Vision-based agv trajectory automatic planning and parking control method and system

Abstract

The present application relates to AGV motion control technical field, disclose a kind of AGV trajectory automatic planning and parking control method and system based on vision, the control method includes two processes of manual control and automatic control, first by manual control guide trolley to specified vision guide point, then execute automatic control procedure again.For automatic control procedure, in the AGV car travel process, deviation of AGV car and target point is detected and obtained by vision guide program, when deviation value is less than the set threshold value, it is considered that deviation correction can be completed in the travel process;When deviation value is greater than the set threshold value, AGV car will be corrected in situ;AGV car reaches parking point, will carry out a final fine adjustment, finally make AGV car accurately park in parking point.The present application can be adapted to most bus protocols, combined with the setting of a variety of motion control algorithms, so that AGV car can realize the complex collaborative motion of multiple axes, increase its overall scope of application, improve overall practicability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of AGV motion control, in particular to a visual-based AGV trajectory automatic planning and parking control method and system. BACKGROUND

[0002] AGV is a kind of transport vehicle equipped with automatic guiding device such as electromagnetic or optical, which can travel along the specified guiding path, has safety protection and various transfer functions. AGV belongs to the category of wheeled mobile robots, has the advantages of high automation, strong flexibility, high reliability, accurate positioning, convenient scheduling management and easy maintenance, therefore, the existing AGV usually needs to cooperate with trajectory planning control system when running.

[0003] The existing AGV can be controlled by computer when running, or the running route can be set by using electromagnetic track. The electromagnetic track is attached to the floor, and AGV moves and acts according to the information brought by the electromagnetic track, so that the movement and action of the existing AGV are relatively simple when used, the application range is small, and the practicability is poor. SUMMARY

[0004] In view of the problems and deficiencies of the prior art, the present application provides a visual-based AGV trajectory automatic planning and parking control method and system, which can adapt to most bus protocols, and combines with various motion control algorithms to make AGV realize multi-axis complex cooperative motion, increase the overall application range and improve the overall practicability.

[0005] In order to achieve the above-mentioned application purpose, the technical scheme of the present application is as follows:

[0006] In one aspect, the present application discloses a visual-based AGV trajectory automatic planning and parking control method, which comprises the following two processes:

[0007] S1, manual control: selecting the running mode, after mode switching, manually operating the handheld touch screen to issue motion direction and motion speed instructions to the main control module, and manually controlling the AGV to run to the vicinity of the visual guide point;

[0008] S2, automatic control: after the AGV runs to the visual guide point, the automatic mode is switched and the automatic guiding function is started, then according to the navigation program and the visual guiding program, the AGV is automatically controlled to run to the parking point and stop at the parking point; wherein,

[0009] The control system acquires the deviation between the AGV and the target point detected by the vision guidance program in real time. When the deviation value is less than the set threshold value, it is considered that the deviation correction can be completed during the travel. When the deviation value is greater than the set threshold value, the AGV will perform deviation correction in place. After the AGV reaches the parking point, a final fine adjustment will be performed to make the AGV accurately park at the parking point.

[0010] As preferred, for the in-place deviation correction, the incremental positioning mode is used for the AGV pose adjustment. First, the walking servo motor movement angle of the corresponding wheel group of the AGV is calculated according to the deviation value detected by the vision guidance program, and then angle positioning control is performed. The angle positioning control includes:

[0011] Angle deviation adjustment, the AGV performs angle deviation adjustment through the in-place rotation mode;

[0012] Left-right deviation adjustment, the AGV performs left-right deviation adjustment through the left-right horizontal movement mode;

[0013] Front-rear deviation adjustment, the AGV performs front-rear deviation adjustment through the longitudinal movement mode.

[0014] Further, the incremental positioning mode is as follows:

[0015] For the in-place rotation mode, the four walking wheels of the AGV rotate to the tangent of the circular arc trajectory, so the steering angle of the four walking wheels is adjusted to:

[0016] ;

[0017] ;

[0018] And the four walking wheels of the AGV have the same speed:

[0019] ;

[0020] If the current angle deviation value of the AGV is φ, the incremental angle M of the walking motor is: φ

[0021] ;

[0022] For the left-right horizontal movement mode, the directions of the four walking wheels of the AGV are all 90°, and the four walking wheels have the same speed. If the current left-right deviation of the AGV is H, the incremental angle M of the walking motor is: H

[0023] ;

[0024] ​​For the longitudinal movement mode, the four walking wheels of the AGV vehicle are all 0°, and the four walking wheels have the same speed; if the current front-back deviation of the AGV vehicle is L, the walking motor rotates an incremental angle M L is:

[0025] ;

[0026] wherein θ1 and θ2 are the steering angles of the two front walking wheels of the AGV vehicle, θ3 and θ4 are the steering angles of the two rear walking wheels of the AGV vehicle, a is the wheelbase of the left and right walking wheels of the AGV vehicle, b is the wheelbase of the front and rear walking wheels of the AGV vehicle, R is the diameter of the walking wheels of the AGV vehicle, and C is the reduction ratio of the walking wheel reducer of the AGV vehicle.

[0027] As preferred, for the deviation adjustment during the movement, the method is as follows:

[0028] During the movement of the AGV vehicle at a given initial forward speed, the system dynamically adjusts the forward speed according to the distance between the AGV vehicle and the target, and corrects the left-right deviation and the angle deviation of the AGV vehicle through the curve movement according to the deviation value; wherein the curve movement is divided into left turning curve and right turning curve, when turning left, the relationship between the steering angle and the speed of each walking wheel of the AGV vehicle satisfies the following constraints:

[0029]

[0030] ;

[0031]

[0032] ;

[0033]

[0034] ;

[0035] ;

[0036] When turning right, the relationship between the steering angle and the speed of each walking wheel of the AGV vehicle satisfies the following formula:

[0037]

[0038] ;

[0039]

[0040] ;

[0041]

[0042] ;

[0043] ;

[0044] Wherein, R1 and R2 are AGV car outer walking wheel turning radius and inner walking wheel turning radius respectively; a is AGV car left and right wheelbase; b is AGV car front and rear wheelbase; V1 and V2 are AGV car two front wheel speeds respectively, and V3 and V4 are AGV car two rear wheel speeds respectively.

[0045] Further, the PID control algorithm is used for deviation adjustment during AGV car running, the input of the PID control algorithm is the angle deviation value, front and rear deviation value and left and right deviation value of the AGV car, and the output of the PID control algorithm is the speed and steering angle of the four walking wheels of the AGV car. After the speed and steering angle of the four walking wheels of the AGV car are obtained by the PID control algorithm, the deviation adjustment is realized through the above constraint conditions of the curve motion.

[0046] As preferred, in step S1, when the mode switching instruction and the motion direction and motion speed instruction are received by the main control module, the main control module sends them to the servo motor of each walking wheel of the AGV car for angle positioning control and speed control, and the AGV car will automatically slow down and stop when encountering an obstacle during movement.

[0047] In the application, the motion direction and motion speed instruction is the angle and speed of each walking wheel of the AGV car.

[0048] Based on the same inventive concept, another aspect of the application also discloses a visual-based AGV trajectory automatic planning and parking control system, which is used to realize the visual-based AGV trajectory automatic planning and parking control method, and comprises an AGV car, wherein the AGV car is externally provided with a main control module, a safety protection module, a chassis control module, a measuring module and a power supply module, the bottom corners of the AGV car are provided with walking modules, the main control module is in communication connection with a handheld touch screen, a twin module and an upper computer through network signals, and the main control module is also connected with the power supply module, the safety protection module and the chassis control module respectively.

[0049] The safety protection module is used for detecting the distance between the AGV car and an obstacle and transmitting the distance to the main control module for obstacle avoidance processing.

[0050] The chassis control module is used for receiving operation instructions transmitted by the main control module and controlling the walking modules to perform movement actions.

[0051] The measurement module internally stores a visual guidance program, which is used to measure the deviation of the feedback AGV vehicle from the parking point in real time and transmit the deviation to the master control module, and the master control module continuously guides the AGV vehicle to correct the running direction;

[0052] The power supply module is used for supplying power for the AGV trajectory automatic planning and parking control system.

[0053] The walking module is used for receiving the motion instructions transmitted by the chassis control module and driving the AGV vehicle to walk or park.

[0054] The handheld touch screen is used for realizing human-computer interaction.

[0055] The twin module is used for acquiring the state of the AGV vehicle and the relative pose of the assembly object through the master control module, and performing full-scene virtual-real mapping.

[0056] The upper computer is used for receiving the data transmitted by the measurement module through the master control module and performing kinematic calculation of the AGV vehicle, and then continuously guiding the AGV vehicle to correct the running direction through the master control module.

[0057] The walking module comprises a lifting plate installed at the bottom of the AGV vehicle, a hydraulic lifting system for adjusting the ground clearance of the lifting plate is arranged between the lifting plate and the AGV vehicle, a rotating plate is rotatably connected to the top of the lifting plate, a walking servo motor is fixedly connected to the top of the rotating plate, a steering servo motor is fixedly connected to the top of the lifting plate, a worm gear transmission assembly is arranged at the output end of the steering servo motor, a steering gear ring is fixedly connected to the bottom of the rotating plate, a steering gear is meshingly connected to the outside of the steering gear ring, the steering gear is in transmission connection with the worm gear transmission assembly, a walking wheel is rotatably connected to the bottom of the rotating plate, a walking transmission assembly is arranged between the walking servo motor and the walking wheel, the walking servo motor drives the walking wheel to rotate through the walking transmission assembly, and a detection gear is meshingly connected to the outside of the steering gear ring.

[0058] The walking wheel comprises a positioning hub, eight adjusting telescopic rods are fixedly connected to the outside of the positioning hub, a first arc plate and a second arc plate are alternately fixedly connected to the outside of the telescopic end of the adjusting telescopic rod, an outer tire is sleeved to the outside of the first arc plate and the second arc plate, a connecting oil cavity is arranged on the outside of the positioning hub, a connecting oil pipe is arranged on the outside of the connecting oil cavity, and the connecting oil cavity is in communication control of the telescopic control of the adjusting telescopic rods.

[0059] The top of the telescopic end of the adjusting telescopic rod is provided with a plugging hole. The inner side of the outer tire is provided with a positioning rod, and the positioning rod is plugged into the interior of the plugging hole. A side limiting hole is opened inside the plugging hole, and a limiting pin is slidably connected inside the side limiting hole. A return spring is arranged between the limiting pin and the side limiting hole. A connecting air hole communicating with the side limiting hole is opened at the bottom of the plugging hole. A limiting groove is opened on the side surface of the positioning rod, and the limiting pin is plugged into the interior of the limiting groove. A through air guide hole is opened inside the positioning rod, and the outer tire includes an outer base tire seat. A plurality of air bag tires are fixedly connected to the outside of the outer base tire seat, and the air guide hole of the positioning rod communicates with the plurality of air bag tires.

[0060] The beneficial effects of the present invention:

[0061] 1. The method and system for automatic trajectory planning and parking control of the AGV based on vision according to the present invention, compared with the prior art, the trajectory automatic planning and parking control method and system, through the setting of a main control module, combined with other control structures and algorithms used in cooperation, can realize the functions of data acquisition, logic control, motion control, data management and communication management during the operation of the AGV vehicle, enabling it to adapt to most bus protocols. And combined with the setting of a variety of motion control algorithms, the AGV vehicle can realize multi-axis complex coordinated motion, increasing its overall applicable range and enhancing the overall practicality.

[0062] 2. When the four walking wheels of the AGV vehicle of the present invention are parked, they can be transformed from the traditional circular shape to a square shape, thereby effectively improving the parking effect and stability. Compared with the existing parking mainly through clip brakes, gear meshing or servo motor parking, it can effectively reduce the wear of the parking mechanism, thereby ensuring the service life of the overall walking mechanism.

[0063] 3. During the walking stage of the AGV vehicle of the present invention, the eight adjusting telescopic rods distributed in a "rice" shape are synchronously controlled, making the outer tire circular to ensure smooth driving. During the parking stage, the telescopic rod connected to the second arc plate contracts, and the telescopic rod connected to the first arc plate extends, and the outer tire turns into a square shape, using the anti-side shift characteristic of the square structure to enhance stability, while avoiding the physical wear of mechanical braking, significantly extending the service life of the walking wheels. Further, the outer tire is fixedly connected to the telescopic rod through the positioning rod. When inflating, the high-pressure gas pushes the limiting pin to lock the positioning rod, which not only ensures the structural stability during the shape switching, but also buffers the ground bumps through the air bag tire design, and can still maintain high-precision driving on the uneven ground of the assembly workshop. And, the outer tire of the walking wheel can be quickly disassembled and assembled through the positioning rod, and there is no need to replace the entire wheel set when it is damaged.

[0064] 4. The present invention detects the deviation value in real time through the vision guidance program. When the deviation is less than the threshold value, the deviation is corrected synchronously during the movement by using the curved motion to avoid the time-consuming of parking. When the deviation is greater than the threshold value, the in-situ deviation correction is started to ensure that the traveling deviation of the AGV vehicle can be quickly adjusted.

[0065] 5、The manual control stage of the application realizes accurate guidance by handheld touch screen, and sends the AGV vehicle to the visual guidance point; the automatic control stage combines navigation program and visual guidance program, supports flexible switching of deviation correction and in-place deviation correction in the process of traveling, and can cover short-distance fine adjustment and long-distance navigation full scene.

[0066] 6、The application fuses PID control algorithm and curve motion constraint formula, and outputs accurate speed and steering angle instructions of four walking wheels for three types of deviations of AGV, left and right, front and back, especially suitable for high-precision collaborative scenes such as assembly of large aircraft power components.

[0067] 7、The system twin module realizes real-time communication with the master module through Modbus TCP, obtains the AGV state (speed, deviation, power) and the relative pose of the assembly object, realizes synchronous mapping of the physical scene and the digital model, and facilitates remote control of the on-site situation by the operator. BRIEF DESCRIPTION OF DRAWINGS

[0068] The foregoing and subsequent specific description of the application becomes clearer when read in conjunction with the following drawings, in which:

[0069] Figure 1 is a control method flow chart of the application;

[0070] Figure 2 is a wheel group schematic diagram of the in-place rotation mode of the AGV vehicle of the application;

[0071] Figure 3 is a schematic diagram of the angle deviation adjustment principle of the AGV vehicle of the application;

[0072] Figure 4 is a wheel group schematic diagram of the left and right horizontal movement mode of the AGV vehicle of the application;

[0073] Figure 5 is a wheel group schematic diagram of the longitudinal movement mode of the AGV vehicle of the application;

[0074] Figure 6 is a wheel group schematic diagram of the curve motion of the AGV vehicle of the application;

[0075] Figure 7 is a control system structure schematic diagram of the application;

[0076] Figure 8 is a control system communication connection schematic diagram of the application;

[0077] Figure 9 is a schematic diagram of the AGV vehicle body of the application;

[0078] Figure 10 is a first perspective schematic diagram of the walking module of the application;

[0079] Figure 11 Second perspective view of the walking module of the present application;

[0080] Figure 12 Second perspective view of the walking module of the present application;

[0081] Figure 13 Second perspective view of the walking module of the present application;

[0082] Figure 14 Second perspective view of the walking module of the present application;

[0083] Figure 15 Second perspective view of the walking module of the present application;

[0084] In the figure:

[0085] 1, AGV car; 2, main control module; 3, safety protection module; 4, chassis control module; 6, measurement module; 7, walking module; 8, power supply module; 9, handheld touch screen; 10, twin module; 11, host computer;

[0086] 71, lifting plate; 711, rotating plate; 72, walking servo motor; 73, steering servo motor; 74, walking wheel; 75, worm gear transmission assembly; 76, steering gear; 77, steering gear ring; 78, detection gear;

[0087] 741, positioning hub; 742, adjusting telescopic rod; 7421, plug-in hole; 7422, side limiting hole; 7423, limiting pin; 7424, reset spring; 743, connecting oil cavity; 744, first arc plate; 745, second arc plate; 746, outer tire; 7461, outer base tire seat; 7462, air bag tire; 747, positioning rod; 7471, limiting groove. DETAILED DESCRIPTION

[0088] In order for those skilled in the art to better understand the technical solutions in the present application, the following will further illustrate the technical solutions for achieving the purposes of the present application through specific examples. It should be noted that the technical solutions claimed by the present application include but are not limited to the following examples. Based on the examples in the present application, all other examples obtained by those skilled in the art without creative labor should fall within the scope of protection of the present application.

[0089] In the assembly process of large power components such as aircraft engines, automatic assembly is realized through an AGV 1, wherein trajectory planning and parking control of the AGV 1 are involved. Based on this, an embodiment of the present application proposes a visual-based AGV trajectory automatic planning and parking control method and system. The control system can not only adapt to most bus protocols, but also realize data acquisition, logic control, motion control, data management and communication management functions during operation. At the same time, based on a variety of motion control algorithms set in the control system, the AGV 1 can realize complex collaborative motion of multiple axes, increase the overall application range, and improve the overall practicability, so as to better adapt to the assembly of large power components of an aircraft.

[0090] An embodiment of the present application first discloses a visual-based AGV trajectory automatic planning and parking control method. The control method includes two processes of manual control and automatic control. First, the AGV 1 is guided to a specified visual guide point through manual control, and then the automatic control process is executed.

[0091] As shown in the control method, the control method is as follows: Figure 1

[0092] S1, manual control: first, select the running mode through the touch screen. After mode switching, the operator continues to issue motion direction and motion speed instructions to the PLC through the handheld touch screen 9. After calculation, the PLC issues motor speed instructions to the servo motor of each wheel group for speed and angle control. The AGV 1 will automatically slow down and stop when encountering obstacles during movement.

[0093] S2, automatic control: after the AGV 1 is manually controlled to run to the visual guide point, the system is switched to automatic mode and the automatic guide function is started. The control system automatically controls the AGV 1 to travel to the parking point and stop at the parking point according to the internally stored navigation program and visual guide program.

[0094] Among them, the more specific control process of automatic control is that the control system obtains the deviation (including angle deviation, left and right deviation, and front and rear deviation) of the AGV 1 and the target point detected by the visual guide program in real time. When the deviation value is less than the set threshold value, it is considered that the deviation correction of the AGV 1 can be completed during the travel process. When the deviation value is greater than the set threshold value, the AGV 1 needs to correct the deviation in place. After the AGV 1 reaches the parking point, a final fine adjustment is performed to make the AGV 1 accurately stop at the parking point.

[0095] It can be understood that the car control logic executed by the present application needs to manually control the car to a specified visual guide point first, and then execute the corresponding automatic control process. Therefore, the motion direction of manual control is the direction towards the visual guide point. ​

[0096] In the embodiment described in the present application, for the above two kinds of deviation correction modes of the AGV vehicle 1, the specific control logic and scheme are as follows,

[0097] (1) AGV vehicle on-site deviation correction

[0098] For on-site deviation correction of the trolley, the incremental positioning mode is used for pose adjustment, the motion angle of each wheel group servo motor of the AGV vehicle 1 is calculated through the deviation value detected by the visual guidance program, and angle positioning control is performed; the angle positioning control includes:

[0099] Angle deviation adjustment, the AGV vehicle 1 realizes angle deviation adjustment through the on-site rotation mode;

[0100] Left-right deviation adjustment, the AGV vehicle 1 realizes left-right deviation adjustment through the left-right transverse mode;

[0101] Front-rear deviation adjustment, the AGV vehicle 1 realizes front-rear deviation adjustment through the longitudinal transverse mode.

[0102] In the present application, angle deviation adjustment refers to angle adjustment with the forward direction through on-site rotation, which is specifically realized by different angle combinations of the four wheel groups of the AGV vehicle 1 to adjust the angle deviation of the vehicle body, and for left-right deviation adjustment and front-rear deviation adjustment, the same direction control of the four wheel groups of the trolley is used to realize the left-right transverse and front-rear movement of the vehicle body. However, the adjustment of the above deviations is all based on the vehicle body forward direction (target point) as the reference and comparison, and then adjustment is performed.

[0103] For the on-site rotation mode, refer to Figure 2 and Figure 3 , the four walking wheels of the AGV vehicle 1 are rotated to the tangent of the circular arc track, so the steering angle of the four walking wheels is adjusted to:

[0104] ;

[0105] ;

[0106] And the speed of the four walking wheels of the AGV vehicle 1 is the same:

[0107] ;

[0108] If the current angle deviation value of the AGV vehicle 1 is φ, the incremental angle M φ of the walking motor is:

[0109] ;

[0110] Wherein, θ1 and θ2 are the steering angles of the two front wheels of the AGV 1, θ3 and θ4 are the steering angles of the two rear wheels of the AGV 1, a is the wheelbase of the left and right wheels of the AGV 1, b is the wheelbase of the front and rear wheels of the AGV 1, R is the diameter of the wheels of the AGV 1, and C is the reduction ratio of the wheel reducer of the AGV 1.

[0111] For the left-right horizontal movement mode, as shown in Figure 4 , the directions of the four wheels of the AGV 1 are all 90°, and the speeds of the four wheels are the same; if the current left-right deviation of the AGV 1 is H, the incremental angle of rotation M of the walking motor is: H

[0112]

[0113] Wherein, R is the diameter of the wheels of the AGV 1, and C is the reduction ratio of the wheel reducer of the AGV 1.

[0114] For the longitudinal movement mode, as shown in Figure 5 , the directions of the four wheels of the AGV 1 are all 0°, and the speeds of the four wheels are the same; if the current front-rear deviation of the AGV 1 is L, the incremental angle of rotation M of the walking motor is: L

[0115]

[0116] Wherein, R is the diameter of the wheels of the AGV 1, and C is the reduction ratio of the wheel reducer of the AGV 1.

[0117] (2) Deviation correction during AGV travel

[0118] For the deviation correction during AGV travel, as shown in Figure 6 , the AGV 1 travels at a given initial forward speed, and during the travel, the control system dynamically adjusts the forward speed according to the distance between the AGV 1 and the target, and corrects the left-right deviation and the angle deviation of the AGV 1 through curve movement according to the deviation value. Since the turning radius of the curve movement is proportional to the steering angle of the wheel set, the steering angle of the wheels of the AGV 1 is dynamically controlled according to the left-right deviation value and the angle deviation detected by the visual guidance program, and the automatic approaching process of the AGV 1 to the parking point is realized; wherein, the curve movement is divided into left turning and right turning, and the center of the curve movement is a certain point on the longitudinal axis of the vehicle, which can be known from Figure 8

[0119] When turning left, the relationship between the steering angle and the speed of each wheel of the AGV 1 satisfies the following constraints:

[0120]

[0121] ​​​​​ ;

[0122]

[0123] ;

[0124]

[0125] ;

[0126] ;

[0127] When the AGV 1 turns right, the relationship between the steering angle and the speed of each walking wheel of the AGV 1 satisfies the following formula:

[0128]

[0129] ;

[0130]

[0131] ;

[0132]

[0133] ;

[0134] ;

[0135] wherein R1 and R2 are the turning radii of the outer walking wheels and the inner walking wheels of the AGV 1 respectively, V1 and V2 are the speeds of the two front walking wheels of the AGV 1 respectively, and V3 and V4 are the speeds of the two rear walking wheels of the AGV 1 respectively.

[0136] In the embodiment depicted in the present application, when turning left or right, the speeds of the two outer walking wheels of the AGV need to be controlled to be the same, and the speeds of the two inner walking wheels of the AGV need to be controlled to be the same.

[0137] Further, the PID control algorithm is used for deviation adjustment during the travel of the AGV 1, the input of the PID control algorithm is the angle deviation value, the front-rear deviation value and the left-right deviation value of the AGV 1, and the output of the PID control algorithm is the walking speed and the steering angle of the four walking wheels of the AGV 1.

[0138] Similarly, the PID control algorithm also belongs to the common knowledge in the art, and will not be described in detail here.

[0139] Based on the same inventive concept, the embodiments of the present application also disclose a visual-based AGV trajectory automatic planning and parking control system, which comprises an AGV 1, likeFigures 7-9 As shown, the AGV vehicle 1 is externally provided with a main control module 2 (i.e., a PLC), a safety protection module 3, a chassis control module 4, a measurement module 6, and a power supply module 8, and the AGV vehicle 1 is provided with a walking module 7 at the bottom of the four corners, as shown in the figure Figure 8 As shown, the main control module 2 of the AGV vehicle 1 is connected with a handheld touch screen 9, a twin module 10, and a host computer 11 through network signals.

[0140] The twin module 10 communicates with the main control module 2 in real time through modbus TCP, and the twin module 10 can obtain the current state of the AGV vehicle and the relative pose of the assembly object through the main control module 2, and then realize full-scene virtual-real mapping based on digital twin technology, and the collision detection function of the twin module 10 can also display safety warnings in the assembly process of the assembly object.

[0141] The assembly process collision warning is scheduled by the assembly process collision detection event, and the system divides the collision warning into three levels, which correspond to prompts, warnings, and errors (the safety strategy threshold refers to the relevant provisions of ISO 3691-4:2020 Industrial Vehicle Safety Requirements regarding AGV dynamic obstacle avoidance).

[0142] Prompt: When there is a possibility of collision between the AGV vehicle 1, the workpiece to be assembled, and the aircraft, the system will remind the operator through a pop-up window, and the actuator will not react at this time. When the collision trend stops, the pop-up window will also hide.

[0143] Warning: When the collision risk approaches the warning threshold set by the safety strategy, the real-time voice alarm is played synchronously and a red pop-up window is prompted, and the voice content can be specified by the user. At the same time, the motion mechanism immediately slows down. When it is away from the warning threshold set by the safety strategy, the real-time voice alarm stops playing, and the pop-up window hides. After resetting, the motion speed of the pose platform returns to normal.

[0144] Error: When the collision risk approaches the collision threshold set by the safety strategy, the real-time voice alarm is played synchronously and a red pop-up window is prompted, and the voice content can be specified by the user. At the same time, the motion mechanism immediately stops moving in the collision direction. After resetting, the motion mechanism can move in the opposite direction at a low speed. When it is away from the collision threshold set by the safety strategy, the real-time voice alarm stops playing, and the pop-up window hides.

[0145] For the above-mentioned system architecture of the embodiment, the main control module 2 is connected with the power supply module 8, the handheld touch screen 9, the safety protection module 3, the chassis control module 4, the twin module 10, and the host computer 11, respectively; wherein,

[0146] The safety protection module 3 is used for detecting the distance between the AGV vehicle 1 and the obstacle, and transmitting it to the main control module 2 for obstacle avoidance processing;

[0147] The chassis control module 4 is used for receiving operation instructions transmitted by the master control module 2 and controlling the walking module 7 to perform a movement action.

[0148] The measurement module 6 internally stores a visual guidance program, is used for measuring the deviation of the AGV vehicle from the parking point in real time, and transmitting to the master control module 2, the master control module 2 continuously guides the AGV vehicle 1 to correct the running direction;

[0149] The power supply module 8 is used for supplying power for the AGV trajectory automatic planning and parking control system;

[0150] The walking module 7 is used for receiving movement instructions transmitted by the chassis control module 4 and driving the AGV vehicle 1 to walk or park;

[0151] The handheld touch screen 9 is used for realizing man-machine interaction;

[0152] The twin module 10 is used for acquiring the state of the AGV vehicle 1 and the relative pose of the assembled object through the master control module 2, and performing full-scene virtual-real mapping;

[0153] The upper computer 11 is used for receiving data transmitted by the measurement module 6 through the master control module 2 and performing kinematics calculation of the AGV vehicle 1, and then continuously guiding the AGV vehicle 1 to correct the running direction through the master control module 2.

[0154] It should be noted that the AGV kinematics algorithm is a common knowledge in the art, which will not be described in detail here.

[0155] For the walking module 7 of the AGV vehicle 1, as shown in the drawing, Figures 9-14 The top of the lifting plate 71 is rotatably connected with a rotating plate 711, the rotating plate 711 is fixedly connected with a walking servo motor 72 at the top, the top of the lifting plate 71 is fixedly connected with a steering servo motor 73, the output end of the steering servo motor 73 is provided with a worm gear transmission assembly 75, the bottom of the rotating plate 711 is fixedly connected with a steering gear ring 77, the outside of the steering gear ring 77 is meshingly connected with a steering gear 76, the steering gear 76 and the worm gear transmission assembly 75 are in transmission connection, the bottom of the rotating plate 711 is rotatably connected with a walking wheel 74, the walking servo motor 72 and the walking wheel 74 are provided with a walking transmission assembly, the walking servo motor 72 drives the walking wheel 74 to rotate through the walking transmission assembly, and the outside of the steering gear ring 77 is meshingly connected with a detection gear 78.

[0156] In the embodiments depicted in the present invention, both the traveling servo motor 72 and the steering servo motor 73 are controlled by the chassis control module 4. The main control module 2 generates operation instructions, and the chassis control module 4 receives the operation instructions and then controls the traveling servo motor 72 and the steering servo motor 73 to execute, completing the control of the traveling and parking of the AGV vehicle 1.

[0157] Further, the traveling wheel 74 includes a positioning hub 741. Eight adjusting telescopic rods 742 are fixedly connected to the outside of the positioning hub 741. The telescopic ends of the adjusting telescopic rods 742 are alternately fixedly connected with first arc plates 744 and second arc plates 745. An outer tire 746 is sleeved on the outside of the first arc plates 744 and the second arc plates 745. A connecting oil cavity 743 is arranged on the outside of the positioning hub 741. A connecting oil pipe is arranged on the outside of the connecting oil cavity 743. The connecting oil cavity 743 is connected to control the telescopic control of a number of adjusting telescopic rods 742.

[0158] It should be noted that the eight adjusting telescopic rods 742 are distributed in a "rice" shape. There are four first arc plates 744 and four second arc plates 745. The first arc plates 744 and the second arc plates 745 are both distributed in a "cross" shape.

[0159] During the parking process, the adjusting telescopic rods 742 connected to the second arc plates 745 contract inward, and the adjusting telescopic rods 742 connected to the first arc plates 744 extend outward, so that the outer tire 746 tends to be square, achieving the effect of changing the shape of the outer tire 746.

[0160] The present invention effectively improves the parking effect by changing the traveling wheel 74 into a square shape. The parking force acts on the square traveling wheel 74 and the weight limit of the vehicle body, thus ensuring the stability of parking. Compared with the existing parking mainly through clip brakes, gear meshing or servo motor parking, it effectively reduces the wear of the parking mechanism, thus ensuring the service life of the overall traveling module 7.

[0161] In some embodiments, such as Figure 14 and Figure 15As shown, the telescopic end of the telescopic rod 742 is provided with a plug-in hole 7421 at the top, the inner side of the outer tire 746 is provided with a positioning rod 747, the positioning rod 747 is plugged into the inside of the plug-in hole 7421, the inside of the plug-in hole 7421 is provided with a side limiting hole 7422, the inside of the side limiting hole 7422 is slidably connected with a limiting pin 7423, the limiting pin 7423 and the side limiting hole 7422 are provided with a reset spring 7424, the bottom of the plug-in hole 7421 is provided with a connecting air hole communicating with the side limiting hole 7422, the side of the positioning rod 747 is provided with a limiting groove 7471, the limiting pin 7423 is plugged into the inside of the limiting groove 7471, the inside of the positioning rod 747 is provided with a through air guide hole, and the outer tire 746 comprises an outer base tire seat 7461, a plurality of air bag tires 7462 are fixedly connected to the outside of the outer base tire seat 7461, and the air guide hole of the positioning rod 747 communicates with the plurality of air bag tires 7462.

[0162] It should be noted that the positioning rod 747 and the plug-in hole 7421 are provided with a sealing ring, the end of the positioning rod 747 and the plug-in hole 7421 form a transition air chamber, and the connecting air hole communicates the transition air chamber and the side limiting hole 7422.

[0163] It should be noted that the outer tire 746 is plugged into the plug-in hole 7421 through the positioning rod 747, when the air bag tire 7462 is inflated, the air bag tire 7462 communicates the plug-in hole 7421 through the air guide hole of the positioning rod 747, the gas in the air bag tire 7462 is introduced into the plug-in hole 7421, and then introduced into the side limiting hole 7422 through the connecting air hole, the high-pressure gas pushes the limiting pin 7423 in the side limiting hole 7422, and further makes the limiting pin 7423 plugged into the inside of the limiting groove 7471.

[0164] The positioning rod 747 is plugged into the inside of the plug-in hole 7421, and the positioning rod 747 is limited by the limiting pin 7423, so that the stability of the connection between the outer tire 746 and the first arc plate 744 and the second arc plate 745 is effectively guaranteed, the telescopic rod 742 is convenient for adjusting the outer tire 746 to be circular or square, the walking wheel 74 can switch the state of the walking wheel 74 according to the walking or parking of the vehicle body, and the use flexibility of the vehicle body is guaranteed, and the stability of the vehicle body when parking is guaranteed.

[0165] The above is only a preferred embodiment of the present application, and does not limit the present application in any form, and any simple modification or equivalent change made on the basis of the technical essence of the present application to the above embodiment falls within the protection scope of the present application.

Claims

1. A vision-based automatic trajectory planning and parking control method for AGVs, characterized in that, Includes the following steps: S1. Manual control: Select the operating mode. After the mode is switched, manually operate the handheld touch screen to send the movement direction and speed commands to the main control module, and manually control the AGV to run to the vicinity of the visual guidance point. S2. Automatic Control: After the AGV reaches the visual guidance point, it switches to automatic mode and activates the automatic guidance function. Then, based on the navigation program and the visual guidance program, it automatically controls the AGV to travel to the parking point and stop there. The system acquires the deviation between the AGV and the target point detected by the vision guidance program in real time. When the deviation value is less than the set threshold, it is considered that the deviation can be corrected during the journey. When the deviation value is greater than the set threshold, the AGV will correct itself in place. After the AGV reaches the parking point, a final fine adjustment will be performed to make the AGV stop accurately at the parking point. For deviation adjustments during travel, the AGV travels at a given initial speed. The system dynamically adjusts the speed based on the distance between the AGV and the target, and simultaneously corrects the AGV's left-right and angular deviations through curvilinear motion based on the deviation value. This curvilinear motion includes left and right turns. During a left turn, the relationship between the steering angle and speed of each wheel of the AGV satisfies the following constraints: ； ； ； ； When turning right, the relationship between the steering angle of each traveling wheel of the AGV and its speed satisfies the following formula: ； ； ； ； Where R1 and R2 are the turning radii of the outer and inner wheels of the AGV, respectively; a is the wheelbase of the left and right wheels of the AGV; b is the wheelbase of the front and rear wheels of the AGV; V1 and V2 are the speeds of the two front wheels of the AGV, respectively; V3 and V4 are the speeds of the two rear wheels of the AGV, respectively; θ1 and θ2 are the turning angles of the two front wheels of the AGV, respectively; and θ3 and θ4 are the turning angles of the two rear wheels of the AGV, respectively.

2. The vision-based AGV trajectory automatic planning and parking control method according to claim 1, characterized in that, For in-situ correction, incremental positioning mode is used to adjust the AGV's position and posture. The deviation value detected by the vision guidance program is used to calculate the movement angle of the AGV's corresponding wheel set servo motor, and angle positioning control is performed. The angle positioning control includes: Angle deviation adjustment: The AGV vehicle adjusts the angle deviation by rotating in place. Left and right deviation adjustment: The AGV vehicle adjusts its left and right deviation through a lateral movement mode. Front and rear deviation adjustment: The AGV vehicle achieves front and rear deviation adjustment through longitudinal movement mode.

3. The vision-based AGV trajectory automatic planning and parking control method according to claim 1, characterized in that, The PID control algorithm is used to adjust the deviation during the movement of the AGV. The input of the PID control algorithm is the angular deviation value, front-to-back deviation value, and left-to-right deviation value of the AGV. The output of the PID control algorithm is the speed and steering angle of the four wheels of the AGV.

4. The vision-based AGV trajectory automatic planning and parking control method according to claim 1, characterized in that, In step S1, when the main control module receives the mode switching command and the commands for movement direction and speed, it sends them to the servo motors of each walking wheel of the AGV for angle positioning control and speed control; when the AGV encounters an obstacle during movement, it will automatically decelerate and stop.

5. The vision-based AGV trajectory automatic planning and parking control method according to claim 1, characterized in that, In the stationary rotation mode, the four wheels of the AGV rotate to the tangent of the circular trajectory, therefore the steering angle of the four wheels is adjusted to: ； ； Furthermore, the four wheels of the AGV travel at the same speed: ； If the current angular deviation of the AGV is φ, the incremental angle of the walking motor is M. φ for: ； Where θ1 and θ2 are the turning angles of the two front wheels of the AGV, θ3 and θ4 are the turning angles of the two rear wheels of the AGV, a is the wheelbase of the left and right wheels of the AGV, b is the wheelbase of the front and rear wheels of the AGV, R is the diameter of the AGV wheels, and C is the reduction ratio of the AGV wheel reducer; V1 and V2 are the speeds of the two front wheels of the AGV, and V3 and V4 are the speeds of the two rear wheels of the AGV.

6. The vision-based AGV trajectory automatic planning and parking control method according to claim 1, characterized in that, In the left-right lateral movement mode, all four traveling wheels of the AGV are at 90° angles and move at the same speed. If the current left-right deviation of the AGV is H, the incremental rotation angle of the traveling motor is M. H for: ； Where R is the diameter of the AGV vehicle's traveling wheels, and C is the reduction ratio of the AGV vehicle's traveling wheel reducer.

7. The vision-based AGV trajectory automatic planning and parking control method according to claim 1, characterized in that, In longitudinal movement mode, all four wheels of the AGV are at 0° and move at the same speed. If the forward / backward deviation of the AGV is L, the incremental rotation angle of the travel motor is M. L for: ； Where R is the diameter of the AGV vehicle's traveling wheels, and C is the reduction ratio of the AGV vehicle's traveling wheel reducer.

8. A vision-based AGV trajectory automatic planning and parking control system, wherein the vision-based AGV trajectory automatic planning and parking control system is used to implement the vision-based AGV trajectory automatic planning and parking control method according to any one of claims 1-7, characterized in that, include: The AGV (Automated Guided Vehicle) is externally equipped with a main control module, a safety protection module, a chassis control module, a measurement module, and a power supply module. Walking modules are located at the four corners of the AGV's bottom. The main control module communicates with a handheld touchscreen, a twin module, and a host computer via network signals. The main control module is also connected to the power supply module, the safety protection module, and the chassis control module. The safety protection module is used to detect the distance between the AGV vehicle and obstacles and transmit the data to the main control module for obstacle avoidance processing. The chassis control module is used to receive operation commands transmitted by the main control module and control the walking module to perform movement actions; The measurement module stores a vision guidance program, which is used to measure and provide feedback on the deviation between the AGV and the parking point in real time, and transmits it to the main control module. The main control module continuously guides the AGV to correct its running direction. The power supply module is used to supply power to the AGV trajectory automatic planning and parking control system; The walking module is used to receive motion commands transmitted from the chassis control module and drive the AGV to move or stop. The handheld touchscreen is used to enable human-computer interaction; The twin module is used to obtain the status of the AGV vehicle and the relative pose of the assembly object through the main control module, and to perform virtual-real mapping in the whole scene; The host computer is used to receive and calculate the data transmitted by the measurement module through the main control module, and then continuously guide the AGV vehicle to correct its running direction through the main control module. The walking module includes a lifting plate installed at the bottom of the AGV vehicle. A hydraulic lifting system for adjusting the height of the lifting plate from the ground is provided between the lifting plate and the AGV vehicle. A rotating plate is rotatably connected to the top of the lifting plate. A walking servo motor is fixedly connected to the top of the rotating plate. A steering servo motor is fixedly connected to the top of the lifting plate. A worm gear transmission assembly is provided at the output end of the steering servo motor. A steering gear ring is fixedly connected to the bottom of the rotating plate. A steering gear is meshed with the outside of the steering gear ring. The steering gear and the worm gear transmission assembly are connected. A walking wheel is rotatably connected to the bottom of the rotating plate. A walking transmission assembly is provided between the walking servo motor and the walking wheel. The walking servo motor drives the walking wheel to rotate through the walking transmission assembly. A detection gear is meshed with the outside of the steering gear ring.

9. The vision-based AGV trajectory automatic planning and parking control system according to claim 8, characterized in that, The walking wheel includes a positioning hub, and eight adjustable telescopic rods are fixedly connected to the outside of the positioning hub. A first arc plate and a second arc plate are alternately fixedly connected to the telescopic ends of the adjustable telescopic rods. An outer tire is sleeved on the outside of the first arc plate and the second arc plate. A connecting oil cavity is provided on the outside of the positioning hub. A connecting oil pipe is provided on the outside of the connecting oil cavity. The connecting oil cavity is connected to control the extension and retraction of several adjustable telescopic rods.

10. The vision-based AGV trajectory automatic planning and parking control system according to claim 9, characterized in that, The telescopic rod has an insertion hole at the top of its telescopic end. A positioning rod is provided on the inner side of the outer tire. The positioning rod is inserted into the insertion hole. A side limiting hole is provided inside the insertion hole. A limiting pin is slidably connected inside the side limiting hole. A return spring is provided between the limiting pin and the side limiting hole. A connecting air hole is provided at the bottom of the insertion hole, which communicates with the side limiting hole. A limiting groove is provided on the side of the positioning rod. The limiting pin is inserted into the limiting groove. A through air guide hole is provided inside the positioning rod. The outer tire includes an outer base tire seat. Several air-filled tires are fixedly connected to the outside of the outer base tire seat. The air guide hole of the positioning rod communicates with several air-filled tires.

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