Rear wheel steering control method and device and vehicle

Abstract

The invention discloses a rear wheel steering control method and device and a vehicle, and belongs to the technical field of vehicles. Comprising the steps that a slip factor is determined based on the first vehicle speed difference value of a target vehicle at multiple moments and the wheel speed of wheels, and the first vehicle speed difference value is the vehicle speed variable quantity of the multiple moments obtained through calculation based on the acceleration of the target vehicle; adjusting the speed change rate of the target vehicle based on the slip factor; and based on the target vehicle speed change rate, the first vehicle speed and the second vehicle speed, the target vehicle is controlled to conduct rear wheel steering, the first vehicle speed is the vehicle speed currently received by the rear wheel steering system and determined based on the wheel speed, and the second vehicle speed is the vehicle speed currently used by the rear wheel steering system. Thus, the influence of slipping can be considered during steering of the rear wheels, and the influence of slipping on the vehicle speed is reduced by adjusting the vehicle speed change rate, so that the accuracy of steering decision making of the target vehicle can be improved, and then the safety of rear wheel steering of the target vehicle under the slipping working condition is improved.

Description

Technical Field

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

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

[0003] However, due to the different slip coefficients of different roads, the vehicle may slip when driving on some roads. Generally, the rear wheel controller relies on the vehicle speed to calculate the rear wheel steering angle. Since the vehicle speed changes rapidly during slipping, the rear wheel steering angle will also change rapidly. Then the rear wheel controller cannot calculate the correct rear wheel steering angle, which will cause errors in rear wheel steering decisions, making the vehicle unable to turn normally. Summary of the invention

[0004] The present application provides a rear-wheel steering control method, device, vehicle and storage medium, which can adjust the speed change rate of the target vehicle based on the slip factor when the target vehicle slips, so that the speed change amount of the target vehicle is adjusted, and then perform rear-wheel steering based on the adjusted speed change amount, so that the impact of slip can be considered when steering the rear wheels, and the impact of slip on the vehicle speed can be reduced, thereby improving the safety of the target vehicle performing rear-wheel steering under slip conditions. The technical solution includes the following contents.

[0005] In a first aspect, a rear wheel steering control method is provided, the method comprising:

[0006] Determine a slip factor based on first vehicle speed differences of the target vehicle at multiple times and wheel speeds, wherein the slip factor is used to indicate the slip degree of the target vehicle, and the first vehicle speed difference is a vehicle speed change at the multiple times calculated based on the acceleration of the target vehicle;

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

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

[0009] In the present application, when performing rear-wheel steering, the slip factor is first determined based on the first speed difference of the target vehicle at multiple moments and the wheel speed of the wheel, that is, the slip degree of the target vehicle at this time is determined. Then, based on the slip factor, the speed change rate of the target vehicle is adjusted, that is, the speed change amount of the target vehicle when slipping is adjusted. For example, if the slip factor is equal to 1, the target speed change rate can be adjusted to 0, that is, the speed change amount of the target vehicle when slipping is controlled to be 0. In other words, when the slip degree of the target vehicle is very large, the speed is controlled not to change. Then, based on the target speed change rate, the first speed and the second speed, the target vehicle is controlled to perform rear-wheel steering, so that the influence of slipping can be considered when steering the rear wheels, and the influence of slipping on the vehicle speed can be reduced by adjusting the speed change rate, so that the situation that the rear wheel angle changes continuously can be avoided, thereby improving the accuracy of the steering decision of the target vehicle, and then improving the safety of the target vehicle performing rear-wheel steering under slip conditions.

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

[0011] Determining a first reference factor based on the wheel speeds of the target vehicle at the plurality of moments, the first reference factor being a degree of slip of the target vehicle determined based on the wheel speeds;

[0012] Determining a second reference factor based on the first vehicle speed difference and the wheel speed of the target vehicle at the plurality of moments, wherein the second reference factor refers to a slip degree of the target vehicle determined based on the wheel speed and the true vehicle speed;

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

[0014] In the present application, the first reference factor and the second reference factor are the slip degree of the target vehicle determined based on different methods. In this way, by determining the slip degree of the target vehicle in different ways, the wheel slip phenomenon can be measured in different dimensions, so that a more accurate slip factor can be determined based on the first reference factor and the second reference factor.

[0015] Optionally, determining the first reference factor based on the wheel speeds of the target vehicle at the multiple moments includes:

[0016] Based on the wheel speeds of the wheels of the target vehicle at the i-th moment, determining the mean wheel speed of the target vehicle at the i-th moment;

[0017] Determining the wheel speed variance corresponding to the i-th moment based on the wheel speed at the i-th moment and the wheel speed mean;

[0018] The first reference factor is determined based on the wheel speed variances corresponding to the multiple moments.

[0019] In the present application, by calculating the wheel speed variance corresponding to the ith moment, the discrete degree of the wheel speed 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 moments. In this way, the deviation between the wheel speed of the four wheels and the mean wheel speed can be accurately and conveniently determined, and then the first reference factor can be accurately and conveniently obtained, that is, whether the wheels of the target vehicle are slipping and the degree of slipping can be accurately judged.

[0020] Optionally, determining the first reference factor based on the wheel speed variances corresponding to the multiple moments includes:

[0021] Determining variance change rates corresponding to the multiple moments based on the wheel speed variances corresponding to the multiple moments;

[0022] The first reference factor is determined based on the wheel speed variances at the plurality of moments and the variance change rate.

[0023] In the present application, the deviations between the wheel speeds of the four wheels and the mean wheel speeds can be measured in different dimensions based on the wheel speed variances at multiple moments and the rate of change of the variances, so that the deviations between the wheel speeds of the four wheels and the mean wheel speeds and the magnitude of the deviation changes at multiple moments can be known, thereby determining a more accurate first reference factor, that is, the degree of slippage of the target vehicle can be accurately estimated.

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

[0025] For any wheel of the target vehicle, determining a change in wheel speed of the wheel at the multiple moments based on the wheel speed of the wheel at the multiple moments;

[0026] Determine an average value of wheel speed changes of the target vehicle's wheels at multiple moments to obtain a third vehicle speed difference, where the third vehicle speed difference is a vehicle speed change of the target vehicle determined based on the wheel speed at the multiple moments;

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

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

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

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

[0031] In the present application, since the first reference factor and the second reference factor both represent the degree of slippage of the target vehicle, but are calculated in different ways. The larger of the first reference factor and the second reference factor indicates that the estimated degree of slippage of the target vehicle is larger, then in order to ensure driving safety and to fully consider the impact of slippage on rear-wheel steering in the future, the slippage degree can be set to be larger. In this way, by obtaining the larger one of the first reference factor and the second reference factor as the slippage factor, the impact of slippage can be fully considered in the rear-wheel steering, thereby ensuring the safety of the subsequent rear-wheel steering.

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

[0033] The target vehicle speed change rate is obtained by subtracting the slip factor from the target threshold.

[0034] In the present application, by subtracting the slip factor from the target threshold, it is equivalent to obtaining the weight of the vehicle speed change (vehicle speed change rate), and then the vehicle speed change during slip can be determined based on this weight. In this way, by setting a corresponding weight for the vehicle speed change, the vehicle speed change can be reduced, thereby reducing the impact of slip on the vehicle 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] Subtracting the second vehicle speed from the first vehicle speed to obtain a second vehicle speed difference;

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

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

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

[0040] In the present application, the vehicle speed change amount that is originally to be increased in the rear-wheel steering system can be adjusted through the target vehicle speed change rate. That is, the influence of the slip factor on the vehicle speed is taken into account, which is equivalent to adjusting the vehicle speed based on the target vehicle speed change rate, so that the rear wheels can be steered more accurately according to the adjusted vehicle speed.

[0041] In a second aspect, a rear wheel steering control device is provided, the device comprising:

[0042] a determination module, configured to determine a slip factor based on first vehicle speed differences of a target vehicle at multiple times and wheel speeds of the wheels, wherein the slip factor is used to indicate a slip degree of the target vehicle, and the first vehicle speed difference is a vehicle speed change at the multiple times calculated based on the acceleration of the target vehicle;

[0043] An adjustment module, configured to adjust a speed change rate of the target vehicle based on the slip factor;

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

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

[0046] Determining a first reference factor based on the wheel speeds of the target vehicle at the plurality of moments, the first reference factor being a degree of slip of the target vehicle determined based on the wheel speeds;

[0047] Determining a second reference factor based on the first vehicle speed difference and the wheel speed of the target vehicle at the plurality of moments, wherein the second reference factor refers to a slip degree of the target vehicle determined based on the wheel speed and the true vehicle speed;

[0048] The slip 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 speeds of the wheels of the target vehicle at the i-th moment, determining the mean wheel speed of the target vehicle at the i-th moment;

[0051] Determining the wheel speed variance corresponding to the i-th moment based on the wheel speed at the i-th moment and the wheel speed mean;

[0052] The first reference factor is determined based on the wheel speed variances corresponding to the multiple moments.

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

[0054] Determining variance change rates corresponding to the multiple moments based on the wheel speed variances corresponding to the multiple moments;

[0055] The first reference factor is determined based on the wheel speed variances at the plurality of moments and the variance change rate.

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

[0057] For any wheel of the target vehicle, determining a change in wheel speed of the wheel at the multiple moments based on the wheel speed of the wheel at the multiple moments;

[0058] Determine an average value of wheel speed changes of the target vehicle's wheels at multiple moments to obtain a third vehicle speed difference, where the third vehicle speed difference is a vehicle speed change of the target vehicle determined based on the wheel speed at the multiple moments;

[0059] The second reference factor is determined based on a 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 of the first reference factor and the second reference factor is determined as the slip factor.

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

[0063] The target vehicle speed change rate is obtained by subtracting the slip factor from the target threshold.

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

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

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

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

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

[0069] In a third aspect, a vehicle is provided, the vehicle comprising:

[0070] A memory for storing executable program codes;

[0071] The processor is used to call and run the executable program code from the memory so that the vehicle executes the above-mentioned rear wheel steering control method.

[0072] In a fourth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the above-mentioned rear-wheel steering control method is implemented.

[0073] In a fifth aspect, a computer program product comprising instructions is provided, which, when executed on a computer, enables the computer to execute the steps of the above-mentioned rear-wheel steering control method.

[0074] It can be understood that the beneficial effects of the second, third, fourth and fifth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

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

[0077] Figure 2 is a scene schematic diagram of a rear wheel steering control method provided by an embodiment of the present application;

[0078] Figure 3 is a flow chart of a rear wheel steering control method provided by an embodiment of the present application;

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

[0080] Figure 5 It is a structural schematic diagram of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0081] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0082] It should be understood that the "multiple" mentioned in this application refers to two or more. In the description of this application, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in order to facilitate the clear description of the technical solution of this application, the words "first" and "second" are used to distinguish between the same items or similar items with basically the same functions and effects. Those skilled in the art can understand that the words "first" and "second" do not limit the quantity and execution order, and the words "first" and "second" do not limit them to be different.

[0083] Before describing the rear-wheel steering control method provided in the embodiment of the present application, the implementation environment involved in the embodiment of the present application is first described.

[0084] For example, Figure 1 is a schematic diagram of an implementation environment of a rear wheel steering control method provided in an embodiment of the present application, see Figure 1 , Figure 1 The invention comprises a vehicle 101. The vehicle 101 may be equipped with a rear wheel steering system 102.

[0085] Vehicle 101 is a vehicle equipped with the above-mentioned rear-wheel steering system 102. For example, vehicle 101 can be a front-wheel drive vehicle (Front-Wheel Drive, FWD), a rear-wheel drive vehicle (Rear-Wheel Drive, RWD), or a four-wheel drive vehicle (All-Wheel Drive, AWD). The embodiment of the present application 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 the handling performance of the vehicle by making the rear wheels of the vehicle rotate in the same direction or in the 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 wire-controlled steering gear. It receives the steering wheel angle, steering wheel speed, vehicle speed and other signals sent by the vehicle controller through wires, and then calculates the angle to be rotated based on the received steering wheel angle, steering wheel speed, vehicle speed and other signals. Generally, when the vehicle is driving in a normal straight line, the rear wheels can remain in the straight position to avoid causing the vehicle to deviate. When the vehicle turns at a low speed, the rear wheels can cooperate with the front wheels to rotate in the opposite direction to reduce the turning radius; when the vehicle changes lanes at high speed, the rear wheels cooperate with the front wheels to rotate in the same direction to improve vehicle stability.

[0087] In an embodiment of the present application, when rear-wheel steering is required in scenarios such as turning and 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 which the rear wheels need to turn based on the signals such as the vehicle speed and steering wheel angle of the vehicle 101, so as to improve the operating performance by rotating the rear wheels by the corresponding angle.

[0088] The application scenarios of the embodiments of the present application are further described.

[0089] For example, Figure 2 is a scene diagram of a rear wheel steering control method provided by an embodiment of the present application, see Figure 2 , Figure 2 Vehicle 201 is included, and vehicle 201 is turning.

[0090] When the vehicle 201 is turning, the rear-wheel steering system can calculate the angle that the rear wheels should turn based on the speed of the vehicle 201, so that the front wheels and the rear wheels can cooperate to achieve more flexible turning.

[0091] Generally, the vehicle 201 may travel on different types of roads, but the slip coefficients of different types of roads may be different. When the vehicle 201 travels on a relatively smooth road, the vehicle 201 may slip.

[0092] When the vehicle is skidding, the wheels will spin, resulting in a higher wheel speed, and the vehicle speed is generally calculated based on the wheel speed, which makes the calculated vehicle speed also larger. Therefore, when the vehicle 201 is skidding, the vehicle speed changes more greatly when skidding than when not skidding, and the vehicle speed calculated based on the wheel speed may have a large error with the actual vehicle speed. In the above case, the rear-wheel steering system will receive an incorrect vehicle speed, and the rear-wheel steering system will calculate an incorrect steering angle based on the incorrect vehicle speed, which will lead to an error in the rear-wheel steering decision, and the vehicle 201 will not be able to steer normally.

[0093] For example, when the vehicle 201 is not skidding, the vehicle speed received by the rear-wheel steering system is 30, and when it is skidding, the vehicle speed received is 50, that is, the vehicle speed of the vehicle 201 changes greatly, that is, the vehicle speed change rate is large, then the rear wheel turning angle calculated by the rear-wheel steering system based on the vehicle speed of 50 and based on the vehicle speed of 30 is quite different, that is to say, the rear-wheel steering system will calculate an incorrect steering angle.

[0094] To this end, an embodiment of the present application provides a rear-wheel steering control method, which can be applied to a scenario of controlling the steering of the rear wheels of a vehicle.

[0095] Specifically, the speed change of the target vehicle at multiple moments is first calculated based on the acceleration of the target vehicle, and then the slip factor is determined based on the speed change of the target vehicle at multiple moments and the wheel speed. Then, based on the slip factor, the speed change rate of the target vehicle is adjusted, that is, the speed change of the target vehicle when slipping is adjusted. For example, if the slip factor is equal to 1, the speed change rate can be adjusted to 0, that is, the speed change of the target vehicle when slipping is controlled to be 0. In other words, when the target vehicle slips greatly, the speed is controlled not to change. Finally, based on the adjusted speed change rate and the wheel speed, the speed change of the target vehicle at multiple moments is adjusted, and the target vehicle is controlled to perform rear-wheel steering accordingly.

[0096] In this case, by adjusting the speed change rate of the target vehicle at multiple moments based on the adjusted speed change rate and the wheel speed, and controlling the target vehicle to perform rear-wheel steering accordingly, the effect of slippage can be taken into account when steering the rear wheels, and the effect of slippage on the vehicle speed is reduced by adjusting the speed change rate to improve the reliability of the vehicle speed when steering the rear wheels, thereby improving the accuracy of the steering decision of the target vehicle, and further improving the safety of the target vehicle performing rear-wheel steering under slippery conditions.

[0097] The rear wheel steering control method provided in the embodiment of the present application is explained in detail below.

[0098] Figure 3 is a flow chart of a rear wheel steering control method provided by an embodiment of the present application. The method can be applied to a rear wheel steering controller of a vehicle. Figure 3 , the method comprises the following steps.

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

[0100] The first vehicle speed difference is used to represent the actual vehicle speed change of the target vehicle at multiple moments. In other words, the first vehicle speed difference is the actual change value of the actual vehicle speed of the target vehicle at multiple moments.

[0101] The slip factor is used to indicate the slip degree of the target vehicle, that is, the severity of wheel slip when the target vehicle is driving on the road. In the embodiment of the present 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 slip; the smaller the slip factor, the milder the wheel slip.

[0102] Since the acceleration of the target vehicle can accurately represent the actual change rate of the speed of the target vehicle, the actual speed change of the target vehicle at multiple moments can be accurately calculated based on the acceleration of the target vehicle. In addition, the vehicle speed is generally calculated based on the wheel speed, so the deviation between the wheel speeds and the actual deviation between the vehicle speed calculated based on the wheel speed and the actual vehicle speed can be obtained based on the first vehicle speed difference and the wheel speed.

[0103] In this case, based on the first speed difference of the target vehicle at multiple times and the wheel speed, the deviation between the wheel speeds and the actual deviation between the speed calculated based on the wheel speed and the actual speed can be obtained, so that the slip degree of the target vehicle can be inferred, that is, the slip factor can be obtained. In this way, the rear wheels are subsequently controlled to steer according to the slip factor, so that the influence of slip can be taken into account in the rear wheel steering, and corresponding control is performed according to the slip degree of the target vehicle, so that more accurate control of the rear wheels of the target vehicle can be achieved.

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

[0105] (1) Based on the wheel speeds of the target vehicle at multiple moments, a first reference factor is determined.

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

[0107] The larger the first reference factor is, the larger the deviation between the wheel speeds of the wheels of the target vehicle is, which indicates that the wheels may slip and the degree of slip of the target vehicle is greater. The smaller the first reference factor is, the smaller the deviation between the wheel speeds of the wheels of the target vehicle is, which indicates that the wheels do not slip or the degree of slip is smaller.

[0108] It should be understood that when the target vehicle is driving normally, the wheel speeds of its wheels are not much different. However, when the target vehicle is skidding, the deviation between the wheel speeds of its wheels will be larger depending on the amount of wheel slippage. For example, there will be a large deviation between the wheel speeds of the skidding wheels and the non-skidding wheels. Therefore, the deviation between the wheel speeds can be determined based on the wheel speeds, and then it can be determined whether the target vehicle is skidding and the severity of the skidding. For example, if the deviation is larger, the skidding is more serious.

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

[0110] Specifically, the operation of step (1) may be: based on the wheel speed of the target vehicle at the i-th moment, determine the mean wheel speed of the target vehicle at the i-th moment; based on the wheel speed of the wheel at the i-th moment and the mean wheel speed, determine the wheel speed variance corresponding to the i-th moment; based on the wheel speed variances corresponding to the multiple moments, determine the first reference factor.

[0111] Variance is a measure of the degree of discreteness of a set of data. In the embodiment of the present application, by calculating the wheel speed variance corresponding to the i-th moment, the discreteness of the wheel speeds of the four wheels can be known. In other words, the deviation between the wheel speeds of the four wheels and the mean wheel speed can be known.

[0112] In this case, it is equivalent to calculating the variance between the four wheels and the average wheel speed for each of the multiple moments, so that the deviation between the wheel speeds of the four wheels and the average wheel speed can be accurately and conveniently determined, and then the first reference factor can be accurately and conveniently obtained, that is, whether the wheels of the target vehicle are slipping and the degree of slipping.

[0113] Among them, based on the wheel speed variances corresponding to the multiple moments, the operation of determining the first reference factor may be: obtaining the maximum value of the wheel speed variances corresponding to the multiple moments to obtain the maximum variance; and normalizing the maximum variance to obtain the first reference factor.

[0114] The maximum value of the wheel speed variance among the multiple moments can represent the maximum deviation between the wheel speed and the mean wheel speed among the multiple moments. Since the subsequent process is to avoid the influence of slippage on the rear wheel steering, if the average value of the wheel speed variance corresponding to the multiple moments is taken, the deviations corresponding to the multiple moments will be averaged, which will not be able to accurately measure the slippage condition of the target vehicle's wheels, and therefore will not be able to accurately judge the degree of slippage. Then, it will not be possible to fully refer to the influence of slippage on the rear wheel steering in the subsequent process.

[0115] In this case, by determining the maximum value of the wheel speed variance corresponding to the multiple moments, it is possible to obtain representative deviation values ​​in the multiple moments, so that the degree of slippage that fully takes slippage into consideration can be determined based on the maximum value, that is, a more accurate reference factor can be determined, and then the impact of slippage on rear wheel steering can be fully referred to.

[0116] Optionally, the operation of determining the first reference factor based on the wheel speed variance corresponding to the multiple moments may also be: determining the variance change rate corresponding to the multiple moments based on the wheel speed variance corresponding to the multiple moments; determining the first reference factor based on the wheel speed variance at the multiple moments and the variance change rate.

[0117] The variance change rate is used to indicate the change of the wheel speed variance over time. Specifically, the variance change rate can indicate the change amplitude of the wheel speed variance of the target vehicle over time. It should be understood that the larger the variance change rate, the larger the change amplitude of the wheel speed variance of the target vehicle over time, which means that the deviation between the wheel speed of the four wheels and the mean wheel speed has changed greatly. The smaller the variance change rate, the smaller the change amplitude of the wheel speed variance of the target vehicle over time, which means that the deviation between the wheel speed of the four wheels and the mean wheel speed has changed less.

[0118] In this case, the deviation between the wheel speed of the four wheels and the mean wheel speed can be measured in different dimensions based on the wheel speed variance at multiple moments and the variance change rate, so that the deviation between the wheel speed of the four wheels and the mean wheel speed and the variation range of the deviation at multiple moments can be known, so that a more accurate first reference factor can be determined, that is, the degree of slippage of the target vehicle can be accurately estimated.

[0119] Optionally, after the variance change rates corresponding to the multiple moments are determined, the variance change rates corresponding to the multiple moments may be filtered.

[0120] When the wheel speed sensor detects an inaccurate wheel speed, the variance calculated by it will deviate greatly from other variances, and the variance change rate will also deviate greatly. Such a variance change rate is called noise data in the variance change rates corresponding to the multiple moments, which will interfere with the accurate calculation of the first reference factor and cause errors in the calculation of the first reference factor. Therefore, the variance change rates corresponding to the multiple moments can be filtered.

[0121] In this way, by filtering the variance change rates corresponding to the multiple moments, the interference of noise on the calculation of the first reference factor can be reduced, so as to obtain a more accurate first reference factor.

[0122] Optionally, the variance change rates at the multiple moments may be filtered by a second-order low-pass filter.

[0123] Among them, the operations of determining the first reference factor based on the wheel speed variance at the multiple moments and the variance change rate can be: determining the variance change trend based on the wheel speed variance at the multiple moments; determining the average value of the variance change rate at the multiple moments to obtain the average variance change rate; based on the variance change trend and the average variance change rate, obtaining the corresponding reference factor from the first corresponding relationship and determining it as the first reference factor.

[0124] The variance change trend is used to indicate the direction of the wheel speed variance at the multiple moments, that is, whether the wheel speed variance at the multiple moments is gradually increasing or stable. The average variance change rate is used to measure the overall change of the wheel speed variance at the multiple moments, that is, it can measure the change amplitude of the wheel speed variance at the multiple moments over time.

[0125] Since the deviation between the wheel speed and the wheel speed mean of the target vehicle should be increasing when it changes from non-slipping to slipping, the wheel speed variance calculated accordingly will also be increasing. Therefore, the variance change trend can be determined in the embodiment of the present application.

[0126] In the embodiment of the present application, based on the variance change trend and the average variance change rate, it can be known whether the wheel speed variance at the multiple moments is gradually increasing or remains stable, and the amplitude of the change of the wheel speed variance at the multiple moments in the process of gradual increase can be known, which means that the deviation between the wheel speed of the four wheels and the wheel speed mean is gradually increasing or remains stable, and the amplitude of the gradual increase of the deviation can be known, so that the degree of slippage of the target vehicle can be accurately known, that is, a more accurate first reference factor can be obtained.

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

[0128] In the embodiment of the present application, the first corresponding relationship can be obtained by pre-calibration by a technician, specifically, by obtaining multiple groups of wheel speed variances with different variance change trends and calculating the variance change rate of each group. For each group of variance data, the technician measures the reference factor corresponding to this group of data according to the variance change trend and the variance change rate, so that the reference factors corresponding to different variance change rates under different variance change trends can be obtained, that is, the first corresponding relationship can be obtained.

[0129] For example, the following Table 1 is an example of the first corresponding relationship, referring to Table 1, which includes different variance change trends, and different variance change trends include multiple different variance change rates, and each variance change rate corresponds to a corresponding reference factor. For example, the variance change trend is a gradually increasing trend, and the average variance change rate is 0.5. From the following Table 1, the corresponding reference factor can be obtained as 0.7.

[0130] Table 1

[0131]

[0132] The embodiment of the present application only uses Table 1 as an example to illustrate the first corresponding relationship, and does not constitute a limitation to the embodiment of the present 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; when the first reference factor is greater than or equal to the preset factor threshold, the second reference factor is determined.

[0134] The preset factor threshold may be set in advance, and the preset factor threshold may be set relatively large. In the embodiment of the present application, the preset factor threshold may be set based on a reference factor calculated based on the wheel speed when the wheel may slip.

[0135] In this case, when the first reference factor is greater than or equal to the preset factor threshold, it means that the first reference factor is large and is greater than the reference factor calculated from the wheel speed when the wheel may slip, which means that the deviation between the wheel speed of the four wheels and the wheel speed average is large, or the deviation has a large variation range at these multiple moments, which means that the wheel may be slipping or about to slip. In this case, it can be further determined whether the wheel is indeed slipping, that is, further performing the following steps.

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

[0137] When the first reference factor is less than the preset factor threshold, it means that the first reference factor is small, smaller than the reference factor calculated from the wheel speed when the wheel may slip. This also means that the deviation between the wheel speeds of the four wheels and the average wheel speed is small, which means that the wheel is not slipping currently. Rear-wheel steering can be performed normally without any other processing.

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

[0139] The second reference factor refers to the degree of slippage of the target vehicle determined based on the wheel speed and the real vehicle speed, specifically the degree of slippage inferred from the deviation between the vehicle speed change calculated based on the wheel speed and the real vehicle speed change. In the embodiment of the present application, the second reference factor can be a number between 0 and 1.

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

[0141] It should be understood that the greater the deviation between the vehicle speed change in the rear-wheel steering system and the actual vehicle speed change, the greater the deviation between the vehicle speed change calculated based on the wheel speed and the actual vehicle speed change, which means that the target vehicle is slipping more seriously. There is also a situation where there is no difference in the wheel speeds of the four wheels but slippage has occurred. This can also mean that the target vehicle is slipping more seriously, and thus the larger the second reference factor is. Conversely, the smaller the deviation is, the target vehicle is not slipping or is slipping slightly, that is, the smaller the second reference factor is.

[0142] In this way, by comparing the vehicle speed change calculated based on the wheel speed with the actual vehicle speed change, it is possible to accurately determine whether the target vehicle is slipping and the degree of slipping, and thus the second reference factor can be accurately determined.

[0143] In the embodiment of the present application, the first vehicle speed difference may be obtained based on the integration of the acceleration of the target vehicle at the first moment among the multiple moments over the multiple moments.

[0144] Optionally, the operation of step (2) may be: for any wheel of the target vehicle, based on the wheel speed of the wheel at multiple moments, determine the wheel speed change of the wheel at multiple moments; determine the average value between the wheel speed changes corresponding to the wheels of the target vehicle to obtain a third vehicle speed difference; based on the difference between the first vehicle speed difference and the third vehicle speed difference, determine the second reference factor.

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

[0146] Since the vehicle speed may be the average of the wheel speeds of the four wheels, then by calculating the average of the wheel speed changes corresponding to the wheels of the target vehicle, it is equivalent to determining the vehicle speed changes calculated based on the wheel speeds at the multiple moments. Therefore, the second reference factor may be determined based on the difference between the first vehicle speed difference and the third vehicle speed difference.

[0147] Among them, based on the difference between the first vehicle speed difference and the third vehicle speed difference, the operation of determining the second reference factor can be: based on the difference between the first vehicle speed difference and the third vehicle speed difference, obtaining the corresponding reference factor from the second corresponding relationship and determining it as the second reference factor.

[0148] The second corresponding relationship is the corresponding relationship between the deviation of the vehicle speed change and the reference factor. The second corresponding relationship includes multiple deviations of the vehicle speed change and multiple reference factors, wherein each of the multiple deviations of the vehicle speed change corresponds to a reference factor.

[0149] In the embodiment of the present application, the reference factor in the second corresponding relationship can be obtained by standardizing the deviation of the vehicle speed variation, 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 variation in the rear wheel steering system and the actual vehicle speed variation, indicating that the slip is more serious, and the corresponding reference factor can be set larger.

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

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

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

[0153] In this way, by integrating the second reference factors corresponding to multiple cycles, it is equivalent to integrating the second reference factor determined by the working conditions over a long period of time, so that a more accurate second reference factor can be determined.

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

[0155] The first reference factor refers to the slippage degree of the target vehicle determined based on the wheel speed, and the second reference factor refers to the slippage degree of the target vehicle determined based on the wheel speed and the true vehicle speed. Therefore, the first reference factor and the second reference factor are based on different ways to determine the slippage degree of the target vehicle.

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

[0157] Optionally, the operation of step (3) may be: determining the maximum value of the first reference factor and the second reference factor as the slip factor.

[0158] Since the first reference factor and the second reference factor both represent the degree of slippage of the target vehicle, but are calculated in different ways, the larger of the first reference factor and the second reference factor indicates that the estimated degree of slippage of the target vehicle is larger. In order to ensure driving safety and to fully consider the impact of slippage on rear wheel steering in the future, the slippage degree can be set larger. Therefore, the larger one of the first reference factor and the second reference factor can be obtained 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), a VDC (vehicle running dynamic control system), etc.

[0160] In the embodiment of the present application, when the ABS system or TCS system of the target vehicle is activated, if the instrument screen of the target vehicle shows that the four-wheel drive is slipping, the slip factor can be set to a first value; if the instrument screen of the target vehicle shows that a single axle is slipping, the slip factor can be set to a second value. When the VDC system of the target vehicle is activated, the slip factor can be set to a second value.

[0161] The first value is greater than the second value. Since the working condition corresponding to the first value is four-wheel drive slippage, the slippage degree of the target vehicle is relatively serious. Therefore, the slip factor can be set to the first value under this working condition. In the embodiment of the present application, the first value can be 1. The second value corresponds to single-axle slippage, that is, there may be two wheels slipping on the target vehicle, so the slip factor can be set to the second value under this working condition. In the embodiment of the present application, the second value can be 0.5.

[0162] In this case, it is equivalent to judging whether the target vehicle is skidding through the ESP system of the target vehicle. Nowadays, there are many assisted driving systems on vehicles, and many assisted driving systems can detect whether the vehicle is skidding. In this way, the assisted driving system can more accurately detect whether the target vehicle is skidding, and then determine a more accurate skidding factor.

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

[0164] The speed change rate is used to indicate the speed change range of the 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 speed change rate, the larger the speed change range of the target vehicle at different times, and the smaller the speed change rate, the smaller the speed change range of the target vehicle at different times.

[0165] When the target vehicle is skidding, its wheels rotate rapidly, which increases the speed change rate, that is, the speed of the target vehicle changes greatly at different times, which makes the rear wheel angle change greatly, so the target vehicle cannot turn at the correct angle. When the target vehicle is driving normally, the speed will not change suddenly, so the rear wheel angle will not change too much. Therefore, after determining the slip factor, the speed change rate of the target vehicle can be adjusted based on the slip factor.

[0166] In this case, by adjusting the speed change rate of the target vehicle based on the slip factor, the speed change amplitude of the target vehicle at multiple moments can be adjusted, thereby reducing the impact of slip on the vehicle speed, and then reducing the impact of the vehicle speed on the rear wheel steering, so that the rear wheels can be accurately steered subsequently.

[0167] Optionally, the operation of step 302 may be: subtracting the slip factor from the target threshold to obtain a target vehicle speed change rate.

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

[0169] The target threshold value may be set in advance. Since the slip factor is a number between 0 and 1, in the embodiment of the present application, the target threshold value may be set to 1.

[0170] In this case, by subtracting the slip factor from the target threshold, it is equivalent to obtaining the weight of the vehicle speed change (vehicle speed change rate). Then, the vehicle speed change during slip can be determined based on this weight. In this way, by setting corresponding weights for the vehicle speed change, the vehicle speed change can be reduced, thereby reducing the impact of slip on the vehicle speed.

[0171] Step 303: 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 being the vehicle speed currently received by the rear-wheel steering system and determined based on the wheel speed, the second vehicle speed being the vehicle speed currently being used by the rear-wheel steering system, and the target vehicle speed change rate being the adjusted vehicle speed change rate.

[0172] Since the difference between the first vehicle speed and the second vehicle speed refers to the difference between the vehicle speed currently received by the rear-wheel steering system and the vehicle speed in use, that is, the original vehicle speed change in the rear-wheel steering system. In addition, the target vehicle speed change rate is the vehicle speed change rate after adjustment, so the vehicle speed change amount of the rear-wheel steering system after adjustment can be determined based on the target vehicle speed change rate, the first vehicle speed and the second vehicle speed.

[0173] In this case, the speed change amount that was originally to be increased in the rear-wheel steering system can be adjusted based on the target vehicle speed change rate, the first vehicle speed and the second vehicle speed, so that the speed change amount that was originally to be increased is reduced, thereby reducing the speed change amplitude at different times. Therefore, the credibility of the vehicle speed will be improved, and the subsequent rear-wheel steering system can calculate the correct rear-wheel steering based on the adjusted vehicle speed, and then control the rear wheels to steer accurately.

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

[0175] The second vehicle speed difference is the vehicle speed change that is originally to be increased in the rear-wheel steering system.

[0176] The fourth vehicle speed difference is the vehicle speed change amount to be increased in the rear wheel steering system after adjustment.

[0177] The target vehicle speed is the vehicle speed that the adjusted rear-wheel steering system uses to calculate the rear wheel steering angle.

[0178] The above operation process is: first, based on the first vehicle speed and the second vehicle speed, the speed change amount that the rear-wheel steering system is supposed to increase is calculated. From the perspective of the cycle, there is a speed change amount between the vehicle speed used by the rear-wheel steering system in the previous cycle and the vehicle speed calculated based on the wheel speed in the current cycle. This is the speed change amount that the rear-wheel steering system is supposed to increase in the current cycle. Then, based on the target vehicle speed change rate, the speed change amount that the rear-wheel steering system is supposed to increase is adjusted, so that the speed change amount that the rear-wheel steering system is supposed to increase is reduced, thereby narrowing the speed difference in the rear-wheel steering system between two adjacent cycles. Then, based on the adjusted speed change amount, the target vehicle speed is determined, that is, the vehicle speed used by the rear-wheel steering system in the current cycle to calculate the rear wheel turning angle is determined, and then the target vehicle can be controlled to perform rear-wheel steering according to the target vehicle speed.

[0179] In this case, the speed change originally to be increased in the rear-wheel steering system can be adjusted through the target speed change rate. That is, the influence of the slip factor on the vehicle speed is taken into account, which is equivalent to adjusting the vehicle speed based on the target speed change rate, so that the rear wheels can be steered more accurately according to the adjusted vehicle speed.

[0180] In the embodiment of the present application, the above operation is also implemented by the following formula (1).

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

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

[0183] From the above formula (1), it can be obtained that when the wheel is not slipping, that is, the slip factor is 0, the target vehicle speed change rate is 1, V rws = V. In this condition, the speed change amount to be added by the rear-wheel steering system is not adjusted, and the rear wheel steering angle is directly calculated using the speed calculated based on the wheel speed. When the wheel is seriously slipping, assuming that the severity of the slip is very large, such as the slip factor is 1, the target speed change rate is 0, then V rws =V1 rws , that is, after adjustment, the vehicle speed input into the rear-wheel steering system does not change.

[0184] Since the greater the rate of change of the vehicle speed, the greater the rate of change of the rear wheel angle calculated by the rear wheel steering system, that is, the rear wheel steering angle will also change continuously, then when the skidding is serious, the faster rate of change of the vehicle speed will cause the rear wheel angle to change continuously. In the embodiment of the present application, when the wheel is slipping, the change of the rear wheel angle can be suppressed by limiting the rate of change of the vehicle speed, so that the incorrect change of the rear wheel angle can be avoided as much as possible when the wheel is slipping, and the rear wheel steering can be correctly controlled.

[0185] Among them, the above-mentioned operation of controlling the target vehicle to perform rear-wheel steering based on the target vehicle speed can be: obtaining the steering wheel angle of the target vehicle; determining the target steering angle based on the steering wheel angle of the target vehicle and the target vehicle speed; controlling the rear wheels of the target vehicle to rotate to the target steering angle to achieve rear-wheel steering.

[0186] In this case, a more accurate rear wheel turning 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 perform correct steering subsequently.

[0187] In the embodiment of the present application, 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 times and the wheel speed of the wheel, that is, determines the slip degree of the target vehicle at this time. Then, based on the slip factor, the speed change rate of the target vehicle is adjusted, that is, the speed change amount of the target vehicle when slipping is adjusted. For example, if the slip factor is equal to 1, the target speed change rate can be adjusted to 0, that is, the speed change amount of the target vehicle when slipping is controlled to be 0. In other words, when the slip degree of the target vehicle is very large, the speed is controlled not to change. Then, based on the target speed change rate, the first speed and the second speed, the target vehicle is controlled to perform rear-wheel steering, so that the influence of slipping can be considered when the rear-wheel steering is performed, and the influence of slipping on the vehicle speed can be reduced by adjusting the speed change rate, so as to improve the credibility of the vehicle speed when the rear-wheel steering is performed, thereby improving the accuracy of the steering decision of the target vehicle, and then improving the safety of the target vehicle performing rear-wheel steering under slipping conditions.

[0188] Figure 4 : is a schematic diagram of the structure of a rear wheel steering control device provided by an embodiment of the present application. The rear wheel steering control device can be implemented by software, hardware or a combination of both to form part or all of a vehicle, and the vehicle can be as follows Figure 5 Vehicle shown. See Figure 4 The device includes: a determination module 401, an adjustment module 402 and a control module 403.

[0189] A determination module 401 is used to determine a slip factor based on a first vehicle speed difference of the target vehicle at multiple times and a wheel speed, the slip factor being used to indicate a slip degree of the target vehicle, wherein the first vehicle speed difference is a vehicle speed change at multiple times calculated based on an acceleration of the target vehicle;

[0190] An adjustment module 402, configured to adjust a speed change rate of the target vehicle 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 and determined 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 vehicle speed change rate after adjustment.

[0192] Optionally, the determination module 401 is used to:

[0193] Determining a first reference factor based on the wheel speeds of the target vehicle at multiple times, the first reference factor being a degree of slippage of the target vehicle determined based on the wheel speeds;

[0194] Determine a second reference factor based on the first vehicle speed difference and the wheel speed of the target vehicle at multiple times, the second reference factor being a skidding degree of the target vehicle determined based on the wheel speed and the true vehicle speed;

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

[0196] Optionally, the determination module 401 is used to:

[0197] Based on the wheel speeds of the wheels of the target vehicle at the i-th moment, determining the mean wheel speed of the target vehicle at the i-th moment;

[0198] Based on the wheel speed and the mean wheel speed at the i-th moment, determine the wheel speed variance corresponding to the i-th moment;

[0199] A first reference factor is determined based on wheel speed variances corresponding to a plurality of moments.

[0200] Optionally, the determination module 401 is used to:

[0201] Determining variance change rates corresponding to the multiple moments based on the wheel speed variances corresponding to the multiple moments;

[0202] A first reference factor is determined based on wheel speed variances and variance change rates at multiple moments.

[0203] Optionally, the determination module 401 is used to:

[0204] For any wheel of the target vehicle, based on the wheel speeds of the wheel at multiple moments, determining the wheel speed changes at multiple moments;

[0205] Determine an average value of wheel speed changes of the target vehicle's wheels at multiple moments to obtain a third vehicle speed difference, where the third vehicle speed difference is a vehicle speed change of the target vehicle determined based on the wheel speed at the multiple moments;

[0206] Based on a difference between the first vehicle speed difference and the third vehicle speed difference, a second reference factor is determined.

[0207] Optionally, the determination module 401 is used to:

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

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

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

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

[0212] Subtract the second vehicle speed from the first vehicle speed to obtain a second vehicle speed difference;

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

[0214] The second vehicle speed is added to the fourth vehicle speed difference to obtain the target vehicle speed;

[0215] Based on the target vehicle speed, the target vehicle is controlled to perform rear wheel steering.

[0216] In the embodiment of the present application, when performing rear-wheel steering, the slip factor is first determined based on the first speed difference of the target vehicle at multiple times and the wheel speed of the wheel, that is, the slip degree of the target vehicle at this time is determined. Then, based on the slip factor, the speed change rate of the target vehicle is adjusted, that is, the speed change amount of the target vehicle when slipping is adjusted. For example, if the slip factor is equal to 1, the target speed change rate can be adjusted to 0, that is, the speed change amount of the target vehicle when slipping is controlled to be 0. In other words, when the slip degree of the target vehicle is very large, the speed is controlled not to change. Then, based on the target speed change rate, the first speed and the second speed, the target vehicle is controlled to perform rear-wheel steering, so that the influence of slipping can be considered when steering the rear wheels, and the influence of slipping on the vehicle speed can be reduced by adjusting the speed change rate, so as to improve the credibility of the vehicle speed when steering the rear wheels, thereby improving the accuracy of the steering decision of the target vehicle, and further improving the safety of the target vehicle performing rear-wheel steering under slipping conditions.

[0217] It should be noted that: when the rear-wheel steering control device provided in the above embodiment controls the rear-wheel steering during the rear-wheel steering process, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned 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 may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit, and the above integrated units may be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the protection scope of the embodiments of the present 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 of the units and modules in the above embodiments and the technical effects brought about can be found in the method embodiment part and will not be repeated here.

[0220] Figure 5 It is a structural schematic diagram of a vehicle provided in an embodiment of the present application.

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

[0222] In this embodiment, the functional modules of the vehicle can be divided according to the above method example. For example, each functional module can be corresponded, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware. It should be noted that the division of modules in this embodiment is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0223] In the case of dividing each functional module according to each function, the vehicle may include: a determination module, an adjustment module and a control module. It should be noted that all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module, which will not be repeated here.

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

[0225] In the case of an integrated unit, the vehicle may include a processing module and a storage module. The processing module may be used to control and manage the actions of the vehicle. The storage module may be used to support the vehicle in executing corresponding program codes and data.

[0226] The processing module may be a processor or a controller, which may implement or execute various exemplary logic blocks, modules and circuits shown in conjunction with the disclosure of the present application. The processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc. The storage module may be a memory.

[0227] This embodiment also provides a computer-readable storage medium, in which a computer program code is stored. When the computer program code is executed on a computer, the computer executes the above-mentioned related method steps to implement the above-mentioned one of the rear-wheel steering control methods in the above-mentioned embodiment.

[0228] This embodiment also provides a computer program product. When the computer program product is run on a computer, the computer is caused to execute the above-mentioned related steps to implement the above-mentioned rear-wheel steering control method in the above-mentioned embodiment.

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

[0230] Through the description of the above implementation methods, technical personnel in the relevant field can understand that for the convenience and brevity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned 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 the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are schematic, for example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0232] The above contents are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A rear wheel steering control method, characterized in that: The method comprises: Determine a slip factor based on first vehicle speed differences of the target vehicle at multiple times and wheel speeds, wherein the slip factor is used to indicate the slip degree of the target vehicle, and the first vehicle speed difference is a vehicle speed change at the multiple times calculated based on the acceleration of the target vehicle; Based on the slip factor, adjusting the speed change rate of the target vehicle; The target vehicle is controlled to perform rear-wheel steering based on a target vehicle speed change rate, a first vehicle speed, and a second vehicle speed, wherein the first vehicle speed is a vehicle speed currently received by a rear-wheel steering system and determined based on the wheel speed, the second vehicle speed is a vehicle speed currently being used by the rear-wheel steering system, and the target vehicle speed change rate is the vehicle speed change rate after adjustment.

2. The method according to claim 1, characterized in that The step of determining the slip factor based on the first vehicle speed difference and the wheel speed of the target vehicle at multiple times includes: Determining a first reference factor based on the wheel speeds of the target vehicle at the plurality of moments, the first reference factor being a degree of slip of the target vehicle determined based on the wheel speeds; Determining a second reference factor based on the first vehicle speed difference and the wheel speed of the target vehicle at the plurality of moments, wherein the second reference factor refers to a slip degree of the target vehicle determined based on the wheel speed and the true vehicle speed; The slip factor is determined based on the first reference factor and the second reference factor.

3. The method according to claim 2, characterized in that The determining of the first reference factor based on the wheel speeds of the target vehicle at the plurality of moments comprises: Based on the wheel speeds of the wheels of the target vehicle at the i-th moment, determining the mean wheel speed of the target vehicle at the i-th moment; Determining the wheel speed variance corresponding to the i-th moment based on the wheel speed at the i-th moment and the wheel speed mean; The first reference factor is determined based on the wheel speed variances corresponding to the multiple moments.

4. The method according to claim 3, characterized in that The determining the first reference factor based on the wheel speed variances corresponding to the multiple moments includes: Determining variance change rates corresponding to the multiple moments based on the wheel speed variances corresponding to the multiple moments; The first reference factor is determined based on the wheel speed variances at the plurality of moments and the variance change rate.

5. The method according to claim 2, characterized in that The determining of the second reference factor based on the first vehicle speed difference and the wheel speed of the target vehicle at the plurality of moments comprises: For any wheel of the target vehicle, determining a change in wheel speed of the wheel at the multiple moments based on the wheel speed of the wheel at the multiple moments; Determine an average value of wheel speed changes of the target vehicle's wheels at multiple moments to obtain a third vehicle speed difference, where the third vehicle speed difference is a vehicle speed change of the target vehicle determined based on the wheel speed at the multiple moments; The second reference factor is determined based on a difference between the first vehicle speed difference and the third vehicle speed difference.

6. The method according to claim 2, characterized in that The determining the slip factor based on the first reference factor and the second reference factor includes: The maximum value of the first reference factor and the second reference factor is determined as the slip factor.

7. The method according to claim 1, characterized in that The adjusting the speed change rate of the target vehicle based on the slip factor includes: The target vehicle speed change rate is obtained by subtracting the slip factor from the target threshold.

8. The method according to claim 1, characterized in that The method 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: Subtracting the second vehicle speed from the first vehicle speed to obtain a second vehicle speed difference; multiplying the target vehicle speed change rate by the second vehicle speed difference to obtain a fourth vehicle speed difference; Add the second vehicle speed to the fourth vehicle speed difference to obtain a target vehicle speed; Based on the target vehicle speed, the target vehicle is controlled to perform rear wheel steering.

9. A rear wheel steering control device, characterized in that: The device comprises: a determination module, configured to determine a slip factor based on first vehicle speed differences of a target vehicle at multiple times and wheel speeds of the wheels, wherein the slip factor is used to indicate a slip degree of the target vehicle, and the first vehicle speed difference is a vehicle speed change at the multiple times calculated based on the acceleration of the target vehicle; An adjustment module, configured to adjust a speed change rate of the target vehicle based on the slip factor; A control module is used to control the target vehicle to perform rear-wheel steering based on a target vehicle speed change rate, a first vehicle speed, and a second vehicle speed, wherein the first vehicle speed is a vehicle speed currently received by a rear-wheel steering system and determined based on the wheel speed, the second vehicle speed is a vehicle speed currently being used by the rear-wheel steering system, and the target vehicle speed change rate is the vehicle speed change rate after adjustment.

10. A vehicle, characterized in that: The vehicle comprises: A memory for storing executable program codes; A processor, configured to call and run the executable program code from the memory so that the vehicle executes the method according to any one of claims 1 to 8.

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