A steering wheel return control method and vehicle control device

Abstract

This disclosure provides a steering wheel return-to-center control method and vehicle control device. The method includes: monitoring the initial steering wheel angle during the last parking maneuver; if the initial steering wheel angle is outside a set angle range; determining a steering return-to-center correction value for the initial steering wheel angle based on a pre-established matrix table of correspondences between the initial steering wheel angle and the return-to-center angle; and controlling the vehicle's steering wheel return-to-center based on the steering return-to-center correction value. The steering wheel return-to-center control method and vehicle control device disclosed in this disclosure can perform steering angle compensation when the initial steering wheel angle is outside the set angle range, thus solving the problem that the steering wheel cannot return to center after the parking system exits.

Description

Technical Field

[0001] This disclosure relates to, but is not limited to, the automotive field, and particularly to a steering wheel return control method and a vehicle control device. Background Technology

[0002] When the vehicle is in automatic parking, if the tires have a large lateral elastic deformation on a certain type of road surface and the stress has not been released when the vehicle completes the final parking maneuver, it will result in a large lateral rebound torque when the steering system turns. After the parking system exits, the steering wheel will not be able to return to center. Summary of the Invention

[0003] This disclosure provides a method for controlling steering wheel return to center, including:

[0004] Monitor the initial steering wheel angle when parking the car for the last time. The initial steering wheel angle When the steering wheel angle is outside the set range, the initial steering wheel angle is determined based on a pre-established matrix table corresponding to the initial steering wheel angle and the return-to-center angle. The steering wheel is returned to center based on the steering return correction value.

[0005] This disclosure also provides a vehicle control device, including a memory and a processor. The memory stores execution instructions, and the processor invokes the execution instructions to execute the steering wheel return control method described in any embodiment.

[0006] The steering wheel return control method and vehicle control device provided in at least one embodiment of this disclosure have the following advantages compared with the prior art: when the initial steering wheel angle is not within the set angle range, steering angle compensation can be performed to solve the problem that the steering wheel cannot return to center after the parking system is disengaged.

[0007] Other features and advantages of this disclosure will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the disclosure. Other advantages of this disclosure may be realized and obtained by means of the methods described in the description and the accompanying drawings. Attached Figure Description

[0008] The accompanying drawings are used to provide an understanding of the technical solutions of this disclosure and form part of the specification. They are used together with the embodiments of this disclosure to explain the technical solutions of this disclosure and do not constitute a limitation on the technical solutions of this disclosure.

[0009] Figure 1 This is a flowchart of a steering wheel return control method provided in an example embodiment of the present disclosure;

[0010] Figure 2A schematic diagram of the modeling process for the compensation angle of steering wheel return to center;

[0011] Figure 3 This is a logic diagram for steering wheel return compensation provided in an embodiment of the present disclosure;

[0012] Figure 4A Original image of a parking space on a cement road surface;

[0013] Figure 4B for Figure 4A Image after edge detection processing;

[0014] Figure 5A Original image of a parking space on a grass brick pavement;

[0015] Figure 5B for Figure 5A Image after edge detection processing;

[0016] Figure 6 This is a flowchart illustrating the identification process for non-uniform road surface types, provided in an example embodiment of this disclosure.

[0017] Figure 7 A data model diagram illustrating the relationship between power steering current, steering angle, and road friction coefficient;

[0018] Figure 8 A schematic diagram illustrating the modeling process for the matrix table of steering current, steering angle, and road friction coefficient.

[0019] Figure 9 A flowchart illustrating a steering wheel return control method provided in another exemplary embodiment of this disclosure;

[0020] Figure 10 This is a structural block diagram of a vehicle control device provided in an embodiment of the present disclosure. Detailed Implementation

[0021] This disclosure describes several embodiments, but these descriptions are exemplary and not limiting, and it will be apparent to those skilled in the art that many more embodiments and implementations are possible within the scope of the embodiments described herein. Although many possible combinations of features are shown in the drawings and discussed in the detailed description, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with, or may replace, any feature or element of any other embodiment.

[0022] This disclosure includes and contemplates combinations of features and elements known to those skilled in the art. The embodiments, features, and elements disclosed in this disclosure may also be combined with any conventional features or elements to form a unique inventive scheme as defined by the claims. Any feature or element of any embodiment may also be combined with features or elements from other inventive schemes to form another unique inventive scheme as defined by the claims. Therefore, it should be understood that any feature shown and / or discussed in this disclosure may be implemented individually or in any suitable combination. Therefore, the embodiments are not limited except by the limitations imposed by the appended claims and their equivalents. Furthermore, various modifications and changes may be made within the scope of the appended claims.

[0023] Furthermore, in describing representative embodiments, the specification may have presented methods and / or processes as a specific sequence of steps. However, the method or process should not be limited to the specific order of steps described herein, to the extent that the method or process does not depend on the specific order of steps described herein. As will be understood by those skilled in the art, other sequences of steps are also possible. Therefore, the specific order of steps set forth in the specification should not be construed as a limitation of the claims. Moreover, the claims relating to the method and / or process should not be limited to the steps performed in the order written, and those skilled in the art will readily understand that these orders can be varied and still remain within the spirit and scope of the embodiments disclosed herein.

[0024] Figure 1 This is a flowchart of a steering wheel return-to-center control method provided in an example embodiment of the present disclosure, as follows: Figure 1 As shown, the control methods for steering wheel return to center may include: S101, S102 and S103.

[0025] S101: Monitors the initial steering wheel angle during the final parking maneuver.

[0026] The steering wheel angle can be monitored using a steering wheel angle sensor on the vehicle. When the parking system (PAS) controls the vehicle to enter a parking space, it continuously sends angle control requests. The PAS can detect the angle fed back by the steering wheel angle sensor to obtain the initial steering wheel angle at the moment of the final turn of the steering wheel when parking.

[0027] S102: At the initial steering wheel angle When the steering wheel is outside the set steering angle range, the initial steering wheel angle is determined based on a pre-established matrix table corresponding to the initial steering wheel angle and the return-to-center angle. The steering correction value.

[0028] The steering wheel deviation acceptance range [-λ, λ] can be defined, where λ > 0. λ can be determined based on empirical values ​​or actual application conditions, provided that the initial steering wheel angle is satisfied. or Steering angle compensation can be performed to solve the problem that the steering wheel cannot return to center after the parking system is disengaged.

[0029] In one example, λ can be determined based on the road surface type; the value of λ will vary depending on the road surface type at the time of parking.

[0030] Collect the initial steering wheel position when parking for the last time. The system retrieves the stored matrix table corresponding to the initial steering wheel angle and the return-to-center angle, checks the corresponding matrix table to determine the steering return-to-center correction value, and resolves the issue of the steering wheel not returning to center after parking.

[0031] In one example, the matrix table corresponding to the initial steering wheel angle and the return-to-center angle records the correspondence between road surface type, initial steering wheel angle, and steering wheel angle after parking. Based on the pre-established matrix table, determining the steering return-to-center correction value for the initial steering wheel angle can include:

[0032] Determine the road surface type when parking u n Based on the correspondence between road surface type, initial steering wheel angle, and steering wheel angle after parking recorded in the corresponding matrix table, the relationship with road surface type u is determined. n Initial steering wheel angle The corresponding steering wheel angle after parking Determine the steering return correction value

[0033] Define road surface type u n Above, when parking, the initial steering wheel angle is... The angle at which the steering wheel does not return to center due to tire deformation after parking is: That is, after parking, the steering wheel angle is The steering wheel angle can be adjusted after parking. As the return-to-center turning angle, compensation is performed for the corresponding steering angle on that road surface.

[0034] Road surface type u was identified before parking was completed. n The system searches for or retrieves a stored matrix table showing the correspondence between the initial steering wheel angle and the return-to-center angle. Table 1 is the matrix table showing the correspondence between the initial steering wheel angle and the return-to-center angle provided in this embodiment of the present disclosure. As shown in Table 1, the matrix table showing the correspondence between the initial steering wheel angle and the return-to-center angle records the road surface type u. n Initial steering wheel angle Steering wheel angle after parking The correspondence.

[0035] Table 1

[0036]

[0037] Road surface type detected during parking n Then, based on the corresponding matrix table shown in Table 1, the steering angle compensation corresponding to this road surface type is given. This solves the problem of the steering wheel not returning to center after parking.

[0038] In one example, the steering wheel return control method may also include: establishing a matrix table corresponding to the initial steering wheel angle and the return angle: on known different road surface types, collecting the initial steering wheel angle when parking for the last time and the steering wheel angle after parking, establishing and storing the correspondence between the road surface type, the initial steering wheel angle and the steering wheel angle after parking.

[0039] It can collect data on different road surface types. n The steering wheel deviation angle during parking is used to establish a corresponding matrix table of the initial steering wheel angle and the return-to-center angle. The parking system determines the parking surface type. n Then, perform different initial steering wheel angles. The test was conducted by collecting data on different road surface types. n Steering wheel deviation angle when parking Steering wheel angle after parking The correspondence between the initial steering wheel angle and the return-to-center angle is established and stored in the controller memory.

[0040] Figure 2 A schematic diagram illustrating the modeling process for the compensation angle of steering wheel return to center, as shown below. Figure 2 As shown, u n Parking on a road surface, making different initial steering wheel angles. The test collected the tire deviation angle. A matrix table corresponding to the initial steering wheel angle and the return-to-center angle is created and written into the memory. The matrix table of the initial steering wheel angle and the return-to-center angle stored in the memory can be called the steering angle compensation module E3.

[0041] In one example, a matrix table mapping initial steering wheel angle to return-to-center angle records the correspondence between the initial steering wheel angle and the steering wheel angle after parking. Based on this pre-established matrix table, determining the steering return-to-center correction value for the initial steering wheel angle can include:

[0042] Based on the correspondence between the initial steering wheel angle and the steering wheel angle after parking recorded in the corresponding matrix table, the relationship between the initial steering wheel angle and the steering wheel angle after parking is determined. The corresponding steering wheel angle after parking

[0043] Different initial steering wheel angles can be set regardless of road surface type. The test collected different steering wheel deviation angles during parking. Steering wheel angle after parking The correspondence between the initial steering wheel angle and the return-to-center angle is established and stored in the controller memory.

[0044] S103: Controls the vehicle's steering wheel to return to center based on the steering return correction value.

[0045] Based on the steering characteristics of EPS, PAS sends a steering return correction value after parking to control the vehicle's steering wheel to return to center, thus solving the problem of the steering wheel not returning to center after parking.

[0046] In one example, controlling the steering wheel return to center based on the steering return correction value can include: controlling the steering wheel angle rotation. Then stop.

[0047] Initial steering wheel angle When not within the set turning range, i.e. or Control the steering wheel angle rotation Stopping the steering wheel allows it to return to center.

[0048] Figure 3 The steering wheel return compensation logic diagram provided in this embodiment of the disclosure is as follows: Figure 3 As shown, PAS recognizes the initial steering wheel angle as... or PAS sends steering correction angle After the parking system controls the vehicle to park in the parking space, the parking system PAS continuously sends angle control requests. The PAS detects the angle fed back by the steering wheel angle sensor. Then exit the handshake, at which point the steering wheel will spring back to center.

[0049] The steering wheel return control method provided in this embodiment can perform steering angle compensation when the initial steering wheel angle is not within the set angle range, thus solving the problem that the steering wheel cannot return to center after the parking system is disengaged.

[0050] In an example embodiment of this disclosure, the road surface type u is determined when parking. n It can include:

[0051] The system acquires road surface images during parking, performs edge detection processing on the road surface images, and determines whether the road surface is uniform. When the road surface is determined to be non-uniform, the specific type of non-uniform road surface is determined based on the pre-set similarity function SSIM. When the road surface is determined to be uniform, the specific type of uniform road surface is determined based on the set steering parameters of the electric power steering system EPS.

[0052] After classifying roads into uniform and non-uniform types using machine vision algorithms, the specific type of non-uniform road surface can be identified through image similarity, while the specific type of uniform road surface can be identified through EPS steering assist.

[0053] Define parking space road surface type label u n ∈{u 1i ,u 2j Common parking space surface types include uniform surfaces. 1i Non-uniform road surface u 2j Uniform road surfaces lack distinct features; common examples include asphalt pavements. 11 Epoxy flooring 12 and marble pavement 13 Non-uniform pavements have more obvious characteristics, such as rectangular grass brick pavements. 21 and polygonal grass brick pavement u 22 or u 23 wait.

[0054] Figure 4A This is the original image of a parking space on a cement road surface. Figure 4B for Figure 4A The image after edge detection processing. Figure 5A This is the original image of a parking space on a grass-paved road. Figure 5B for Figure 5A The image after edge detection processing, such as Figures 4A to 5B As shown, machine vision methods can effectively detect objects with obvious features. Digital images of non-uniform road surfaces contain obvious points and lines, and the road surface edges in the image can be detected by the Canny edge detection algorithm in the image processing system.

[0055] In one example embodiment of this disclosure, determining whether the road surface is uniform after edge detection processing of the road surface image may include:

[0056] Determine the pixel matrix of the road surface image after edge detection processing. m ij =0 represents a black pixel in the image, m ij =1 represents a white pixel in the image; the uniformity of the road surface is determined by the edge point ratio ξ. When ξ ≥ threshold ξ1, the road surface is judged to be non-uniform; when ξ < threshold ξ1, the road surface is judged to be uniform.

[0057] The original road surface image, after edge detection processing, can be defined as a pixel matrix M. ij i > 0, j > 0, m ij This represents the pixel in the i-th row and j-th column. For the image after edge detection processing, the uniformity of the road surface can be determined based on the edge point ratio. The edge point ratio formula can be defined as:

[0058] The threshold for determining whether a road surface is uniform or non-uniform is defined as ξ1. If ξ ≥ ξ1, the road surface is considered non-uniform; if ξ < ξ1, the road surface is considered uniform. The threshold ξ1 can be determined based on empirical values, and this embodiment will not limit or elaborate on it here.

[0059] In one example embodiment of this disclosure, determining the specific type of a non-uniform road surface based on a pre-defined similarity function SSIM may include:

[0060] The formula SSIM(x,y)=[a(x,y)] is used. m [b(x,y)] n [c(x,y)] o Determine the similarity SSIM(x,y) between the road surface image x and the set data images y of different road surface types; determine the road surface type corresponding to the maximum similarity as the specific type of the non-uniform road surface to be identified;

[0061] Where m>0, n>0, o>0, and a(x,y), b(x,y), and c(x,y) represent the brightness, contrast, and structure of the image, respectively.

[0062] The structural similarity function SSIM can be used to calculate the quality index of image similarity, quantifying it from three aspects: image brightness (a), contrast (b), and structure (c). For a known non-uniform road surface u... 2j The SSIM similarity function can be used to calculate the u of a non-uniform road surface. 2j The similarity.

[0063] Let x and y be digital images of different road surface categories. The mathematical definition of the similarity function SSIM can be expressed as: SSIM(x,y)=[a(x,y)] m [b(x,y)] n [c(x,y)] o m > 0, n > 0, o > 0, and the values ​​can be defined according to the actual situation; a(x,y), b(x,y), c(x,y) can be constructed by calling existing mathematical definitions using the mean difference, standard deviation, and covariance of x and y, which will not be elaborated here.

[0064] Figure 6 This is a flowchart illustrating the identification process for non-uniform road surface types, provided in an example embodiment of this disclosure. Figure 6 As shown, the identification of non-uniform road surface types can include:

[0065] S601: Data collection of non-uniform road surface u 2j image.

[0066] S602: Construct the digital image standard library X.

[0067] Collect known images of different road surface types. 2j Defined as the digital image standard library X = u 2j The digital image standard library X stored in the memory can be called the visual recognition non-uniform road surface module E1.

[0068] S603: Write to memory.

[0069] S604: Obtain the image Y of the non-uniform road surface to be identified.

[0070] S605: Call the SSIM function to calculate similarity k j .

[0071] Acquire a real-time road surface image Y to be identified, and call function k. j =SSIM(x j ,y j ), calculate the similarity value k between the Y image and all road surface types in the standard library X. j Table 2 is the pavement type similarity matrix. As shown in Table 2, the pavement type similarity matrix records the pavement type and the similarity value k. j The correspondence.

[0072] Table 2

[0073] Road surface category <![CDATA[k j ]]> <![CDATA[u 21 ]]> <![CDATA[K(k1,u 21 )]]> <![CDATA[u 22 ]]> <![CDATA[K(k2,u 22 )]]> …… …… <![CDATA[u 2j ]]> <![CDATA[K(k j ,in 2j )]]>

[0074] S606:k j =maxK(k j ,u 2j ).

[0075] S607: Confirm the non-uniform road surface category.

[0076] Take the maximum value from the similarity matrix table, i.e., k j =maxK(k j ,u 2j The road surface type corresponding to the similarity value is the road surface type to be identified.

[0077] In one example embodiment of this disclosure, determining the specific type of a uniform road surface based on the set steering parameters of the electric power steering (EPS) system may include:

[0078] Collect at least one of the power steering current and steering angle; based on a pre-established matrix table of power steering current, steering angle and road friction coefficient, determine the road friction coefficient that matches at least one of the collected power steering current and steering angle; determine the specific type of uniform road surface based on the road friction coefficient.

[0079] In related technologies, identifying uniform road conditions when tires have no slippage is a challenge. According to steering mechanics, different friction coefficients on uniform road surfaces result in different steering assist levels and steering assist currents from the EPS (Electric Power Steering). In this embodiment, the type of uniform road surface can be identified by the difference in EPS steering assist. Figure 7 To generate a data model diagram showing the relationship between power steering current, steering angle, and road friction coefficient, a model can be built based on the specific vehicle model, such as... Figure 7 The three-dimensional data model shown.

[0080] based on Figure 7 The three-dimensional data model shown yields the power steering current, steering angle, and road friction coefficient matrix table in Table 3. The steering angle is the steering wheel angle for EPS power steering, which can be represented by SAS. The steering current can be represented by I, with units of amperes (A). 1i This represents the coefficient of friction of the ground.

[0081] Table 3

[0082]

[0083] When parking, the power steering current and steering angle are collected. Based on the power steering current, steering angle and road friction coefficient matrix table shown in Table 3, the road friction coefficient corresponding to the collected power steering current and steering angle is found in the matrix table. The specific type of uniform road surface can be determined based on the road friction coefficient.

[0084] Different types of homogeneous pavements have different coefficients of friction, while the coefficient of friction for a homogeneous pavement remains constant. A pre-established correspondence between the coefficient of friction of a pavement and the specific type of homogeneous pavement can be used to determine the specific type of homogeneous pavement based on its coefficient of friction. For example, the coefficient of friction for asphalt roads can reach 0.95, and a correspondence between 0.95 and asphalt roads can be established.

[0085] In one example embodiment of this disclosure, it may further include:

[0086] Establish a matrix table of power steering current, steering angle and road friction coefficient: On known different road surface types, collect power steering current at different steering angles, and establish and store a matrix table of power steering current, steering angle and road friction coefficient.

[0087] Figure 8 A schematic diagram illustrating the modeling process for the matrix table of steering current, steering angle, and road friction coefficient is shown below. Figure 8 As shown, images of different types of homogeneous road surfaces were collected. 1i , collect u 1i The power steering current at different steering angles during parking on the road is calculated; a matrix table of power steering current, steering angle, and road friction coefficient is constructed and written into memory. The matrix table of power steering current, steering angle, and road friction coefficient stored in memory can be called the steering identification uniform road surface module E2.

[0088] Figure 9 A flowchart of a steering wheel return control method provided in another exemplary embodiment of this disclosure is shown below. Figure 9 As shown, the methods for controlling steering wheel return to center can include:

[0089] S901: Automatic parking enters the parking space for the last time.

[0090] S902: Real-time acquisition of digital images.

[0091] S903: PAS calls the E1 or E2 module to identify the road surface type.

[0092] S904: Confirm road surface type u n .

[0093] S905: Based on the initial steering wheel angle at the last entry into the parking space. Determine whether to call module E3. If yes, execute S906; otherwise, execute S908.

[0094] S906:

[0095] S907: The parking system sends a request to return the steering wheel to center.

[0096] S908:

[0097] S909: Parking complete, PAS exits.

[0098] Figure 10 This is a structural block diagram of the vehicle control device provided in the embodiments of this disclosure, such as... Figure 10 As shown, the vehicle control device may include a memory 101 and a processor 102.

[0099] The memory stores execution instructions. The processor can be a Central Processing Unit (CPU), an Application Specific Integrated Circuit (ASIC), or one or more integrated circuits that implement the embodiments of this disclosure. When the vehicle control device is running, the processor communicates with the memory, and the processor invokes execution instructions to perform the following operations:

[0100] Monitor the initial steering wheel angle when parking the car for the last time.

[0101] The initial steering wheel angle When the steering wheel angle is outside the set range, the initial steering wheel angle is determined based on a pre-established matrix table corresponding to the initial steering wheel angle and the return-to-center angle. The steering return correction value;

[0102] The steering wheel of the vehicle is controlled to return to center based on the steering return correction value.

[0103] In one example embodiment of this disclosure, the matrix table corresponding to the initial steering wheel angle and the return-to-center angle records the correspondence between road surface type, initial steering wheel angle, and steering wheel angle after parking.

[0104] Based on a pre-established matrix table corresponding to the initial steering wheel angle and the return-to-center angle, the processor determines the steering return-to-center correction value for the initial steering wheel angle, which may include:

[0105] Determine the road surface type when parking u n Based on the correspondence between the road surface type, the initial steering wheel angle, and the steering wheel angle after parking recorded in the corresponding matrix table, the relationship between the road surface type u and the road surface type u is determined. n Initial steering wheel angle The corresponding steering wheel angle after parking

[0106] Determine the steering return correction value

[0107] In one example embodiment of this disclosure, the processor controls the vehicle's steering wheel to return to center based on the steering return correction value, which may include:

[0108] Control the steering wheel angle rotation Then stop.

[0109] In one example embodiment of this disclosure, the processor is further configured to:

[0110] Establish a matrix table corresponding to the initial steering wheel angle and the return-to-center angle: On known different road surface types, collect the initial steering wheel angle when parking for the last time and the steering wheel angle after parking, and establish and store the correspondence between the initial steering wheel angle and the steering wheel angle after parking.

[0111] In one example embodiment of this disclosure, the processor determines the road surface type u when parking. n It can include:

[0112] Collect road surface images when parking, and determine whether the road surface is uniform after edge detection processing of the road surface images;

[0113] When determining that the road surface is a non-uniform road surface, the specific type of the non-uniform road surface is determined based on the pre-defined similarity function SSIM;

[0114] When the road surface is determined to be uniform, the specific type of uniform road surface is determined based on the steering parameters set by the electric power steering system (EPS).

[0115] In one example embodiment of this disclosure, the processor determines whether the road surface is uniform after edge detection processing of the road surface image, which may include:

[0116] Determine the pixel matrix of the road surface image after edge detection processing. m ij =0 represents a black pixel in the image, m ik =1 represents a white pixel in the image;

[0117] The uniformity of the road surface is determined by the edge point ratio ξ.

[0118] When ξ ≥ threshold ξ1, the road surface is determined to be a non-uniform road surface;

[0119] When ξ < threshold ξ1, the road surface is judged to be a uniform road surface.

[0120] In one example embodiment of this disclosure, the processor determines the specific type of non-uniform road surface based on a pre-defined similarity function SSIM, which may include:

[0121] The formula SSIM(x,y)=[a(x,y)] is used. m [b(x,y)] n [c(x,y)] o Determine the similarity SSIM(x,y) between the road surface image x and the set data images y of different road surface types;

[0122] The road surface type corresponding to the maximum similarity is determined as the specific type of the non-uniform road surface to be identified.

[0123] Where m>0, n>0, o>0, and a(x,y), b(x,y), and c(x,y) represent the brightness, contrast, and structure of the image, respectively.

[0124] In one example embodiment of this disclosure, the processor determines the specific type of a uniform road surface based on the set steering parameters of the electric power steering system (EPS), which may include:

[0125] Collect at least one of the power steering current and steering angle;

[0126] Based on a pre-established matrix table of power steering current, steering angle and road friction coefficient, determine the road friction coefficient that matches at least one of the collected power steering current and steering angle.

[0127] The specific type of uniform road surface is determined based on the road surface friction coefficient.

[0128] In one example embodiment of this disclosure, the processor is further configured to:

[0129] Establish a matrix table of power steering current, steering angle and road friction coefficient: On known different road surface types, collect power steering current at different steering angles, and establish and store a matrix table of power steering current, steering angle and road friction coefficient.

[0130] It will be understood by those skilled in the art that all or some of the steps, systems, or apparatuses disclosed above, and their functional modules / units, can be implemented as software, firmware, hardware, or suitable combinations thereof. In hardware implementations, the division between functional modules / units mentioned above does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit (ASIC). Such software may be distributed on a computer-readable medium, which may include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and can be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

Claims

1. A method for controlling steering wheel return to center, characterized in that, include: Monitor the initial steering wheel angle when parking the car for the last time. ; The initial steering wheel angle When the steering wheel angle is outside the set range, the initial steering wheel angle is determined based on a pre-established matrix table corresponding to the initial steering wheel angle and the return-to-center angle. The steering return correction value; The vehicle's steering wheel is controlled to return to center based on the steering return correction value; The matrix table corresponding to the initial steering wheel angle and the return-to-center angle records the correspondence between road surface type, initial steering wheel angle, and steering wheel angle after parking. Furthermore, the step of determining the steering wheel return correction value based on a pre-established matrix table of the correspondence between the initial steering wheel angle and the return angle includes: Determine the road surface type when parking Based on the correspondence between the road surface type, the initial steering wheel angle, and the steering wheel angle after parking recorded in the corresponding matrix table, the relationship between the road surface type and the steering wheel angle after parking is determined. Initial steering wheel angle The corresponding steering wheel angle after parking ; Determine the steering return correction value .

2. The method according to claim 1, characterized in that, Controlling the vehicle's steering wheel to return to center based on the steering return correction value includes: Control the steering wheel angle rotation .

3. The method according to claim 1, characterized in that, The method further includes: Establish a matrix table corresponding to the initial steering wheel angle and the return-to-center angle: On known different road surface types, collect the initial steering wheel angle when parking for the last time and the steering wheel angle after parking, and establish and store the correspondence between the initial steering wheel angle and the steering wheel angle after parking.

4. The method according to claim 1, characterized in that, The road surface type at the time of parking is determined. ,include: Collect road surface images when parking, and determine whether the road surface is uniform after edge detection processing of the road surface images; When determining that the road surface is a non-uniform road surface, the specific type of the non-uniform road surface is determined based on the pre-defined similarity function SSIM; When the road surface is determined to be uniform, the specific type of uniform road surface is determined based on the steering parameters set by the electric power steering system (EPS).

5. The method according to claim 4, characterized in that, The step of determining whether the road surface is uniform after edge detection processing of the road surface image includes: Determine the pixel matrix of the road surface image after edge detection processing. , Represents black pixels in the image. Represents white pixels in an image; Based on edge point ratio To determine whether the road surface is uniform, the ratio of edge points is used. ; exist At that time, the road surface was determined to be non-uniform. exist At that time, the road surface was determined to be a uniform road surface.

6. The method according to claim 4, characterized in that, The determination of the specific type of non-uniform road surface based on the pre-defined similarity function SSIM includes: Using the formula SSIM(x,y) = Determine the similarity SSIM(x,y) between the road surface image x and the set data images y of different road surface types; The road surface type corresponding to the maximum similarity is determined as the specific type of the non-uniform road surface to be identified. Where m>0, n>0, o>0, and a(x,y), b(x,y), and c(x,y) represent the brightness, contrast, and structure of the image, respectively.

7. The method according to claim 4, characterized in that, The determination of the specific type of uniform road surface based on the steering parameters set by the electric power steering (EPS) system includes: Collect at least one of the power steering current and steering angle; Based on a pre-established matrix table of power steering current, steering angle and road friction coefficient, determine the road friction coefficient that matches at least one of the collected power steering current and steering angle. The specific type of uniform road surface is determined based on the road surface friction coefficient.

8. The method according to claim 7, characterized in that, The method further includes: Establish a matrix table of power steering current, steering angle and road friction coefficient: On known different road surface types, collect power steering current at different steering angles, and establish and store a matrix table of power steering current, steering angle and road friction coefficient.

9. A vehicle control device, characterized in that, It includes a memory and a processor, wherein the memory is used to store execution instructions; the processor invokes the execution instructions to execute the steering wheel return control method as described in any one of claims 1-8.

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