodiment sets the weight of the current front axle vehicle speed to be less than the weight of the current rear axle vehicle speed; when the vehicle is a four-wheel drive vehicle, this embodiment sets the weight of the current front axle vehicle speed to be equal to the weight of the current rear axle vehicle speed, that is, 0.5:0.5.

[0145] In this embodiment, under the vehicle speed separation and slip condition, after calculating the cumulative speed change value at the current time, if the slip duration exceeds the preset time threshold, the integration of the acceleration is corrected based on the attenuation function to suppress the long-term integration drift.

[0146] Specifically, the calculation formula for the cumulative speed change value after entering the vehicle speed separation and slip condition is:

[0147]

[0148] where t 0 represents the preset time threshold, and Δt represents the duration in the vehicle speed separation and slip state. Among them, the preset time threshold can be 5 - 10s.

[0149] Similarly, in order to avoid calculation deviation, when the absolute value of the detected vehicle body acceleration is less than the preset acceleration threshold, it is considered that the vehicle is in a uniform speed or low acceleration state, and at this time, the reference vehicle speed before slipping is directly used as the estimated value of the current vehicle speed. Exemplarily, the preset acceleration threshold can be 0.1m / s 2 .

[0150] As another specific embodiment, the specific implementation process of the above S103 includes:

[0151] Take the front axle vehicle speed at the moment immediately before the vehicle enters the vehicle speed separation and skidding condition as the current front axle vehicle speed; the vehicle speed separation and skidding condition is a condition in which the front axle or the rear axle of the vehicle is in a skidding state at the current moment, and the difference between the front axle vehicle speed and the rear axle vehicle speed is greater than a preset threshold;

[0152] Take the rear axle vehicle speed at the moment immediately before the vehicle enters the vehicle speed separation and skidding condition as the current rear axle vehicle speed;

[0153] Average the current front axle vehicle speed and the current rear axle vehicle speed to obtain the current average vehicle speed;

[0154] Integrate the current vehicle body acceleration for a first preset duration to obtain the cumulative change speed; the first preset duration is the time interval between the current moment and the moment when it is simultaneously detected that both the front axle and the rear axle enter the skidding state;

[0155] If the absolute value of the current vehicle body acceleration is greater than the first acceleration threshold, take the first value as the first weight; if the absolute value of the current vehicle body acceleration is less than the second acceleration threshold, take the second value as the first weight; multiply the first weight by the cumulative change speed to obtain the corrected cumulative change speed;

[0156] Add the current average vehicle speed and the corrected cumulative change speed to obtain the second vehicle speed estimation value.

[0157] In a possible implementation manner, the specific implementation process of integrating the current vehicle body acceleration for a first preset duration in S103 to obtain the cumulative change speed includes:

[0158] If it is detected that the vehicle is in a steering condition, freeze the cumulative change speed at the previous moment. Among them, the steering condition can be determined based on the steering angle of the steering wheel. When the steering angle of the steering wheel is greater than the preset angle or the change rate of the steering angle of the steering wheel is greater than the preset angle change rate, it is determined that the vehicle is in a steering condition at this time.

[0159] Specifically, in order to avoid large errors caused by the vehicle body acceleration in the steering condition, in this embodiment, when the vehicle is in the vehicle speed separation condition and in the steering condition, the cumulative change speed is frozen until the steering is completed.

[0160] As can be seen from the above embodiments, in this embodiment, for the working condition where the vehicle speed is separated and slips and the vehicle speed is separated, at the moment when it is determined that at least one of the front axle and the rear axle is in a slipping state, the vehicle speeds of the front axle and the rear axle at the previous moment are locked, avoiding the problem of large deviation in vehicle speed estimation caused by selecting the inflated wheel speed after slipping. At the same time, since the vehicle speed is separated under this working condition, this embodiment eliminates the extreme value deviation caused by the vehicle speed separation and slipping through the average vehicle speed; at the same time, the integration of the current vehicle body acceleration can adjust the vehicle speed in real time under the slipping state, further improving the accuracy of vehicle speed estimation.

[0161] In a possible implementation manner, the specific implementation process of S101 includes:

[0162] If both the front axle and the rear axle of the vehicle are in a slipping state at the current moment, calculate a first vehicle speed estimation value based on the vehicle speed before the slipping state and the current vehicle body acceleration, otherwise use a first preset speed as the first vehicle speed estimation value; the first preset speed is greater than the vehicle speed upper limit value of the vehicle;

[0163] The specific implementation process of S103 includes:

[0164] If either the front axle or the rear axle of the vehicle is in a slipping state at the current moment, and the difference between the front axle vehicle speed and the rear axle vehicle speed is greater than a preset threshold, calculate a second vehicle speed estimation value based on the front axle vehicle speed, the rear axle vehicle speed and the vehicle body acceleration, otherwise use a first preset speed as the second vehicle speed estimation value; the first preset speed is greater than the vehicle speed upper limit value of the vehicle.

[0165] Specifically, the first preset speed can be a high vehicle speed that the vehicle cannot achieve. For example, the first preset speed is equal to 300 km / h.

[0166] In this embodiment, in order to improve the system reliability, when the conditions of the double-bridge slipping vehicle speed estimation path are not met and the conditions of the vehicle speed separation and slipping vehicle speed estimation path are not met, a high-inflated vehicle speed estimation value is output, so that the subsequent motor controller directly takes the minimum of the first vehicle speed estimation value, the second vehicle speed estimation value and the third vehicle speed estimation value, and thus outputs a real vehicle speed estimation value.

[0167] The above embodiments provide a protection mechanism for the double-bridge and vehicle speed separation and slipping working conditions. When the working condition conditions are not met, the corresponding estimation value is set to an invalid value, avoiding the incorrect application of the compensation algorithm under non-slipping working conditions. At the same time, invalidating can avoid conflicts with the real wheel speed, effectively improving the system reliability and reducing the accident risk caused by algorithm failure.

[0168] In a possible implementation manner, the specific implementation process of S105 includes:

[0169] Select the minimum value among the first vehicle speed estimation value, the second vehicle speed estimation value, and the third vehicle speed estimation value as the reference vehicle speed of the vehicle at the current moment.

[0170] As can be seen from the above embodiments, in order to meet the safety - first strategy of TCS, in this embodiment, the minimum value of the results of three estimation rules is finally taken as the vehicle speed estimation value, and then the calculated reference vehicle speed is used for the calculation of the slip ratio, avoiding the distortion of the slip rate calculation caused by over - estimating the vehicle speed, and then effectively controlling the vehicle stability state and enhancing the system safety. In addition, compared with the ESC (Electronic Stability Control) control system, the method provided in this embodiment can be applied to the motor controller, perform signal processing in the motor controller, reduce the signal transmission time between multiple controllers, and calculate the vehicle body state earlier.

[0171] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The execution order of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0172] The following is the device embodiment of the present application. For the details not described in detail, reference can be made to the corresponding method embodiments above.

[0173] Figure 2 The structural schematic diagram of the vehicle speed estimation device provided by the embodiment of the present application is shown. For the convenience of description, only the parts related to the embodiment of the present application are shown and are described in detail as follows:

[0174] As Figure 2 shown, the vehicle speed estimation device 100 includes:

[0175] A slip - state judgment module 110, configured to judge whether the front axle and the rear axle of the vehicle are in a slip state at the current moment;

[0176] A first vehicle speed estimation module 120, configured to calculate a first vehicle speed estimation value based on the vehicle speed before the slip state and the current vehicle body acceleration if both the front axle and the rear axle of the vehicle are in a slip state at the current moment;

[0177] A second vehicle speed estimation module 130, configured to calculate a second vehicle speed estimation value based on the front axle vehicle speed, the rear axle vehicle speed, and the vehicle body acceleration if either the front axle or the rear axle of the vehicle is in a slip state at the current moment and the difference between the front axle vehicle speed and the rear axle vehicle speed is greater than a preset threshold;

[0178] A third vehicle speed estimation module 140, configured to select the smaller value between the front axle vehicle speed and the rear axle vehicle speed of the vehicle at the current moment as the third vehicle speed estimation value;

[0179] A reference vehicle speed determination module 150, configured to determine a reference vehicle speed of the vehicle at the current moment according to the first estimated vehicle speed, the second estimated vehicle speed, and the third estimated vehicle speed.

[0180] In a possible implementation manner, the slip state determination module 110 includes:

[0181] Obtain the front axle vehicle speed at the current moment, and take the derivative of the front axle vehicle speed at the current moment to obtain the front axle acceleration;

[0182] Obtain the rear axle vehicle speed at the current moment, and take the derivative of the rear axle vehicle speed at the current moment to obtain the rear axle acceleration;

[0183] If the front axle acceleration is greater than the acceleration calibration value, it is determined that the front axle is in a slip state;

[0184] If the rear axle acceleration is greater than the acceleration calibration value, it is determined that the rear axle is in a slip state.

[0185] In a possible implementation manner, the first vehicle speed estimation module 120 includes:

[0186] Use the front axle vehicle speed at the previous moment when both the front axle and the rear axle are simultaneously monitored to enter the slip state as the current front axle vehicle speed;

[0187] Use the rear axle vehicle speed at the previous moment when both the front axle and the rear axle are simultaneously monitored to enter the slip state as the current rear axle vehicle speed;

[0188] Select the smaller value of the current front axle vehicle speed and the current rear axle vehicle speed as the target vehicle speed;

[0189] Integrate the current vehicle body acceleration for a first preset duration to obtain the cumulative change speed; the first preset duration is the time interval between the current moment and the moment when both the front axle and the rear axle are simultaneously monitored to enter the slip state;

[0190] Add the target vehicle speed and the cumulative change speed to obtain the first estimated vehicle speed.

[0191] In a possible implementation manner, the second vehicle speed estimation module 130 includes:

[0192] Use the front axle vehicle speed at the previous moment when the vehicle enters the vehicle speed separation slip condition as the current front axle vehicle speed; the vehicle speed separation slip condition is a condition where either the front axle or the rear axle of the vehicle is in a slip state at the current moment, and the difference between the front axle vehicle speed and the rear axle vehicle speed is greater than a preset threshold;

[0193] Use the rear axle vehicle speed at the previous moment when the vehicle enters the vehicle speed separation slip condition as the current rear axle vehicle speed;

[0194] Average the current front axle vehicle speed and the current rear axle vehicle speed to obtain the current average vehicle speed;

[0195] Integrate the current vehicle body acceleration for a second preset duration to obtain the cumulative change speed; the second preset duration is the time interval between the current moment and the moment when the front axle or the rear axle is detected to enter the slipping state;

[0196] Add the current average vehicle speed and the cumulative change speed to obtain a second vehicle speed estimation value.

[0197] In a possible implementation manner, the first vehicle speed estimation module 120 includes:

[0198] If both the front axle and the rear axle of the vehicle are in the slipping state at the current moment, calculate the first vehicle speed estimation value based on the vehicle speed before the slipping state and the current vehicle body acceleration, otherwise use the first preset speed as the first vehicle speed estimation value; the first preset speed is greater than the vehicle speed upper limit value of the vehicle;

[0199] The second vehicle speed estimation module 110 includes:

[0200] If the front axle or the rear axle of the vehicle is in the slipping state at the current moment, and the difference between the front axle vehicle speed and the rear axle vehicle speed is greater than a preset threshold, calculate the second vehicle speed estimation value based on the front axle vehicle speed, the rear axle vehicle speed and the vehicle body acceleration, otherwise use the first preset speed as the second vehicle speed estimation value; the first preset speed is greater than the vehicle speed upper limit value of the vehicle.

[0201] In a possible implementation manner, the reference vehicle speed determination module 150 includes:

[0202] Select the minimum value among the first vehicle speed estimation value, the second vehicle speed estimation value and the third vehicle speed estimation value as the reference vehicle speed of the vehicle at the current moment.

[0203] The embodiment of the present application also provides a computer program product, which has program codes. When the program codes run in a corresponding processor, controller, computing device or terminal, they execute the steps in any one of the above-mentioned vehicle speed estimation method embodiments, for example Figure 1Steps S101 to S105 shown. Those skilled in the art should understand that the methods and the devices belonging thereto proposed in the embodiments of the present application can be implemented in various forms of hardware, software, firmware, a dedicated processor, or a combination thereof. The dedicated processor may include an application specific integrated circuit (ASIC), a reduced instruction set computer (RISC), and / or a field programmable gate array (FPGA). The proposed methods and devices are preferably implemented as a combination of hardware and software. The software is preferably installed as an application program on a program storage device. It is typically a machine based on a computer platform with hardware, such as one or more central processing units (CPUs), a random access memory (RAM), and one or more input / output (I / O) interfaces. An operating system is typically also installed on the computer platform. The various processes and functions described herein may be part of an application program, or a part of it may be executed by the operating system.

[0204] Figure 3 is a schematic diagram of a terminal provided by an embodiment of the present application. As Figure 3 shown, the controller 3 of this embodiment includes: a processor 30, a memory 31, and a computer program 32 stored in the memory 31 and executable on the processor 30. When the processor 30 executes the computer program 32, it implements the steps in the above-mentioned embodiments of each vehicle speed estimation method, such as Figure 1 the steps S101 to S105 shown. Alternatively, when the processor 30 executes the computer program 32, it implements the functions of each module / unit in the above-mentioned device embodiments, such as Figure 2 the functions of the modules 110 to 150 shown.

[0205] Exemplarily, the computer program 32 may be divided into one or more modules / units. The one or more modules / units are stored in the memory 31 and executed by the processor 30 to complete / implement the solution provided by the present application. The one or more modules / units may be a series of computer program instruction segments capable of performing specific functions, and this instruction segment is used to describe the execution process of the computer program 32 in the controller 3. For example, the computer program 32 may be divided into Figure 2 the modules 110 to 150 shown.

[0206] The controller 3 may include, but is not limited to, a processor 30 and a memory 31. Those skilled in the art can understand that Figure 3 merely being examples of the controller 3 does not constitute a limitation on the controller 3. It may include more or fewer components than shown in the figure, or combine some components, or different components. For example, the terminal may further include input / output devices, network access devices, a bus, etc.

[0207] The so-called processor 30 may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0208] The memory 31 may be an internal storage unit of the controller 3, such as the hard disk or memory of the controller 3. The memory 31 may also be an external storage device of the controller 3, such as a plug-in hard disk equipped on the controller 3, a Smart Media Card (SMC), a Secure Digital (SD) card, a Flash Card, etc. Further, the memory 31 may also include both the internal storage unit of the controller 3 and the external storage device. The memory 31 is used to store the computer program and other programs and data required by the terminal. The memory 31 may also be used to temporarily store the data that has been output or will be output.

[0209] Those skilled in the art can clearly understand that, for the convenience and conciseness of description, only the above division of each functional unit and module is used as an example. In actual applications, the above functions can be allocated to different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiments can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction and do not limit the protection scope of this application. The specific working processes of the units and modules in the above system can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0210] In the above embodiments, the descriptions of the various embodiments have their own emphases. For the parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0211] Those of ordinary skill in the art will realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. A professional technician can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this application.

[0212] In the embodiments provided in this application, it should be understood that the disclosed device / terminal and method can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For example, the division of the modules or units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of the device or unit can be in electrical, mechanical or other forms.

[0213] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place, or they can be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0214] In addition, the functional units in each embodiment of this application can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units.

[0215] When the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, to implement all or part of the processes in the above-described embodiment methods of this application, it can also be completed by instructing relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above-described embodiments of various vehicle speed estimation methods can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disc, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0216] In addition, the features of the embodiments shown in the drawings of this application or various embodiments mentioned in this specification do not have to be understood as independent embodiments of each other. Instead, each feature described in one example of an embodiment can be combined with one or more other desired features from other embodiments, thereby generating other embodiments not described in words or with reference to the drawings.

[0217] The above-described embodiments are only used to illustrate the technical solutions of this application, rather than to limit them; although this application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A vehicle speed estimation method, characterized in that: include: Determine whether the front axle and the rear axle of the vehicle are in a slipping state at the current moment; If both the front axle and the rear axle of the vehicle are in a slipping state at the current moment, calculating a first vehicle speed estimation value based on the vehicle speed before the slipping state and the current vehicle body acceleration; If the front axle or the rear axle of the vehicle is in a slipping state at the current moment, and the difference between the front axle speed and the rear axle speed is greater than a preset threshold, calculating a second vehicle speed estimation value based on the front axle speed, the rear axle speed and the vehicle body acceleration; Selecting the smaller value of the front axle speed and the rear axle speed of the vehicle at the current moment as the third vehicle speed estimation value; A reference vehicle speed of the vehicle at a current moment is determined according to the first vehicle speed estimation value, the second vehicle speed estimation value, and the third vehicle speed estimation value.

2. The vehicle speed estimation method according to claim 1, characterized in that: The determining whether the front axle and the rear axle of the vehicle are in a slipping state at the current moment includes: Obtain the front axle speed at the current moment, and derive the front axle speed at the current moment to obtain the front axle acceleration; Obtain the rear axle speed at the current moment, and derive the rear axle speed at the current moment to obtain the rear axle acceleration; If the front axle acceleration is greater than the acceleration calibration value, it is determined that the front axle is in a slipping state; If the rear axle acceleration is greater than the acceleration calibration value, it is determined that the rear axle is in a slipping state.

3. The vehicle speed estimation method according to claim 1, characterized in that: The calculating the first vehicle speed estimation value based on the vehicle speed before the slipping state and the current vehicle body acceleration includes: The front axle vehicle speed at the moment before both the front axle and the rear axle are detected to be in a slipping state is used as the current front axle vehicle speed; The rear axle speed at the moment before both the front axle and the rear axle are detected to be in a slipping state is used as the current rear axle speed; Selecting the smaller value of the current front axle vehicle speed and the current rear axle vehicle speed as the target vehicle speed; Integrating the current vehicle body acceleration for a first preset time period to obtain a cumulative change speed; the first preset time period is the time interval between the current moment and the moment when both the front axle and the rear axle are monitored to enter a slipping state; The target vehicle speed is added to the accumulated change speed to obtain a first vehicle speed estimation value.

4. The vehicle speed estimation method according to claim 1, characterized in that: The calculating a second vehicle speed estimation value based on the front axle vehicle speed, the rear axle vehicle speed and the vehicle body acceleration includes: The front axle speed at the moment before the vehicle enters the speed separation slipping condition is used as the current front axle speed; the speed separation slipping condition is a condition in which the front axle or the rear axle of the vehicle is in a slipping state at the current moment, and the difference between the front axle speed and the rear axle speed is greater than a preset threshold; The rear axle speed at the moment before the vehicle enters the speed separation slipping condition is used as the current rear axle speed; averaging the current front axle vehicle speed and the current rear axle vehicle speed to obtain a current average vehicle speed; Integrating the current vehicle body acceleration for a second preset time period to obtain a cumulative change speed; the second preset time period is a time interval between the current moment and the moment when the front axle or the rear axle is monitored to enter a slipping state; The current average vehicle speed is added to the accumulated change speed to obtain a second vehicle speed estimation value.

5. The vehicle speed estimation method according to claim 1, characterized in that: If both the front axle and the rear axle of the vehicle are in a slipping state at the current moment, a first vehicle speed estimation value is calculated based on the vehicle speed before the slipping state and the current vehicle body acceleration, including: If both the front axle and the rear axle of the vehicle are in a slipping state at the current moment, a first vehicle speed estimation value is calculated based on the vehicle speed before the slipping state and the current vehicle body acceleration; otherwise, a first preset speed is used as the first vehicle speed estimation value; the first preset speed is greater than the vehicle speed upper limit value; If the front axle or the rear axle of the vehicle is in a slipping state at the current moment, and the difference between the front axle speed and the rear axle speed is greater than a preset threshold, a second vehicle speed estimation value is calculated based on the front axle speed, the rear axle speed and the vehicle body acceleration, including: If the front axle or rear axle of the vehicle is in a slipping state at the current moment, and the difference between the front axle speed and the rear axle speed is greater than a preset threshold, a second vehicle speed estimate is calculated based on the front axle speed, the rear axle speed and the vehicle body acceleration; otherwise, a first preset speed is used as the second vehicle speed estimate; the first preset speed is greater than the vehicle speed upper limit.

6. The vehicle speed estimation method according to claim 1, characterized in that: The determining the reference vehicle speed of the vehicle at the current moment according to the first vehicle speed estimation value, the second vehicle speed estimation value and the third vehicle speed estimation value comprises: The minimum value among the first vehicle speed estimation value, the second vehicle speed estimation value and the third vehicle speed estimation value is selected as the reference vehicle speed of the vehicle at the current moment.

7. A vehicle speed estimation device, characterized in that: include: A skidding state judgment module is used to judge whether the front axle and the rear axle of the vehicle are in a skidding state at the current moment; a first vehicle speed estimation module, configured to calculate a first vehicle speed estimation value based on the vehicle speed before the slipping state and the current vehicle body acceleration if both the front axle and the rear axle of the vehicle are in a slipping state at the current moment; a second vehicle speed estimation module, configured to calculate a second vehicle speed estimation value based on the front axle speed, the rear axle speed and the vehicle body acceleration if the front axle or the rear axle of the vehicle is in a slipping state at a current moment and the difference between the front axle speed and the rear axle speed is greater than a preset threshold; A third vehicle speed estimation module, used for selecting the smaller value of the front axle speed and the rear axle speed of the vehicle at the current moment as a third vehicle speed estimation value; The reference vehicle speed determination module is used to determine a reference vehicle speed of the vehicle at a current moment according to the first vehicle speed estimation value, the second vehicle speed estimation value and the third vehicle speed estimation value.

8. A controller comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the vehicle speed estimation method as described in any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the vehicle speed estimation method as described in any one of claims 1 to 6 are implemented.

10. A vehicle, characterized in that: include: A controller as claimed in claim 8.

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