AGV track automatic planning and parking control method and system based on vision

Abstract

The invention relates to the technical field of AGV motion control, and discloses a vision-based AGV track automatic planning and parking control method and system, the control method comprises a manual control process and an automatic control process, firstly, a guiding trolley is manually controlled to a specified vision guiding point, and then the automatic control process is executed. For the automatic control process, in the advancing process of the AGV, the deviation between the AGV and a target point is detected and obtained through a visual guidance program, and when the deviation value is smaller than a set threshold value, it is considered that deviation correction can be completed in the advancing process; when the deviation value is larger than a set threshold value, the AGV carries out deviation correction in situ; and after the AGV arrives at the parking point, final fine adjustment is carried out once, and finally the AGV is accurately parked at the parking point. The AGV multi-axis cooperative motion control method can adapt to most bus protocols and is combined with multiple set motion control algorithms, so that the AGV can realize multi-axis complex cooperative motion, the overall application range of the AGV is enlarged, and the overall practicability is improved.

Description

Technical Field

[0001] This invention relates to the field of AGV motion control technology, and more specifically to a vision-based method and system for automatic AGV trajectory planning and parking control. Background Technology

[0002] An AGV (Automated Guided Vehicle) is a transport vehicle equipped with electromagnetic or optical automatic guidance devices, capable of traveling along a prescribed guidance path, and possessing safety protection and various transfer functions. AGVs fall under the category of wheeled mobile robots and have advantages such as high automation, high flexibility, high reliability, precise positioning, convenient scheduling and management, and easy maintenance. Therefore, existing AGVs typically require a trajectory planning and control system to operate in conjunction with them.

[0003] When existing AGVs are in use, their travel routes and behaviors can be controlled by computers, or their travel routes can be set using electromagnetic tracks. The electromagnetic tracks are attached to the floor, and the AGVs move and perform actions based on the information provided by the electromagnetic tracks. As a result, the overall movement and actions that existing AGVs can perform are relatively simple, their application range is small, and their practicality is poor. Summary of the Invention

[0004] To address the problems and shortcomings of existing technologies, this invention proposes a vision-based AGV trajectory automatic planning and parking control method and system, which can adapt to most bus protocols and, combined with various motion control algorithms, enables AGV vehicles to achieve complex multi-axis coordinated movements, thereby increasing their overall applicability and improving their overall practicality.

[0005] To achieve the above-mentioned objectives, the technical solution of the present invention is as follows: This invention discloses a vision-based automatic trajectory planning and parking control method for AGVs, the control method comprising the following two processes: 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 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, 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.

[0006] Preferably, for in-situ correction, incremental positioning mode is used to adjust the AGV's vehicle position posture; wherein, firstly, the movement angle of the walking servo motor of the corresponding wheel set of the AGV is calculated based on the deviation value detected by the vision guidance program, and then 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.

[0007] Furthermore, the incremental positioning mode is specifically as follows: 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: ; 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: ; 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 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.

[0008] As a preferred method, the following approach is used to adjust deviations during the journey: During the AGV's movement at a given initial speed, the system dynamically adjusts the speed based on the distance between the AGV and the target. Simultaneously, it corrects the AGV's left-right and angular deviations through curvilinear motion based on the deviation value. This curvilinear motion is divided into left-turn and right-turn curves. During a left turn, the relationship between the steering angle and speed of each of the AGV's wheels satisfies the following constraints:

[0009] ;

[0010] ;

[0011] ; ; When turning right, the relationship between the steering angle of each traveling wheel of the AGV and its speed satisfies the following formula:

[0012] ;

[0013] ;

[0014] ; ; Where R1 and R2 are the turning radii of the outer and inner wheels of the AGV vehicle, respectively; a is the wheelbase of the left and right wheels of the AGV vehicle; b is the wheelbase of the front and rear wheels of the AGV vehicle; V1 and V2 are the speeds of the two front wheels of the AGV vehicle, respectively; and V3 and V4 are the speeds of the two rear wheels of the AGV vehicle.

[0015] Furthermore, a PID control algorithm is used to adjust the deviation during the AGV's movement. The inputs to the PID control algorithm are the AGV's angular deviation, forward / backward deviation, and left / right deviation. The outputs of the PID control algorithm are the speeds and steering angles of the AGV's four wheels. After obtaining the speeds and steering angles of the AGV's four wheels from the PID control algorithm, the deviation is adjusted using the aforementioned constraints of curvilinear motion.

[0016] Preferably, in step S1, when the main control module receives the mode switching command and the movement direction and speed command, it sends them to the servo motors of each walking wheel of the AGV vehicle for angle positioning control and speed control. When the AGV vehicle encounters an obstacle during movement, it will automatically decelerate and stop.

[0017] In this invention, the movement direction and speed commands are the angle and speed of each walking wheel of the AGV vehicle.

[0018] Based on the same inventive concept, another aspect of this invention discloses a vision-based AGV trajectory automatic planning and parking control system. This control system is used to implement the aforementioned vision-based AGV trajectory automatic planning and parking control method, and includes: an AGV vehicle, the AGV vehicle 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 vehicle's bottom; the main control module is communicatively connected to 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, respectively; wherein... 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 data transmitted by the measurement module through the main control module and perform kinematic calculations for the AGV vehicle. Then, the main control module continuously guides the AGV vehicle to correct its running direction.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] The beneficial effects of this invention are: 1. The present invention relates to a vision-based AGV trajectory automatic planning and parking control method and system. Compared with the prior art, this trajectory automatic planning and parking control method and system, by setting up a main control module and combining other control structures and algorithms, can realize the functions of data acquisition, logic control, motion control, data management and communication management when the AGV is in use. It can adapt to most bus protocols, and by combining multiple motion control algorithms, the AGV can achieve complex multi-axis coordinated motion, increasing its overall applicability and improving its overall practicality.

[0023] 2. When the four driving 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 methods 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. 3. During the walking stage of the AGV vehicle of the present invention, eight adjusting telescopic rods distributed in a "rice" shape are synchronously controlled to make the outer tire circular, ensuring smooth driving; during the parking stage, the telescopic rods connected to the second arc plate contract and the telescopic rods connected to the first arc plate extend, and the outer tire turns into a square shape. The anti-side shift characteristic of the square structure is used to improve stability, and at the same time, the physical wear of mechanical braking is avoided, significantly extending the service life of the driving wheels. Further, the outer tire of the driving wheel is inserted and fixed to the telescopic rod through a positioning rod. When inflating, the high-pressure gas pushes the limit 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 airbag tire design, and can still maintain high-precision driving on the uneven ground of the assembly workshop. Moreover, the outer tire of the driving wheel can be quickly disassembled and assembled through the positioning rod, and when it is damaged, there is no need to replace the entire wheel set.

[0024] 4. The present invention uses a vision guidance program to detect the deviation value in real time. When the deviation is less than the threshold, curve motion is used to synchronously correct the deviation during driving to avoid parking time consumption; when the deviation is greater than the threshold, in-situ correction is started to ensure that the traveling deviation of the AGV vehicle can be quickly adjusted.

[0025] 5. In the manual control stage of the present invention, precise guidance is achieved through a handheld touch screen to send the AGV vehicle to the vision guidance point; in the automatic control stage, combined with the navigation program and the vision guidance program, it supports flexible switching between deviation correction during driving and in-situ correction, and can cover full scenarios of short-distance fine-tuning and long-distance navigation.

[0026] 6. The present invention integrates the PID control algorithm and the curve motion constraint formula, and outputs precise speed and steering angle commands for the four driving wheels for the three types of deviations of the AGV vehicle left and right, front and back, especially suitable for high-precision collaborative scenarios such as the assembly of large aircraft power components.

[0027] 7. The system twin module of the present invention communicates with the main control module in real time through Modbus TCP, obtains the AGV status (speed, deviation, power) and the relative pose of the assembly object, and realizes the synchronous mapping of the physical scene and the digital model, facilitating the operator to remotely master the on-site situation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The foregoing and following specific descriptions of the present invention become clearer when read in conjunction with the following drawings, in which: Figure 1 is the flow chart of the control method of the present invention; Figure 2 is the schematic diagram of the wheel set in the in-situ rotation mode of the AGV vehicle of the present invention; Figure 3 This is a schematic diagram illustrating the principle of AGV vehicle angle deviation adjustment in this invention. Figure 4 This is a schematic diagram of the wheel set for the AGV vehicle's left and right lateral movement mode according to the present invention; Figure 5 This is a schematic diagram of the wheel set for the longitudinal movement mode of the AGV vehicle of the present invention; Figure 6 This is a schematic diagram of the AGV vehicle's curved motion wheel set according to the present invention; Figure 7 This is a schematic diagram of the control system structure of the present invention; Figure 8 This is a schematic diagram of the communication connection of the control system of the present invention; Figure 9 This is a schematic diagram of the main body of the AGV vehicle of the present invention; Figure 10 This is a first-view schematic diagram of the walking module of the present invention; Figure 11 This is a schematic diagram of the second perspective of the walking module of the present invention; Figure 12 This is a schematic diagram showing that the walking wheels of the present invention are circular. Figure 13 This is a schematic diagram showing the square shape of the walking wheels in this invention; Figure 14 This is a schematic diagram showing the connection state of the adjusting telescopic rod, the first arc plate (second arc plate), and the outer tire according to the present invention; Figure 15 This is a schematic diagram showing the connection between the outer tire and the positioning rod of the present invention.

[0029] In the picture: 1. AGV vehicle; 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; 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 ring gear; 78. Detection gear; 741. Positioning hub; 742. Adjusting telescopic rod; 7421. Insertion hole; 7422. Side limiting hole; 7423. Limiting pin; 7424. Return spring; 743. Connecting oil chamber; 744. First arc plate; 745. Second arc plate; 746. Outer tire; 7461. Outer base tire seat; 7462. Airbag tire; 747. Positioning rod; 7471. Limiting groove. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solutions of this invention, specific embodiments will be used to further illustrate the technical solutions for achieving the objectives of this invention. It should be noted that the technical solutions claimed by this invention include, but are not limited to, the following embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort should fall within the scope of protection of this invention. In the assembly of large power components such as aircraft engines, automated assembly is achieved using AGV (Automated Guided Vehicle) vehicle 1, which involves trajectory planning and parking control of AGV vehicle 1. Based on this, this invention proposes a vision-based AGV trajectory automatic planning and parking control method and system. The control system is compatible with most bus protocols and, during operation, can perform data acquisition, logic control, motion control, data management, and communication management functions for AGV vehicle 1. Furthermore, based on various motion control algorithms internally set in the control system, AGV vehicle 1 can achieve complex multi-axis coordinated motion, increasing its overall applicability and practicality, thus better adapting to the assembly of large aircraft power components.

[0031] This invention first discloses a vision-based AGV trajectory automatic planning and parking control method. The control method includes two processes: manual control and automatic control. First, the AGV vehicle 1 needs to be manually guided to move to the designated visual guidance point, and then the automatic control process is executed.

[0032] like Figure 1 As shown, the control method is as follows: S1. Manual Control: First, select the operating mode via the touch screen. After the mode is switched, the operator continues to send movement direction and speed commands to the PLC via the handheld touch screen 9. After calculation, the PLC sends the motor speed and other commands to the servo motors of each wheel set for speed and angle control. When the AGV 1 encounters an obstacle during movement, it will automatically decelerate and stop. S2. Automatic control: After the AGV vehicle 1 is manually controlled to run to the visual guidance point, the system switches to automatic mode and starts the automatic guidance function. The control system automatically controls the AGV vehicle 1 to drive to the parking point and stop at the parking point according to the internally stored navigation program and visual guidance program.

[0033] The more specific control process for automatic control is as follows: The control system acquires the deviation (including angular deviation, left and right deviation, and front and back deviation) between AGV 1 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 correction of AGV 1 can be completed during the movement. When the deviation value is greater than the set threshold, AGV 1 needs to correct itself in place. After AGV 1 reaches the parking point, a final fine adjustment will be performed to make AGV 1 stop accurately at the parking point.

[0034] It is understood that the vehicle control logic implemented in this invention requires manual control of the vehicle to reach a designated visual guidance point before executing the corresponding automatic control process. Therefore, the direction of manual control is the direction towards the visual guidance point.

[0035] In the embodiments described in this invention, the specific control logic and scheme for the two correction methods of AGV vehicle 1 are as follows: (1) AGV vehicle corrects deviation in place For in-situ correction of the AGV, incremental positioning mode is used for pose adjustment. The motion angles of the servo motors of each wheel set of the AGV are calculated based on the deviation values ​​detected by the vision guidance program, and angle positioning control is performed. The angle positioning control includes: Angle deviation adjustment: AGV vehicle 1 achieves angle deviation adjustment through in-situ rotation mode; Left and right deviation adjustment: AGV vehicle 1 achieves left and right deviation adjustment through left and right lateral movement mode; Forward and backward deviation adjustment, AGV vehicle 1 achieves forward and backward deviation adjustment through longitudinal and lateral movement mode.

[0036] In this invention, angle deviation adjustment refers to adjusting the angle relative to the forward direction by rotating in place. Specifically, this is achieved by using different angle combinations of the four wheel sets of the AGV vehicle 1 to adjust the vehicle's angle deviation. Left-right deviation adjustment and front-back deviation adjustment are achieved by controlling the four wheel sets of the vehicle in the same direction to move the vehicle laterally and backward. However, all these deviation adjustments are based on the vehicle's forward direction (target point) as a reference for comparison and adjustment.

[0037] For the in-place rotation mode, refer to Figure 2 and Figure 3 The four wheels of AGV 1 rotate to the tangent of the circular trajectory, therefore the steering angle of the four wheels is adjusted to: ; ; Furthermore, the four wheels of AGV vehicle 1 travel at the same speed: ; If the current angular deviation value of AGV vehicle 1 is φ, the incremental angle M of the walking motor φ for: ; Where θ1 and θ2 are the turning angles of the two front wheels of AGV 1, θ3 and θ4 are the turning angles of the two rear wheels of AGV 1, a is the wheelbase of the left and right wheels of AGV 1, b is the wheelbase of the front and rear wheels of AGV 1, R is the diameter of the wheels of AGV 1, and C is the reduction ratio of the wheel reducer of AGV 1.

[0038] For horizontal swipe mode, refer to Figure 4 As shown, the four wheels of AGV 1 are all 90° in direction and move at the same speed. If the current left-right deviation of AGV 1 is H, the incremental rotation angle of the walking motor is M. H for: ; Where R is the diameter of the AGV vehicle 1's traveling wheel, and C is the reduction ratio of the AGV vehicle 1's traveling wheel reducer.

[0039] For the vertical movement mode, refer to Figure 5 As shown, the four traveling wheels of AGV 1 are all at 0° and move at the same speed. If the forward / backward deviation of AGV 1 is L, the incremental rotation angle of the traveling motor is M. L for: ; Where R is the diameter of the AGV vehicle 1's traveling wheel, and C is the reduction ratio of the AGV vehicle 1's traveling wheel reducer.

[0040] (2) Correction of deviation during AGV vehicle movement For AGV vehicle 1 to correct deviations during its movement, such as Figure 6 As shown, AGV 1 travels at a given initial forward speed. During travel, the control system dynamically adjusts the forward speed based on the distance between AGV 1 and the target. Simultaneously, it corrects the AGV 1's left-right and angular deviations through curved motion based on the deviation value. Since the turning radius of the curved motion is proportional to the wheel steering angle, the steering angle of the AGV 1's wheels is dynamically controlled based on the left-right and angular deviations detected by the vision guidance program, achieving the automatic approach process of AGV 1 to the parking point. The curved motion includes left and right turns, with the center of the curved motion being a point on the vehicle's longitudinal axis. Figure 8 It can be known that: When turning left, the relationship between the steering angle and speed of each traveling wheel of AGV 1 satisfies the following constraints:

[0041] ;

[0042] ;

[0043] ; ; When turning right, the relationship between the steering angle of each traveling wheel of AGV 1 and its speed satisfies the following formula:

[0044] ;

[0045] ;

[0046] ; ; Where R1 and R2 are the turning radii of the outer and inner wheels of AGV 1, respectively; V1 and V2 are the speeds of the two front wheels of AGV 1, respectively; and V3 and V4 are the speeds of the two rear wheels of AGV 1, respectively.

[0047] In the embodiments described in this invention, when turning left or right, it is necessary to control the speed of the two outer walking wheels of the AGV to be the same as the speed of the two inner walking wheels.

[0048] Furthermore, the PID control algorithm is used to adjust the deviation during the movement of AGV 1. The input of the PID control algorithm is the angular deviation value, front-to-back deviation value, and left-to-right deviation value of AGV 1. The output of the PID control algorithm is the walking speed and steering angle of the four walking wheels of AGV 1.

[0049] Similarly, PID control algorithms are common knowledge in this field and will not be explained in detail here.

[0050] Based on the same inventive concept, embodiments of the present invention also disclose a vision-based AGV trajectory automatic planning and parking control system, including an AGV vehicle 1, such as... Figures 7-9 As shown, the AGV vehicle 1 is externally equipped with a main control module 2 (i.e., PLC), a safety protection module 3, a chassis control module 4, a measurement module 6, and a power supply module 8. The AGV vehicle 1 has walking modules 7 located at its four bottom corners, as shown... Figure 8As shown, the main control module 2 of the AGV vehicle 1 is connected to a handheld touch screen 9, a twin module 10, and a host computer 11 via network signals.

[0051] The twin module 10 communicates with the main control module 2 in real time via Modbus TCP. The twin module 10 can obtain the current status of the AGV vehicle and the relative pose of the assembly object through the main control module 2, and then realize the virtual-real mapping of the whole scene based on digital twin technology. At the same time, the collision detection function of the twin module 10 can also display safety warnings during the assembly process of the assembly object.

[0052] The collision warning during the assembly process is scheduled based on collision detection events during the assembly process. The system divides the collision warning into three levels, corresponding to prompt, warning and error respectively (the safety policy threshold refers to the relevant provisions on AGV dynamic obstacle avoidance in ISO 3691-4:2020 "Safety requirements for industrial vehicles").

[0053] Note: When there is a potential collision tendency between AGV 1, the workpiece to be assembled, and the aircraft, the system will alert the operator through a pop-up warning. At this time, the actuator will not react. The pop-up will also be hidden when the collision tendency stops.

[0054] Warning: When the collision risk approaches the warning threshold set by the safety policy, a real-time voice alarm will be played simultaneously and a red pop-up window will be displayed. The voice content can be specified by the user, and the motion mechanism will immediately decelerate. When the collision risk exceeds the warning threshold set by the safety policy, the real-time voice alarm will stop playing, the pop-up window will be hidden, and the posture adjustment platform's motion speed will resume after a reset.

[0055] Error: When the collision risk approaches the collision threshold of the safety policy, a voice alarm is played simultaneously and a red pop-up is displayed as a reminder. The voice content can be specified by the user. At the same time, the motion mechanism immediately stops moving in the direction of the collision. After resetting, the motion mechanism can move at a low speed in the opposite direction of the collision. When the collision risk exceeds the collision threshold set by the safety policy, the real-time voice alarm stops playing and the pop-up is hidden.

[0056] In the system architecture described in this embodiment, the main control module 2 is connected to the power supply module 8, the handheld touchscreen 9, the safety protection module 3, the chassis control module 4, the twin module 10, and the host computer 11, respectively; wherein... The safety protection module 3 is used to detect the distance between the AGV vehicle 1 and obstacles and transmit the data to the main control module 2 for obstacle avoidance processing. The chassis control module 4 is used to receive operation commands transmitted by the main control module 2 and control the walking module 7 to perform movement actions; The measurement module 6 stores a vision guidance program, which is used to measure and feedback the deviation between the AGV vehicle and the parking point in real time, and transmit it to the main control module 2. The main control module 2 continuously guides the AGV vehicle 1 to correct its running direction. The power supply module 8 is used to supply power to the AGV trajectory automatic planning and parking control system; The walking module 7 is used to receive motion commands transmitted by the chassis control module 4 and drive the AGV vehicle 1 to move or stop. The handheld touchscreen 9 is used to enable human-computer interaction; The twin module 10 is used to obtain the state of the AGV vehicle 1 and the relative pose of the assembly object through the main control module 2, and to perform virtual-real mapping in the whole scene; The host computer 11 is used to receive data transmitted by the measurement module 6 through the main control module 2 and perform kinematic calculations on the AGV vehicle 1, and then continuously guide the AGV vehicle 1 to correct its running direction through the main control module 2.

[0057] It should be noted that the AGV kinematics algorithm is common knowledge in this field, and will not be explained in detail here.

[0058] For the walking module 7 of AGV vehicle 1, such as Figures 9-14 As shown, the AGV includes a lifting plate 71 installed at the bottom of the AGV vehicle 1. A hydraulic lifting system is provided between the lifting plate 71 and the vehicle body. A rotating plate 711 is rotatably connected to the top of the lifting plate 71. A travel servo motor 72 is fixedly connected to the top of the rotating plate 711. A steering servo motor 73 is fixedly connected to the top of the lifting plate 71. A worm gear transmission assembly 75 is provided at the output end of the steering servo motor 73. A steering gear ring 77 is fixedly connected to the bottom of the rotating plate 711. A steering gear 76 is meshed with the outside of the steering gear ring 77. The steering gear 76 and the worm gear transmission assembly 75 are connected in a transmission connection. A travel wheel 74 is rotatably connected to the bottom of the rotating plate 711. A travel transmission assembly is provided between the travel servo motor 72 and the travel wheel 74. The travel servo motor 72 drives the travel wheel 74 to rotate through the travel transmission assembly. A detection gear 78 is meshed with the outside of the steering gear ring 77.

[0059] In the embodiments described in this invention, both the walking servo motor 72 and the steering servo motor 73 are controlled by the chassis control module 4. The main control module 2 generates operation commands, the chassis control module 4 receives the operation commands, and then controls the walking servo motor 72 and the steering servo motor 73 to execute them, thereby completing the walking and parking control of the AGV vehicle 1.

[0060] 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 first arc plates 744 and the second arc plates 745 are alternately and fixedly connected to the outside of the telescopic ends of the adjusting telescopic rods 742. An outer tire 746 is sleeved outside the first arc plates 744 and the second arc plates 745. A connecting oil cavity 743 is arranged outside the positioning hub 741. A connecting oil pipe is arranged outside the connecting oil cavity 743. The connecting oil cavity 743 is connected to control the telescopic control of several adjusting telescopic rods 742.

[0061] 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.

[0062] 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 �46 tends to be square, achieving the effect of changing the shape of the outer tire

[0063] In the present invention, by changing the traveling wheel 74 into a square shape, the parking effect is effectively improved. The parking force acts on the weight limitation of the square traveling wheel 74 and the vehicle body, thereby ensuring the stability of parking. Compared with the existing parking mainly through clip brakes, gear meshing or servo motor parking, the wear of the parking mechanism is effectively reduced, thereby ensuring the service life of the overall traveling module 7.

[0064] In some embodiments, as Figure 14 and Figure 15 shown, a plug hole 7421 is opened at the top of the telescopic end of the adjusting telescopic rod 742. A positioning rod 747 is arranged on the inner side surface of the outer tire 746. The positioning rod 747 is inserted into the inside of the plug hole 7421. A side limiting hole 7422 is opened in the inside of the plug hole 7421. A limiting pin 7423 is slidably connected in the side limiting hole 7422. A return spring 7424 is arranged between the limiting pin 7423 and the side limiting hole 7422. A connecting air hole communicating with the side limiting hole is opened at the bottom of the plug hole 7421. A limiting groove 7471 is opened on the side surface of the positioning rod 747. The limiting pin 7423 is inserted into the inside of the limiting groove 7471. A through air guide hole is opened in the inside of the positioning rod 747. The outer tire 746 includes 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. The air guide hole of the positioning rod 747 communicates with the plurality of air bag tires 7462.

[0065] It should be noted that a sealing ring is arranged between the positioning rod 747 and the plug hole 7421. A transition air cavity is formed between the end of the positioning rod 747 and the plug hole 7421. The connecting air hole communicates the transition air cavity and the side limiting hole 7422.

[0066] It should be noted that the outer tire 746 is inserted into the insertion hole 7421 via the positioning rod 747. When the airbag tire 7462 is inflated, the airbag tire 7462 is connected to the insertion hole 7421 through the air guide hole of the positioning rod 747. The gas inside the airbag tire 7462 enters the insertion hole 7421, and then is introduced into the side limiting hole 7422 through the connecting air hole. The high-pressure gas pushes the limiting pin 7423 inside the side limiting hole 7422, further causing the limiting pin 7423 to be inserted into the inside of the limiting groove 7471.

[0067] The positioning rod 747 of the present invention is inserted into the insertion hole 7421 and is limited by the positioning pin 7423, thereby effectively ensuring the stability of the connection between the outer tire 746 and the first arc plate 744 and the second arc plate 745. It is also convenient to adjust the telescopic rod 742 to control the outer tire 746 to be round or square, so that the driving wheel 74 can switch the state of the driving wheel 74 according to the vehicle body when it is walking or parked, thereby ensuring the flexibility of the vehicle body and the stability of the vehicle body when parked.

[0068] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A visual-based AGV trajectory automatic planning and parking control method, characterized in that, The method comprises the following steps: S1, manual control: selecting a running mode, after mode switching, manually operating a handheld touch screen to send a motion direction and motion speed instruction to a main control module, and manually controlling the AGV to run to the vicinity of a visual guide point; S2, automatic control: after the AGV runs to the visual guide point, switching to an automatic mode and starting an automatic guide function, and then automatically controlling the AGV to run to a parking point and park at the parking point according to a navigation program and the visual guide program; wherein, The system acquires a deviation of the AGV from a target point detected by the visual guide program in real time, and when the deviation value is less than a set threshold value, it is considered that the deviation can be corrected during running; when the deviation value is greater than the set threshold value, the AGV will correct the deviation 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. 2.The vision-based AGV trajectory automatic planning and parking control method according to claim 1, characterized in that, For in-place deviation correction, an incremental positioning mode is used to adjust the pose of the AGV, the deviation value detected by the visual guide program is used to calculate the movement angle of the walking servo motor of the corresponding wheel group of the AGV, and angle positioning control is performed; the angle positioning control comprises: Angle deviation adjustment: the AGV adjusts the angle deviation through a in-place rotation mode; Left-right deviation adjustment: the AGV adjusts the left-right deviation through a left-right horizontal movement mode; Front-rear deviation adjustment: the AGV adjusts the front-rear deviation through a longitudinal movement mode. 3.The vision-based AGV trajectory automatic planning and parking control method according to claim 1, characterized in that, For deviation adjustment during running, the AGV runs at a given initial forward speed, the system dynamically adjusts the forward speed according to the distance between the AGV and the target, and simultaneously corrects the left-right deviation and the angle deviation of the AGV through curve motion according to the deviation value; wherein, the curve motion is divided into left turning and right turning; when left turning, the relationship between the turning angle and the speed of each walking wheel of the AGV satisfies the following constraint: ； ； ； ； When right turning, the relationship between the turning angle and the speed of each walking wheel of the AGV satisfies the following formula: ； ； ； ； Wherein, R1 and R2 are the turning radii of the outer walking wheels and the inner walking wheels of the AGV respectively; a is the wheelbase of the left and right walking wheels of the AGV; b is the wheelbase of the front and rear walking wheels of the AGV; V1 and V2 are the speeds of the two front walking wheels of the AGV respectively, V3 and V4 are the speeds of the two rear walking wheels of the AGV respectively; θ1 and θ2 are the turning angles of the two front walking wheels of the AGV respectively, and θ3 and θ4 are the turning angles of the two rear walking wheels of the AGV respectively. 4.The visual-based AGV trajectory automatic planning and parking control method according to claim 1, characterized in that, A PID control algorithm is used for deviation adjustment during running of the AGV, 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, and the output of the PID control algorithm is the speed and the turning angle of the four walking wheels of the AGV.

5. The visual-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 instruction and the motion direction and motion speed instruction, it sends them to the servo motors of the walking wheels of the AGV for angle positioning control and speed control; when encountering an obstacle during movement, the AGV will automatically slow down and stop. 6.The visual-based AGV trajectory automatic planning and parking control method according to claim 1, characterized in that, For the in-place rotation mode, the four walking wheels of the AGV rotate to the tangent of the circular arc trajectory, so the turning angles of the four walking wheels are adjusted to: ； ； And the speeds of the four walking wheels of the AGV are the same: ； If the current angle deviation value of the AGV is φ, the incremental angle M of the walking motor is: φ M = φ / 2 ； Wherein, θ1 and θ2 are the steering angles of the two front wheels of the AGV, θ3 and θ4 are the steering angles of the two rear wheels of the AGV, a is the wheelbase of the AGV, b is the wheelbase of the AGV, R is the diameter of the AGV wheel, and C is the reduction ratio of the AGV wheel reducer.

7. The visual-based AGV trajectory automatic planning and parking control method according to claim 1, characterized in that, For the left-right horizontal moving mode, the directions of the four walking wheels of the AGV vehicle are all 90°, and the speeds of the four walking wheels are the same; if the current left-right deviation of the AGV vehicle is H, the rotation increment angle M of the walking motor is: H H / M. ； Wherein, R is the diameter of the AGV wheel, and C is the reduction ratio of the AGV wheel reducer. 8.The vision-based AGV trajectory automatic planning and parking control method according to claim 1, characterized in that, 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: ； Wherein, R is the diameter of the AGV wheel, and C is the reduction ratio of the AGV wheel reducer.

9. A visual-based AGV trajectory automatic planning and parking control system, the visual-based AGV trajectory automatic planning and parking control system is used to realize the visual-based AGV trajectory automatic planning and parking control method in any one of claims 1-8, characterized in that, It comprises: The AGV is externally provided with a main control module, a safety protection module, a chassis control module, a measurement module and a power supply module, and the bottom corners of the AGV are provided with walking modules. The safety protection module is used for detecting the distance between the AGV and the obstacle and transmitting it to the main control module for obstacle avoidance processing. The chassis control module is used for receiving the operation instructions transmitted by the main control module and controlling the walking modules to execute movement actions. The measurement module internally stores a visual guidance program and is used for measuring the deviation between the AGV and the parking point in real time and transmitting it to the main control module, which continuously guides the AGV to correct the running direction. The power supply module is used for supplying power to the AGV trajectory automatic planning and parking control system. The walking module is used for receiving the movement instructions transmitted by the chassis control module and driving the AGV to walk or park. The handheld touch screen is used for realizing human-computer interaction. The twin module is used for obtaining the state of the AGV and the relative pose of the assembly object through the main control module and performing full-scene virtual-real mapping. The host computer is used for receiving the data transmitted by the measurement module and solving it through the main control module, and then continuously guiding the AGV to correct the running direction through the main control module. 10.The vision-based AGV trajectory automatic planning and parking control system according to claim 9, characterized in that, The walking module comprises a lifting plate installed at the bottom of the AGV, a hydraulic lifting system for adjusting the ground clearance of the lifting plate is arranged between the lifting plate and the AGV, 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. 11.The vision-based AGV trajectory automatic planning and parking control system of claim 10, wherein, The walking wheel comprises a positioning hub, eight adjusting telescopic rods are fixedly connected to the outside of the positioning hub, first arc plates and second arc plates are alternately fixedly connected to the outside of the telescopic ends of the adjusting telescopic rods, an outer tire is sleeved to the outside of the first arc plates and the second arc plates, 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 connected to control the telescopic control of the adjusting telescopic rods. 12.The vision-based AGV trajectory automatic planning and parking control system of claim 11, wherein, A plug-in hole is formed in the top of the telescopic end of the adjusting telescopic rod, a positioning rod is arranged on the inner side of the outer tire and is plugged into the inside of the plug-in hole, a side limiting hole is formed in the inside of the plug-in hole, a limiting pin is slidably connected to the inside of the side limiting hole, a return spring is arranged between the limiting pin and the side limiting hole, a connecting air hole is formed in the bottom of the plug-in hole and is connected to the side limiting hole, a limiting groove is formed in the side of the positioning rod and the limiting pin is plugged into the inside of the limiting groove, a through air guide hole is formed in the inside of the positioning rod, the outer tire comprises 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 is connected to the plurality of air bag tires.

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