Conveyor belt continuous tracking method under repeated triggering of industrial robot

Abstract

The invention discloses a conveyor belt continuous tracking method under repeated triggering of an industrial robot, which comprises a workpiece triggering management unit, a conveyor belt movement speed evaluation unit and a tracking execution unit, and comprises the following steps: step 1, a conveyor belt has a workpiece reaching a triggering point; in the tracking process, the workpiece trigger management unit, the conveyor belt movement speed evaluation unit and the tracking execution unit are activated at the same time and run synchronously in a multi-thread mode, so that workpieces passing through trigger points cannot be lost in the tracking process, tracking interruption and tracking recovery can be conducted repeatedly, and the tracking efficiency is improved. Therefore, the phenomenon that a new workpiece is neglected cannot occur under the condition that the interval between the workpieces is relatively short; and the tracking recovery adopts offset calculation, directly enters a tracking state by utilizing an interval offset mode, does not need to be triggered and starts from a specified tracking starting point, so that the industrial robot can continuously and sequentially track a plurality of workpieces and does not need to return to a waiting position, and the working efficiency is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of conveyor belt tracking, and in particular to a method for continuously tracking a conveyor belt when an industrial robot is triggered multiple times. Background Art

[0002] Automated production lines usually take the form of assembly lines, where the workpieces to be processed follow the conveyor belt from one station to another. The industrial robots at each station need to cooperate with the moving conveyor belt to complete corresponding operations such as grabbing, placing, and spraying the workpieces during the movement of the conveyor belt. At present, industrial robots complete conveyor belt tracking on the assembly line, usually using cameras or photoelectric switches to detect whether the workpiece passes through at the trigger point, to achieve positioning of the workpiece, and then trigger the industrial robot. The conveyor belt has a known movement speed or is equipped with an encoder to calculate the movement speed when the workpiece runs from the trigger point to the tracking starting point. After the industrial robot is triggered at the waiting position, it starts to run towards the tracking starting point. After the workpiece reaches the tracking starting point, the tracking process is started. The end tool speed is synthesized according to the conveyor belt speed and the preset teaching speed, and the operation of the workpiece on the moving conveyor belt is completed during the tracking process. After the operation is completed, the industrial robot exits the conveyor belt tracking, returns to the waiting position, and waits for the next trigger.

[0003] For example, the Chinese invention patent with the authorization announcement number CN108608463A discloses a method for dynamic tracking of an industrial robot conveyor belt, including: according to the relative position between the industrial robot and the conveyor belt, the conveyor belt tracking is divided into the following stages in sequence: the starting section, the tracking section and the disengagement section. When the workpiece enters the starting window and the industrial robot is in a waiting state, the industrial robot starts to track the workpiece and adjusts the running speed so that the end tool speed of the industrial robot is consistent with the speed of the conveyor belt before the industrial robot enters the tracking area; when the workpiece enters the tracking section, the industrial robot synthesizes the end speed of the industrial robot according to the preset teaching speed and the conveyor belt speed measured by the encoder; when the robot enters the disengagement section, the actual speed of the industrial robot is reduced from the conveyor belt speed to 0. For another example, the Chinese invention patent with the authorization announcement number CN111347423A discloses a method for dynamic tracking and gluing of an industrial robot conveyor belt, which can enable the industrial robot to locate and track the object after the gluing object on the conveyor belt reaches the operating range. The gluing operation of the object contour is realized after the robot and the object are relatively stationary. The conveyor belt does not need to be stopped during the whole process. The specific design includes the following stages: when the object just enters the robot's operating range, the robot locates the object after obtaining the object's position, and the robot moves from point to point; after the robot locates the object, it starts to track the object until it is relatively stationary with the object; the robot remains relatively stationary with the object while performing the gluing operation on the object's contour, and the robot moves in a continuous trajectory. Both methods use the above tracking method, but the current conveyor belt tracking method has the following defects:

[0004] Although this method is simple and practical, the workpieces on the conveyor belt must be spaced far apart. When the industrial robot is in the process of tracking a workpiece, no new workpiece can arrive at the trigger point, otherwise the new workpiece will be ignored. In actual applications, in order to improve operating efficiency, the workpieces on the conveyor belt are closely spaced. It often happens that when the industrial robot is in the process of tracking a workpiece, a new workpiece has arrived at the trigger point, resulting in the new workpiece being ignored. Secondly, each time the industrial robot completes tracking and operating a workpiece, it needs to return to the waiting position and will not start the next tracking until it receives the trigger signal again, which affects operating efficiency.

[0005] To this end, we propose a method for continuous conveyor belt tracking under multiple triggering of industrial robots to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to provide a method for continuously tracking a conveyor belt under multiple triggering of an industrial robot, so as to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for continuous tracking of a conveyor belt under multiple triggering of an industrial robot, comprising a workpiece triggering management unit, a conveyor belt motion speed evaluation unit and a tracking execution unit, comprising the following steps:

[0008] Step 1: The conveyor belt with the workpiece arrives at the trigger point, and the workpiece trigger management unit, the conveyor belt movement speed evaluation unit and the tracking execution unit are activated at the same time;

[0009] Step 2: The conveyor belt speed evaluation unit obtains the real-time running speed of the conveyor belt. The tracking execution unit reads the conveyor belt running speed from the conveyor belt speed evaluation unit, and then controls the industrial robot to track the workpiece from the tracking starting point. The workpiece trigger management unit starts to monitor the conveyor belt trigger device. During the tracking process of the industrial robot, if a new workpiece passes the trigger point, the conveyor belt encoder value is obtained and placed in the FIFO queue.

[0010] Step 3: After the industrial robot tracks and processes a workpiece, the tracking execution unit reads the first address of the workpiece trigger management unit FIFO queue to determine whether there is workpiece data. If yes, it goes to step 4; if not, it goes to step 5

[0011] Step 4: If there is workpiece data, the tracking is interrupted, the conveyor speed is read from the conveyor speed evaluation unit, the workpiece tracking starting point offset value is calculated, the subsequent motion trajectory is offset, the tracking is restored, and the industrial robot is controlled to continue the tracking processing of the next workpiece. At the same time, the first address of the FIFO queue is moved down by one, and then step 3 is repeated;

[0012] Step 5: If there is no workpiece data, the tracking ends and the industrial robot returns to the waiting position.

[0013] Preferably, in step 1, the conveyor belt movement speed evaluation unit obtains the real-time running speed of the conveyor belt by directly obtaining the conveyor belt linear speed configured by the system or periodically obtaining the encoder value of the conveyor belt to calculate the running speed.

[0014] Preferably, the method for calculating the workpiece tracking starting point offset value by the tracking execution unit in step 4 comprises the following steps:

[0015] Step 1: Use the dedicated global variable GV01 to save the distance from the trigger point to the specified tracking starting point;

[0016] Step 2: Get the current encoder value of the conveyor belt, calculate the forward distance of the conveyor belt after the first trigger, and save it in the dedicated global variable GV02;

[0017] Step 3: Read the conveyor encoder value at the moment when the workpiece passes the trigger point in the FIFO queue of the workpiece trigger management unit, calculate the conveyor advance distance from the first trigger to the moment when the workpiece is triggered, and save it in a dedicated global variable GV03;

[0018] Step 4: Calculate the workpiece tracking starting point offset value as GV02-GV01-GV03.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] In the tracking process of the present invention, the workpiece trigger management unit, the conveyor belt movement speed evaluation unit and the tracking execution unit are activated at the same time, and multiple threads run synchronously, so that the workpiece that has passed the trigger point will not be lost in the tracking process, and the tracking interruption and tracking recovery can be performed multiple times, so that when the workpiece interval is short, the new workpiece will not be ignored; and the tracking recovery adopts the calculation of the offset and the use of the interval offset method to directly enter the tracking state, without triggering and starting from the specified tracking starting point, so that the industrial robot can continuously perform tracking operations on multiple workpieces in sequence without returning to the waiting position, which greatly improves the working efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the process of the present invention; DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Embodiment 1:

[0024] See also Figure 1 The present invention provides a technical solution: a method for continuous tracking of a conveyor belt under multiple triggering of an industrial robot, comprising a workpiece triggering management unit, a conveyor belt motion speed evaluation unit and a tracking execution unit, comprising the following steps:

[0025] Step 1: The conveyor belt with the workpiece arrives at the trigger point, and the workpiece trigger management unit, the conveyor belt movement speed evaluation unit and the tracking execution unit are activated at the same time;

[0026] Step 2: The conveyor belt speed evaluation unit obtains the real-time running speed of the conveyor belt. The tracking execution unit reads the conveyor belt running speed from the conveyor belt speed evaluation unit, and then controls the industrial robot to track the workpiece from the tracking starting point. The workpiece trigger management unit starts to monitor the conveyor belt trigger device. During the tracking process of the industrial robot, if a new workpiece passes the trigger point, the conveyor belt encoder value is obtained and placed in the FIFO queue.

[0027] Step 3: After the industrial robot tracks and processes a workpiece, the tracking execution unit reads the first address of the workpiece trigger management unit FIFO queue to determine whether there is workpiece data. If yes, it goes to step 4; if not, it goes to step 5

[0028] Step 4: If there is workpiece data, the tracking is interrupted, the conveyor belt running speed is read from the conveyor belt motion speed evaluation unit, the workpiece tracking starting point offset value is calculated, the subsequent motion trajectory is offset, the tracking is restored, and the industrial robot is controlled to continue the tracking processing of the next workpiece. At the same time, the first address of the FIFO queue is moved down by one, and then step 3 is repeated; if the forward direction of the conveyor belt is not the direction of the coordinate axis of the industrial robot base coordinate system, a user coordinate system can be established with the forward direction of the conveyor belt as the coordinate axis, and the interval offset calculation of the subsequent motion trajectory can be performed based on the user coordinate system;

[0029] Step 5: If there is no workpiece data, the tracking ends and the industrial robot returns to the waiting position.

[0030] Embodiment 2:

[0031] See also Figure 1 , which is the second embodiment of the present invention. This embodiment is based on the previous embodiment. In step 1, the conveyor belt movement speed evaluation unit obtains the real-time running speed of the conveyor belt by directly obtaining the conveyor belt linear speed configured by the system or periodically obtaining the encoder value of the conveyor belt to calculate the running speed.

[0032] The method for calculating the workpiece tracking starting point offset value by the tracking execution unit in step 4 includes the following steps:

[0033] Step 1: Use the dedicated global variable GV01 to save the distance from the trigger point to the specified tracking starting point;

[0034] Step 2: Get the current encoder value of the conveyor belt, calculate the forward distance of the conveyor belt after the first trigger, and save it in the dedicated global variable GV02;

[0035] Step 3: Read the conveyor encoder value at the moment when the workpiece passes the trigger point in the FIFO queue of the workpiece trigger management unit, calculate the conveyor advance distance from the first trigger to the moment when the workpiece is triggered, and save it in a dedicated global variable GV03;

[0036] Step 4: Calculate the workpiece tracking starting point offset value as GV02-GV01-GV03.

[0037] Embodiment 3:

[0038] See also Figure 1 , which is the third embodiment of the present invention. This embodiment is based on the above two embodiments. This embodiment is a continuous tracking of an industrial robot when painting a workpiece on a moving conveyor belt. There are three workpieces on the moving conveyor belt, namely, workpiece A, workpiece B and workpiece C. During the tracking and painting process of the previous workpiece A, workpiece B and workpiece C pass through the trigger point in sequence, causing a trigger. The continuous tracking steps are as follows:

[0039] Step 1: The conveyor belt with workpiece A arrives at the trigger point, and the workpiece trigger management unit, conveyor belt motion speed evaluation unit and tracking execution unit are activated at the same time;

[0040] Step 2: The conveyor speed evaluation unit obtains the real-time running speed of the conveyor, and the tracking execution unit reads the conveyor speed from the conveyor speed evaluation unit, and then controls the industrial robot to track and process workpiece A from the tracking starting point. The workpiece trigger management unit starts to monitor the conveyor trigger device. During the tracking process of the industrial robot, workpieces B and C pass through the trigger point, and the conveyor encoder value at that moment is obtained and put into the FIFO queue;

[0041] Step 3: After the industrial robot tracks and completes painting of workpiece A, the tracking execution unit reads the first address of the FIFO queue of the workpiece trigger management unit, determines that there is data of workpiece B, then interrupts the tracking, reads the conveyor belt running speed from the conveyor belt motion speed evaluation unit, calculates the offset value of the tracking starting point of workpiece B, performs interval offset on the subsequent motion trajectory, tracks and resumes, and controls the industrial robot to continue tracking processing of workpiece B; at the same time, the first address of the FIFO queue is moved down by one, wherein the offset value of the tracking starting point of workpiece B is calculated, including the following steps:

[0042] Step 1: Use the dedicated global variable GV01 to save the distance from the trigger point to the specified tracking starting point;

[0043] Step 2: Get the current encoder value of the conveyor belt, calculate the forward distance of the conveyor belt after the workpiece A is triggered, and save it in the dedicated global variable GV02;

[0044] Step 3: Read the conveyor encoder value at the moment when workpiece B passes the trigger point in the FIFO queue of the workpiece trigger management unit, calculate the conveyor advance distance from the moment when workpiece A is triggered to the moment when workpiece B is triggered, and save it in a dedicated global variable GV03;

[0045] Step 4: Calculate the tracking starting point offset value of workpiece B as GV02-GV01-GV03;

[0046] Step 4: After the industrial robot tracks and completes painting of workpiece B, the tracking execution unit reads the first address of the FIFO queue of the workpiece trigger management unit, determines that there is workpiece C data, then interrupts the tracking, reads the conveyor belt running speed from the conveyor belt movement speed evaluation unit, calculates the offset value of the tracking starting point of workpiece C, performs interval offset on the subsequent motion trajectory, tracks and resumes, and controls the industrial robot to continue tracking processing of workpiece C; at the same time, the first address of the FIFO queue is moved down by one, wherein the offset value of the tracking starting point of workpiece C is calculated, including the following steps:

[0047] Step 1: Use the dedicated global variable GV01 to save the distance from the trigger point to the specified tracking starting point;

[0048] Step 2: Get the current encoder value of the conveyor belt, calculate the forward distance of the conveyor belt after the workpiece A is triggered, and save it in the dedicated global variable GV02;

[0049] Step 3: Read the conveyor encoder value when workpiece C passes the trigger point in the FIFO queue of the workpiece trigger management unit, calculate the conveyor advance distance from the start of workpiece A triggering to the moment when workpiece C triggers, and save it in a dedicated global variable GV03;

[0050] Step 4: Calculate the offset value of the tracking starting point of workpiece C as GV02-GV01-GV03;

[0051] Step 5: After the industrial robot tracks and completes painting of workpiece C, the tracking execution unit reads the first address of the FIFO queue of the workpiece trigger management unit and determines that there is no workpiece data. The tracking ends and the industrial robot returns to the waiting position.

[0052] Embodiment 4:

[0053] See also Figure 1 , which is the fourth embodiment of the present invention. This embodiment is based on the above three embodiments. During the tracking process of the present invention, the workpiece trigger management unit, the conveyor belt movement speed evaluation unit and the tracking execution unit are activated at the same time, and multiple threads run synchronously, so that the workpiece that has passed the trigger point will not be lost during the tracking process, and the tracking interruption and tracking recovery can be performed multiple times, so that when the workpiece interval is short, there will be no phenomenon that new workpieces are ignored; and the tracking recovery uses the calculation of the offset and the interval offset method to directly enter the tracking state, without triggering and starting from the specified tracking starting point, so that the industrial robot can continuously perform tracking operations on multiple workpieces in sequence without returning to the waiting position, which greatly improves the working efficiency.

[0054] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for continuous tracking of a conveyor belt under multiple triggering of an industrial robot, comprising a workpiece triggering management unit, a conveyor belt motion speed evaluation unit and a tracking execution unit, characterized in that The following steps are involved: Step 1: The conveyor belt with the workpiece arrives at the trigger point, and the workpiece trigger management unit, the conveyor belt movement speed evaluation unit and the tracking execution unit are activated at the same time; Step 2: The conveyor belt speed evaluation unit obtains the real-time running speed of the conveyor belt. The tracking execution unit reads the conveyor belt running speed from the conveyor belt speed evaluation unit, and then controls the industrial robot to track the workpiece from the tracking starting point. The workpiece trigger management unit starts to monitor the conveyor belt trigger device. During the tracking process of the industrial robot, if a new workpiece passes the trigger point, the conveyor belt encoder value is obtained and placed in the FIFO queue. Step 3: After the industrial robot tracks and processes a workpiece, the tracking execution unit reads the first address of the workpiece trigger management unit FIFO queue to determine whether there is workpiece data. If yes, it goes to step 4; if not, it goes to step 5 Step 4: If there is workpiece data, the tracking is interrupted, the conveyor speed is read from the conveyor speed evaluation unit, the workpiece tracking starting point offset value is calculated, the subsequent motion trajectory is offset, the tracking is restored, and the industrial robot is controlled to continue the tracking processing of the next workpiece. At the same time, the first address of the FIFO queue is moved down by one, and then step 3 is repeated; Step 5: If there is no workpiece data, the tracking ends and the industrial robot returns to the waiting position.

2. The method for continuously tracking a conveyor belt by triggering multiple times an industrial robot according to claim 1, characterized in that: In the step 1, the conveyor belt movement speed evaluation unit obtains the real-time running speed of the conveyor belt by directly obtaining the linear speed of the conveyor belt configured by the system or periodically obtaining the encoder value of the conveyor belt to calculate the running speed.

3. The method for continuously tracking a conveyor belt by triggering multiple times an industrial robot according to claim 1, characterized in that: The method for calculating the workpiece tracking starting point offset value by the tracking execution unit in step 4 comprises the following steps: Step 1: Use the dedicated global variable GV01 to save the distance from the trigger point to the specified tracking starting point; Step 2: Get the current encoder value of the conveyor belt, calculate the forward distance of the conveyor belt after the first trigger, and save it in the dedicated global variable GV02; Step 3: Read the conveyor encoder value at the moment when the workpiece passes the trigger point in the FIFO queue of the workpiece trigger management unit, calculate the conveyor advance distance from the first trigger to the moment when the workpiece is triggered, and save it in a dedicated global variable GV03; Step 4: Calculate the workpiece tracking starting point offset value as GV02-GV01-GV03.

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