Double-vehicle linkage docking method and medium with left and right reflectors provided at the front end of the rear vehicle

Abstract

The present invention relates to a method and medium for linkage docking of two vehicles in which left and right reflectors are arranged at the front end of a rear vehicle. Based on the recognition of the left and right reflectors by a laser radar, the current x-coordinate, y-coordinate and angle of the control center point of the rear vehicle in the control center coordinate system of the front vehicle are obtained; the x-coordinate, y-coordinate and angle that the control center point of the rear vehicle is expected to maintain in the control center coordinate system of the front vehicle are obtained; the relative x-coordinate, relative y-coordinate and relative angle of the x-coordinate, y-coordinate and angle that are expected to be maintained relative to the current x-coordinate, y-coordinate and angle are calculated; based on the relative x-coordinate, relative y-coordinate and relative angle, the speed, vertical speed and angular velocity that need to be controlled for the rear vehicle in the same direction as the front direction of the rear vehicle are calculated. Based on the recognition of the left and right reflectors by the laser radar arranged in the two vehicles, the relative positions of the two vehicles are obtained, so that the docking before linkage of the two vehicles with high accuracy is realized by solving the speed of the vehicle motion model, and the structure is simpler and the cost is lower.

Description

Technical Field

[0001] The invention relates to the technical field of intelligent transport equipment control systems, and in particular to a double-vehicle linkage docking method and a medium in which left and right reflective plates are arranged at the front end of a rear vehicle. Background Art

[0002] In the field of heavy-load AGVs, the omnidirectional motion model is a mobile chassis with a more flexible motion effect. Among the omnidirectional motion models, the four-steering wheel model has the characteristics of high precision, heavy load and simple control.

[0003] In the field of heavy-load AGVs, most of the large equipment that actually needs to be transported are overweight, overlong, and overwide. In this context, the limitations of single-vehicle transportation have gradually become apparent, and the split-type double-vehicle linkage transportation solution has been proposed and applied to a certain extent.

[0004] In the current main technical solutions for docking two vehicles before linkage, the position accuracy of the front and rear vehicles cannot be guaranteed during manual remote control, which affects the accuracy of the two-vehicle linkage. Summary of the invention

[0005] The technical problem to be solved by the present application is to provide a method and medium for docking two vehicles in linkage, which has the characteristic of improving the docking accuracy before the two vehicles are linked.

[0006] In a first aspect, an embodiment provides a dual-vehicle linkage docking method, which is applied to a front-rear dual-vehicle linkage system, wherein the front-rear dual-vehicle linkage system includes a front vehicle and a rear vehicle in a traveling direction; wherein a laser radar is disposed at the rear end of the front vehicle and left and right reflectors are disposed at the front end of the rear vehicle, or, the left and right reflectors are disposed at the rear end of the front vehicle and the laser radar is disposed at the front end of the rear vehicle; the method includes:

[0007] Based on the laser radar's recognition of the left and right reflectors, the current x-coordinate, y-coordinate and angle of the rear vehicle's control center point in the front vehicle's control center coordinate system are obtained;

[0008] Obtain the x-coordinate, y-coordinate and angle that the rear vehicle control center point is expected to maintain in the front vehicle control center coordinate system;

[0009] Calculate the relative x coordinate, relative y coordinate and relative angle of the x coordinate, y coordinate and angle you want to keep relative to the current x coordinate, y coordinate and angle;

[0010] Based on the relative x-coordinate, relative y-coordinate and relative angle, the speed, perpendicular speed and angular speed of the rear vehicle that need to be controlled in the same direction as the front direction of the rear vehicle are calculated.

[0011] In a second aspect, an embodiment provides a computer-readable storage medium, wherein the medium stores a program, and the program can be loaded by a processor to execute the dual-vehicle linkage docking method of any of the above embodiments.

[0012] The beneficial effects of the present invention are:

[0013] Because the laser radar installed on one of the two vehicles recognizes the left and right reflectors installed on the other vehicle, the relative positions of the two vehicles are obtained, and the docking of the two vehicles before linkage is achieved with high precision by solving the speed of the vehicle motion model. The structure is also simpler and the cost is lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of a linkage system for rear vehicle identification reflectors according to an embodiment of the present application;

[0015] Figure 2 It is a schematic diagram of a linkage system for a front vehicle identification reflector according to an embodiment of the present application;

[0016] Figure 3 It is a method flow diagram of one embodiment of the method of the present application;

[0017] Figure 4 This application Figure 3 A method flow diagram of an embodiment of step S10;

[0018] Figure 5 This application Figure 3 A schematic diagram of a method flow chart of another embodiment of step S10;

[0019] Figure 6 This is a schematic diagram of the speed calculation in a bicycle mode according to one embodiment of the present application;

[0020] Figure 7 It is a schematic diagram of the dual-vehicle docking process of one embodiment of the present application. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are for making the present application better understood. However, those skilled in the art can easily recognize that some features can be omitted in different situations, or can be replaced by other elements, materials, methods. In some cases, some operations related to the present application are not shown or described in the specification, this is to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and the general technical knowledge in the art.

[0022] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a required sequence, unless otherwise specified that a certain sequence must be followed.

[0023] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0024] To facilitate the description of the inventive concept of the present application, the dual-vehicle linkage technology is briefly described below.

[0025] In the current dual-vehicle linkage scheme, most of them use cameras to identify the laser beam emitted by the laser beacon transmitter to obtain the position deviation of the two vehicles, and use a laser rangefinder to obtain the distance deviation of the two vehicles, so as to achieve linkage control based on these two deviations. However, the applicant found in the research that in this type of scheme, on the one hand, it is affected by the camera's viewing angle, and the range of the position deviation of the two vehicles that can be identified is limited, and a two-dimensional turntable is required to rotate the laser beacon transmitter for auxiliary identification; on the other hand, the camera cannot obtain the actual position and angle deviation of the two vehicles, and can only judge the deviation direction and estimate the deviation size through the pixel point difference. Therefore, it is impossible to solve the specific vehicle motion model speed, which also leads to low docking accuracy before the dual-vehicle linkage.

[0026] In view of this, the present application provides a dual-vehicle linkage docking method and medium, which can obtain the coordinates and angles of the control center point of the rear vehicle in the coordinate system of the control center of the front vehicle based on the recognition of the left and right reflectors on the other vehicle by the laser radar on one vehicle, and obtain the coordinates and angles that are expected to be maintained, thereby obtaining the relative coordinates and angles, and then obtaining the speed, perpendicular speed and angular velocity in the same direction as the front direction of the rear vehicle that need to be controlled for docking, thereby achieving high-precision docking before the linkage of the two vehicles by solving the vehicle motion model speed.

[0027] In order to better explain the dual-vehicle linkage docking method, the following first describes the front and rear dual-vehicle linkage system used. Figure 1 and Figure 2 In this front and rear double-vehicle linkage system, the following can be used: Figure 1 The linkage system of the rear vehicle identification reflector shown in FIG. Figure 2 The linkage system of the front vehicle identification reflector shown in FIG. Figure 1 In the linkage system for rear vehicle identification reflectors shown in the figure, the rear end of the front vehicle is provided with left and right reflectors and the front end of the rear vehicle is provided with a laser radar. Figure 2 In the linkage system for the front vehicle to identify the reflector, a laser radar is provided at the rear end of the front vehicle and left and right reflectors are provided at the front end of the rear vehicle. The laser radar can rotate to emit laser to the left and right reflectors. In one embodiment, the laser radar can rotate 360 ​​degrees.

[0028] Since the laser radar can obtain the light intensity value of the reflected laser beam based on the reflectivity of the scanned object, and according to physical properties, the reflectivity of the reflector to light is significantly higher than that of other materials, the laser radar can identify the left and right reflectors installed symmetrically along the central axis of the vehicle body.

[0029] By filtering out other laser beams except the reflector according to the light intensity value, the coordinates of the left and right reflectors in the laser radar coordinate system can be directly obtained.

[0030] In one embodiment, the front and rear dual-vehicle linkage system also includes a remote control, and the front vehicle control center or the rear vehicle control center receives the control command of the remote control, and calculates the control parameters based on the control command and the relative positions of the two vehicles, thereby realizing the docking of the dual-vehicle linkage based on the calculated control parameters.

[0031] In one embodiment, the remote control command of the remote controller includes controlling the angular velocity, the velocity in the same direction as the vehicle head direction, and the velocity perpendicular to the vehicle head direction.

[0032] For the front and rear dual-vehicle linkage system based on any of the above embodiments, please refer to Figure 3 A dual-vehicle linkage docking method includes:

[0033] Step S10, based on the laser radar's recognition of the left and right reflectors, the current x-coordinate, y-coordinate and angle of the rear vehicle's control center point in the front vehicle's control center coordinate system are obtained.

[0034] In one embodiment, please refer to Figure 1 , when the front vehicle has left and right reflectors at the rear end and the rear vehicle has a laser radar at the front end, please refer to Figure 4 , step S10 comprises:

[0035] Step S1011, based on the laser radar's recognition of the left and right reflectors, calculate the coordinates of the center points of the left and right reflectors at the rear end of the front vehicle in the radar coordinate system, and the angle of the vertical line connecting the left and right reflectors at the rear end of the front vehicle in the radar coordinate system.

[0036] In one embodiment, it includes:

[0037] , ,

[0038] ,

[0039] in, It represents the x-coordinate of the center point of the left and right reflectors at the rear end of the front vehicle in the radar coordinate system. Indicates the y coordinate of the center point of the left and right reflectors at the rear end of the front vehicle in the radar coordinate system, It indicates the angle of the vertical line connecting the left and right reflectors at the rear end of the front vehicle in the radar coordinate system. It represents the x-coordinate of the left reflector at the rear end of the front vehicle in the radar coordinate system. Indicates the y coordinate of the left reflector at the rear end of the front vehicle in the radar coordinate system, It represents the x-coordinate of the right reflector at the rear end of the front vehicle in the radar coordinate system. Indicates the y coordinate of the right reflector at the rear end of the front vehicle in the radar coordinate system.

[0040] Please refer to Figure 1 , through the coordinates of the left and right reflectors, the coordinates of the midpoint O3 of the two reflectors behind the front vehicle body in the radar coordinate system O2 can be calculated and , where the direction of the O3 coordinate system is perpendicular to the line connecting the left and right reflectors, that is, the angle in the O2 coordinate system is .

[0041] In this way, the necessary conditions for converting the front vehicle control center coordinate system O4 to the rear vehicle control center coordinate system O1 have been obtained, that is, the origin coordinates of the front vehicle control center system O4 are converted to the left and right reflector symmetry center coordinate system O3, and then the coordinates of the left and right reflector symmetry center coordinate system O3 are converted to the laser radar coordinate system O2, and finally the coordinates of the laser radar coordinate system O2 are converted to the rear vehicle control center coordinate system O1.

[0042] It is known (from the mechanical parameters) that the coordinates of the origin of the control center coordinate system O4 of the front vehicle in the symmetric center coordinate system O3 of the left and right reflectors are P5 ( , , ), create a new coordinate system with the same origin as O3 and the direction as New coordinate system .

[0043] For the convenience of calculation, let point P5 be expressed in polar coordinates as ( , ),in

[0044] , ,

[0045] , ,

[0046] Use polar coordinates to express P5 in the new coordinate system The coordinates of P5 are The coordinates of , ) can be expressed as ( , ).

[0047] Then there is

[0048] ,

[0049] ,

[0050] The simplified expression is:

[0051] ,

[0052] in,

[0053] ,

[0054] ,

[0055] Assume that the point from the origin of the front vehicle control center coordinate system O4 to the laser radar coordinate system O2 is ( , ), from the above calculation, we can know that the coordinate system With respect to the laser radar coordinate system O2, the X-axis translation is , the Y-axis translation is , so through translation transformation we get:

[0056] ,

[0057] Step S1012, based on the coordinates of the center point of the left and right reflectors at the rear end of the front vehicle in the radar coordinate system, and the angle of the vertical line connecting the left and right reflectors at the rear end of the front vehicle in the radar coordinate system, calculate the coordinates and angle of the control center point of the front vehicle in the control center coordinate system of the rear vehicle.

[0058] In one implementation, based on the embodiment of step S1011, the coordinates and angles of the control center point of the leading vehicle in the coordinate system of the control center of the trailing vehicle can be calculated to include:

[0059] ,

[0060] ,

[0061] in,

[0062] ,

[0063] ,

[0064] , and They represent the x-coordinate, y-coordinate and angle of the front vehicle control center in the rear vehicle control center coordinate system. and They represent the x-coordinate and y-coordinate of the front vehicle control center point in the symmetrical center coordinate system of the left and right reflectors, , and They respectively represent the x-coordinate, y-coordinate and angle of the laser radar under the control center of the rear vehicle.

[0065] Among them, the direction of the symmetric center coordinate system of the left and right reflectors is perpendicular to the line connecting the left and right reflectors, and the positive direction of the y-axis is vertical to the left. The control center coordinate system of the front vehicle has the same direction as the symmetric center coordinate system of the left and right reflectors. When the front vehicle and the rear vehicle are aligned front and back, the symmetric center coordinate system of the left and right reflectors has the same direction as the radar coordinate system, and the control center coordinate system of the rear vehicle has the same direction as the radar coordinate system.

[0066] Step S1013, based on the coordinates and angles of the leading vehicle control center point in the trailing vehicle control center coordinate system, obtain the coordinates and orientation of the leading vehicle control center coordinate system in the trailing vehicle control center coordinate system.

[0067] In one embodiment, it includes: using the coordinates and angle of the front vehicle control center point in the rear vehicle control center coordinate system as the coordinates and orientation of the front vehicle control center coordinate system in the rear vehicle control center coordinate system.

[0068] Step S1014, based on the coordinates and orientation of the front vehicle control center coordinate system in the rear vehicle control center coordinate system, obtain the current x-coordinate, y-coordinate and angle of the rear vehicle control center point in the front vehicle control center coordinate system.

[0069] In one embodiment, it includes:

[0070] ,

[0071] ,

[0072] ,

[0073] in, , and They respectively represent the current x-coordinate, y-coordinate and angle of the rear vehicle control center point in the front vehicle control center coordinate system.

[0074] In one embodiment, please refer to Figure 2 , when the rear vehicle is equipped with left and right reflectors at the front end and the front vehicle is equipped with a laser radar at the rear end, please refer to Figure 5 , step S10 comprises:

[0075] Step S1021, based on the laser radar's recognition of the left and right reflectors, calculate the coordinates of the center points of the left and right reflectors at the front end of the rear vehicle in the radar coordinate system, and the angle of the vertical line connecting the left and right reflectors at the front end of the rear vehicle in the radar coordinate system.

[0076] In one embodiment, it includes:

[0077] , ,

[0078] ,

[0079] in, It represents the x-coordinate of the center point of the left and right reflectors at the front end of the rear vehicle in the radar coordinate system. Indicates the y coordinate of the center point of the left and right reflectors at the front end of the rear vehicle in the radar coordinate system, It indicates the angle of the vertical line connecting the left and right reflectors at the front end of the rear vehicle in the radar coordinate system. Indicates the x-coordinate of the left reflector at the front end of the rear vehicle in the radar coordinate system, Indicates the y coordinate of the left reflector at the front end of the rear vehicle in the radar coordinate system, It represents the x-coordinate of the right reflector at the front end of the rear vehicle in the radar coordinate system. Indicates the y coordinate of the right reflector at the front end of the rear vehicle in the radar coordinate system.

[0080] Step S1022, based on the coordinates of the center points of the left and right reflectors at the front end of the rear vehicle in the radar coordinate system, and the angle of the vertical line connecting the left and right reflectors at the front end of the rear vehicle in the radar coordinate system, calculate the coordinates and angle of the control center point of the rear vehicle in the control center coordinate system of the front vehicle.

[0081] Please refer to Figure 2 Similarly, based on the analysis of step S1011 and step S1021, in one embodiment, the calculated coordinates and angles of the rear vehicle control center point in the front vehicle control center coordinate system include:

[0082] ,

[0083] ,

[0084] in,

[0085] ,

[0086] ,

[0087] ,

[0088] , and They represent the x-coordinate, y-coordinate and angle of the rear vehicle control center point in the front vehicle control center coordinate system. and They represent the x-coordinate and y-coordinate of the rear vehicle control center point in the symmetrical center coordinate system of the left and right reflectors, respectively. They can be obtained based on the mechanical parameters. , and They represent the x-coordinate, y-coordinate and angle of the laser radar under the control center of the preceding vehicle, respectively, and can be obtained according to the mechanical parameters;

[0089] Among them, the direction of the symmetric center coordinate system of the left and right reflectors is perpendicular to the line connecting the left and right reflectors, and the positive direction of the y-axis is vertical to the left. The control center coordinate system of the rear vehicle has the same direction as the symmetric center coordinate system of the left and right reflectors. When the front and rear vehicles are aligned front and back, the symmetric center coordinate system of the left and right reflectors has the same direction as the radar coordinate system, and the control center coordinate system of the front vehicle has the same direction as the radar coordinate system.

[0090] Step S20, obtaining the x-coordinate, y-coordinate and angle that the control center point of the rear vehicle is expected to maintain in the coordinate system of the control center of the front vehicle.

[0091] Please refer to Figure 6 , , , These three variables are the control inputs of the four-steering wheel motion model, i.e., the control values ​​sent by the remote control, which constitute the three-dimensional vector of the vehicle's motion state. The input control quantity needs to be solved to calculate the angle that each steering wheel should turn to. and the velocity V, which is the velocity vector of each steering wheel on the two-dimensional plane. Among them, the forward direction of the vehicle can be calculated by , and the combined vehicle speed can be obtained The rotation radius of the vehicle can be calculated from the total speed of the vehicle and the rotation angular velocity .

[0092] The radius of motion of each wheel can be calculated by the Pythagorean theorem and the body motion radius R:

[0093] ,

[0094] in, Indicates wheelbase, Indicates wheelbase, Indicates the turning radius of the front right wheel, Indicates the turning radius of the front left wheel, Indicates the rotation radius of the rear right wheel, Indicates the rotation radius of the rear left wheel.

[0095] Since the angular velocity of all positions of the vehicle body is the same, the speed of each wheel can be calculated based on the rotation radius formula:

[0096] , , , ,

[0097] in, Indicates the front right wheel speed, Indicates the front left wheel speed, Indicates the rear right wheel speed, Indicates the rear left wheel speed.

[0098] At the same time, according to the geometric principle, the steering wheel deflection angle required for each wheel can be calculated:

[0099] ,

[0100] in, Indicates the steering angle of the front right wheel. Indicates the steering angle of the front left wheel. Indicates the steering angle of the rear right wheel. Indicates the steering angle of the rear left wheel.

[0101] At this point the steering wheel deflection angle and speed of each steering wheel based on the control input has been solved.

[0102] The premise of dual-vehicle linkage is that the relative posture of the front vehicle and the rear vehicle first reaches the desired posture. However, the position accuracy of the main and rear vehicles cannot be guaranteed by manual remote control. Figure 6 From the analysis of the single-vehicle motion model shown, it can be seen that the four-steering wheel motion model can control the translation and rotation of the vehicle at the same time, so it is only necessary to send the X-direction deviation, Y-direction deviation and angle deviation of the current position of the slave vehicle and the expected position of the slave vehicle through control values.

[0103] Please refer to Figure 7 According to the laser radar recognition results, the coordinates of the rear vehicle control center point in the front vehicle control center coordinate system are ( , , ). At the same time, the position that the rear vehicle should maintain is directly behind the origin of the coordinate system of the control center of the front vehicle plus half of the front vehicle's wheelbase, plus the linkage distance between the two vehicles, plus half of the rear vehicle's wheelbase, that is, . Then we have:

[0104] ,

[0105] ,

[0106] ,

[0107] in, Indicates the wheelbase, Indicates the distance between two cars, the wheelbase of the front and rear cars is the same; , and They respectively represent the x-coordinate, y-coordinate and angle that the rear vehicle control center point is expected to maintain in the front vehicle control center coordinate system.

[0108] Step S30, calculating the relative x coordinate, relative y coordinate and relative angle of the x coordinate, y coordinate and angle that are expected to be maintained relative to the current x coordinate, y coordinate and angle.

[0109] In one embodiment, it includes:

[0110] ,

[0111] ,

[0112] ,

[0113] in,

[0114] ,

[0115] ,

[0116] , and Respectively represent the current x-coordinate, y-coordinate and angle, , and They represent the relative x-coordinate, relative y-coordinate, and relative angle respectively.

[0117] Step S40, based on the relative x-coordinate, the relative y-coordinate and the relative angle, calculate the speed, perpendicular speed and angular speed of the rear vehicle that need to be controlled in the same direction as the front direction of the rear vehicle.

[0118] In one embodiment, it includes:

[0119] , , ,

[0120] in, and They respectively represent the speed in the same direction as the front direction and the speed perpendicular to the front direction of the vehicle that need to be controlled for the rear vehicle. Indicates the angular velocity that needs to be controlled for the following vehicle.

[0121] Eventually, the following vehicle will reach the expected position of the following vehicle. When the position deviation of the following vehicle is less than the set accuracy, the dual-vehicle linkage mode can be entered.

[0122] In any of the above embodiments, only one controller and one laser radar sensor are needed, which is low in cost, and the front and rear vehicles can be interchanged and combined at will. The laser radar sensor solution used can obtain the recognition results of all angles within the unobstructed range, and the laser radar sensor can directly obtain the actual distance value and light intensity value of all light beam measurements, and it is very easy to obtain the coordinates of the recognized object relative to the laser radar sensor, and it can also switch between the two recognition schemes of the master vehicle identifying the slave vehicle and the slave vehicle identifying the master vehicle. A detailed speed solution process based on the four-steering wheel motion model is provided, which improves the docking accuracy of the front and rear vehicles while making the structure simpler and the cost lower.

[0123] In one embodiment of the present application, a computer-readable storage medium is provided, on which a program is stored. The stored program includes a method for dual-vehicle linkage docking in any of the above embodiments that can be loaded by a processor and processed.

[0124] Those skilled in the art will appreciate that all or part of the functions of the various methods in the above-mentioned embodiments can be implemented by hardware or by computer programs. When all or part of the functions in the above-mentioned embodiments are implemented by computer programs, the program can be stored in a computer-readable storage medium, and the storage medium can include: read-only memory, random access memory, disk, optical disk, hard disk, etc., and the program is executed by a computer to implement the above-mentioned functions. For example, the program is stored in the memory of the device, and when the program in the memory is executed by the processor, all or part of the above-mentioned functions can be implemented. In addition, when all or part of the functions in the above-mentioned embodiments are implemented by computer programs, the program can also be stored in a storage medium such as a server, another computer, disk, optical disk, flash disk or mobile hard disk, and can be downloaded or copied and saved in the memory of the local device, or the system of the local device is updated, and when the program in the memory is executed by the processor, all or part of the functions in the above-mentioned embodiments can be implemented.

[0125] The above specific examples are used to illustrate the present invention, which is only used to help understand the present invention and is not intended to limit the present invention. For those skilled in the art, according to the concept of the present invention, some simple deductions, modifications or substitutions can be made.

Claims

1. A method for connecting two vehicles in linkage mode, wherein the front end of the rear vehicle is provided with left and right reflectors, and is applied to a front and rear double vehicle linkage system, and is characterized in that: The front and rear dual-vehicle linkage system includes a front vehicle and a rear vehicle in the traveling direction; wherein a laser radar is provided at the rear end of the front vehicle and left and right reflectors are provided at the front end of the rear vehicle; the method includes: Based on the laser radar's recognition of the left and right reflectors, the current x-coordinate, y-coordinate and angle of the rear vehicle's control center point in the front vehicle's control center coordinate system are obtained; Obtain the x-coordinate, y-coordinate and angle that the rear vehicle control center point is expected to maintain in the front vehicle control center coordinate system; Calculate the relative x coordinate, relative y coordinate and relative angle of the x coordinate, y coordinate and angle you want to keep relative to the current x coordinate, y coordinate and angle; Based on the relative x-coordinate, relative y-coordinate and relative angle, calculate the speed, perpendicular speed and angular speed of the rear vehicle in the same direction as the front direction of the rear vehicle that need to be controlled; The method of obtaining the current x-coordinate, y-coordinate and angle of the rear vehicle control center point in the front vehicle control center coordinate system based on the laser radar recognition of the left and right reflectors includes: Based on the laser radar's recognition of the left and right reflectors, the coordinates of the center points of the left and right reflectors at the front end of the rear vehicle in the radar coordinate system and the angle of the vertical line connecting the left and right reflectors at the front end of the rear vehicle in the radar coordinate system are calculated; Based on the coordinates of the center point of the left and right reflectors at the front end of the rear vehicle in the radar coordinate system, and the angle of the vertical line connecting the left and right reflectors at the front end of the rear vehicle in the radar coordinate system, the coordinates and angle of the control center point of the rear vehicle in the control center coordinate system of the front vehicle are calculated.

2. The dual-vehicle linkage docking method according to claim 1, characterized in that: The calculation of the coordinates of the center points of the left and right reflectors at the front end of the rear vehicle in the radar coordinate system and the angle of the vertical line connecting the left and right reflectors at the front end of the rear vehicle in the radar coordinate system based on the recognition of the left and right reflectors by the laser radar includes: ， ， ， in, It represents the x-coordinate of the center point of the left and right reflectors at the front end of the rear vehicle in the radar coordinate system. Indicates the y coordinate of the center point of the left and right reflectors at the front end of the rear vehicle in the radar coordinate system, It indicates the angle of the vertical line connecting the left and right reflectors at the front end of the rear vehicle in the radar coordinate system. Indicates the x-coordinate of the left reflector at the front end of the rear vehicle in the radar coordinate system, Indicates the y coordinate of the left reflector at the front end of the rear vehicle in the radar coordinate system, It represents the x-coordinate of the right reflector at the front end of the rear vehicle in the radar coordinate system. Indicates the y coordinate of the right reflector at the front end of the rear vehicle in the radar coordinate system.

3. The dual-vehicle linkage docking method according to claim 2, characterized in that: The calculation of the coordinates and angle of the control center point of the rear vehicle in the control center coordinate system of the front vehicle based on the coordinates of the center points of the left and right reflectors at the front end of the rear vehicle in the radar coordinate system and the angle of the perpendicular direction of the connecting line of the left and right reflectors at the front end of the rear vehicle in the radar coordinate system includes: ， ， in, ， ， ， , and They represent the x-coordinate, y-coordinate and angle of the rear vehicle control center point in the front vehicle control center coordinate system. and They represent the x-coordinate and y-coordinate of the rear vehicle control center point in the symmetrical center coordinate system of the left and right reflectors, respectively. They can be obtained based on the mechanical parameters. , and They represent the x-coordinate, y-coordinate and angle of the laser radar under the rear vehicle control center, which can be obtained according to the mechanical parameters; Among them, the direction of the symmetric center coordinate system of the left and right reflectors is perpendicular to the line connecting the left and right reflectors, and the positive direction of the y-axis is vertical to the left. The control center coordinate system of the rear vehicle has the same direction as the symmetric center coordinate system of the left and right reflectors. When the front and rear vehicles are aligned front and back, the symmetric center coordinate system of the left and right reflectors has the same direction as the radar coordinate system, and the control center coordinate system of the front vehicle has the same direction as the radar coordinate system.

4. The dual-vehicle linkage docking method according to claim 1, characterized in that: The obtaining of the x-coordinate, y-coordinate and angle that the rear vehicle control center point is expected to maintain in the front vehicle control center coordinate system includes: ， ， ， in, Indicates the wheelbase, Indicates the distance between two cars, the wheelbase of the front and rear cars is the same; , and They respectively represent the x-coordinate, y-coordinate and angle that the rear vehicle control center point is expected to maintain in the front vehicle control center coordinate system; The calculation of the relative x coordinate, relative y coordinate and relative angle of the x coordinate, y coordinate and angle expected to be maintained relative to the current x coordinate, y coordinate and angle includes: ， ， ， in, ， ， , and Respectively represent the current x-coordinate, y-coordinate and angle, , and Respectively represent the relative x-coordinate, relative y-coordinate and relative angle; The calculation of the speed, vertical speed and angular speed in the same direction as the front direction of the rear vehicle that need to be controlled for the rear vehicle based on the relative x-coordinate, relative y-coordinate and relative angle includes: ， ， ， in, and They respectively represent the speed in the same direction as the front direction and the speed perpendicular to the front direction of the vehicle that need to be controlled for the rear vehicle. Indicates the angular velocity that needs to be controlled for the following vehicle.

5. A computer-readable storage medium, characterized in that: The medium stores a program, which can be loaded by a processor and execute the dual-vehicle linkage docking method as claimed in any one of claims 1 to 4.

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