Tracking method and device for disc conveyor belt system

Abstract

The invention discloses a disc conveyor belt system tracking method, and relates to the technical field of industrial automation control, and the method comprises the steps: carrying out the real-time counting of the rotation of a disc through an incremental encoder, initializing the data of the encoder, and calculating the increment of the encoder after the rotation of a circle; establishing a robot user coordinate system taking the center of the disc as an original point, and determining the coordinate system and a rotation direction through a three-point method; four key point positions are selected on the outer edge of the disc and serve as an earliest initial synchronization point, a latest initial synchronization point, a synchronization end point and a working area end point respectively; an object trigger point is arranged, and a photoelectric sensor is arranged at the trigger point, so that real-time detection of the object entering a tracking area is realized; starting disc rotation and object putting, and after an object enters a tracking queue, calculating a real-time rotation angle of the object and a position of the object in a robot coordinate system according to encoder data and key point teaching information; when the object is in the preset angle interval, the state of the object is updated and a signal is output through the control system.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial automation control, in particular to a method for tracking a disc conveyor system. Background Art

[0002] In existing industrial production lines, conveyor-based target object tracking methods are relatively common and are mainly designed for linear conveyor systems. However, for disc-type rotating conveyor systems, the target object constantly changes with the rotation trajectory, and traditional linear tracking methods cannot be directly applied. This makes it difficult for robots to accurately determine the object's position and status, which in turn affects operational accuracy and production efficiency.

[0003] In the existing disc-type conveyor system, it is difficult for the robot to accurately track the target object rotating with the disc. The main technical problems are as follows: the coordinate system of the traditional linear transmission method cannot be applied to the rotating motion of the disc, resulting in complex coordinate calculation and large errors when the robot tracks; since the position of the object changes continuously over time, the existing tracking method is difficult to calculate the exact position of the target object in real time, resulting in a lag in the robot's response, affecting the operation accuracy; the traditional method lacks a trigger mechanism for the disc-type motion characteristics, resulting in inaccurate object recognition, affecting the robot's operation timing; when the object is displaced or rotated on the disc, it is difficult for the robot to continuously and accurately adjust the working path, affecting the quality and consistency of applications such as spraying and gluing; therefore, there is an urgent need for a target tracking method specifically for the disc-type conveyor system that can solve problems such as coordinate system matching, state update lag and insufficient trigger synchronization mechanism, so as to achieve high-precision tracking and efficient processing of objects. Summary of the Invention

[0004] In view of the above existing problems, the present invention is proposed.

[0005] The present invention provides a disc conveyor system tracking method to solve the problem in existing disc conveyor systems that it is difficult for a robot to accurately track a target object rotating with the disc.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: An embodiment of the present invention provides a method for tracking a carousel system, which includes: Step S1, using an incremental encoder to record the disk rotation data in real time, and obtaining the encoder increment per rotation by calibrating the reference point; Step S2, using the three-point method to establish the robot user coordinate system with the center of the disk as the origin, and determine the disk's rotation direction and the angle range of 0° to 360°; Step S3: Select four points in the robot working area on the outer edge of the disk as the earliest starting synchronization point Ps1, the latest starting synchronization point Ps2, the synchronization end point Ps3, and the working area end point Ps4; Step S4: Based on the mold center of the object on the disc, a raised trigger point is set along a straight line extending to the edge of the disc, and a photoelectric sensor is installed at position Ps1 to detect when the object enters the tracking area; Step S5: Start the disk rotation and object placement, collect encoder data and object initial status in real time, and add objects to the tracking queue in sequence; Step S6, based on the encoder data and angle information, using the coordinate transformation formula to calculate the real-time rotation angle of the object and its position in the robot coordinate system; Step S7, when the object rotates to between Ps1 and Ps2, the object state is updated to an activatable state, and the robot is controlled to track according to the dynamically calculated coordinates; Step S8, when the object rotates beyond the preset angle range, the state is updated to Miss, Done, or UnDone according to its angle, and it is removed from the tracking queue after reaching the end point Ps4 of the work area; Step S9: During the entire tracking process, the robot performs corresponding operations based on the dynamic movement coordinates updated in real time; Step S10, repeating steps S5 to S8 to continuously track and control multiple objects.

[0007] As a preferred solution of the carousel system tracking method of the present invention, the step of using an incremental encoder to record the disc rotation data in real time includes: Preset the reference point on the disk and read the initial encoder value En1. After the disk rotates one circle, read the encoder value En2. Calculate the encoder increment En3 = En2 – En1.

[0008] As a preferred solution of the disc conveyor system tracking method described in the present invention, in which: in step S2, the step of establishing the robot user coordinate system adopts the three-point method to determine the center of the disc, and stipulates that the direction and angle range of the X+ axis when the disc rotates is 0° to 360°.

[0009] As a preferred solution of the carousel system tracking method of the present invention, in step S3, the step of selecting four points includes: Switch the robot coordinate system to CRS1; Move the robot to four points on the outer edge of the disk in sequence and record the (X, Y) coordinates of each point; Use the formula radians = atan2(Y, X) to calculate the rotation angle of each point relative to the X+ axis and convert it into angle values, which are recorded as θ1, θ2, θ3, and θ4 respectively; The points are defined in sequence as the earliest starting synchronization point Ps1 (X1, Y1, A1, θ1), the latest starting synchronization point Ps2 (θ2), the synchronization end point Ps3 (θ3) and the working area end point Ps4 (θ4).

[0010] As a preferred embodiment of the method for tracking a carousel system according to the present invention, in step S5, the step of establishing a raised trigger point includes: Determine the connecting line based on the position of each object at the center of the mold on the disk and extending outward to the edge of the disk; A corresponding raised trigger point is set where the connecting line extends to the edge of the disk. When the trigger point passes through the photoelectric sensor installed at the Ps1 position, a signal is triggered, and the object is added to the tracking queue.

[0011] As a preferred embodiment of the method for tracking a carousel system according to the present invention, the step of adding an object to the tracking queue records the corresponding current encoder value En_obj when the object triggers a photoelectric signal for the first time, and stores the object's original position information (X1, Y1, A1, θ1) and the initial state is Wait.

[0012] As a preferred embodiment of the carousel system tracking method of the present invention, the step of using the coordinate transformation formula to calculate the real-time rotation angle of the object and its position in the robot coordinate system includes: Get the current encoder value En_current in real time; Calculate the object rotation angle θn = [(En_current – ​​En_obj) / En3] × 360° + θ1; The object's current position in the robot coordinate system is calculated using the formulas Xn=X×cos(θn)–Y×sin(θn) and Yn=X×sin(θn)+Y×cos(θn). The object's orientation is also updated using An=(A+θ1) mod 360.

[0013] As a preferred embodiment of the carousel system tracking method of the present invention, in step S7, the object status update method includes: When the object rotates to between Ps1 and Ps2, update the state from Wait to Active; When the object rotates beyond Ps2 and the robot has not started tracking, update the state to Miss; When the robot completes the task and the object rotates to Ps3, the status is updated to Done; When the object rotates beyond Ps3 but the job is not completed, the status is updated to UnDone and removed from the tracking queue after the object rotates to Ps4.

[0014] As a preferred embodiment of the method for tracking a carousel system according to the present invention, the incremental encoder and the photoelectric sensor constitute a synchronous detection device, and the synchronous detection device includes: An incremental encoder is used to collect real-time disk rotation data; and a photoelectric sensor is set at the earliest starting synchronization point Ps1. Its output signal and the data collected by the incremental encoder are processed to generate real-time object rotation angle and position information; thereby realizing dynamic update of the position and status of the object after entering the tracking area.

[0015] As a preferred solution of the disc conveyor system tracking method described in the present invention, the disc conveyor system tracking method adopts a visual detection module to collect and identify the position information of objects in the disc conveyor system in real time. The visual detection module includes an industrial camera and a computer vision processing unit. The visual detection module, the incremental encoder and the photoelectric sensor constitute an auxiliary detection unit; to improve the reliability of object position identification, but the synchronous detection of the incremental encoder and the photoelectric sensor is the main technical solution.

[0016] The beneficial effects of the present invention are as follows: the present invention adopts a dynamic phase tracking algorithm and utilizes the synchronous detection of an incremental encoder and a photoelectric sensor to achieve high-precision tracking of the target object on the disc conveyor belt; the present invention accurately grasps the rotation state of the disc through a real-time angle calculation model based on the encoder incremental value; it iteratively calculates the object phase angle and dynamically tracks the angle change of the object during the rotation process; in addition, it establishes and maintains a user coordinate system CRS1 with the center of the disc as the origin, so that the spatial relationship mapping between the robot and the object is more accurate; by generating a dynamic moving coordinate system (Xn, Yn, 0, An, 0, 0) in real time, it realizes the real-time conversion of the position and orientation of the object on the rotating platform, and provides accurate motion parameters for robot tracking.

[0017] The present invention realizes target detection based on synchronous recognition by combining incremental encoder and photoelectric sensor signals, greatly improving the accuracy of object recognition and tracking; in view of the characteristic that the position of the target object on the rotating platform changes with time, the object tracking method proposed in the present invention is different from the traditional linear conveyor belt solution, can effectively solve the problem of precise tracking, and has significant industrial application prospects.

[0018] In summary, the present invention has obvious advantages in improving target recognition accuracy, real-time dynamic tracking and spatial mapping conversion, and can provide reliable technical support and operation optimization for industrial robots working on rotating platforms. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 Schematic diagram of the process of the carousel system tracking method in Example 1. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0022] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0023] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0024] Example 1, reference Figure 1 , this embodiment provides a method for tracking a carousel system, comprising: Carry out system deployment, the system components include: industrial robot, disc-shaped rotating platform, incremental encoder, photoelectric signal sensor; The robot is fixed next to the disc. The disc can adjust its rotation speed after power is applied. An incremental encoder is connected to the drive motor to record the change in rotation angle in real time. A photoelectric sensor is installed on the outer edge of the disc to detect objects entering the robot's working area. The tracking control method specifically includes: 1. Initialize encoder data: ①Mark a reference point on the disc and read the initial value En1 of the encoder; ② Let the disk rotate one circle. When the reference point returns to the original position, read the encoder value En2. ③Calculate the encoder increment En3 = En2 - En1 for one rotation of the disk.

[0025] 2. Robot coordinate system calibration: ① The robot TCP moves to the center of the circle and establishes the user coordinate system CRS1 (x, y, z, a, b, c) using the three-point method. ② The direction of rotation of the disk is set to be counterclockwise from the X+ axis to the Y+ axis; ③ Setting angle range: X+ axis to Y+ axis is 0° to 90°, and a full rotation is 0° to 360°.

[0026] 3. Define key points: Select four key points on the outer edge of the disk, on the side of the robot's working range: The earliest starting synchronization point Ps1; The latest starting synchronization point Ps2; Synchronization end point Ps3; The work area ends at point Ps4.

[0027] 4. Key points of teaching: 1. Switch the robot's coordinate system to CRS1, move the robot to the four points in sequence, and teach the (X, Y) values ​​of each point respectively. Radians:= atan2(Y,X); θ1:= radian value * 180 / PI; A := θ1+180; The rotation angle of each point to the X+ axis can be obtained in sequence and defined as: θ1, θ2, θ3, θ4; and the angle A between the placement angle of the object at each point and X+.

[0028] 2. At this point, the key information of the four points obtained through the above calculation teaching is as follows: The earliest starting synchronization point Ps1 (X1, Y1, A1, θ1); The latest starting synchronization point Ps2(θ2); Synchronous end point Ps3 (θ3); The working area end point Ps4 (θ4).

[0029] 5. Trigger point setting: ① Connect the center of the circle with the center of each object mold on the disk, and extend the connecting line to the edge of the disk; ② Set up a corresponding raised trigger point on the edge. When the disc rotates to the position of the photoelectric sensor, the trigger point moves to the bottom of the sensor, triggering a photoelectric signal, thereby adding the object to the tracking queue.

[0030] 6. Installation of photoelectric sensor: Install the photoelectric sensor at position Ps1 to accurately detect the moment an object enters the tracking area.

[0031] 7. Even arrangement of trigger points: 1) Place the trigger points of all objects on the disk at fixed angles and distances to unify the tracking logic and improve detection stability and accuracy; 8. Disc rotation and object placement ① Start the disk rotation, and the incremental encoder starts counting at the same time, recording the rotation angle changes in real time; ② Place the objects in sequence according to the preset mold positions on the disc to ensure that the objects can enter the working area according to the set trajectory during rotation.

[0032] 9. Objects enter the queue ① When an object (Obj) rotates to the Ps1 position, a photoelectric signal is triggered, and the object is added to the object tracking queue and defined as Obj1. Its initial state is set to Wait. ②Record the current value of the encoder En_obj1 and store all the original information of the object: (X1, Y1, A1, θ1, Wait, En_obj1); ③ Then, when the second object rotates to Ps1, it also triggers the photoelectric signal and joins the queue, defined as Obj2, with the following initial information: (X_2, Y_2, θ1_2, Wait_2, En_obj1_2); ④ Similarly, subsequent objects (Obj3, Obj4...) enter the queue and record their status in the same way.

[0033] 10. The robot controller needs to continuously calculate the real-time position of the object. Take Obj1 as an example: Current encoder position: En The angle of rotation of the object after joining the queue is θn1:= (En-En_obj1) / En3 * 360° + θ1; Current Xn1:= X * COS(θn) - Y * SIN(θn); Current Yn1:= X * SIN(θn) + Y * COS(θn); Current An1:= (A + θ1)% 360; At this time, all the information of Obj1 is updated to (X1, Y1, A1, θ1, Wait, En_obj1, [Xn1, Yn1, An1, θn1]).

[0034] 11. The object rotates with the disk. When the object is between Ps1->Ps2, that is, θ1<θn1<θ2, the object can be activated; 12. If the robot has not started tracking the object after it rotates to Ps2, the object status is updated to Miss, that is, (X1, Y1, A1, θ1, Miss, En_obj1, [Xn1, Yn1, An1, θn1]). When the object further rotates to Ps4, that is, θn1>θ4, the system automatically removes the object information from the queue.

[0035] 13. If the robot activates and starts tracking while the object is between Ps1 and Ps2, the object state changes to Active and the information is updated to: (X1, Y1, A1, θ1, Active, En_obj1, [Xn1, Yn1, An1, θn1]), based on the mobile tracking coordinate system calculated in step 10 (Xn1, Yn1, 0, An1, 0, 0).

[0036] 14. The motion tracking coordinates (Xn1, Yn1, 0, An1, 0, 0) are dynamically changing coordinates and are continuously adjusted and calculated in real time based on the encoder's changing speed.

[0037] 15. After the robot is cut into this coordinate system, when the robot executes the motion command, the robot end will maintain a relative motion relationship with the object. During this tracking process, the robot can perform the corresponding gluing or spraying operations.

[0038] 16. Before the object rotates to Ps3, that is, θn1<θ3, if the robot has completed the work, the object information is changed to (X1, Y1, A1, θ1, Done, En_obj1, [Xn1, Yn1, An1, θn1]), until θn1>θ4, and the object is discarded from the queue.

[0039] 17. If the object has not completed its work after passing Ps3, that is, θn1>= θ3, the robot stops tracking, switches the coordinate system to the robot's own coordinate system, breaks away from the object's tracking system, returns to a safe position, and changes the object information to (X1, Y1, A1, θ1, UnDone, En_obj1, [Xn1, Yn1, An1, θn1]) until θn1>θ4, at which point the object is discarded from the queue.

[0040] 18. Follow steps 11 to 17 to process the objects in the queue.

[0041] This embodiment uses photoelectric sensors and incremental encoders to ensure accurate positioning and real-time coordinate conversion of objects; adopts contact detection and parallel tracking of multiple objects to improve production efficiency and is suitable for high-speed assembly lines; automatically updates object status to prevent misoperation and improve system stability; supports objects of different sizes and shapes and is suitable for mixed-flow production; compared with AI vision and lidar solutions, it has lower hardware costs and is easy to integrate into existing production lines; it can be combined with AI vision, quality inspection and other systems to further improve the level of automation.

[0042] Through the above implementation, real-time and accurate tracking of multiple objects can be achieved under the condition of high-speed rotation of the disk; specifically, 1) Relying on an incremental encoder to obtain the disk rotation angle, combined with trigger detection by a photoelectric sensor, ensures high positioning accuracy when the object enters the working area; 2) Through a unified state management unit, the object's Wait, Active, Miss, Done, UnDone and other states are automatically switched, avoiding missed detection or misjudgment caused by manual intervention; 3) While meeting the low cost of existing hardware, this method can be further combined with visual inspection or other sensing devices to detect and locate objects with complex shapes or multiple specifications; 4) In industrial production, only the radius of the disc, the installation position of the photoelectric sensor and the key points of teaching need to be adjusted to adapt to rotary tables of different sizes, which has good versatility.

[0043] In summary, this invention achieves dynamic tracking and automated operation of objects on a carousel by acquiring encoder increments per disc rotation, detecting trigger signals from a photoelectric sensor, and teaching key points. This implementation effectively improves robot operation accuracy and production efficiency, is low-cost, and easily adaptable, making it suitable for a variety of industrial automation applications.

[0044] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for tracking a carousel system, characterized in that: include, Step S1, using an incremental encoder to record the disk rotation data in real time, and obtaining the encoder increment per rotation by calibrating the reference point; Step S2, using the three-point method to establish the robot user coordinate system with the center of the disk as the origin, and determine the disk's rotation direction and the angle range of 0° to 360°; Step S3: Select four points in the robot working area on the outer edge of the disk as the earliest starting synchronization point Ps1, the latest starting synchronization point Ps2, the synchronization end point Ps3, and the working area end point Ps4; Step S4: Based on the mold center of the object on the disc, a raised trigger point is set along a straight line extending to the edge of the disc, and a photoelectric sensor is installed at position Ps1 to detect when the object enters the tracking area; Step S5: Start the disk rotation and object placement, collect encoder data and object initial status in real time, and add objects to the tracking queue in sequence; Step S6, based on the encoder data and angle information, using the coordinate transformation formula to calculate the real-time rotation angle of the object and its position in the robot coordinate system; Step S7, when the object rotates to between Ps1 and Ps2, the object state is updated to an activatable state, and the robot is controlled to track according to the dynamically calculated coordinates; Step S8, when the object rotates beyond the preset angle range, the state is updated to Miss, Done, or UnDone according to its angle, and it is removed from the tracking queue after reaching the end point Ps4 of the work area; Step S9: During the entire tracking process, the robot performs corresponding operations based on the dynamic movement coordinates updated in real time; Step S10, repeating steps S5 to S8 to continuously track and control multiple objects.

2. A method for tracking a carousel system according to claim 1, characterized in that: The step of using an incremental encoder to record the disk rotation data in real time includes: Preset the reference point on the disk and read the initial encoder value En1. After the disk rotates one circle, read the encoder value En2. Calculate the encoder increment En3 = En2 – En1.

3. The method for tracking a carousel system according to claim 1, wherein: In step S2, the step of establishing the robot user coordinate system adopts the three-point method to determine the center of the disk, and stipulates that the direction and angle range of the X+ axis when the disk rotates is 0° to 360°.

4. The method for tracking a carousel system according to claim 1, wherein: In step S3, the step of selecting four points includes: Switch the robot coordinate system to CRS1; Move the robot to four points on the outer edge of the disk in sequence and record the (X, Y) coordinates of each point; Use the formula radians = atan2(Y, X) to calculate the rotation angle of each point relative to the X+ axis and convert it into angle values, which are recorded as θ1, θ2, θ3, and θ4 respectively; The points are defined in sequence as the earliest starting synchronization point Ps1 (X1, Y1, A1, θ1), the latest starting synchronization point Ps2 (θ2), the synchronization end point Ps3 (θ3) and the working area end point Ps4 (θ4).

5. The method for tracking a carousel system according to claim 1, wherein: In step S5, the step of establishing the raised trigger point includes: Determine the connecting line based on the position of each object at the center of the mold on the disk and extending outward to the edge of the disk; A corresponding raised trigger point is set where the connecting line extends to the edge of the disk. When the trigger point passes through the photoelectric sensor installed at the Ps1 position, a signal is triggered, and the object is added to the tracking queue.

6. A method for tracking a carousel system according to claim 5, characterized in that: The step of adding the object to the tracking queue records the corresponding current encoder value En_obj when the object triggers the photoelectric signal for the first time, and stores the original position information (X1, Y1, A1, θ1) of the object and the initial state is Wait.

7. A method for tracking a carousel system according to claim 6, characterized in that: The step of using the coordinate transformation formula to calculate the real-time rotation angle of the object and its position in the robot coordinate system includes: Get the current encoder value En_current in real time; Calculate the object rotation angle θn = [(En_current – ​​En_obj) / En3] × 360° + θ1; The object's current position in the robot coordinate system is calculated using the formulas Xn=X×cos(θn)–Y×sin(θn) and Yn=X×sin(θn)+Y×cos(θn). The object's orientation is also updated using An=(A+θ1) mod 360.

8. A method for tracking a carousel system according to claim 7, characterized in that: In step S7, the object status is updated in the following manner: When the object rotates to between Ps1 and Ps2, update the state from Wait to Active; When the object rotates beyond Ps2 and the robot has not started tracking, update the state to Miss; When the robot completes the task and the object rotates to Ps3, the status is updated to Done; When the object rotates beyond Ps3 but the job is not completed, the status is updated to UnDone and removed from the tracking queue after the object rotates to Ps4.

9. The method for tracking a carousel system according to claim 1, wherein: The incremental encoder and the photoelectric sensor constitute a synchronous detection device, and the synchronous detection device includes: An incremental encoder for real-time collection of disk rotation data; and a photoelectric sensor located at the earliest starting synchronization point Ps1, whose output signal is processed with the data collected by the incremental encoder to generate real-time rotation angle and position information of the object.

10. The method for tracking a carousel system according to claim 1, wherein: The disc conveyor system tracking method adopts a visual detection module to collect and identify the position information of objects in the disc conveyor system in real time. The visual detection module includes an industrial camera and a computer vision processing unit. The visual detection module, the incremental encoder and the photoelectric sensor constitute an auxiliary detection unit.

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