A method of adjusting the field of view of an electronic exterior mirror

Abstract

The application relates to the technical field of automobile control, and provides a kind of electronic outside rearview mirror field of vision adjusting method, according to the semi-trailer calibration vehicle body data, then respectively to tractor and trailer are kinematic model building, collect real-time transmission steering wheel angle and vehicle speed information, real-time calculation of the real-time angle of tractor and trailer, and then combine the focal length of the camera, pixel calculation camera moving pixel value distance, through the dynamic adjustment of the display field of view range of camera, realize the follow-up field of view adjustment of semi-trailer truck, keep the driver always in the field of view range that can see the traffic condition of the vehicle tail, improve the safety of the vehicle.

Description

Technical Field

[0001] This invention relates to the field of automotive control technology, and in particular to a method for adjusting the field of view of an electronic exterior rearview mirror. Background Technology

[0002] Currently, semi-trailer trucks play a crucial role in my country's logistics and transportation industry. However, due to their large overall length and the articulated connection between the tractor and trailer, traditional physical rearview mirrors cannot detect traffic conditions near the rear of the trailer when the vehicle is turning, resulting in a significant blind spot. Many low-speed accidents involving semi-trailer trucks are caused by this blind spot during turns. Therefore, it is necessary to have rearview mirrors that adjust to maintain visibility when the truck is turning, ensuring the driver can always see the rear of the vehicle.

[0003] In recent years, camera imaging systems have developed rapidly, and their functions have become increasingly sophisticated. Compared with traditional physical rearview mirrors, electronic exterior rearview mirrors offer advantages such as reduced blind spots, a wider field of vision, clearer visibility in rainy or foggy weather, and the ability to automatically adjust the field of vision according to driving conditions. For semi-trailer trucks, the ability to adjust the field of vision dynamically ensures that the driver can always see the traffic conditions behind the truck, avoiding blind spots caused by turning and reducing the likelihood of traffic accidents.

[0004] Because semi-trailer trucks have large blind spots, which easily lead to traffic accidents, reducing these blind spots has long been a research focus for many scholars. Some researchers calculate the steering angle of the tractor's front wheels by using the steering wheel rotation angle and steering ratio, collect data on the relationship between the angle of the tractor's front wheels and the vehicle body at different speeds, and use algorithms to calculate and display the field of vision of the trailer's rear on the steering side. This makes the field of vision change with the steering wheel angle and vehicle speed. However, in reality, different vehicle speeds and the angle of the tractor's front wheels vary greatly, making it difficult to capture all situations. When the data is insufficient, the field of vision display will be abrupt, possibly jumping suddenly, and unable to achieve a smooth, dynamic field of vision. Moreover, since semi-trailer trucks are sold separately from their tractors and trailers, a user can purchase a tractor and attach trailers of different lengths and sizes, and a trailer can be towed by different tractors. The pre-collected relationship on the angle between the tractor's front wheels and the vehicle body at different speeds cannot be used when the tractor or trailer is changed, making this method less versatile. Summary of the Invention

[0005] This invention provides a method for adjusting the field of view of an electronic exterior rearview mirror, which solves the technical problems of existing semi-trailer truck electronic exterior rearview mirror field of view adjustment technology relying on a large amount of data analysis, resulting in poor flexibility and incompatibility with different tractor vehicles and trailers.

[0006] To solve the above technical problems, the present invention provides a method for adjusting the field of view of an electronic exterior rearview mirror, comprising the following steps:

[0007] S1. Calibrate the current vehicle body data and obtain the vehicle's motion information;

[0008] S2. Based on the vehicle body data and motion information, construct kinematic models for the tractor and trailer of the current vehicle respectively;

[0009] S3. Calculate the real-time angle between the tractor and the trailer based on the kinematic model;

[0010] S4. Calculate the distance the camera has moved by pixels based on the real-time angle;

[0011] S5. Adjust the camera field of view in real time based on the pixel value distance.

[0012] This basic solution is based on the calibrated body data of the semi-trailer truck. Then, kinematic models are built for the tractor and trailer respectively. Real-time steering wheel angle and vehicle speed information are collected and transmitted. The real-time angles of the tractor and trailer are calculated. Then, the pixel value distance of the camera movement is calculated by combining the focal length and pixel of the camera. By dynamically adjusting the display field of view of the camera, the semi-trailer truck's field of view can be adjusted accordingly, keeping the driver in a field of view that can see the traffic situation behind the vehicle, thus improving vehicle safety.

[0013] In a further embodiment, in step S1:

[0014] The vehicle body data includes the wheelbase L1 of the front and rear axles of the tractor, the distance d between the articulation point and the center of the rear axle of the tractor, the distance L2 between the articulation point and the center of the rear axle of the trailer, and the steering ratio between the steering wheel and the front wheels of the tractor.

[0015] The process of acquiring vehicle motion information includes: acquiring the current steering wheel angle of the vehicle, the speed of the tractor, and calculating the steering angle δ of the front wheels of the tractor based on the steering ratio.

[0016] In a further implementation, in step S2, building a kinematic model of the tractor of the current vehicle includes:

[0017] S21. Establish a right-handed coordinate system with the vehicle's position at any moment of motion as the origin and the vehicle's direction of travel as the positive X-axis.

[0018] S22. Based on Ackermann kinematics and the vehicle body data and motion information, establish the kinematic model of the corresponding tractor vehicle. The model formula is as follows;

[0019]

[0020] In the formula, (x 1，k-1 y 1，k-1 Φ 1，k-1 (x) represents the pose of the rear axle center of the tractor at time k-1. 1，k y 1，k Φ 1，k ) represents the pose of the rear axle center of the tractor at time k, Δt is the sampling time interval, Φ1 is the yaw angle of the tractor, δ is the steering angle of the front wheels of the tractor, and V is the speed of the tractor.

[0021] S23. Based on the speed of the tractor and the steering angle of the front wheels of the tractor, calculate the turning angular velocity equation of the tractor. The calculation formula is as follows:

[0022]

[0023] In the formula, R1 is the turning angular velocity of the tractor vehicle, and R2 is the rotation radius of the rear axle center of the tractor vehicle.

[0024] In a further implementation, step S2, the kinematic model construction of the trailer of the current vehicle includes:

[0025] S24. Calculate the speed of the articulation point based on the vehicle body data and the speed of the tractor.

[0026] S25. Calculate the trailer's speed based on the tractor's speed at the articulated point;

[0027] S26. Based on the trailer's speed and the radius of rotation of the trailer's rear axle center, calculate the trailer's turning angular velocity equation. The calculation formula is as follows:

[0028]

[0029] In the formula, R2 is the turning angular velocity of the trailer, V2 is the rotation radius of the rear axle center of the trailer, θ is the angle between the speed of the articulation point and the speed of the tractor, and λ is the angle between the trailer and the tractor at the current moment.

[0030] After calibrating the vehicle body data, this solution establishes a right-handed coordinate system based on the vehicle's direction of motion to create kinematic models for the corresponding tractor and semi-trailer. Based on Ackerman kinematics, the pose of the semi-trailer is accurately calculated. It is compatible with different types of tractor and trailer combinations, providing accurate and effective data for calculating the real-time angles of the tractor and trailer, and has good versatility.

[0031] In a further embodiment, step S3 includes:

[0032] S31. Calculate the difference between the turning angular velocity of the tractor and the turning angular velocity of the trailer to obtain the angular velocity of the angle between the trailer and the tractor.

[0033] S32. Calculate the real-time angle between the tractor and the trailer based on the angular velocity of the angle between the trailer and the tractor.

[0034] In a further implementation, the formula for calculating the real-time angle is as follows:

[0035]

[0036] In the formula, λ k Let λ be the real-time angle between the tractor and the trailer at time k. k-1 Let k-1 be the real-time angle between the tractor and the trailer. The angular velocity of the real-time angle is given.

[0037] This solution uses the truck speed, steering wheel angle, and the initial angle λ0 between the tractor and trailer of the semi-trailer truck transmitted through an interactive system to calculate and save the angle λ1 between the tractor and trailer after a time interval Δt. After another time interval Δt, the interactive system transmits the truck speed and steering wheel angle at the current moment. Combining this with the angle λ1 calculated at the previous time interval Δt, the angle λ2 between the tractor and trailer at the next time interval Δt can be calculated. Therefore, by using the truck speed and steering wheel angle transmitted through the interactive system, the real-time angle λ between the tractor and trailer can be calculated in real time, with high data accuracy and precise coverage of trailer blind spots.

[0038] In a further embodiment, step S4 includes the following steps:

[0039] S41. Obtain the focal length and vehicle body data of the vehicle's camera;

[0040] S42. Calculate the lateral distance of the trailer's blind spot based on the real-time angle between the trailer and the tractor.

[0041] S43. Based on the pinhole imaging principle, substitute the lateral distance to calculate the pixel value distance of the camera movement.

[0042] In a further embodiment, in step S42, the formula for calculating the lateral distance is as follows:

[0043] n = L2*sinλ k

[0044] In step S43, the pixel value distance calculation formula is as follows:

[0045]

[0046] In the formula, n is the lateral distance of the blind zone, h is the pixel distance the camera moves, f is the focal length of the camera, and λ is the distance of the camera movement. k This refers to the real-time angle between the tractor and the trailer.

[0047] In a further embodiment, step S5 includes the following steps:

[0048] S51. Obtain the camera's shooting parameters;

[0049] S52. Calculate the number of moving pixels to adjust the field of view based on the pixel value distance and the shooting parameters;

[0050] S53. Determine whether the field of view exceeds the displayable area based on the number of moving pixels. If so, adjust the camera to the boundary of the displayable area. Otherwise, adjust the camera's field of view in real time based on the number of moving pixels.

[0051] In a further embodiment, the shooting parameters include resolution and maximum horizontal angle;

[0052] Then, step S52 includes the following steps:

[0053] A. Calculate the lateral angle of a single pixel based on the resolution;

[0054] B. Calculate the pixel length of a single pixel based on the horizontal angle;

[0055] C. Calculate the number of moving pixels to adjust the camera's field of view based on the horizontal angle and pixel value distance.

[0056] This solution determines the lateral distance of the trailer's blind spot based on the real-time angle between the trailer and the tractor. Then, by calculating the pixel value distance of the blind spot and combining it with the camera resolution, it determines the actual number of pixels to be moved to adjust the camera's field of view in real time. By automatically and temporarily adjusting the field of view of the electronic rearview mirror according to the vehicle's driving status, it can free the driver's attention from adjusting the rearview mirror, providing enhanced image quality, a wider field of view, and a safer driving experience. Attached Figure Description

[0057] Figure 1 This is a flowchart illustrating the process of an electronic exterior rearview mirror field of view adjustment method provided in an embodiment of the present invention;

[0058] Figure 2 This is a schematic diagram of the right-handed coordinate system provided in an embodiment of the present invention;

[0059] Figure 3 This is a schematic diagram of the state when the angle between the tractor and the trailer body is 0°, provided in an embodiment of the present invention.

[0060] Figure 4This is a schematic diagram of the state when the included angle between the tractor and trailer bodies is λ, provided in an embodiment of the present invention.

[0061] Figure 5 This is an abstract schematic diagram of the tractor and trailer model provided in the embodiments of the present invention;

[0062] Among them: tractor unit E, trailer unit F. Detailed Implementation

[0063] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. The embodiments are given for illustrative purposes only and should not be construed as limiting the present invention. The accompanying drawings are for reference and illustration only and do not constitute a limitation on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0064] This invention provides a method for adjusting the field of view of an electronic exterior rearview mirror, such as... Figure 1 As shown, in this embodiment, steps S1 to S5 are included:

[0065] S1. Calibrate the current vehicle body data and obtain the vehicle's motion information;

[0066] In this embodiment, the vehicle body data includes the wheelbase L1 of the tractor's front and rear axles, the distance d between the articulation point and the center of the tractor's rear axle, the distance L2 between the articulation point and the center of the trailer's rear axle, and the steering ratio of the steering wheel to the tractor's front wheels. See also Figure 2 If the articulation point is behind the center of the rear axle of the tractor, then d is a positive value; if the articulation point is in front of the center of the rear axle of the tractor, then d is a negative value; if the articulation point coincides with the center of the rear axle of the tractor, then d is 0.

[0067] Obtaining vehicle motion information includes: obtaining the vehicle's current steering wheel angle (positive value for left, negative value for right), the tractor's speed, and calculating the steering angle δ of the tractor's front wheels (positive value for left, negative value for right) based on the steering ratio.

[0068] S2. Based on the vehicle body data and motion information, construct kinematic models for the tractor E and trailer F of the current vehicle respectively.

[0069] In this embodiment, the kinematic model construction of the tractor unit of the current vehicle includes S21 to S23:

[0070] S21. Establish a right-handed coordinate system with the vehicle's position at any moment of motion as the origin and the vehicle's direction of travel as the positive X-axis.

[0071] S22. Based on Ackermann kinematics and vehicle body data and motion information, establish the kinematic model of the corresponding tractor vehicle. The model formula is as follows;

[0072]

[0073] In the formula, (x 1，k-1 y 1，k-1 Φ 1，k-1 (x) represents the pose of the rear axle center of the tractor at time k-1. 1，k y 1，k Φ 1，k ) represents the pose of the rear axle center of the tractor at time k, Δt is the sampling time interval, Φ1 is the yaw angle of the tractor, δ is the steering angle of the front wheels of the tractor, and V is the speed of the tractor.

[0074] S23. Calculate the turning angular velocity equation of the tractor based on the tractor's speed and the steering angle of its front wheels.

[0075] See Figure 2 When there is an angle between the tractor and the trailer, determine the turning radius R1, turning center O1, and steering angle δ of the tractor's front wheels. The yaw angle of the tractor is Φ1. Determine the turning radius R2 and turning center O2 of the trailer. The yaw angle of the tractor is Φ2. Extend the line along the trailer body... Figure 2 (dashed arrow), set the angle between the trailer and the tractor as λ.

[0076] In the tractor unit, since every point on the vehicle body moves around the same turning center O1, the turning radius of the rear axle center of the tractor unit is:

[0077]

[0078] The turning angular velocity of the tractor is:

[0079]

[0080] In the formula, R1 is the turning angular velocity of the tractor vehicle, and R2 is the rotation radius of the rear axle center of the tractor vehicle.

[0081] In this embodiment, the kinematic model construction of the trailer of the current vehicle includes S24 to S26:

[0082] S24. Calculate the speed of the articulation point based on the vehicle body data and the speed of the tractor.

[0083] See Figure 2 :

[0084]

[0085] In the tractor unit, the direction of the velocity at articulation point P is not the direction of the tractor unit's body, but rather perpendicular to the radius of rotation O1P of articulation point P. The direction of the velocity at P is as follows: Figure 2 V inP Then V p The angle between the trailer and the tractor unit is θ, then the steering angle of the trailer is λ-θ. Analyzing point P in the trailer, since the articulation point P is the same point in both the tractor unit and the trailer, the magnitude and direction of the velocity at point P are completely consistent in both. Therefore, V P The speed is:

[0086]

[0087] S25. Calculate the trailer's speed based on the tractor's speed at the articulated point;

[0088] When a vehicle turns, the turning angular velocity is the same at all points on the vehicle body, and the direction is perpendicular to the turning radius corresponding to each point. (V) P From the direction and magnitude of the velocity, we can deduce the magnitude and direction of the velocity V2 at the center of the trailer's rear axle:

[0089]

[0090] S26. Calculate the turning angular velocity equation of the trailer based on the trailer's speed and the radius of rotation of the trailer's rear axle center.

[0091] Within the trailer, every point on the vehicle body moves around the turning center O2, where the turning radius of the trailer's rear axle center is:

[0092]

[0093] The angular velocity of the trailer rotation is:

[0094]

[0095] In the formula, R2 is the turning angular velocity of the trailer, V2 is the rotation radius of the rear axle center of the trailer, θ is the angle between the speed of the articulation point and the speed of the tractor, and λ is the angle between the trailer and the tractor at the current moment.

[0096] After calibrating the vehicle body data, this embodiment establishes a right-handed coordinate system based on the vehicle's direction of motion to create kinematic models for the corresponding tractor and semi-trailer. The pose of the semi-trailer is accurately calculated based on Ackerman kinematics, which is compatible with different types of tractor and trailer combinations. It provides accurate and effective data for calculating the real-time angles of the tractor and trailer, and has good versatility.

[0097] S3. Calculate the real-time angles between the tractor and trailer based on the kinematic model, including steps S31 to S32:

[0098] S31. Calculate the difference between the turning angular velocity of the tractor and the turning angular velocity of the trailer to obtain the angular velocity of the angle between the trailer and the tractor. The calculation formula is as follows;

[0099]

[0100] S32. Calculate the real-time angle between the trailer and the tractor based on the angular velocity of the angle between them.

[0101] In this embodiment, the formula for calculating the real-time angle is as follows:

[0102]

[0103] In the formula, λ k Let λ be the real-time angle between the tractor and the trailer at time k. k-1 Let k-1 be the real-time angle between the tractor and the trailer. Angular velocity is the real-time angle.

[0104] Therefore, based on the angle λ between the tractor and the trailer at time k-1... k-1 The angle λ between the tractor and the trailer after time Δt k The relationship can be combined with the vehicle's own calibrated body data, and the truck speed, steering wheel angle, and the initial input angle λ0 of the tractor and trailer can be obtained in real time through the interactive system to calculate the angle of the semi-trailer truck's tractor and trailer in real time.

[0105] This embodiment uses the truck speed, steering wheel angle, and the initial angle λ0 between the tractor and trailer of the semi-trailer truck transmitted by the interactive system to calculate and save the angle λ1 between the tractor and trailer after a time interval Δt. After another time interval Δt, the interactive system transmits the truck speed and steering wheel angle at the current moment. Combining this with the angle λ1 calculated at the previous time interval Δt, the angle λ2 between the tractor and trailer at the next time interval Δt can be calculated. Therefore, by using the truck speed and steering wheel angle transmitted by the interactive system, the real-time angle λ of the tractor and trailer can be calculated in real time, with high data accuracy and precise coverage of trailer blind spots.

[0106] S4. Calculate the pixel value distance of the camera movement based on the real-time angle, including steps S41 to S43:

[0107] S41. Obtain the focal length and vehicle body data of the vehicle's camera;

[0108] S42. Calculate the lateral distance of the trailer's blind spot based on the real-time angle between the trailer and the tractor.

[0109] S43. Based on the principle of pinhole imaging, substitute the horizontal distance to calculate the pixel value distance of the camera movement.

[0110] In this embodiment, see Figure 3 , Figure 4 The left and right rearview mirror cameras of the tractor unit have a relatively wide field of view, corresponding to the entire adjustable field of view area. In practical applications, only the "display area" needs to be viewed. When blind spots occur due to the tractor unit's turning, the "display area" is adjusted. The tractor unit's wheelbase is set to L1, and the trailer's wheelbase to L2. The tractor unit and trailer model are abstracted as follows: Figure 5 A reference point (e.g., the last corner of the trailer) is set as the baseline state when the angle between the tractor and the trailer is 0. When the tractor turns, the trailer and the tractor have a certain angle. In order to ensure that the reference point is still in the center of the display area, the camera display area needs to be moved in the full FOV image.

[0111] Given the focal length f of the camera, and λ being the angle between the tractor and the trailer, then:

[0112] The formula for calculating lateral distance is as follows:

[0113] n = L2*sinλ k

[0114] Based on the principle of pinhole imaging, we can conclude that:

[0115]

[0116] The formula for calculating pixel distance is as follows:

[0117]

[0118] In the formula, n is the lateral distance of the blind zone, h is the pixel distance the camera moves, f is the focal length of the camera, and λ is the distance of the camera movement. k This refers to the real-time angle between the tractor and the trailer.

[0119] S5. Adjust the camera's field of view in real time based on pixel value distance, including steps S51 to S53:

[0120] S51. Obtain the camera's shooting parameters;

[0121] In this embodiment, the shooting parameters include resolution u (pixel) * V (pixel) and maximum horizontal angle m; u is the horizontal field of view size, and V represents the vertical field of view.

[0122] S52. Based on the pixel value distance and shooting parameters, calculate the number of pixels that need to be moved to adjust the field of view, including steps A to C:

[0123] A. Calculate the horizontal angle of a single pixel based on the resolution;

[0124]

[0125] B. Calculate the pixel length of a single pixel based on the horizontal angle;

[0126]

[0127] C. Calculate the number of moving pixels to adjust the camera's field of view based on the horizontal angle and pixel value distance.

[0128] The number of pixels that need to be moved to adjust the field of view:

[0129]

[0130] S53. Determine whether the field of view exceeds the displayable area based on the number of moving pixels. If so, adjust to the boundary of the camera's displayable area. Otherwise, adjust the camera's field of view in real time based on the number of moving pixels.

[0131] Assuming the angle λ between the tractor and trailer is 0, the pixel points at the four corners of the display area of ​​the left rearview mirror are set as (x... 1,0 ,y 1,0 ), (x 1,0 ,y 2,0 ), (x 2,0 ,y 1,0 ), (x 2,0 ,y 2,0 When the angle λ between the tractor and trailer is 0, the number of pixels at the four corners of the display area of ​​the right rearview mirror are (p... 1,0 ,q 1,0 ), (p 1,0 ,q 2,0 ), (p 2,0 ,q 1,0 ), (p 2,0 ,q 2,0 ).

[0132] When the field of view is adjusted, if the display range does not exceed the visible area, the pixels at the four corners of the adjusted left rearview mirror display area are (x... 1,next ,y 1,0 ), (x 1,next ,y 2,0 ), (x 2,next ,y 1,0 ), (x 2,next ,y 2,0 The adjusted right rearview mirror display area has four corner pixels (p). 1,next ,q 1,0 ), (p 1,next ,q 2,0 ), (p 2,next ,q 1,0 ), (p2,next ,q 2,0 ).in:

[0133]

[0134]

[0135] If the field of view exceeds the displayable area, the field of view can only be adjusted to the boundary of the displayable area and cannot exceed the displayable range.

[0136] This embodiment determines the lateral distance of the trailer's blind spot based on the real-time angle between the trailer and the tractor, and then determines the actual number of pixels to be moved by calculating the pixel value distance of the blind spot and combining it with the camera resolution to adjust the camera's field of view in real time. By automatically and temporarily adjusting the field of view of the electronic rearview mirror according to the vehicle's driving status, the driver's attention can be freed from adjusting the rearview mirror, providing enhanced image quality, a wider field of view, and a safer driving experience.

[0137] Based on the calibrated body data of the semi-trailer truck, the present invention builds kinematic models of the tractor and trailer respectively, collects real-time transmission of steering wheel angle and vehicle speed information, calculates the real-time angle of the tractor and trailer, and then calculates the pixel value distance of the camera movement by combining the focal length and pixel of the camera. By dynamically adjusting the display field of view of the camera, the semi-trailer truck's field of view can be adjusted accordingly, keeping the driver in a field of view that can see the traffic conditions behind the vehicle, thereby improving vehicle safety.

[0138] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for adjusting the field of view of an electronic exterior rearview mirror, characterized in that, Including the following steps: S1. Calibrate the current vehicle body data and obtain the vehicle's motion information; S2. Based on the vehicle body data and motion information, construct kinematic models for the tractor and trailer of the current vehicle respectively; S3. Calculate the real-time angle between the tractor and the trailer based on the kinematic model; S4. Calculate the distance the camera has moved by pixels based on the real-time angle; S5. Adjust the camera's field of view in real time based on the pixel value distance; In step S1: The vehicle body data includes the wheelbase L1 of the front and rear axles of the tractor, the distance d between the articulation point and the center of the rear axle of the tractor, the distance L2 between the articulation point and the center of the rear axle of the trailer, and the steering ratio between the steering wheel and the front wheels of the tractor. The process of acquiring vehicle motion information includes: acquiring the current steering wheel angle of the vehicle and the speed of the tractor, and calculating the steering angle δ of the front wheels of the tractor based on the steering ratio; In step S2, building a kinematic model of the tractor unit of the current vehicle includes: S21. Establish a right-handed coordinate system with the vehicle's position at any moment of motion as the origin and the vehicle's direction of travel as the positive X-axis. S22. Based on Ackermann kinematics and the vehicle body data and motion information, establish the kinematic model of the corresponding tractor vehicle. The model formula is as follows; In the formula, Let k-1 be the position of the rear axle center of the tractor. Let k be the position of the center of the rear axle of the tractor unit. The sampling time interval, , Let yaw angle be the yaw angle of the tractor at time k-1 and time k, respectively; δ be the steering angle of the front wheel of the tractor; and V be the speed of the tractor. S23. Based on the speed of the tractor and the steering angle of the front wheels of the tractor, calculate the turning angular velocity equation of the tractor. The calculation formula is as follows: In the formula, R1 is the turning angular velocity of the tractor vehicle, and R1 is the rotation radius of the center of the rear axle of the tractor vehicle. Step S3 includes: S31. Calculate the difference between the turning angular velocity of the tractor and the turning angular velocity of the trailer to obtain the angular velocity of the angle between the trailer and the tractor. S32. Calculate the real-time angle between the tractor and the trailer based on the angular velocity of the angle between the trailer and the tractor. Step S4 includes the following steps: S41. Obtain the focal length and vehicle body data of the vehicle's camera; S42. Calculate the lateral distance of the trailer's blind spot based on the real-time angle between the trailer and the tractor. S43. Based on the pinhole imaging principle, substitute the lateral distance to calculate the pixel value distance of the camera movement; Step S5 includes the following steps: S51. Obtain the camera's shooting parameters; S52. Calculate the number of moving pixels to adjust the field of view based on the pixel value distance and the shooting parameters; S53. Determine whether the field of view exceeds the displayable area based on the number of moving pixels. If so, adjust the camera to the boundary of the displayable area. Otherwise, adjust the camera's field of view in real time based on the number of moving pixels.

2. The electronic exterior rearview mirror field of view adjustment method as described in claim 1, characterized in that, In step S2, building a kinematic model of the trailer for the current vehicle includes: S24. Calculate the speed of the articulation point based on the vehicle body data and the speed of the tractor. S25. Calculate the trailer's speed based on the tractor's speed at the articulated point; S26. Based on the trailer's speed and the radius of rotation of the trailer's rear axle center, calculate the trailer's turning angular velocity equation. The calculation formula is as follows: In the formula, R2 is the turning angular velocity of the trailer, V2 is the rotation radius of the rear axle center of the trailer, θ is the angle between the speed of the articulation point and the speed of the tractor, and λ is the angle between the trailer and the tractor at the current moment.

3. The electronic exterior rearview mirror field of view adjustment method as described in claim 1, characterized in that, The formula for calculating the real-time angle is as follows: In the formula, Let k be the real-time angle between the tractor and the trailer. Let k-1 be the real-time angle between the tractor and the trailer. The angular velocity of the real-time angle is given.

4. The electronic exterior rearview mirror field of view adjustment method as described in claim 1, characterized in that: In step S42, the formula for calculating the lateral distance is as follows: In step S43, the pixel value distance calculation formula is as follows: In the formula, n is the lateral distance of the blind zone, h is the pixel distance the camera moves, and f is the focal length of the camera. This refers to the real-time angle between the tractor and the trailer.

5. The electronic exterior rearview mirror field of view adjustment method as described in claim 4, characterized in that: The shooting parameters include resolution and maximum horizontal angle; Then, step S52 includes the following steps: A. Calculate the lateral angle of a single pixel based on the resolution; B. Calculate the pixel length of a single pixel based on the horizontal angle; C. Calculate the number of moving pixels to adjust the camera's field of view based on the horizontal angle and pixel value distance.

Images