Map graph construction of rear wheel steering angle and rear wheel steering control method and device

Abstract

The invention relates to the technical field of vehicle control, and discloses a rear wheel steering angle Map graph construction method and device and a rear wheel steering control method and device.According to the method, a vehicle dynamics model of a target vehicle is established, and based on the vehicle dynamics model, the vehicle speed, the steering wheel angle and calibration parameters are established, the reference vehicle model takes the expected yaw velocity as the output, the real vehicle model takes the expected yaw velocity as the input and the rear wheel steering angle as the output, and the output of the reference vehicle model is connected with the input of the real vehicle model to construct a vehicle control model; a vehicle speed set, a steering wheel angle set and preset calibration quantity parameters are input into a vehicle control model, Map maps corresponding to the vehicle speed, the steering wheel angle and the rear wheel steering angle can be obtained in advance, the rear wheel steering failure probability caused by algorithm logic Bug is reduced, the calculation load of a rear wheel steering controller is reduced, the target rear wheel angle calculation speed is increased, and the vehicle control efficiency is improved. And response delay is reduced.

Description

Technical Field

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

[0002] For vehicles equipped with active rear-wheel steering technology, the determination of the rear-wheel steering angle will be more complicated. The existing technology adjusts the steering angle of the rear wheels in real time through an electronic control system based on the steering angle signal, vehicle speed and other sensor inputs to optimize the vehicle's handling and stability. However, in the process of real-time adjustment of the rear-wheel steering angle, the rear-wheel steering may fail due to algorithm logic bugs, and the calculation process requires the consumption of computing resources of the controller. There may also be problems such as rear-wheel steering angle adjustment response delay, affecting the use of the vehicle. Summary of the invention

[0003] In view of this, the present invention provides a Map construction of the rear-wheel steering angle and a rear-wheel steering control method and device to solve the problem that the rear-wheel steering may fail due to algorithm logic bugs during the real-time adjustment of the rear-wheel steering angle, and the calculation process needs to consume the computing resources of the controller, and there may also be problems such as rear-wheel steering angle adjustment response delay, which affects the use effect of the vehicle.

[0004] In a first aspect, the present invention provides a method for constructing a Map of a rear-wheel steering angle, the method comprising: establishing a vehicle dynamics model of a target vehicle, and obtaining a vehicle speed set and a steering wheel angle set of the target vehicle within a drivable medium- and high-speed range, wherein the drivable medium- and high-speed range is a range between a preset maximum vehicle speed and an expected maximum vehicle speed of the target vehicle; based on the vehicle dynamics model, establishing a reference vehicle model with vehicle speed, steering wheel angle and calibration parameters as inputs and an expected yaw angular velocity as output, and a real vehicle model with the expected yaw angular velocity as input and a rear-wheel steering angle as output; connecting the output of the reference vehicle model with the input of the real vehicle model to construct a vehicle control model; inputting the vehicle speed set, the steering wheel angle set and the preset calibration parameters into the vehicle control model to obtain a medium- and high-speed control Map corresponding to the vehicle speed, steering wheel angle and rear-wheel steering angle.

[0005] The method for constructing a Map of a rear wheel steering angle provided by the present invention establishes a vehicle dynamics model of a target vehicle, and based on the vehicle dynamics model, establishes a reference vehicle model with vehicle speed, steering wheel angle and calibration parameters as inputs and expected yaw rate as output, and an actual vehicle model with expected yaw rate as input and rear wheel steering angle as output, and connects the output of the reference vehicle model with the input of the actual vehicle model to construct a vehicle control model, and inputs a vehicle speed set, a steering wheel angle set and preset calibration parameters into the vehicle control model, so that a Map corresponding to the vehicle speed, steering wheel angle and rear wheel steering angle can be obtained in advance, and the Map is completed by first constructing it offline, so that only a simple search of the Map is required in subsequent actual vehicle control, thereby reducing the probability of rear wheel steering failure due to algorithm logic bugs, reducing the calculation load of the rear wheel steering controller, improving the target rear wheel angle calculation speed, and reducing response delays.

[0006] In an optional embodiment, the preset calibration parameter is obtained by the following steps: inputting the preset calibration parameter, the vehicle speed set, and the current vehicle speed and steering wheel angle in the steering wheel angle set into the vehicle control model to obtain the rear wheel steering angle corresponding to the current vehicle speed and steering wheel angle; outputting the rear wheel steering angle to the rear wheel steering actuator for execution, calculating the yaw rate gain of the vehicle, and determining whether the yaw rate gain reaches a preset gain threshold; if the yaw rate gain does not reach the preset gain threshold, changing the preset calibration parameter until the yaw rate gain reaches the preset gain threshold to obtain the calibration parameter corresponding to the current vehicle speed; traversing all vehicle speeds in the vehicle speed set to obtain the calibration parameters corresponding to all vehicle speeds respectively.

[0007] In an optional embodiment, the method also includes: obtaining a tire wear Map corresponding to the target vehicle, the tire wear Map being a Map of vehicle speed, steering wheel angle and rear wheel steering angle corresponding to a preset vehicle speed less than a preset minimum speed; based on the tire wear Map corresponding to the target vehicle and the medium and high speed control Map, using an interpolation algorithm to calculate a transition area Map, the transition area Map being a Map of vehicle speed, steering wheel angle and rear wheel steering angle corresponding to a vehicle speed between a preset minimum speed and a preset maximum speed; combining the tire wear Map, the transition area Map and the medium and high speed control Map based on the vehicle speed to obtain a full speed range Map.

[0008] In an optional embodiment, the vehicle speed set, the steering wheel angle set and the preset calibration parameters are input into the vehicle control model to obtain a medium- and high-speed control Map corresponding to the vehicle speed, the steering wheel angle and the rear wheel steering angle, including: inputting the vehicle speed set, the steering wheel angle set and the preset calibration parameters into the vehicle control model to obtain a to-be-processed Map corresponding to the vehicle speed, the steering wheel angle and the rear wheel steering angle; extracting angle sampling points at a preset first angle sampling interval within a first steering wheel angle range in the to-be-processed Map; extracting a to-be-processed Map according to a preset first steering wheel angle sampling interval; extracting a to-be-processed Map according to a preset first steering wheel angle range .... Angle sampling points are extracted from the second steering wheel angle range area in the figure at a preset second angle sampling interval, the minimum steering wheel angle within the second steering wheel angle range is equal to the maximum steering wheel angle within the first steering wheel angle range, and the first angle sampling interval is smaller than the second angle sampling interval; the steering wheel angle corresponding to the maximum value of the rear wheel steering angle in the Map diagram is extracted as the angle sampling point; the vehicle speed sampling points are extracted from the Map diagram to be processed at a preset vehicle speed sampling point interval; based on the angle sampling points, vehicle speed sampling points and the corresponding rear wheel steering angles, a medium and high speed control Map diagram is constructed.

[0009] In a second aspect, the present invention provides a rear-wheel steering control method, the method comprising: obtaining the vehicle speed and steering wheel angle of a target vehicle; based on the vehicle speed and steering wheel angle of the target vehicle, searching for a medium- and high-speed control Map corresponding to the speed, steering wheel angle and rear-wheel steering angle of the target vehicle to obtain a rear-wheel steering angle currently to be executed, the medium- and high-speed control Map corresponding to the speed, steering wheel angle and rear-wheel steering angle of the target vehicle being constructed using the rear-wheel steering angle Map construction method of the first aspect or any corresponding embodiment thereof; controlling the rear-wheel steering actuator to execute rear wheel steering based on the rear-wheel steering angle currently to be executed.

[0010] The rear-wheel steering control method provided by the present invention obtains the vehicle speed and steering wheel angle during vehicle driving, and based on the vehicle speed and steering wheel angle, it only needs to simply look up the medium- and high-speed control Map corresponding to the speed, steering wheel angle and rear-wheel steering angle of the target vehicle to obtain the current rear-wheel steering angle to be executed, and finally controls the rear-wheel steering actuator to execute the steering of the rear wheels based on the current rear-wheel steering angle to be executed, thereby improving the speed of determining and executing the rear-wheel steering angle.

[0011] In an optional embodiment, the rear-wheel steering actuator is controlled to execute the steering of the rear wheels based on the current rear-wheel steering angle to be executed, including: determining the steering direction of the rear wheels of the current vehicle based on the relative steering relationship between the current rear wheels of the target vehicle and the current steering wheel and the current steering direction of the steering wheel; determining an actual rear-wheel steering angle control target based on the steering direction of the rear wheels and the absolute value of the current rear-wheel steering angle to be executed; and controlling the rear-wheel steering actuator to execute the steering of the rear wheels based on the actual rear-wheel steering angle control target.

[0012] In an optional embodiment, the positive and negative values ​​of the rear wheel steering angle in the medium and high speed control Map represent the relative steering relationship between the vehicle's rear wheels and the steering wheel, and the steering direction of the rear wheels of the current vehicle is determined based on the relative steering relationship between the current rear wheels of the target vehicle and the current steering wheel and the current steering direction of the steering wheel, including: determining the relative steering relationship between the current rear wheels of the target vehicle and the current steering wheel based on the positive and negative values ​​of the rear wheel steering angle currently to be executed; when the relative steering relationship between the current rear wheels of the target vehicle and the current steering wheel is in the same direction, using the steering direction of the current steering wheel as the steering direction of the current rear wheels; when the relative steering relationship between the current rear wheels of the target vehicle and the current steering wheel is in the opposite direction, using the opposite direction of the steering of the current steering wheel as the steering direction of the current rear wheels.

[0013] In a third aspect, the present invention provides a Map construction device for a rear-wheel steering angle, the device comprising: a vehicle dynamics model establishment module, for establishing a vehicle dynamics model of a target vehicle, and obtaining a vehicle speed set and a steering wheel angle set of the target vehicle within a drivable medium-high speed range, wherein the drivable medium-high speed range is a range between a preset maximum vehicle speed and an expected maximum vehicle speed of the target vehicle; a vehicle model establishment module, for establishing, based on the vehicle dynamics model, a reference vehicle model having a vehicle speed, a steering wheel angle and calibration parameters as inputs and an expected yaw angular velocity as output, and a real vehicle model having the expected yaw angular velocity as input and a rear-wheel steering angle as output; a vehicle control model establishment module, for connecting the output of the reference vehicle model with the input of the real vehicle model to construct a vehicle control model; a Map establishment module, for inputting the vehicle speed set, the steering wheel angle set and the preset calibration parameters into the vehicle control model to obtain a medium-high speed control Map corresponding to the vehicle speed, the steering wheel angle and the rear-wheel steering angle.

[0014] In a fourth aspect, the present invention provides a rear-wheel steering control device, characterized in that the device includes: a vehicle driving parameter acquisition module, used to obtain the vehicle speed and steering wheel angle of the target vehicle; a rear-wheel steering angle calculation module, used to search for a medium- and high-speed control Map corresponding to the speed, steering wheel angle and rear-wheel steering angle of the target vehicle based on the vehicle speed and steering wheel angle of the target vehicle, and obtain the rear-wheel steering angle currently to be executed, wherein the medium- and high-speed control Map corresponding to the speed, steering wheel angle and rear-wheel steering angle of the target vehicle is constructed using the rear-wheel steering angle Map construction device as described in claim 8; a rear-wheel steering execution module, used to control the rear-wheel steering actuator to execute the steering of the rear wheels based on the rear-wheel steering angle currently to be executed.

[0015] In a fifth aspect, the present invention provides a vehicle, comprising a controller, wherein the controller comprises: a memory and a processor, wherein the memory and the processor are communicatively connected to each other, computer instructions are stored in the memory, and the processor executes the rear-wheel steering control method of the second aspect or any corresponding embodiment thereof by executing the computer instructions.

[0016] In an optional embodiment, the vehicle is a three-axle vehicle with three-axle steering.

[0017] In a sixth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the rear wheel steering angle map construction method of the first aspect or any corresponding embodiment thereof, or to execute the rear wheel steering control method of the second aspect or any corresponding embodiment thereof.

[0018] In a seventh aspect, the present invention provides a computer program product, comprising computer instructions for causing a computer to execute the method for constructing a Map of rear wheel steering angles according to the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 is a schematic diagram of the process of constructing a Map of rear wheel steering angles according to an embodiment of the present invention;

[0021] Figure 2is a structural example diagram of a three-axle steering vehicle according to an embodiment of the present invention;

[0022] Figure 3 is a structural example diagram of a vehicle control model according to an embodiment of the present invention;

[0023] Figure 4 is a schematic flow chart of another method for constructing a rear wheel steering angle map according to an embodiment of the present invention;

[0024] Figure 5 is a diagram showing an example of the structure of a full-speed domain Map according to an embodiment of the present invention;

[0025] Figure 6 is a flow chart of a rear wheel steering control method according to an embodiment of the present invention;

[0026] Figure 7 is a flow chart of another rear wheel steering control method according to an embodiment of the present invention;

[0027] Figure 8 is a structural block diagram of a device for constructing a map of rear wheel steering angles according to an embodiment of the present invention;

[0028] Fig. 9 is a structural block diagram of a rear wheel steering control device according to an embodiment of the present invention;

[0029] Fig.10 is a structural example diagram of a vehicle according to an embodiment of the present invention;

[0030] Fig.11 Schematic diagram of the hardware structure of the controller according to the embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0032] According to an embodiment of the present invention, a map construction of a rear wheel steering angle and an embodiment of a rear wheel steering control method are provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0033] In this embodiment, a method for constructing a map of rear wheel steering angles is provided, which can be used in the above-mentioned mobile device. Figure 1 FIG. 4 is a flow chart of a method for constructing a Map of rear wheel steering angles according to an embodiment of the present invention. Figure 1 As shown, the process includes the following steps:

[0034] Step S101, establishing a vehicle dynamics model of a target vehicle, and obtaining a vehicle speed set and a steering wheel angle set of the target vehicle within a drivable medium and high speed range.

[0035] The drivable medium and high speed range is the range between the preset maximum speed of the target vehicle and the expected maximum speed.

[0036] The target vehicle of the embodiment of the present invention is not limited to the multi-axle vehicle with all-wheel steering and the multi-axle vehicle with non-all-wheel steering, and can be determined according to the actual design of the vehicle. For example, a three-axle vehicle with three-axle steering Figure 2 As shown, it is assumed that when the vehicle is moving, the tire stiffness is in the linear region, the mass of the vehicle is m, and the velocity in the x direction of the vehicle coordinate system is v x , the distance between the first axis and the second axis is L1, the distance between the first axis and the third axis is L2, and the rotation angles of the first, second, and third axes are δ f , δ m , δ r The tire slip angles of the first, second, and third axles are α f , α m , α r , the distances from the first, second, and third axes to the center of mass of the vehicle are l a , l b , l c The tire stiffness of the first, second and third axles are k f , k m , k r , the motion of the three-axle vehicle satisfies the following equation when the vehicle is in steady state:

[0037]

[0038] The turning angle of a three-axle vehicle satisfies the following relationship:

[0039]

[0040] Among them, for a three-axle steering vehicle, the second axis angle δ m =0, and the above two equations can be combined to obtain the three-axis steering vehicle dynamics model.

[0041] Because the tire wear control map corresponding to low speed belongs to the prior art, it will not be repeated here. The present invention can obtain the speed set and steering wheel angle set of the target vehicle in the drivable medium and high speed range, wherein the drivable medium and high speed range is the preset maximum speed and the maximum speed expected to be controlled.

[0042] Obtain the speed set and steering wheel angle set of the target vehicle within the drivable medium and high speed range.

[0043] Among them, the drivable medium and high speed range is the range between the preset maximum speed Vmax and the expected maximum speed VcMax of the target vehicle, generally taking the value as 42km / h to 120km / h. The steering wheel angle set can be the steering angle range of the steering wheel, i.e. the front wheels, for example only.

[0044] Step S102, based on the vehicle dynamics model, establish a reference vehicle model with vehicle speed, steering wheel angle and calibration parameters as input and expected yaw rate as output, and a real vehicle model with expected yaw rate as input and rear wheel steering angle as output.

[0045] like Figure 3 As shown, the embodiment of the present invention is based on the established vehicle dynamics model as the core of the reference vehicle model and the real vehicle model, and establishes a reference vehicle model with vehicle speed, steering wheel angle and calibration parameters as input and expected yaw rate as output, wherein the calibration parameters at least include parameters such as the distance from the first axis to the center of mass, the distance from the first axis to the third axis, the vehicle mass, the tire stiffness and the vehicle yaw inertia, which are used to change the calculation parameters in the reference vehicle model to generate the expected yaw rate, and then establish a real vehicle model with the expected yaw rate as input and the rear wheel steering angle as output, wherein the real vehicle model is an actual vehicle model, and the actual calculation parameters integrated in the real vehicle model, such as the distance from the center of mass to the first axis, are consistent with the actual collected vehicle data, which is only taken as an example.

[0046] Step S103, connecting the output of the reference vehicle model with the input of the real vehicle model to construct a vehicle control model.

[0047] like Figure 3 As shown, the embodiment of the present invention connects the output of the reference vehicle model with the input of the real vehicle model, that is, the expected yaw angular velocity output by the reference vehicle model is used as the input of the real vehicle model to calculate the rear wheel steering angle and construct a vehicle control model.

[0048] Step S104, inputting the vehicle speed set, the steering wheel angle set and the preset calibration parameters into the vehicle control model to obtain a medium and high speed control Map corresponding to the vehicle speed, the steering wheel angle and the rear wheel steering angle.

[0049] The embodiment of the present invention inputs the acquired vehicle speed set, steering wheel angle set and preset calibration parameters within the medium and high speed range into the vehicle control model, outputs the rear wheel steering angle corresponding to any vehicle speed and steering wheel angle, and then constructs a medium and high speed control Map corresponding to the vehicle speed, steering wheel angle and rear wheel steering angle.

[0050] The detailed process of inputting the vehicle speed, steering wheel angle set and preset calibration parameters into the vehicle control model to obtain the corresponding rear wheel angle is as follows:

[0051] The following relationship is satisfied when a three-axle vehicle turns:

[0052] mv x (β&+γ)=F f cosδ f +F m cosδ m +F r cosδ r

[0053] I z γ&=l a F f cosδ f -l b F m cosδ m -l c F r cosδ r

[0054] Among them, β is the sideslip angle of the center of mass, γ is the yaw rate, and F f ,F m ,F r are the cornering forces of the front, middle and rear axles, I z is the yaw inertia of the vehicle.

[0055] The relationship satisfied when a three-axle vehicle turns can be written as follows:

[0056]

[0057] Among them, X, U and C were not used later. Figure 2 D1, D2 and D3 in FIG. 1 are not used and will not be described in detail here.

[0058] Assume δ m and δ r Satisfy δ m =K 12 δ f ,δ r =K 13 δ f ,but:

[0059]

[0060] in, represents the yaw rate gain, s represents the Laplace operator (complex variable), K 12 is the ratio of the second axis angle to the first axis angle, K 13 is the ratio of the third axis angle to the first axis angle.

[0061] The reference vehicle model only considers the first axis steering, at this time K 12 =0, K 13 =0, let s = 0, and we can get the yaw rate gain in steady state:

[0062]

[0063] The first and third axis steering in the real vehicle model, K 12 =0. We get:

[0064]

[0065] Among them, γ 13 represents the yaw rate of the first and third axis steering, γ front is the yaw rate of the front axle steering;

[0066] make We can get:

[0067]

[0068] By δ r =K 13 δ f , you can get the rear wheel steering angle control target of the real car model, just as an example.

[0069] The method for constructing a Map of a rear wheel steering angle provided in this embodiment establishes a vehicle dynamics model of a target vehicle, and based on the vehicle dynamics model, establishes a reference vehicle model with vehicle speed, steering wheel angle and calibration parameters as inputs and expected yaw rate as output, and an actual vehicle model with expected yaw rate as input and rear wheel steering angle as output, and connects the output of the reference vehicle model with the input of the actual vehicle model to construct a vehicle control model, and inputs a vehicle speed set, a steering wheel angle set and preset calibration parameters into the vehicle control model, so that a Map corresponding to the vehicle speed, steering wheel angle and rear wheel steering angle can be obtained in advance, and the Map is completed by first constructing it offline, so that only a simple search of the Map is required in subsequent actual vehicle control, thereby reducing the probability of rear wheel steering failure due to algorithm logic bugs, reducing the computational load of the rear wheel steering controller, improving the target rear wheel angle calculation speed, and reducing response delays.

[0070] In this embodiment, a method for constructing a rear wheel steering angle map is provided, which can be used in the above controller. Figure 4 FIG. 4 is a flow chart of a method for constructing a Map of rear wheel steering angles according to an embodiment of the present invention. Figure 4 As shown, the process includes the following steps:

[0071] Step S401: Establish a vehicle dynamics model of the target vehicle, and obtain a set of vehicle speeds and steering wheel angles of the target vehicle within a drivable medium and high speed range. The drivable medium and high speed range is the range between the preset maximum speed of the target vehicle and the expected maximum speed. Figure 1 Step S101 of the illustrated embodiment will not be described in detail here.

[0072] Step S402: Based on the vehicle dynamics model, a reference vehicle model is established with vehicle speed, steering wheel angle and calibration parameters as input and expected yaw rate as output, as well as a real vehicle model with expected yaw rate as input and rear wheel steering angle as output. Figure 1 Step S102 of the illustrated embodiment will not be described in detail here.

[0073] Step S403: Connect the output of the reference vehicle model with the input of the real vehicle model to construct a vehicle control model. Figure 1 Step S103 of the illustrated embodiment will not be described in detail here.

[0074] Step S404, inputting the vehicle speed set, the steering wheel angle set and the preset calibration parameters into the vehicle control model to obtain a medium and high speed control Map corresponding to the vehicle speed, the steering wheel angle and the rear wheel steering angle.

[0075] Specifically, the preset calibration quantity parameters are obtained through the following steps: inputting the preset calibration quantity parameters, the vehicle speed set, and the current vehicle speed and steering wheel angle in the steering wheel angle set into the vehicle control model to obtain the rear wheel steering angle corresponding to the current vehicle speed and the steering wheel angle; outputting the rear wheel steering angle to the rear wheel steering actuator for execution, calculating the yaw rate gain of the vehicle, and judging whether the yaw rate gain reaches the preset gain threshold; if the yaw rate gain does not reach the preset gain threshold, changing the preset calibration quantity parameters until the yaw rate gain reaches the preset gain threshold, and obtaining the calibration quantity parameters corresponding to the current vehicle speed; traversing all vehicle speeds in the vehicle speed set to obtain the calibration quantity parameters corresponding to all vehicle speeds respectively.

[0076] In the embodiment of the present invention, the currently set calibration quantity parameters and the current vehicle speed and steering wheel angle in the vehicle speed set can be input into the vehicle control model, and the rear wheel steering angle corresponding to the current vehicle speed and steering wheel angle can be obtained, wherein the specific steering wheel angle is not limited, and the rear wheel steering angle can be set according to the steering wheel angle of the actual vehicle, and the rear wheel steering angle can be output to the rear wheel steering actuator for execution, and the yaw rate gain of the vehicle can be calculated, and the driver's actual vehicle evaluation can be used to determine whether the yaw rate gain of the vehicle meets the desired requirements. If the yaw rate gain corresponding to the currently set calibration quantity parameters does not meet the desired requirements, the set calibration quantity parameters can be changed, and the rear wheel steering angle is repeatedly output to calculate the yaw rate gain of the vehicle until the yaw rate gain corresponding to the currently changed calibration quantity parameters meets the desired requirements, and the calibration quantity parameters corresponding to the current vehicle speed can be recorded. Then, all vehicle speeds in the vehicle speed set can be traversed, and finally the calibration quantity parameters that meet the driver's expectations at each vehicle speed can be obtained.

[0077] In the embodiment of the present invention, any vehicle speed and steering wheel angle in the vehicle speed set and a calibration parameter corresponding to the vehicle speed are input into the vehicle control model to obtain the rear wheel steering angle.

[0078] The present invention sets the yaw rate gain at each vehicle speed to meet the expected calibration parameters, and then inputs the vehicle speed set, the steering wheel angle set and the calibration parameters corresponding to each vehicle speed into the vehicle control model, thereby obtaining a medium- and high-speed control Map with the yaw rate gain as the target. During subsequent actual vehicle control, the vehicle controls the rear wheel steering based on the medium- and high-speed control Map, thereby improving the user's driving experience.

[0079] Specifically, a vehicle speed set, a steering wheel angle set and preset calibration parameters are input into a vehicle control model to obtain a map to be processed corresponding to the vehicle speed, steering wheel angle and rear wheel steering angle; angle sampling points are extracted at a preset first angle sampling interval in a first steering wheel angle range in the map to be processed; angle sampling points are extracted at a preset second angle sampling interval in a second steering wheel angle range in the map to be processed, the minimum steering wheel angle in the second steering wheel angle range is equal to the maximum steering wheel angle in the first steering wheel angle range, and the first angle sampling interval is less than the second angle sampling interval; the steering wheel angle corresponding to the maximum value of the rear wheel steering angle in the map is extracted as the angle sampling point; vehicle speed sampling points are extracted at a preset vehicle speed sampling point interval in the map to be processed; a medium and high speed control map is constructed based on the angle sampling points, vehicle speed sampling points and the corresponding rear wheel steering angle.

[0080] In the embodiment of the present invention, a vehicle speed set, a steering wheel angle set, and a preset calibration quantity parameter are input into the vehicle control model. After obtaining a to-be-processed map corresponding to the vehicle speed, the steering wheel angle, and the rear wheel steering angle, sampling points can be extracted at different sampling intervals in different steering wheel angle regions according to the usage frequency of the map. f In a smaller area, a smaller sampling interval is used to extract the corner sampling points, which can be f For larger areas, a larger sampling interval is used to extract the corner sampling points. For example, in the 1-7° front wheel angle area, breakpoints are taken at intervals of 1°; in the angle area above 7°, breakpoints are taken at intervals of 3°. Other equidistant or non-equidistant strategies can also be used to extract sampling points, just as an example; in order to improve the accuracy of Map interpolation in the control algorithm, the saturation value of the rear wheel steering angle, that is, the steering wheel steering angle corresponding to the maximum value, is used as the angle sampling point; based on the speed sampling point value selection strategy, the speed sampling points can be extracted at a fixed speed sampling point interval in the map to be processed, such as taking values ​​at intervals of 3km / h, just as an example. Finally, the extracted corner sampling points, speed sampling points and corresponding rear wheel steering angles can be constructed to obtain a medium- and high-speed control map.

[0081] In this aspect, the sampling interval of the steering wheel angle is adjusted in a targeted manner according to the frequency of map use, reducing unnecessary space occupation. At the same time, the steering wheel angle corresponding to the rear wheel steering saturation point is used as the angle sampling point to ensure the accuracy of map search.

[0082] Step S405, obtaining a tire wear Map corresponding to the target vehicle.

[0083] Among them, the tire wear Map is a Map of the vehicle speed, steering wheel angle and rear wheel steering angle corresponding to a preset vehicle speed less than a preset minimum speed.

[0084] Step S406, based on the tire wear Map and the medium and high speed control Map corresponding to the target vehicle, an interpolation algorithm is used to calculate a transition area Map.

[0085] The transition area map is a map of the vehicle speed, steering wheel angle and rear wheel steering angle corresponding to a vehicle speed between a preset minimum speed and a preset maximum speed.

[0086] Step S407, combining the tire wear map, transition area map and medium and high speed control map based on the vehicle speed to obtain a full speed range map.

[0087] In the embodiment of the present invention, for a three-axle vehicle with three-axle steering, low-speed control is aimed at tire wear control, and medium- and high-speed control is aimed at adjusting the yaw rate gain. The vehicle speed range of the tire wear control Map is [0~Vmin], and the vehicle speed range of the medium- and high-speed control Map is [Vmax, Vcmax]. At this time, the tire wear control Map and the medium- and high-speed control Map are combined based on the vehicle speed. The transition interval [Vmin, Vmax] is missing in the synthesized Map. Therefore, the Map in the transition area [Vmin, Vmax] can be calculated by an interpolation algorithm, so that the tire wear control and the medium- and high-speed control can be smoothly transitioned to obtain a better driving experience. The interpolation algorithm is not limited, and can be a two-dimensional linear interpolation algorithm or other difference algorithms, such as Hermite interpolation, cubic spline interpolation, adjacent point interpolation, etc., for example only. Finally, the tire wear Map, the transition area Map and the medium- and high-speed control Map are combined based on the vehicle speed to obtain the following: Figure 5 Full-speed domain map of the structure shown.

[0088] The control Map designed by the present invention takes different driving experiences into consideration within different vehicle speed ranges. The tire wear Map, transition area Map and medium and high speed control Map are combined to obtain a full-speed range Map, so that all vehicle speeds and steering wheel angles that may occur during driving can be searched in the Map to find their corresponding rear wheel steering angles, thereby improving the user's driving experience.

[0089] In this embodiment, a rear wheel steering control method is also provided, which can be used in the above controller. Figure 6 is a flow chart of a rear wheel steering control method according to an embodiment of the present invention. Figure 6 As shown, the process includes the following steps:

[0090] Step S601, obtaining the speed and steering wheel angle of the target vehicle.

[0091] Step S602, based on the speed and steering wheel angle of the target vehicle, find the medium and high speed control Map corresponding to the speed, steering wheel angle and rear wheel steering angle of the target vehicle to obtain the rear wheel steering angle to be executed.

[0092] The medium and high speed control Map corresponding to the speed, steering wheel angle and rear wheel steering angle of the target vehicle is constructed by using the Map construction method of the rear wheel steering angle described in the above embodiment.

[0093] Step S603, controlling the rear wheel steering actuator to perform rear wheel steering based on the current rear wheel steering angle to be executed.

[0094] During vehicle driving, the present invention can obtain the vehicle speed and steering wheel angle, i.e., the front wheel angle, in real time, and search a pre-obtained Map based on the vehicle speed and the steering wheel angle to obtain the current rear wheel steering angle to be executed, and can output the current rear wheel steering angle to be executed to the rear wheel steering actuator to execute the steering of the rear wheels.

[0095] The rear-wheel steering control method provided by the present invention obtains the vehicle speed and steering wheel angle during vehicle driving, and based on the vehicle speed and steering wheel angle, it only needs to simply look up the medium- and high-speed control Map corresponding to the speed, steering wheel angle and rear-wheel steering angle of the target vehicle to obtain the current rear-wheel steering angle to be executed, and finally controls the rear-wheel steering actuator to execute the steering of the rear wheels based on the current rear-wheel steering angle to be executed, thereby improving the speed of determining and executing the rear-wheel steering angle.

[0096] In this embodiment, a rear wheel steering control method is also provided, which can be used in the above controller. Figure 7 is a flow chart of a rear wheel steering control method according to an embodiment of the present invention. Figure 7 As shown, the process includes the following steps:

[0097] Step S701, obtain the speed and steering wheel angle of the target vehicle. Figure 6 Step S601 of the illustrated embodiment will not be described in detail here.

[0098] Step S702, based on the speed and steering wheel angle of the target vehicle, find the medium and high speed control Map corresponding to the speed, steering wheel angle and rear wheel steering angle of the target vehicle to obtain the rear wheel steering angle to be executed. The medium and high speed control Map corresponding to the speed, steering wheel angle and rear wheel steering angle of the target vehicle is constructed by using the Map construction method of the rear wheel steering angle described in the above embodiment. For details, please refer to Figure 6 Step S602 of the illustrated embodiment will not be described in detail here.

[0099] Step S703: Controlling the rear wheel steering actuator to perform rear wheel steering based on the current rear wheel steering angle to be executed.

[0100] Specifically, step S703 includes:

[0101] Step S7031, determining the steering direction of the rear wheels of the current vehicle based on the relative steering relationship between the current rear wheels of the target vehicle and the current steering wheel and the current steering direction of the steering wheel.

[0102] Specifically, the positive and negative values ​​of the rear wheel steering angle in the medium and high speed control Map indicate the relative steering relationship between the vehicle's rear wheels and the steering wheel. Based on the positive and negative values ​​of the rear wheel steering angle to be executed, the relative steering relationship between the current rear wheels and the current steering wheel of the target vehicle is determined; when the relative steering relationship between the current rear wheels and the current steering wheel of the target vehicle is in the same direction, the steering direction of the current steering wheel is used as the steering direction of the current rear wheels; when the relative steering relationship between the current rear wheels and the current steering wheel of the target vehicle is in the opposite direction, the opposite direction of the steering of the current steering wheel is used as the steering direction of the current rear wheels.

[0103] The embodiment of the present invention is designed to unify the left and right turns of the rear wheels into a full-speed domain Map, wherein the positive and negative values ​​of the rear wheel steering angle in the Map can represent the relative steering relationship between the rear wheels of the vehicle and the steering wheel angle. For example, it can be defined that when the steering wheel angle and the rear wheel steering angle are in the same direction, the rear wheel steering angle in the full-speed domain Map is positive, and when the steering wheel angle and the rear wheel steering angle are in opposite directions, the rear wheel steering angle in the full-speed domain Map is negative. As an example only, it can also be defined that when the steering wheel angle and the rear wheel steering angle are in the same direction, the rear wheel steering angle in the full-speed domain Map is negative, and when the steering wheel angle and the rear wheel steering angle are in opposite directions, the rear wheel steering angle in the full-speed domain Map is positive, which does not affect the use effect.

[0104] In the embodiment of the present invention, when the rear wheel steering angle is found to be a positive value, it can be determined that the current rear wheel steering angle is in the same direction as the steering wheel angle, and the steering direction of the current steering wheel can be used as the steering direction of the current rear wheel; if the rear wheel steering angle is found to be a negative value, it can be determined that the current rear wheel steering angle is opposite to the steering wheel angle, and the opposite steering direction of the current steering wheel can be used as the steering direction of the current rear wheel, just as an example.

[0105] Step S7032, determining an actual rear wheel steering angle control target based on the steering direction of the rear wheels and the absolute value of the rear wheel steering angle to be currently executed;

[0106] When defining the vehicle signal, the embodiment of the present invention may define a left turn as positive and a right turn as negative. For example, if the rear-wheel steering angle is a positive value, it means that the current rear-wheel steering angle is in the same direction as the steering wheel angle, and the positive or negative value of the steering wheel angle may be assigned to the absolute value of the rear-wheel steering angle to obtain an actual rear-wheel steering angle control target. If the rear-wheel steering angle is a negative value, it means that the current rear-wheel steering angle is in the opposite direction of the steering wheel angle, and the positive or negative value of the steering wheel angle may be reversed and assigned to the absolute value of the rear-wheel steering angle to obtain an actual rear-wheel steering angle control target.

[0107] Step S7033, controlling the rear wheel steering actuator to perform rear wheel steering based on the actual rear wheel steering angle control target.

[0108] The present invention unifies the left turn and right turn of the rear wheel steering angle into a full-speed range Map based on positive and negative values, thereby reducing the storage space occupied.

[0109] In an optional implementation, the embodiment of the present invention takes into account that the vehicle speed in R gear (reverse gear) is relatively low and the low speed is mainly controlled by tire wear, so the R gear and D gear (forward gear) use the same Map to reduce storage space occupancy.

[0110] In this embodiment, a rear wheel steering angle map construction device and a rear wheel steering control device are also provided, which are used to implement the above-mentioned embodiments and preferred implementation modes, and will not be repeated hereafter. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0111] This embodiment provides a device for constructing a map of rear wheel steering angles. Figure 8 As shown, it includes: a vehicle dynamics model building module 801, which is used to build a vehicle dynamics model of the target vehicle, and obtain a speed set and a steering wheel angle set of the target vehicle within a drivable medium and high speed range, where the drivable medium and high speed range is a range between a preset maximum speed of the target vehicle and an expected maximum speed; a vehicle model building module 802, which is used to build a reference vehicle model with a vehicle speed, a steering wheel angle and a calibration parameter as input and an expected yaw rate as output, and a real vehicle model with an expected yaw rate as input and a rear wheel steering angle as output based on the vehicle dynamics model; a vehicle control model building module 803, which is used to connect the output of the reference vehicle model with the input of the real vehicle model to construct a vehicle control model; a map building module 804, which is used to input the vehicle speed set, the steering wheel angle set and the preset calibration parameter into the vehicle control model to obtain a medium and high speed control map corresponding to the vehicle speed, the steering wheel angle and the rear wheel steering angle.

[0112] In some optional embodiments, the map establishment module 804 includes: a rear-wheel steering angle calculation unit, which is used to input the preset calibration parameters, the vehicle speed set, and the current vehicle speed and steering wheel angle in the steering wheel angle set into the vehicle control model to obtain the rear-wheel steering angle corresponding to the current vehicle speed and steering wheel angle; an angular velocity gain calculation unit, which is used to output the rear-wheel steering angle to the rear-wheel steering actuator for execution, calculate the yaw angular velocity gain of the vehicle, and determine whether the yaw angular velocity gain reaches a preset gain threshold; a calibration parameter change unit, which is used to change the preset calibration parameters if the yaw angular velocity gain does not reach the preset gain threshold until the yaw angular velocity gain reaches the preset gain threshold to obtain the calibration parameters corresponding to the current vehicle speed; a calibration parameter set determination unit, which is used to traverse all vehicle speeds in the vehicle speed set to obtain the calibration parameters corresponding to all vehicle speeds.

[0113] In some optional embodiments, the rear wheel steering angle Map construction device also includes: a tire wear Map acquisition module, used to obtain a tire wear Map corresponding to the target vehicle, the tire wear Map being a Map of vehicle speed, steering wheel angle and rear wheel steering angle corresponding to a preset vehicle speed less than a preset minimum speed; a transition area Map calculation module, used to calculate a transition area Map based on the tire wear Map and the medium and high speed control Map corresponding to the target vehicle by using an interpolation algorithm, the transition area Map being a Map of vehicle speed, steering wheel angle and rear wheel steering angle corresponding to a vehicle speed between a preset minimum speed and a preset maximum speed; a full-speed range Map determination module, used to combine the tire wear Map, the transition area Map and the medium and high speed control Map based on the vehicle speed to obtain a full-speed range Map.

[0114] In some optional embodiments, the map establishment module 804 includes: a map output unit, which is used to input the vehicle speed set, the steering wheel angle set and the preset calibration parameters into the vehicle control model to obtain a map to be processed corresponding to the vehicle speed, the steering wheel angle and the rear wheel steering angle; a first corner sampling point extraction unit, which is used to extract corner sampling points at a preset first corner sampling interval within a first steering wheel angle range area in the map to be processed; a second corner sampling point extraction unit, which is used to extract corner sampling points at a preset second corner sampling interval within a second steering wheel angle range area in the map to be processed. Extract the angle sampling points, the minimum steering wheel angle within the second steering wheel angle range is equal to the maximum steering wheel angle within the first steering wheel angle range, and the first angle sampling interval is smaller than the second angle sampling interval; the third angle sampling point extraction unit is used to extract the steering wheel angle corresponding to the maximum value of the rear wheel steering angle in the Map as the angle sampling point; the vehicle speed sampling point extraction unit is used to extract the vehicle speed sampling points at a preset vehicle speed sampling point interval in the Map to be processed; the Map determination unit is used to construct a medium and high speed control Map based on the angle sampling points, the vehicle speed sampling points and the corresponding rear wheel steering angles.

[0115] This embodiment provides a rear wheel steering control device, such as Fig. 9 As shown, it includes: a vehicle driving parameter acquisition module 901, which is used to obtain the speed and steering wheel angle of the target vehicle; a rear-wheel steering angle calculation module 902, which is used to find the medium and high-speed control Map corresponding to the speed, steering wheel angle and rear-wheel steering angle of the target vehicle based on the speed and steering wheel angle of the target vehicle, and obtain the rear-wheel steering angle currently to be executed. The medium and high-speed control Map corresponding to the speed, steering wheel angle and rear-wheel steering angle of the target vehicle is constructed by using the Map construction device of the rear-wheel steering angle described in the above embodiment; a rear-wheel steering execution module 903, which is used to control the rear-wheel steering actuator to execute the steering of the rear wheels based on the rear-wheel steering angle currently to be executed.

[0116] In some optional embodiments, the rear-wheel steering execution module 903 includes: a rear-wheel steering direction determination unit, used to determine the steering direction of the rear wheels of the current vehicle based on the relative steering relationship between the current rear wheels of the target vehicle and the current steering wheel and the current steering direction of the steering wheel; an actual rear-wheel steering angle determination unit, used to determine the actual rear-wheel steering angle control target based on the steering direction of the rear wheels and the absolute value of the rear-wheel steering angle currently to be executed; and a rear-wheel steering execution unit, used to control the rear-wheel steering actuator to execute the steering of the rear wheels based on the actual rear-wheel steering angle control target.

[0117] In some optional embodiments, the positive and negative values ​​of the rear wheel steering angle in the medium and high speed control Map indicate the relative steering relationship between the rear wheels and the steering wheel of the vehicle, and the rear wheel steering direction determination unit includes: a relative special relationship determination subunit, for determining the relative steering relationship between the current rear wheels and the current steering wheel of the target vehicle based on the positive and negative values ​​of the rear wheel steering angle currently to be executed; a first steering determination subunit, for using the steering direction of the current steering wheel as the steering direction of the current rear wheels when the relative steering relationship between the current rear wheels and the current steering wheel of the target vehicle is in the same direction; and a second steering determination subunit, for using the opposite direction of the current steering wheel as the steering direction of the current rear wheels when the relative steering relationship between the current rear wheels and the current steering wheel of the target vehicle is in the opposite direction.

[0118] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0119] The rear wheel steering angle map construction device and the rear wheel steering control device in this embodiment are presented in the form of functional units, where the units refer to ASIC (Application Specific Integrated Circuit) circuits, processors and memories that execute one or more software or fixed programs, and / or other devices that can provide the above functions.

[0120] The embodiment of the present invention further provides a vehicle, such as Fig.10 As shown, the vehicle includes a controller having the above Fig. 9 Rear wheel steering controls shown.

[0121] See also Fig.11 , Fig.11 is a schematic diagram of the structure of a controller provided by an optional embodiment of the present invention, such as Fig.11 As shown, the controller includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. The various components are connected to each other using different buses for communication, and can be installed on a common mainboard or installed in other ways as needed. The processor can process instructions executed in the controller, including instructions stored in or on the memory to display graphical information of the GUI on an external input / output device (such as a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple controllers can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Fig.11 A processor 10 is taken as an example.

[0122] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0123] The memory 20 stores instructions executable by at least one processor 10, so that at least one processor 10 executes the method shown in the above embodiment.

[0124] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required by at least one function; the data storage area may store data created according to the use of the controller, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the controller via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0125] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0126] The controller also includes an input device 30 and an output device 40. The processor 10, the memory 20, the input device 30 and the output device 40 may be connected via a bus or other means. Fig.11 The example of connecting through bus is taken in the following.

[0127] The input device 30 can receive input digital or character information and generate key signal input related to the user settings and function control of the controller, such as a touch screen, a keypad, a mouse, a track pad, a touch pad, an indicator bar, one or more mouse buttons, a trackball, a joystick, etc. The output device 40 may include a display device, an auxiliary lighting device (e.g., an LED) and a tactile feedback device (e.g., a vibration motor), etc. The above-mentioned display device includes but is not limited to a liquid crystal display, a light emitting diode, a display and a plasma display. In some optional embodiments, the display device can be a touch screen.

[0128] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0129] A part of the present invention may be applied as a computer program product, such as a computer program instruction, which, when executed by a computer, can call or provide the method and / or technical solution according to the present invention through the operation of the computer. Those skilled in the art should understand that the existence of the computer program instruction in a computer-readable medium includes, but is not limited to, a source file, an executable file, an installation package file, etc., and accordingly, the way in which the computer program instruction is executed by the computer includes, but is not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Here, the computer-readable medium may be any available computer-readable storage medium or communication medium accessible to the computer.

[0130] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A method for constructing a map of rear wheel steering angles, characterized in that: The method comprises: Establishing a vehicle dynamics model of the target vehicle, and obtaining a vehicle speed set and a steering wheel angle set of the target vehicle within a drivable medium-high speed range, wherein the drivable medium-high speed range is a range between a preset maximum vehicle speed of the target vehicle and an expected maximum vehicle speed; Based on the vehicle dynamics model, a reference vehicle model is established, which takes the vehicle speed, steering wheel angle and calibration parameters as inputs and the expected yaw rate as output, and a real vehicle model is established, which takes the expected yaw rate as input and the rear wheel steering angle as output; Connecting the output of the reference vehicle model with the input of the real vehicle model to construct a vehicle control model; The vehicle speed set, the steering wheel angle set and preset calibration parameters are input into the vehicle control model to obtain a medium and high speed control Map corresponding to the vehicle speed, steering wheel angle and rear wheel steering angle.

2. The method according to claim 1, characterized in that The preset calibration parameters are obtained by the following steps: Inputting the preset calibration quantity parameter, the vehicle speed set, and the current vehicle speed and steering wheel angle in the steering wheel angle set into the vehicle control model to obtain the rear wheel steering angle corresponding to the current vehicle speed and steering wheel angle; Outputting the rear wheel steering angle to a rear wheel steering actuator for execution, calculating a yaw rate gain of the vehicle, and determining whether the yaw rate gain reaches a preset gain threshold; If the yaw rate gain does not reach the preset gain threshold, the preset calibration parameter is changed until the yaw rate gain reaches the preset gain threshold, and the calibration parameter corresponding to the current vehicle speed is obtained; All vehicle speeds in the vehicle speed set are traversed to obtain calibration parameters corresponding to all vehicle speeds.

3. The method according to claim 1, characterized in that The method further comprises: Obtaining a tire wear map corresponding to the target vehicle, wherein the tire wear map is a map of vehicle speed, steering wheel angle, and rear wheel steering angle corresponding to a preset vehicle speed less than a preset minimum vehicle speed; Based on the tire wear map corresponding to the target vehicle and the medium and high speed control map, a transition area map is calculated using an interpolation algorithm, wherein the transition area map is a map of vehicle speed, steering wheel angle, and rear wheel steering angle corresponding to a vehicle speed between a preset minimum speed value and a preset maximum speed value; The tire wear Map, the transition area Map and the medium and high speed control Map are combined and processed based on the vehicle speed to obtain a full speed range Map.

4. The method according to claim 1, characterized in that The vehicle speed set, the steering wheel angle set and the preset calibration quantity parameters are input into the vehicle control model to obtain a medium and high speed control Map corresponding to the vehicle speed, the steering wheel angle and the rear wheel steering angle, including: Inputting the vehicle speed set, the steering wheel angle set and the preset calibration quantity parameters into the vehicle control model to obtain a to-be-processed Map corresponding to the vehicle speed, the steering wheel angle and the rear wheel steering angle; Extracting angle sampling points at a preset first angle sampling interval in a first steering wheel angle range area in the map to be processed; Extracting angle sampling points at a preset second angle sampling interval in a second steering wheel angle range in the map to be processed, wherein the minimum steering wheel angle in the second steering wheel angle range is equal to the maximum steering wheel angle in the first steering wheel angle range, and the first angle sampling interval is smaller than the second angle sampling interval; Extract the steering wheel angle corresponding to the maximum value of the rear wheel steering angle in the Map as the angle sampling point; Extracting vehicle speed sampling points at preset vehicle speed sampling point intervals in the map to be processed; Based on the turning angle sampling points, vehicle speed sampling points and corresponding rear wheel steering angles, a medium and high speed control Map is constructed.

5. A rear wheel steering control method, characterized in that: The method comprises: Obtain the speed and steering wheel angle of the target vehicle; Based on the speed and steering wheel angle of the target vehicle, searching for a medium- and high-speed control Map corresponding to the speed, steering wheel angle and rear wheel steering angle of the target vehicle to obtain a rear wheel steering angle to be currently executed, wherein the medium- and high-speed control Map corresponding to the speed, steering wheel angle and rear wheel steering angle of the target vehicle is constructed by using the Map construction method for the rear wheel steering angle according to any one of claims 1 to 4; The rear wheel steering actuator is controlled to perform the steering of the rear wheels based on the rear wheel steering angle to be currently performed.

6. The method according to claim 5, characterized in that Controlling a rear wheel steering actuator to perform rear wheel steering based on the current rear wheel steering angle to be performed includes: Determining the steering direction of the rear wheels of the current vehicle based on the relative steering relationship between the current rear wheels of the target vehicle and the current steering wheel and the current steering direction of the steering wheel; Determining an actual rear wheel steering angle control target based on the steering direction of the rear wheels and the absolute value of the rear wheel steering angle currently to be executed; The rear wheel steering actuator is controlled to perform the steering of the rear wheels based on the actual rear wheel turning angle control target.

7. The method according to claim 6, characterized in that The positive and negative values ​​of the rear wheel steering angle in the medium and high speed control map represent the relative steering relationship between the rear wheels of the vehicle and the steering wheel. The determining the steering direction of the rear wheels of the current vehicle based on the relative steering relationship between the current rear wheels of the target vehicle and the current steering wheel and the current steering direction of the steering wheel includes: Determining a relative steering relationship between current rear wheels and a current steering wheel of the target vehicle based on the positive and negative values ​​of the current rear wheel steering angle to be executed; When the relative steering relationship between the current rear wheels and the current steering wheel of the target vehicle is in the same direction, the steering direction of the current steering wheel is used as the steering direction of the current rear wheels; When the relative steering relationship between the current rear wheels and the current steering wheel of the target vehicle is reverse, the reverse direction of the steering of the current steering wheel is used as the steering direction of the current rear wheels.

8. A device for constructing a map of rear wheel steering angles, characterized in that: The device comprises: A vehicle dynamics model building module is used to build a vehicle dynamics model of a target vehicle and obtain a vehicle speed set and a steering wheel angle set of the target vehicle within a drivable medium and high speed range, wherein the drivable medium and high speed range is a range between a preset maximum vehicle speed of the target vehicle and an expected maximum vehicle speed; A vehicle model building module, for building, based on the vehicle dynamics model, a reference vehicle model with vehicle speed, steering wheel angle and calibration parameters as inputs and expected yaw rate as output, and a real vehicle model with the expected yaw rate as input and rear wheel steering angle as output; A vehicle control model building module, used to connect the output of the reference vehicle model with the input of the real vehicle model to construct a vehicle control model; The map establishment module is used to input the vehicle speed set, the steering wheel angle set and the preset calibration parameters into the vehicle control model to obtain a medium and high speed control map corresponding to the vehicle speed, steering wheel angle and rear wheel steering angle.

9. A rear wheel steering control device, characterized in that: The device comprises: A vehicle driving parameter acquisition module is used to obtain the speed and steering wheel angle of the target vehicle; a rear wheel steering angle calculation module, for searching a medium and high speed control Map corresponding to the speed, steering wheel angle and rear wheel steering angle of the target vehicle based on the speed and steering wheel angle of the target vehicle, and obtaining a rear wheel steering angle to be executed currently, wherein the medium and high speed control Map corresponding to the speed, steering wheel angle and rear wheel steering angle of the target vehicle is constructed by using the rear wheel steering angle Map construction device according to claim 8; The rear wheel steering execution module is used to control the rear wheel steering actuator to execute the steering of the rear wheels based on the rear wheel steering angle to be currently executed.

10. A vehicle, characterized in that: The vehicle includes a controller, which includes: a memory and a processor, the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the rear-wheel steering control method according to any one of claims 5 to 7 by executing the computer instructions.

11. The vehicle according to claim 10, characterized in that The vehicle is a three-axle vehicle with three-axle steering.

12. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the rear wheel steering angle Map construction method described in any one of claims 1 to 4, or to execute the rear wheel steering control method described in any one of claims 5 to 7.

13. A computer program product, characterized in that The method comprises computer instructions for causing a computer to execute the method for constructing a rear wheel steering angle map according to any one of claims 1 to 4.

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