Rear wheel steering control method, device and vehicle

Abstract

The application discloses a rear wheel steering control method and device and a vehicle, and belongs to the technical field of vehicles. The method comprises the following steps: determining a slip factor based on a first vehicle speed difference value of the target vehicle at multiple time points and wheel speeds of the wheels, wherein the first vehicle speed difference value is a vehicle speed change amount at multiple time points calculated based on the acceleration of the target vehicle; adjusting a target vehicle speed change rate based on the slip factor; and controlling the target vehicle to perform rear wheel steering based on the target vehicle speed change rate, a first vehicle speed and a second vehicle speed, wherein the first vehicle speed is a vehicle speed determined based on the wheel speed currently received by the rear wheel steering system, and the second vehicle speed is a vehicle speed currently used by the rear wheel steering system. In this way, the influence of slip can be considered when the rear wheel is steered, and the influence of slip on the vehicle speed is reduced by adjusting the vehicle speed change rate, so that the accuracy of the steering decision of the target vehicle can be improved, and the safety of the target vehicle in the slip working condition can be improved.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, and in particular to a rear-wheel steering control method, device, and vehicle. Background Technology

[0002] With the development of technology, in order to improve the flexibility and stability of vehicles, both the front and rear wheels can rotate to a certain extent. For example, when a vehicle is turning at low speed, by controlling the front and rear wheels to rotate in opposite directions, the turning radius can be shortened, thereby improving the vehicle's turning flexibility. As another example, when a vehicle is changing lanes at high speed, by controlling the front and rear wheels to rotate in the same direction, the yaw rate during overtaking and lane changes can be reduced, thereby improving the vehicle's high-speed stability.

[0003] However, due to the varying coefficients of smoothness on different road surfaces, vehicles may experience skidding on some surfaces. Normally, the rear wheel controller relies on vehicle speed to calculate the rear wheel steering angle. Since vehicle speed changes rapidly during skidding, the rear wheel steering angle also changes rapidly. Therefore, the rear wheel controller may be unable to calculate the correct rear wheel steering angle, leading to errors in rear wheel steering decisions and preventing the vehicle from steering properly. Summary of the Invention

[0004] This application provides a rear-wheel steering control method, device, vehicle, and storage medium. When a target vehicle slips, the rate of change of the target vehicle's speed is adjusted based on a slip factor, thereby adjusting the amount of speed change. Rear-wheel steering is then performed based on this adjusted speed change, allowing the impact of slippage to be taken into account during rear-wheel steering and reducing its influence on vehicle speed. This improves the safety of rear-wheel steering under slippage conditions. The technical solution includes the following:

[0005] Firstly, a rear-wheel steering control method is provided, the method comprising:

[0006] Based on the first speed difference of the target vehicle at multiple moments and the wheel speed, a slip factor is determined. The slip factor is used to represent the degree of slippage of the target vehicle. The first speed difference is the change in vehicle speed at multiple moments calculated based on the acceleration of the target vehicle.

[0007] Based on the slip factor, adjust the rate of change of the target vehicle's speed;

[0008] Based on the target vehicle speed change rate, a first vehicle speed, and a second vehicle speed, the target vehicle is controlled to perform rear-wheel steering. The first vehicle speed is the vehicle speed currently received by the rear-wheel steering system based on wheel speed, and the second vehicle speed is the vehicle speed currently being used by the rear-wheel steering system. The target vehicle speed change rate is the adjusted vehicle speed change rate.

[0009] In this application, when performing rear-wheel steering, a slip factor is first determined based on the first speed difference of the target vehicle at multiple moments and the wheel speed, that is, the degree of slippage of the target vehicle at these moments. Then, based on the slip factor, the rate of change of the target vehicle's speed is adjusted, that is, the amount of speed change of the target vehicle during slippage is adjusted. For example, if the slip factor is equal to 1, the rate of change of the target speed can be adjusted to 0, that is, the amount of speed change of the target vehicle during slippage is controlled to be 0. In other words, when the degree of slippage of the target vehicle is very large, the speed is kept constant. Then, based on the target rate of change of speed, the first speed, and the second speed, the target vehicle is controlled to perform rear-wheel steering. This allows the impact of slippage to be taken into account during rear-wheel steering, and by adjusting the rate of change of speed, the impact of slippage on speed can be reduced, thus avoiding the situation where the rear wheel angle changes continuously. This improves the accuracy of the target vehicle's steering decisions and, consequently, enhances the safety of the target vehicle performing rear-wheel steering under slippage conditions.

[0010] Optionally, determining the slippage factor based on the first speed difference of the target vehicle at multiple moments and the wheel speed includes:

[0011] Based on the wheel speed of the target vehicle at the plurality of times, a first reference factor is determined, wherein the first reference factor refers to the degree of slippage of the target vehicle determined based on the wheel speed.

[0012] Based on the first speed difference of the target vehicle at the multiple times and the wheel speed, a second reference factor is determined. The second reference factor refers to the degree of slippage of the target vehicle determined based on the wheel speed and the actual vehicle speed.

[0013] The slippage factor is determined based on the first reference factor and the second reference factor.

[0014] In this application, the first reference factor and the second reference factor are based on the degree of slippage of the target vehicle determined by different methods. Thus, by determining the degree of slippage of the target vehicle through different methods, the phenomenon of wheel slippage can be measured from different dimensions, thereby allowing for a more accurate slippage factor to be determined based on the first and second reference factors.

[0015] Optionally, determining the first reference factor based on the wheel speed of the target vehicle at the plurality of times includes:

[0016] Based on the wheel speed of the target vehicle at time i, determine the average wheel speed of the target vehicle at time i.

[0017] Based on the wheel speed at the i-th time moment and the mean wheel speed, determine the wheel speed variance corresponding to the i-th time moment;

[0018] The first reference factor is determined based on the variance of wheel speed at the multiple time points.

[0019] In this application, by calculating the variance of the wheel speed at the i-th time moment, the dispersion of the wheel speeds of the four wheels can be known. In addition, the above operation is equivalent to calculating the variance between the four wheels and the mean wheel speed for each of the multiple time moments. In this way, the deviation between the wheel speeds of the four wheels and the mean wheel speed can be accurately and conveniently determined, thereby accurately and conveniently obtaining the first reference factor, that is, accurately determining whether the wheels of the target vehicle are slipping and the degree of slippage.

[0020] Optionally, determining the first reference factor based on the wheel speed variance corresponding to the plurality of time points includes:

[0021] Based on the wheel speed variance corresponding to the multiple time points, determine the variance change rate corresponding to the multiple time points;

[0022] The first reference factor is determined based on the wheel speed variance and the rate of change of the variance at the multiple time points.

[0023] In this application, by using the wheel speed variance and the rate of change of the variance at multiple times, the deviation between the wheel speed and the mean wheel speed of the four wheels can be measured in different dimensions. This allows us to know the deviation between the wheel speed and the mean wheel speed of the four wheels and the magnitude of the deviation at multiple times, thereby determining a more accurate first reference factor, which means we can accurately predict the degree of slippage of the target vehicle.

[0024] Optionally, determining the second reference factor based on the first speed difference of the target vehicle at the plurality of times and the wheel speed includes:

[0025] For any wheel of the target vehicle, the change in wheel speed at the multiple times is determined based on the wheel speed at the multiple times.

[0026] The average value of the wheel speed changes of the target vehicle at multiple times is determined to obtain a third vehicle speed difference value, which is the vehicle speed change of the target vehicle at those multiple times based on the wheel speed.

[0027] The second reference factor is determined based on the difference between the first vehicle speed difference and the third vehicle speed difference.

[0028] In this application, by using the first vehicle speed difference and the third vehicle speed difference, which are equivalent to the vehicle speed change calculated based on wheel speed and the vehicle speed change calculated based on acceleration, that is, based on the vehicle speed change in the rear wheel steering system at multiple moments (the vehicle speed change calculated based on wheel speed) and the actual vehicle speed change, it is possible to accurately determine whether the target vehicle is slipping and the degree of slipping by comparing the vehicle speed change calculated based on wheel speed with the actual vehicle speed change. Therefore, the second reference factor can be accurately determined.

[0029] Optionally, determining the slippage factor based on the first reference factor and the second reference factor includes:

[0030] The maximum value between the first reference factor and the second reference factor is determined as the slippage factor.

[0031] In this application, both the first reference factor and the second reference factor essentially represent the degree of slippage of the target vehicle, only calculated in different ways. The larger of the first and second reference factors indicates a higher predicted degree of slippage for the target vehicle. Therefore, to ensure driving safety and to fully consider the impact of slippage on rear-wheel steering, the degree of slippage can be set to be larger. Thus, by selecting the larger of the first and second reference factors as the slippage factor, the impact of slippage can be fully considered in rear-wheel steering, thereby ensuring the safety of subsequent rear-wheel steering.

[0032] Optionally, adjusting the rate of change of the target vehicle's speed based on the slip factor includes:

[0033] Subtracting the slippage factor from the target threshold yields the target vehicle speed change rate.

[0034] In this application, by subtracting the slip factor from the target threshold, the weight of the speed change (speed change rate) is obtained. Then, based on this weight, the speed change during slippage can be determined. Thus, by setting an appropriate weight for the speed change, the speed change can be reduced, thereby reducing the impact of slippage on the speed.

[0035] Optionally, controlling the target vehicle to perform rear-wheel steering based on the target vehicle speed change rate, the first vehicle speed, and the second vehicle speed includes:

[0036] Subtract the second vehicle speed from the first vehicle speed to obtain the second vehicle speed difference;

[0037] Multiply the target vehicle speed change rate by the second vehicle speed difference to obtain the fourth vehicle speed difference;

[0038] Add the second vehicle speed to the fourth vehicle speed difference to obtain the target vehicle speed;

[0039] Based on the target vehicle speed, control the target vehicle to perform rear-wheel steering.

[0040] In this application, the target vehicle speed change rate can be used to adjust the amount of vehicle speed change that would normally be added to the rear wheel steering system. This means that the influence of slippage on vehicle speed is taken into account, which is equivalent to adjusting the vehicle speed based on the target vehicle speed change rate. As a result, the rear wheels can be steered more accurately based on the adjusted vehicle speed.

[0041] Secondly, a rear-wheel steering control device is provided, the device comprising:

[0042] The determination module is used to determine a slip factor based on the first speed difference of the target vehicle at multiple times and the wheel speed. The slip factor is used to represent the degree of slip of the target vehicle. The first speed difference is the change in vehicle speed at the multiple times calculated based on the acceleration of the target vehicle.

[0043] An adjustment module is used to adjust the rate of change of the target vehicle's speed based on the slip factor;

[0044] The control module is used to control the target vehicle to perform rear-wheel steering based on the target vehicle speed change rate, a first vehicle speed, and a second vehicle speed. The first vehicle speed is the vehicle speed currently received by the rear-wheel steering system based on the wheel speed, the second vehicle speed is the vehicle speed currently being used by the rear-wheel steering system, and the target vehicle speed change rate is the adjusted vehicle speed change rate.

[0045] Optionally, the determining module is used to:

[0046] Based on the wheel speed of the target vehicle at the plurality of times, a first reference factor is determined, wherein the first reference factor refers to the degree of slippage of the target vehicle determined based on the wheel speed.

[0047] Based on the first speed difference of the target vehicle at the multiple times and the wheel speed, a second reference factor is determined. The second reference factor refers to the degree of slippage of the target vehicle determined based on the wheel speed and the actual vehicle speed.

[0048] The slippage factor is determined based on the first reference factor and the second reference factor.

[0049] Optionally, the determining module is used to:

[0050] Based on the wheel speed of the target vehicle at time i, determine the average wheel speed of the target vehicle at time i.

[0051] Based on the wheel speed at the i-th time moment and the mean wheel speed, determine the wheel speed variance corresponding to the i-th time moment;

[0052] The first reference factor is determined based on the variance of wheel speed at the multiple time points.

[0053] Optionally, the determining module is used to:

[0054] Based on the wheel speed variance corresponding to the multiple time points, determine the variance change rate corresponding to the multiple time points;

[0055] The first reference factor is determined based on the wheel speed variance and the rate of change of the variance at the multiple time points.

[0056] Optionally, the determining module is used to:

[0057] For any wheel of the target vehicle, the change in wheel speed at the multiple times is determined based on the wheel speed at the multiple times.

[0058] The average value of the wheel speed changes of the target vehicle at multiple times is determined to obtain a third vehicle speed difference value, which is the vehicle speed change of the target vehicle at those multiple times based on the wheel speed.

[0059] The second reference factor is determined based on the difference between the first vehicle speed difference and the third vehicle speed difference.

[0060] Optionally, the determining module is used to:

[0061] The maximum value between the first reference factor and the second reference factor is determined as the slippage factor.

[0062] Optionally, the adjustment module is used for:

[0063] Subtracting the slippage factor from the target threshold yields the target vehicle speed change rate.

[0064] Optionally, the control module is used for:

[0065] Subtract the second vehicle speed from the first vehicle speed to obtain the second vehicle speed difference;

[0066] Multiply the target vehicle speed change rate by the second vehicle speed difference to obtain the fourth vehicle speed difference;

[0067] Add the second vehicle speed to the fourth vehicle speed difference to obtain the target vehicle speed;

[0068] Based on the target vehicle speed, control the target vehicle to perform rear-wheel steering.

[0069] Thirdly, a vehicle is provided, the vehicle comprising:

[0070] Memory, used to store executable program code;

[0071] A processor is configured to call and run the executable program code from the memory, causing the vehicle to perform the aforementioned rear-wheel steering control method.

[0072] Fourthly, a computer-readable storage medium is provided, the computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-described rear-wheel steering control method.

[0073] Fifthly, a computer program product containing instructions is provided, which, when run on a computer, causes the computer to perform the steps of the aforementioned rear-wheel steering control method.

[0074] It is understood that the beneficial effects of the second, third, fourth, and fifth aspects mentioned above can be found in the relevant descriptions in the first aspect above, and will not be repeated here. Attached Figure Description

[0075] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0076] Figure 1 This is a schematic diagram of the implementation environment of a rear-wheel steering control method provided in an embodiment of this application;

[0077] Figure 2 This is a schematic diagram of a scenario for a rear-wheel steering control method provided in an embodiment of this application;

[0078] Figure 3 This is a flowchart of a rear-wheel steering control method provided in an embodiment of this application;

[0079] Figure 4 This is a schematic diagram of the structure of a rear wheel steering control device provided in an embodiment of this application;

[0080] Figure 5 This is a schematic diagram of the structure of a vehicle provided in an embodiment of this application. Detailed Implementation

[0081] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0082] It should be understood that "multiple" as mentioned in this application refers to two or more. In the description of this application, unless otherwise stated, " / " indicates "or," for example, A / B can mean A or B; "and / or" in this document 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, to facilitate a clear description of the technical solutions of this application, the terms "first," "second," etc., are used to distinguish identical or similar items with essentially the same function and effect. Those skilled in the art will understand that the terms "first," "second," etc., do not limit the quantity or execution order, and that "first," "second," etc., do not necessarily imply differences.

[0083] Before describing the rear wheel steering control method provided in the embodiments of this application, the implementation environment involved in the embodiments of this application will be described first.

[0084] For example, Figure 1 This is a schematic diagram illustrating the implementation environment of a rear-wheel steering control method provided in an embodiment of this application. See also... Figure 1 , Figure 1 This includes vehicle 101. Vehicle 101 may be equipped with a rear-wheel steering system 102.

[0085] Vehicle 101 is a vehicle equipped with the aforementioned rear-wheel steering system 102. For example, vehicle 101 can be a front-wheel drive (FWD), a rear-wheel drive (RWD), or an all-wheel drive (AWD) vehicle. This application embodiment does not limit the type of vehicle 101.

[0086] The rear-wheel steering system 102 is a technology that can adjust the direction angle of the rear wheels. It improves vehicle handling performance by causing the rear wheels to rotate in the same direction or opposite direction relative to the front wheels under certain conditions. The rear-wheel steering system 102 consists of a rear-wheel steering controller and a steer-by-wire system. It receives signals such as steering wheel angle, steering wheel speed, and vehicle speed from the vehicle controller via wires, and then calculates the required rotation angle based on these signals. Under normal straight-line driving conditions, the rear wheels remain in a straight position to prevent the vehicle from veering off course. When the vehicle is turning at low speed, the rear wheels can rotate in the opposite direction to the front wheels to reduce the turning radius; when changing lanes at high speed, the rear wheels rotate in the same direction as the front wheels to improve vehicle stability.

[0087] In this embodiment of the application, when rear wheel steering is required in scenarios such as turning or changing lanes, the rear wheel steering system 102 can receive signals such as the vehicle speed and steering wheel angle of the vehicle 101, and calculate the angle to be turned by the rear wheels based on the vehicle speed and steering wheel angle, so as to improve the handling performance by turning the rear wheels by the corresponding angle.

[0088] The application scenarios of the embodiments of this application will be further described.

[0089] For example, Figure 2 This is a schematic diagram of a scenario for a rear-wheel steering control method provided in an embodiment of this application. See also... Figure 2 , Figure 2 Vehicle 201 is included, and vehicle 201 is turning.

[0090] During the turning process of vehicle 201, the rear wheel steering system can calculate the angle that the rear wheels should turn based on the vehicle speed of vehicle 201, so that the front wheels and rear wheels can work together to achieve more flexible turning.

[0091] Under normal circumstances, vehicle 201 may travel on different types of road surfaces, but the coefficient of smoothness may vary for different types of road surfaces. When vehicle 201 travels on a relatively smooth road surface, vehicle 201 may experience slippage.

[0092] When a vehicle slips, the wheels spin freely, resulting in a higher wheel speed. Since vehicle speed is generally calculated based on wheel speed, this calculated speed is also higher. Therefore, when vehicle 201 slips, its speed changes significantly compared to when it is not slipping. Consequently, the speed calculated based on wheel speed may have a large error compared to the actual speed. In this situation, the rear-wheel steering system will receive an incorrect speed reading and calculate an incorrect steering angle based on it. This leads to a misjudgment in the rear-wheel steering decision, causing vehicle 201 to fail to steer properly.

[0093] For example, when vehicle 201 is not slipping, the rear wheel steering system receives a vehicle speed of 30, while when slipping, it receives a vehicle speed of 50. This means that the vehicle speed of vehicle 201 changes significantly, or the rate of change of vehicle speed is large. Therefore, the rear wheel steering system calculates a large difference between the rear wheel steering angle based on a vehicle speed of 50 and the rear wheel steering system calculates an incorrect steering angle.

[0094] Therefore, this application provides a rear-wheel steering control method that can be applied to scenarios where the rear wheels of a vehicle are controlled to steer.

[0095] Specifically, the process first calculates the change in vehicle speed at multiple moments based on the target vehicle's acceleration. Then, based on the change in vehicle speed at these moments and the wheel speeds, a slip factor is determined. Next, based on the slip factor, the rate of change of vehicle speed is adjusted, meaning the change in speed during slippage is adjusted. For example, if the slip factor is 1, the rate of change of speed can be adjusted to 0, meaning the change in vehicle speed during slippage is controlled to be zero. In other words, when the target vehicle is slipping significantly, the speed remains unchanged. Finally, based on the adjusted rate of change of speed and the wheel speeds, the change in vehicle speed at multiple moments is adjusted, and the target vehicle is then controlled to perform rear-wheel steering.

[0096] In this scenario, by adjusting the vehicle speed change rate and the wheel speed, the target vehicle's speed change at multiple moments is adjusted, and the target vehicle is controlled to perform rear-wheel steering accordingly. This allows the impact of slippage to be taken into account during rear-wheel steering, and by adjusting the vehicle speed change rate, the impact of slippage on vehicle speed is reduced, thereby improving the reliability of vehicle speed during rear-wheel steering. This improves the accuracy of the target vehicle's steering decisions and ultimately enhances the safety of the target vehicle performing rear-wheel steering under slippage conditions.

[0097] The rear-wheel steering control method provided in the embodiments of this application will be explained in detail below.

[0098] Figure 3 This is a flowchart illustrating a rear-wheel steering control method provided in an embodiment of this application. This method can be applied to the rear-wheel steering controller of a vehicle. See also... Figure 3 The method includes the following steps.

[0099] Step 301: Determine the slip factor based on the first speed difference of the target vehicle at multiple times and the wheel speed. The slip factor is used to represent the degree of slip of the target vehicle. The first speed difference is the change in vehicle speed at multiple times calculated based on the acceleration of the target vehicle.

[0100] The first speed difference is used to represent the actual change in the target vehicle's speed at multiple times. In other words, the first speed difference is the actual change in the target vehicle's speed at multiple times.

[0101] The slip factor is used to represent the degree of slippage of the target vehicle, that is, the severity of wheel slippage when the target vehicle is driving on the road. In the embodiments of this application, the slip factor is a number between 0 and 1. It should be understood that the larger the slip factor, the more severe the wheel slippage; the smaller the slip factor, the less severe the wheel slippage.

[0102] Since the acceleration of a target vehicle can accurately represent the actual rate of change of its speed, the actual speed change of the target vehicle at multiple moments can be accurately calculated based on its acceleration. Furthermore, since vehicle speed is generally calculated based on wheel speed, the deviation between wheel speeds and the actual speed calculated based on the first speed difference and the wheel speeds can be determined.

[0103] In this scenario, by considering the first speed difference of the target vehicle at multiple moments and the wheel speeds, the deviation between wheel speeds and the actual deviation between the calculated speed and the actual speed can be determined. Based on this, the degree of slippage of the target vehicle can be inferred, i.e., the slippage factor can be obtained. Subsequently, the rear wheels are controlled to steer based on this slippage factor, allowing the influence of slippage to be taken into account during rear wheel steering. Furthermore, control is made according to the degree of slippage of the target vehicle, enabling more accurate control of the rear wheels.

[0104] Optionally, the operation of step 301 may include the following steps (1)-(3).

[0105] (1) Determine the first reference factor based on the wheel speed of the target vehicle at multiple times.

[0106] The first reference factor refers to the degree of slippage of the target vehicle determined based on wheel speed, specifically based on the deviation between the wheel speeds of the target vehicle's wheels. In the embodiments of this application, the first reference factor is a number between 0 and 1.

[0107] The larger the first reference factor, the greater the deviation between the wheel speeds of the target vehicle, indicating that wheel slippage is likely and the degree of slippage is greater. The smaller the first reference factor, the smaller the deviation between the wheel speeds of the target vehicle, indicating that wheel slippage has not occurred or the degree of slippage is smaller.

[0108] It should be understood that when a target vehicle is driving normally, the wheel speeds of its wheels do not differ significantly. However, when the target vehicle is slipping, the deviation between wheel speeds will be larger depending on the number of wheels slipping. For example, there will be a significant difference in wheel speed between slipping and non-slipping wheels. Therefore, the deviation between wheel speeds can be determined first based on the wheel speeds, thereby determining whether the target vehicle is slipping and the severity of the slippage. For example, a larger deviation indicates more severe slippage.

[0109] Optionally, the wheel speeds of the four wheels of the target vehicle can be detected by wheel speed sensors installed on each of the four wheels.

[0110] Specifically, step (1) can be performed as follows: based on the wheel speed of the target vehicle at time i, determine the mean wheel speed of the target vehicle at time i; based on the wheel speed of the target vehicle at time i and the mean wheel speed, determine the wheel speed variance corresponding to time i; based on the wheel speed variance corresponding to the multiple times, determine the first reference factor.

[0111] Variance is a measure of the dispersion of a set of data. In this embodiment, by calculating the variance of the wheel speed at the i-th time moment, the dispersion of the wheel speeds of the four wheels can be determined; in other words, the deviation between the wheel speeds of the four wheels and the mean wheel speed can be determined.

[0112] In this case, it is equivalent to calculating the variance between the four wheels and the mean wheel speed for each of multiple moments. This allows for an accurate and convenient determination of the deviation between the wheel speed of the four wheels and the mean wheel speed, thereby accurately and conveniently obtaining the first reference factor, which is to accurately determine whether the target vehicle's wheels are slipping and the degree of slippage.

[0113] The operation of determining the first reference factor based on the wheel speed variance corresponding to the multiple time points can be as follows: obtain the maximum value of the wheel speed variance corresponding to the multiple time points to obtain the maximum variance; standardize the maximum variance to obtain the first reference factor.

[0114] The maximum value of the wheel speed variance at these multiple moments can represent the maximum deviation between the wheel speed and the mean wheel speed at these multiple moments. Since the subsequent goal is to avoid the impact of slippage on the rear wheel steering, if the average value of the wheel speed variance at these multiple moments is taken, the deviations at multiple moments will be averaged. This will make it impossible to accurately measure the wheel slippage condition of the target vehicle, and therefore impossible to accurately determine the degree of slippage. Consequently, the impact of slippage on the rear wheel steering cannot be fully considered in the subsequent steps.

[0115] In this case, by determining the maximum value of the wheel speed variance corresponding to these multiple moments, a representative deviation value can be obtained from these multiple moments. Subsequently, based on the maximum value, the degree of slippage that fully considers slippage can be determined, that is, a more accurate reference factor can be determined. Then, the impact of slippage on rear wheel steering can be fully considered.

[0116] Optionally, the operation of determining the first reference factor based on the wheel speed variance at the multiple time points can also be as follows: determining the variance change rate at the multiple time points based on the wheel speed variance at the multiple time points; and determining the first reference factor based on the wheel speed variance at the multiple time points and the variance change rate.

[0117] The rate of change of variance is used to represent how the wheel speed variance changes over time. Specifically, it indicates the magnitude of change in the wheel speed variance of a target vehicle over time. It should be understood that a larger rate of change of variance indicates a greater magnitude of change in the wheel speed variance of the target vehicle over time, meaning a larger deviation between the wheel speeds of the four wheels and the mean wheel speed. Conversely, a smaller rate of change of variance indicates a smaller magnitude of change in the wheel speed variance of the target vehicle over time, meaning a smaller deviation between the wheel speeds of the four wheels and the mean wheel speed.

[0118] In this case, by using the wheel speed variance and the rate of change of the variance at multiple times, the deviation between the wheel speed of the four wheels and the mean wheel speed can be measured in different dimensions. This allows us to know the deviation between the wheel speed of the four wheels and the mean wheel speed, as well as the magnitude of the deviation at multiple times. This enables us to determine a more accurate first reference factor, which in turn allows us to accurately predict the degree of slippage of the target vehicle.

[0119] Optionally, after determining the variance change rate corresponding to multiple time points, the variance change rate corresponding to these multiple time points can be filtered.

[0120] When the wheel speed sensor detects an inaccurate wheel speed, the variance it calculates will deviate significantly from other variances, resulting in a large deviation in the variance change rate. Such variance change rate is referred to as noise data among the variance change rates corresponding to multiple time points. This noise data interferes with the accurate calculation of the first reference factor, leading to errors in the calculation of the first reference factor. Therefore, the variance change rate corresponding to multiple time points can be filtered.

[0121] Thus, by filtering the variance change rate corresponding to these multiple time points, the interference of noise on the calculation of the first reference factor can be reduced, thereby obtaining a more accurate first reference factor.

[0122] Alternatively, the variance change rate at these multiple time points can be filtered using a second-order low-pass filter.

[0123] The operation of determining the first reference factor based on the variance of wheel speed at multiple times and the rate of change of the variance can be as follows: determine the trend of variance change based on the variance of wheel speed at multiple times; determine the average value of the rate of change of variance at multiple times to obtain the average rate of change of variance; and obtain the corresponding reference factor from the first correspondence based on the trend of variance change and the average rate of change of variance to determine the first reference factor.

[0124] The variance trend indicates the direction of change of the wheel speed variance at multiple time points, that is, whether the wheel speed variance at these multiple time points gradually increases or remains stable. The average variance rate of change measures the overall change of the wheel speed variance at these multiple time points, that is, it can measure the magnitude of the change of the wheel speed variance at these multiple time points over time.

[0125] Since the deviation between the wheel speed and the mean wheel speed of the target vehicle should increase when it transitions from zero slippage to slippage, the calculated wheel speed variance will also increase. Therefore, the variance change trend can be determined in this embodiment.

[0126] In this embodiment, based on the variance change trend and the average variance change rate, it can be determined whether the wheel speed variance at multiple moments is gradually increasing or remaining stable. It can also be determined the magnitude of the change in the wheel speed variance at multiple moments during the gradual increase. This indicates whether the deviation between the wheel speed of the four wheels and the average wheel speed is gradually increasing or remaining stable, and the magnitude of the gradual increase in deviation can be determined. Based on this, the degree of slippage of the target vehicle can be accurately determined, that is, a more accurate first reference factor can be obtained.

[0127] In the above embodiments, the first correspondence is the correspondence between the variance change trend, the variance change rate, and the reference factor. The first correspondence includes the variance change trend, multiple variance change rates, and multiple reference factors, and the first correspondence is obtained based on different wheel speed variances and wheel speed change rates.

[0128] In this embodiment, the first correspondence can be pre-defined by a technician. Specifically, this is achieved by acquiring multiple sets of wheel speed variances with different variance change trends and calculating the variance change rate for each set. For each set of variance data, the technician measures the reference factor corresponding to this set of data based on the variance change trend and the variance change rate. In this way, the reference factors corresponding to different variance change rates under different variance change trends can be obtained, which is to say, the first correspondence can be obtained.

[0129] For example, Table 1 below shows an example of the first correspondence mentioned above. Table 1 includes different variance trends, each with multiple different variance change rates, and each variance change rate corresponds to a specific reference factor. For instance, if the variance trend is gradually increasing and the average variance change rate is 0.5, the corresponding reference factor can be obtained from Table 1 as 0.7.

[0130] Table 1

[0131]

[0132] The embodiments of this application are merely illustrative examples of the first correspondence relationship described in Table 1 above, and do not constitute a limitation on the embodiments of this application.

[0133] It is worth noting that after determining the first reference factor, it is also possible to determine whether the first reference factor is greater than a preset factor threshold; if the first reference factor is greater than or equal to the preset factor threshold, then the second reference factor is determined.

[0134] The preset factor threshold can be set in advance, and the preset factor threshold can be set to a large value. In this embodiment, the preset factor threshold can be set based on the reference factor calculated when the wheel may slip.

[0135] In this situation, if the first reference factor is greater than or equal to a preset factor threshold, it indicates that the first reference factor is large, exceeding the reference factor calculated when the wheel may slip. This means that the deviation between the wheel speed of the four wheels and the average wheel speed is large, or that the deviation varies significantly at multiple moments, suggesting that the wheel may be slipping or is about to slip. In this case, it can be further determined whether the wheel is indeed slipping, which involves performing the following steps.

[0136] Optionally, if the first reference factor is less than a preset factor threshold, the rear wheels can be directly controlled to steer based on the current vehicle speed.

[0137] If the first reference factor is less than the preset factor threshold, it means that the first reference factor is small. It is smaller than the reference factor calculated when the wheel may slip. This means that the deviation between the wheel speed of the four wheels and the average wheel speed is small. Therefore, it can be concluded that the wheel is not slipping and the rear wheel steering can be performed normally without any other processing.

[0138] (2) Determine the second reference factor based on the first speed difference of the target vehicle at multiple times and the wheel speed.

[0139] The second reference factor refers to the degree of slippage of the target vehicle determined based on wheel speed and actual vehicle speed. Specifically, it is the degree of slippage inferred from the deviation between the calculated change in vehicle speed based on wheel speed and the actual change in vehicle speed. In the embodiments of this application, the second reference factor can be a number between 0 and 1.

[0140] In this case, by using the first speed difference and the wheel speed, the speed change calculated based on wheel speed and the speed change calculated based on acceleration can be determined. That is, the speed change in the rear wheel steering system at multiple moments (the speed change calculated based on wheel speed) and the actual speed change can be known. Based on this, the deviation between the speed change in the rear wheel steering system and the actual speed change can be known, and the severity of the target vehicle's slippage can be determined based on this deviation.

[0141] It should be understood that the greater the deviation between the change in vehicle speed in the rear-wheel steering system and the actual change in vehicle speed, the greater the deviation between the change in vehicle speed calculated based on wheel speed and the actual change in vehicle speed. This indicates that the target vehicle is slipping more severely. There is also a situation where the wheel speeds of the four wheels are the same, but all of them slip, which also indicates that the target vehicle is slipping more severely, thus the second reference factor is larger. Conversely, the smaller the deviation, the greater the deviation, indicating that the target vehicle is not slipping or is only slipping slightly, that is, the smaller the second reference factor is.

[0142] Thus, by comparing the change in vehicle speed calculated based on wheel speed with the actual change in vehicle speed, it is possible to accurately determine whether the target vehicle is slipping and the degree of slippage, thereby accurately determining the second reference factor.

[0143] In this embodiment of the application, the first speed difference can be obtained by integrating the acceleration of the target vehicle at the first moment among the multiple moments.

[0144] Optionally, step (2) can be performed as follows: for any wheel of the target vehicle, based on the wheel speed of the wheel at multiple times, determine the wheel speed change of the wheel at multiple times; determine the average value between the wheel speed changes of the target vehicle's wheels to obtain the third vehicle speed difference; and determine the second reference factor based on the difference between the first vehicle speed difference and the third vehicle speed difference.

[0145] Optionally, for any wheel of the target vehicle, the change in wheel speed at multiple moments can be the difference between the wheel speed at the first moment and the wheel speed at the last moment in those multiple moments, that is, the change in wheel speed between the initial moment and the final moment in the whole process.

[0146] Since vehicle speed can be the average of the wheel speeds of all four wheels, calculating the average of the changes in wheel speeds at the target vehicle's wheels is equivalent to determining the changes in vehicle speed based on wheel speeds at those multiple moments. Therefore, a second reference factor can be determined subsequently based on the difference between the first and third vehicle speed differences.

[0147] The operation of determining the second reference factor based on the difference between the first vehicle speed difference and the third vehicle speed difference can be as follows: based on the difference between the first vehicle speed difference and the third vehicle speed difference, obtain the corresponding reference factor from the second correspondence relationship and determine it as the second reference factor.

[0148] The second correspondence is the correspondence between the deviation of vehicle speed change and the reference factor. The second correspondence includes the deviation of multiple vehicle speed changes and multiple reference factors. Each deviation of multiple vehicle speed changes corresponds to a reference factor.

[0149] In this embodiment, the reference factor in the second correspondence can be obtained by standardizing the deviation of the vehicle speed change, that is, by standardizing the difference between the first vehicle speed difference and the third vehicle speed difference. Of course, it can also be pre-calibrated by a technician. For example, the larger the difference between the first vehicle speed difference and the third vehicle speed difference, the larger the deviation between the vehicle speed change in the rear wheel steering system and the actual vehicle speed change, indicating more severe slippage. In this case, the corresponding reference factor can be set to a larger value.

[0150] It is worth noting that, in this embodiment of the application, the above step (2) can be performed in multiple periods to obtain the second reference factor corresponding to multiple periods; then the average value of the second reference factor corresponding to multiple periods is determined as the final second reference factor.

[0151] It should be understood that each of the multiple cycles includes multiple moments.

[0152] In this case, it is equivalent to performing the above step (2) in each of the multiple cycles to obtain the second reference factor corresponding to each cycle, and then combining the second reference factors corresponding to multiple cycles to determine the final second reference factor.

[0153] Thus, by integrating the second reference factors corresponding to multiple cycles, which is equivalent to integrating the second reference factors determined by working conditions over a long period of time, a more accurate second reference factor can be determined.

[0154] (3) Determine the slippage factor based on the first reference factor and the second reference factor.

[0155] The first reference factor refers to the degree of skidding of the target vehicle determined based on wheel speed, while the second reference factor is determined based on both wheel speed and actual vehicle speed. Therefore, the first and second reference factors are the degree of skidding of the target vehicle determined using different methods.

[0156] In this case, by determining the degree of slippage of the target vehicle in different ways, the phenomenon of wheel slippage can be measured from different dimensions, and a more accurate slippage factor can be determined based on the first reference factor and the second reference factor.

[0157] Optionally, step (3) can be performed by determining the maximum value between the first reference factor and the second reference factor as the slippage factor.

[0158] Since both the first and second reference factors essentially represent the degree of slippage of the target vehicle, they are calculated in different ways. The larger of the first and second reference factors indicates a higher predicted degree of slippage for the target vehicle. Therefore, to ensure driving safety and to fully consider the impact of slippage on rear wheel steering, the degree of slippage can be set to be larger. Thus, the larger of the first and second reference factors can be used as the slippage factor.

[0159] Optionally, the target vehicle may also be equipped with an ESP (Electronic Stability Program) system. Generally, the ESP system may include an ABS (anti-lock braking system), a TCS (Traction Control System), or a VDC (vehicle running dynamic control system).

[0160] In this embodiment, when the ABS or TCS system of the target vehicle is activated, if the instrument panel of the target vehicle displays four-wheel drive slippage, the slippage factor can be set to a first value; if the instrument panel of the target vehicle displays slippage on a single axle, the slippage factor can be set to a second value. When the VDC system of the target vehicle is activated, the slippage factor can be set to the second value.

[0161] The first value is greater than the second value. Since the first value corresponds to a four-wheel drive slippage condition, the slippage of the target vehicle is relatively severe. Therefore, under this condition, the slippage factor can be set to the first value. In this embodiment, the first value can be 1. The second value corresponds to single-axle slippage, meaning that two wheels on the target vehicle may be slipping. Therefore, under this condition, the slippage factor can be set to the second value. In this embodiment, the second value can be 0.5.

[0162] In this scenario, it's equivalent to using the target vehicle's ESP system to determine if the target vehicle is skidding. Modern vehicles offer various driver assistance systems, many of which can detect skidding. Therefore, by utilizing these driver assistance systems, it's possible to more accurately detect whether the target vehicle is skidding, and thus determine a more precise skid factor.

[0163] Step 302: Based on the slip factor, adjust the rate of change of the target vehicle's speed.

[0164] The rate of change of vehicle speed is used to indicate the magnitude of change in the speed of a target vehicle at different times; that is, how much the speed of the target vehicle changes at different times. It should be understood that the larger the rate of change of vehicle speed, the greater the magnitude of change in the speed of the target vehicle at different times; the smaller the rate of change of vehicle speed, the smaller the magnitude of change in the speed of the target vehicle at different times.

[0165] When the target vehicle slips, its wheels rotate rapidly, increasing the rate of change of speed. This means the vehicle's speed varies significantly at different times, resulting in a large change in the rear wheel steering angle. Consequently, the target vehicle cannot steer at the correct angle. However, when the target vehicle is driving normally, its speed does not change drastically, so the rear wheel steering angle does not change much either. Therefore, after determining this slip factor, the rate of change of speed of the target vehicle can be adjusted based on it.

[0166] In this case, by adjusting the rate of change of the target vehicle's speed based on the slip factor, the range of speed change of the target vehicle at multiple moments can be adjusted, thereby reducing the impact of slip on speed and consequently reducing the impact of speed on rear wheel steering, enabling accurate steering of the rear wheels in the future.

[0167] Optionally, step 302 can be performed by subtracting the slippage factor from the target threshold to obtain the target vehicle speed change rate.

[0168] The target vehicle speed change rate is the adjusted vehicle speed change rate.

[0169] The target threshold can be preset. Since the slippage factor is a number between 0 and 1, the target threshold can be set to 1 in this embodiment.

[0170] In this case, by subtracting the slippage factor from the target threshold, we can obtain the weight of the speed change (speed change rate). Then, based on this weight, we can determine the speed change when slipping. Thus, by setting an appropriate weight for the speed change, we can reduce the speed change and thereby reduce the impact of slipping on the speed.

[0171] Step 303: Based on the target vehicle speed change rate, the first vehicle speed, and the second vehicle speed, control the target vehicle to perform rear-wheel steering. The first vehicle speed is the vehicle speed currently received by the rear-wheel steering system based on the wheel speed, the second vehicle speed is the vehicle speed currently being used by the rear-wheel steering system, and the target vehicle speed change rate is the adjusted vehicle speed change rate.

[0172] The difference between the first and second vehicle speeds refers to the difference between the vehicle speed currently received by the rear-wheel steering system and the speed being used, which is the original speed change in the rear-wheel steering system. Furthermore, the target speed change rate is the adjusted speed change rate. Therefore, based on the target speed change rate, the first speed, and the second speed, the adjusted speed change of the rear-wheel steering system can be determined.

[0173] In this case, by adjusting the speed change that would normally be added to the rear-wheel steering system based on the target speed change rate, the first speed, and the second speed, the speed change that would normally be added can be reduced. This reduces the magnitude of speed change at different times, thus improving the reliability of the speed. Subsequently, the rear-wheel steering system can calculate the correct rear-wheel steering based on the adjusted speed, thereby controlling the rear wheels to steer accurately.

[0174] Optionally, step 303 can be performed as follows: subtract the second vehicle speed from the first vehicle speed to obtain the second vehicle speed difference; multiply the target vehicle speed change rate by the second vehicle speed difference to obtain the fourth vehicle speed difference; add the second vehicle speed to the fourth vehicle speed difference to obtain the target vehicle speed; and control the target vehicle to perform rear wheel steering based on the target vehicle speed.

[0175] The second speed difference is the amount of speed change that would normally be added to the rear wheel steering system.

[0176] The fourth speed difference is the amount of speed change that needs to be added to the rear wheel steering system after adjustment.

[0177] The target speed refers to the speed at which the adjusted rear-wheel steering system calculates the rear wheel steering angle.

[0178] The above operation process is as follows: First, based on the first and second vehicle speeds, the amount of speed change that the rear-wheel steering system would normally need to increase is calculated. From a periodic perspective, there is a speed change between the vehicle speed used by the rear-wheel steering system in the previous period and the vehicle speed calculated based on wheel speed in the current period. This is the amount of speed change that the rear-wheel steering system would normally need to increase in the current period. Then, based on the target speed change rate, the amount of speed change that the rear-wheel steering system would normally need to increase is adjusted, reducing the amount of speed change that the rear-wheel steering system would normally need to increase, thereby narrowing the speed difference in the rear-wheel steering system between adjacent periods. Then, based on the adjusted speed change, the target speed is determined, which is the speed at which the rear-wheel steering system is used to calculate the rear wheel steering angle in the current period. Subsequently, the target vehicle can be controlled to perform rear-wheel steering based on the target speed.

[0179] In this case, the target speed change rate can be used to adjust the amount of speed change that would normally be added to the rear wheel steering system. This means that the influence of slippage on the speed is taken into account, which is equivalent to adjusting the speed based on the target speed change rate. As a result, the rear wheels can be steered more accurately based on the adjusted speed.

[0180] In the embodiments of this application, the above operation is also achieved by the following formula (1).

[0181] V rws =V1 rws +(1-K)×(V-V1 rws (1)

[0182] Among them, V rws For the target vehicle speed, V1 rws V is the second vehicle speed, K is the first vehicle speed, and 1-K is the rate of change of the target vehicle speed.

[0183] From the above formula (1), we can obtain that when the wheels are not slipping, i.e., the slip factor is 0, the rate of change of the target vehicle speed is 1, V rws =V, in this condition, that is, no adjustment is made to the vehicle speed change required by the rear wheel steering system; the rear wheel steering angle is directly calculated using the vehicle speed calculated based on wheel speed. When the wheels slip severely, assuming the slippage is very high, for example, a slippage factor of 1, the target vehicle speed change rate is 0, then V rws =V1 rws In other words, the adjustment ensures that the vehicle speed input to the rear wheel steering system remains unchanged.

[0184] Because a greater rate of change in vehicle speed results in a greater rate of change in the calculated rear wheel steering angle, meaning the rear wheel steering angle will continuously change, a rapid rate of change in vehicle speed during severe slippage will cause the rear wheel steering angle to change continuously. In this embodiment, when the wheels slip, by limiting the rate of change in vehicle speed, the change in the rear wheel steering angle can be suppressed. This helps to minimize incorrect changes in the rear wheel steering angle during wheel slippage, thereby enabling proper control of the rear wheel steering.

[0185] The operation of controlling the rear wheels of the target vehicle to steer based on the target vehicle speed can be as follows: obtaining the steering wheel angle of the target vehicle; determining the target steering angle based on the steering wheel angle and the target vehicle speed; and controlling the rear wheels of the target vehicle to rotate at the target steering angle to achieve rear wheel steering.

[0186] In this situation, a more accurate rear wheel steering angle can be determined based on the adjusted target vehicle speed, that is, the correct target steering angle can be determined, so that the rear wheels can be controlled to steer correctly.

[0187] In this embodiment, when performing rear-wheel steering, the rear-wheel steering controller first determines the slip factor based on the first speed difference of the target vehicle at multiple moments and the wheel speed, that is, it determines the degree of slippage of the target vehicle at that moment. Then, based on the slip factor, it adjusts the rate of change of the target vehicle's speed, that is, it adjusts the amount of speed change of the target vehicle when slipping. For example, if the slip factor is equal to 1, then the rate of change of the target speed can be adjusted to 0, that is, the amount of speed change of the target vehicle when slipping is controlled to be 0. In other words, when the degree of slippage of the target vehicle is very large, the speed is controlled to remain unchanged. Then, based on the target speed rate of change, the first speed, and the second speed, the target vehicle is controlled to perform rear-wheel steering. This allows the impact of slippage to be taken into account during rear-wheel steering, and by adjusting the rate of change of speed, the impact of slippage on the speed can be reduced, thereby improving the reliability of the speed during rear-wheel steering. This improves the accuracy of the target vehicle's steering decisions, and thus improves the safety of the target vehicle performing rear-wheel steering under slippage conditions.

[0188] Figure 4 This is a schematic diagram of a rear-wheel steering control device provided in an embodiment of this application. The rear-wheel steering control device can be implemented as part or all of a vehicle by software, hardware, or a combination of both. The vehicle can be described below. Figure 5 The vehicle shown. See also Figure 4 The device includes: a determining module 401, an adjusting module 402, and a controlling module 403.

[0189] The determination module 401 is used to determine a slip factor based on the first speed difference of the target vehicle at multiple times and the wheel speed. The slip factor is used to represent the degree of slip of the target vehicle. The first speed difference is the change in vehicle speed at multiple times calculated based on the acceleration of the target vehicle.

[0190] Adjustment module 402 is used to adjust the rate of change of the target vehicle's speed based on the slip factor;

[0191] The control module 403 is used to control the target vehicle to perform rear-wheel steering based on the target vehicle speed change rate, the first vehicle speed, and the second vehicle speed. The first vehicle speed is the vehicle speed currently received by the rear-wheel steering system based on the wheel speed, the second vehicle speed is the vehicle speed currently being used by the rear-wheel steering system, and the target vehicle speed change rate is the adjusted vehicle speed change rate.

[0192] Optionally, the determining module 401 is used for:

[0193] Based on the wheel speed of the target vehicle at multiple times, a first reference factor is determined. The first reference factor refers to the degree of slippage of the target vehicle determined based on the wheel speed.

[0194] Based on the first speed difference of the target vehicle at multiple times and the wheel speed, a second reference factor is determined. The second reference factor refers to the degree of slippage of the target vehicle determined based on the wheel speed and the actual vehicle speed.

[0195] The slippage factor is determined based on the first reference factor and the second reference factor.

[0196] Optionally, the determining module 401 is used for:

[0197] Based on the wheel speed of the target vehicle at time i, determine the average wheel speed of the target vehicle at time i.

[0198] Based on the wheel speed and mean wheel speed at time i, determine the wheel speed variance at time i.

[0199] The first reference factor is determined based on the variance of wheel speed at multiple time points.

[0200] Optionally, the determining module 401 is used for:

[0201] Based on the wheel speed variance at multiple time points, determine the variance change rate at multiple time points;

[0202] The first reference factor is determined based on the wheel speed variance and variance change rate at multiple time points.

[0203] Optionally, the determining module 401 is used for:

[0204] For any wheel of the target vehicle, determine the change in wheel speed at multiple times based on the wheel speed at multiple times.

[0205] The average value of the wheel speed changes of the target vehicle at multiple times is determined to obtain the third speed difference value, which is the speed change of the target vehicle based on the wheel speed at those multiple times.

[0206] The second reference factor is determined based on the difference between the first vehicle speed difference and the third vehicle speed difference.

[0207] Optionally, the determining module 401 is used for:

[0208] The maximum value between the first reference factor and the second reference factor is determined as the slippage factor.

[0209] Optionally, the adjustment module 402 is used for:

[0210] Subtract the slippage factor from the target threshold to obtain the target vehicle speed change rate.

[0211] Optionally, the control module 403 is used for:

[0212] Subtract the second speed from the first speed to get the second speed difference;

[0213] Multiply the target vehicle speed change rate by the second vehicle speed difference to obtain the fourth vehicle speed difference;

[0214] Add the difference between the second and fourth vehicle speeds to obtain the target vehicle speed.

[0215] Based on the target vehicle speed, control the target vehicle to steer the rear wheels.

[0216] In this embodiment, when performing rear-wheel steering, a slip factor is first determined based on the first speed difference of the target vehicle at multiple moments and the wheel speed, that is, the degree of slippage of the target vehicle at that moment is determined. Then, based on the slip factor, the rate of change of the target vehicle's speed is adjusted, that is, the amount of speed change of the target vehicle during slippage is adjusted. For example, if the slip factor is equal to 1, then the rate of change of the target speed can be adjusted to 0, that is, the amount of speed change of the target vehicle during slippage is controlled to be 0. In other words, when the degree of slippage of the target vehicle is very large, the speed is controlled to remain unchanged. Then, based on the target speed rate of change, the first speed, and the second speed, the target vehicle is controlled to perform rear-wheel steering. This allows the impact of slippage to be taken into account during rear-wheel steering, and by adjusting the rate of change of speed, the impact of slippage on the speed can be reduced, thereby improving the reliability of the speed during rear-wheel steering. This improves the accuracy of the target vehicle's steering decisions, and thus improves the safety of the target vehicle performing rear-wheel steering under slippage conditions.

[0217] It should be noted that the rear wheel steering control device provided in the above embodiments controls the rear wheel steering during the rear wheel steering process. This is only an example of the division of the above functional modules. 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.

[0218] The functional units and modules in the above embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of the embodiments of this application.

[0219] The rear wheel steering control device and the rear wheel steering control method provided in the above embodiments belong to the same concept. The specific working process and technical effects of the units and modules in the above embodiments can be found in the method embodiments section, and will not be repeated here.

[0220] Figure 5 This is a schematic diagram of the structure of a vehicle provided in an embodiment of this application.

[0221] For example, such as Figure 5 As shown, the vehicle 500 includes a memory 51 and a processor 50, wherein the memory 51 stores executable program code 52, and the processor 50 is used to call and execute the executable program code 52 to perform the aforementioned rear wheel steering control method.

[0222] This embodiment can divide the vehicle into functional modules according to the above method example. For example, each function can be assigned to a separate 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.

[0223] When each functional module is divided according to its corresponding function, the vehicle may include: a determination module, an adjustment module, and a control module. It should be noted that all relevant content regarding the steps involved in the above method embodiments can be referenced from the functional descriptions of the corresponding functional modules, and will not be repeated here.

[0224] The vehicle provided in this embodiment is used to execute the above-described rear-wheel steering control method, and thus can achieve the same effect as the above-described implementation method.

[0225] 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 actions. The storage module is used to support the vehicle in executing corresponding program code and data.

[0226] 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 a microprocessor, etc., and the storage module may be a memory.

[0227] This embodiment also provides a computer-readable storage medium storing computer program code. When the computer program code is run on a computer, the computer executes the aforementioned related method steps to implement the aforementioned rear wheel steering control method in the above embodiment.

[0228] This embodiment also provides a computer program product that, when run on a computer, causes the computer to perform the aforementioned related steps to implement the rear wheel steering control method described in the above embodiment.

[0229] In this embodiment, the vehicle, computer-readable storage medium, computer program product, or chip are all used to execute the method described above. Therefore, the beneficial effects that can be achieved can be referred to the beneficial effects of the method described above, and will not be repeated here.

[0230] 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.

[0231] 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 illustrative; for instance, the division of modules or units is merely 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.

[0232] 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 rear-wheel steering control method, characterized in that, The method includes: Based on the first speed difference of the target vehicle at multiple moments and the wheel speed, a slip factor is determined. The slip factor is used to represent the degree of slippage of the target vehicle. The first speed difference is the change in vehicle speed at multiple moments calculated based on the acceleration of the target vehicle. Based on the slip factor, adjust the rate of change of the target vehicle's speed; Based on the target vehicle speed change rate, the first vehicle speed, and the second vehicle speed, the target vehicle is controlled to perform rear-wheel steering. The first vehicle speed is the vehicle speed currently received by the rear-wheel steering system based on the wheel speed, and the second vehicle speed is the vehicle speed currently being used by the rear-wheel steering system. The target vehicle speed change rate is the adjusted vehicle speed change rate. The determination of the slippage factor based on the first speed difference of the target vehicle at multiple moments and the wheel speed includes: Based on the wheel speed of the target vehicle at the plurality of times, a first reference factor is determined, wherein the first reference factor refers to the degree of slippage of the target vehicle determined based on the wheel speed. Based on the first speed difference of the target vehicle at the multiple times and the wheel speed, a second reference factor is determined. The second reference factor refers to the degree of slippage of the target vehicle determined based on the wheel speed and the actual vehicle speed. The slippage factor is determined based on the first reference factor and the second reference factor.

2. The method as described in claim 1, characterized in that, Determining the first reference factor based on the wheel speed of the target vehicle at the multiple times includes: Based on the wheel speed of the target vehicle at time i, determine the average wheel speed of the target vehicle at time i. Based on the wheel speed at the i-th time moment and the mean wheel speed, determine the wheel speed variance corresponding to the i-th time moment; The first reference factor is determined based on the variance of wheel speed at the multiple time points.

3. The method as described in claim 2, characterized in that, Determining the first reference factor based on the wheel speed variance corresponding to the multiple time points includes: Based on the wheel speed variance corresponding to the multiple time points, determine the variance change rate corresponding to the multiple time points; The first reference factor is determined based on the wheel speed variance and the rate of change of the variance at the multiple time points.

4. The method as described in claim 1, characterized in that, The determination of the second reference factor based on the first speed difference of the target vehicle at multiple times and the wheel speed includes: For any wheel of the target vehicle, the change in wheel speed at the multiple times is determined based on the wheel speed at the multiple times. The average value of the wheel speed changes of the target vehicle at multiple times is determined to obtain a third vehicle speed difference value, which is the vehicle speed change of the target vehicle at those multiple times based on the wheel speed. The second reference factor is determined based on the difference between the first vehicle speed difference and the third vehicle speed difference.

5. The method as described in claim 1, characterized in that, Determining the slippage factor based on the first reference factor and the second reference factor includes: The maximum value between the first reference factor and the second reference factor is determined as the slippage factor.

6. The method as described in claim 1, characterized in that, The step of adjusting the rate of change of the target vehicle's speed based on the slippage factor includes: Subtracting the slippage factor from the target threshold yields the target vehicle speed change rate.

7. The method as described in claim 1, characterized in that, The step of controlling the target vehicle to perform rear-wheel steering based on the target vehicle speed change rate, the first vehicle speed, and the second vehicle speed includes: Subtract the second vehicle speed from the first vehicle speed to obtain the second vehicle speed difference; Multiply the target vehicle speed change rate by the second vehicle speed difference to obtain the fourth vehicle speed difference; Add the second vehicle speed to the fourth vehicle speed difference to obtain the target vehicle speed; Based on the target vehicle speed, control the target vehicle to perform rear-wheel steering.

8. A rear-wheel steering control device, characterized in that, The device includes: The determination module is used to determine a slip factor based on the first speed difference of the target vehicle at multiple times and the wheel speed. The slip factor is used to represent the degree of slip of the target vehicle. The first speed difference is the change in vehicle speed at the multiple times calculated based on the acceleration of the target vehicle. An adjustment module is used to adjust the rate of change of the target vehicle's speed based on the slip factor; The control module is used to control the target vehicle to perform rear-wheel steering based on the target vehicle speed change rate, a first vehicle speed, and a second vehicle speed. The first vehicle speed is the vehicle speed currently received by the rear-wheel steering system based on the wheel speed, the second vehicle speed is the vehicle speed currently being used by the rear-wheel steering system, and the target vehicle speed change rate is the adjusted vehicle speed change rate. The determining module is specifically used for: determining a first reference factor based on the wheel speed of the target vehicle at the plurality of times, wherein the first reference factor refers to the degree of slippage of the target vehicle determined based on the wheel speed; determining a second reference factor based on the first vehicle speed difference and the wheel speed of the target vehicle at the plurality of times, wherein the second reference factor refers to the degree of slippage of the target vehicle determined based on the wheel speed and the actual vehicle speed; and determining the slippage factor based on the first reference factor and the second reference factor.

9. 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 7.

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