TWI832052B - Method of teaching and correcting for robotic arm - Google Patents

Abstract

A method of teaching and correcting for robotic arm is provided. The teaching method comprises picking-and-placing an object to an initial placement position. After recording the initial placement position of the object, completing the teaching method of the robotic arm. When a tool of the robotic arm is replaced or the tool is offset by collision, it needs to be corrected. The correcting method comprises picking-and-placing the object to an offset position according to an offset picking-and-placing position, and obtain the offset position of the object for a correction.

Description

Robot arm teaching methods and correction methods

The invention relates to a robot arm, and in particular to a teaching method and a correction method for the robot arm, so that the robot arm can quickly return to working condition.

Generally, robot arms can perform various tasks to meet the needs of most industries, such as assembly, processing, welding, cutting, pressurizing, cargo handling or inspection, etc. In order to perform different tasks, the robot arm needs to be equipped with different tools, and then a number of positioning and corrections are required to enable the robot arm to move the tools accurately to perform various tasks. Therefore, when the robot arm changes tools or the tool is hit by a collision, each correction needs to be made from scratch, causing the robot arm to spend a lot of time teaching and calibrating.

In view of the above problems, the present invention uses different teaching methods to reduce the number of re-teaching and correction items for the robot arm and reduce the time for each teaching and correction.

The object of the present invention is to provide a teaching method for a robot arm. During the teaching, the robot arm grabs an initial pick-and-place position of an object, and after picking up and placing the object to an initial placement position, the initial placement position of the object is recorded. To calculate a compensation value for re-teaching and correction.

Another object of the present invention is to provide a method for calibrating a robot arm. During calibration, the robot arm grabs an offset pick-and-place point of an object, and after picking up and placing the object to an offset position, the offset position of the object is obtained. The offset amount between the offset position and the initial placement position is calculated to obtain the compensation amount for correction.

In order to achieve the purpose of the foregoing invention, the teaching method of the robot arm of the present invention includes picking up and placing an object to an initial placement position, recording the initial placement position of the object, and then completing the teaching method of the robot arm. The correction method includes picking and placing objects to an offset position based on an offset pick and place point, and obtaining the offset position of the object for correction.

10: Robot arm

11:Control device

20: base

21:First joint

22:First axis arm

23:Second joint

24: Second axis arm

25:Third joint

26:Third axis arm

27: Tool end

28:Visual installation

29:Tools

30:Working area

31: Calibration target

32:Object

33: Initial pick and place point

34:Environmental area

35: Offset pick and place point

40:Visual teaching

41: Initial placement for shooting

42: Shooting offset position

The first figure is a schematic diagram of the robot arm of the present invention.

The second figure is a schematic diagram of the robot arm installation tool of the present invention.

The third figure is a schematic diagram of the robot arm of the present invention controlling the tool end in the first posture.

The fourth figure is a schematic diagram of the robot arm of the present invention controlling the tool end in the second attitude.

The fifth figure is a schematic diagram of the robot arm of the present invention controlling the tool end in the third posture.

The sixth figure is a schematic diagram of the teaching robot arm vision device of the present invention.

The seventh figure is a schematic diagram of the teaching point of picking and placing the robot arm tool according to the present invention.

Figure 8 is a schematic diagram of the present invention teaching the robot arm tool to pick up and place objects to an initial placement position.

Figure 9 is a schematic diagram of the robot arm of the present invention recording the initial placement position of an object.

Figure 10 is a schematic diagram of the robot arm tool offset to pick up and place objects according to the present invention.

Figure 11 is a schematic diagram of the robot arm vision device of the present invention obtaining the offset position of an object.

The technical means and effects adopted by the present invention to achieve the above objects are described below with examples and drawings.

Please refer to the first figure, which is a schematic diagram of the robot arm of the present invention. As shown in the figure, the robot arm 10 includes a base 20, a first joint 21, a first axis arm 22, a second joint 23, a second axis arm 24, a third joint 25, and a third axis arm. 26. A tool end 27 and a vision device 28, wherein the tool end 27 may be a flange end. The robot arm 10 of the embodiment in the first figure is for illustration only. The robot arm 10 may have other joints, other numbers of axle arms, or other types of robot arms. A control device 11 is coupled to the robot arm 10 and transmits a control signal to the robot arm 10 to control the robot arm 10 to perform various movements with multiple degrees of freedom. This can complete teaching or/and correction of the robot arm 10, so a The control method includes a teaching method or/and a correction method of the robot arm 10 . The vision device 28 is installed at the end of the robot arm 10 and is used to capture images and transmit them back to the control device 11 for the control device 11 to calculate relevant information.

Please refer to the second figure, which is a schematic diagram of the robot arm installation tool of the present invention. As shown in the figure, a tool 29 is installed on the robot arm 10 , in the embodiment, it is installed on the tool end 27 , so that the robot arm 10 drives the tool 29 to perform various tasks. In this embodiment, the tool 29 is a suction nozzle, but the embodiment does not limit the type of the tool 29. For example, the tool 29 can be a tool fixture such as a clamping jaw or a suction nozzle.

Please refer to the third figure, which is a schematic diagram of the robot arm of the present invention controlling the tool end in the first attitude. After the tool 29 is installed, it needs to be calibrated to accurately perform various tasks to obtain the relative position of the tool 29 in the coordinate system of the robot arm 10. Therefore, the control device 11 controls the robot arm 10 to calibrate the tool on the tool end 27 in multiple postures. First, a calibration target 31 is set in a working area 30. The working area 30 can be an area on a work machine table, or other areas that can be used for calibration. Furthermore, the calibration target 31 is also for illustration purposes, and its shape is not limited. embodiments of the present invention. Therefore, the robot arm in the third figure drives the tool 29 to perform calibration in the first posture, and controls the tool 29 to point to the calibration target 31 to obtain a first relative position of the tool 29 relative to the calibration target 31 in the first posture of the robot arm 10 .

Please refer to the fourth figure, which is a schematic diagram of the robot arm of the present invention controlling the tool end in the second attitude. As shown in the figure, the control device 11 changes the posture of the robot arm 10. The robot arm 10 drives the tool 29 in a posture different from that shown in the third figure. That is, the robot arm 10 drives the tool 29 in the second posture to align with the calibration target 31, thereby obtaining the tool. 29 is a second relative position relative to the calibration target 31 in the second posture of the robot arm 10 .

Please refer to Figure 5, which is a schematic diagram of the robot arm of the present invention controlling the tool end in the third posture. As shown in the figure, the control device 11 also changes the posture of the robot arm 10 so that the robot arm 10 drives the tool 29 in a posture different from that shown in the third and fourth figures, that is, the robot arm 10 moves the tool 29 in the third posture to align with the calibration target 31 , and obtain a third relative position of the tool 29 relative to the calibration target 31 in the third posture of the robot arm 10 . In this way, through the three postures of the robot arm 10, the tool 29 is controlled to move toward the same position of the calibration target 31 with different actions, and three relative positions are obtained, and then the relative position of the tool 29 in the coordinate system of the robot arm 10 is calculated to complete a tool calibration. Make the robot arm 10 accurately control the tool 29 to execute each kind of task. However, the embodiment does not limit the control device 11 to control the robot arm 10 to drive the tool 29 in more postures for correction.

Please refer to Figure 6, which is a schematic diagram of the teaching robot arm vision device of the present invention. As shown in the figure, after the tool 29 is calibrated, the control device 11 controls the robot arm 10 to move a vision device 28 above the object 32 so that the vision device 28 can photograph the object 32 and obtain an image-related feature of the object 32, that is, using vision The device 28 identifies an object characteristic of the object 32 to perform a visual guidance 40 to confirm the pick-up and placement of a specific object. Among them, the characteristics of the object 32 may be shape, color, etc.

Please refer to Figure 7, which is a schematic diagram of the teaching pick-and-place point of the robot arm tool according to the present invention. As shown in the figure, after the visual teaching 40, an initial pick-and-place point 33 for picking and placing the object 32 is determined according to the object characteristics of the object 32. Therefore, the initial pick-and-place point 33 is a position on the object 32 for Picking and placing objects 32. The initial pick-and-place point 33 depicted in the embodiment of the seventh figure can also be the center of the upper surface of the object 32, which is for illustrative purposes and is not limited to the embodiment.

Refer to Figure 8, which is a schematic diagram of teaching the robot arm tool to pick up and place objects to an initial placement position according to the present invention. As shown in the figure, after completing the teaching of the point for picking and placing the object 32, the robot arm 10 drives the tool 29 to extract the object 32 according to the initial picking and placing point 33, and places the object 32 from the work area 30 to an environmental area 34. An initial placement position. The environmental area 34 is an area near the working area 30, or the environmental area 34 can be the working area 30, which is not limited by the present invention. In other words, the embodiment of the eighth figure can be changed so that the robot arm 10 controls the tool 29 within the scope of the working area 30 to pick up the object 32 and place it at the initial placement position according to the initial pick-and-place point 33 . The initial placement position is the position where the object 32 is placed after tool calibration is completed.

Please refer to Figure 9, which is a schematic diagram of the robot arm of the present invention recording the initial placement position of an object. As shown in the figure, after using the tool 29 to place the object 32 in the initial placement position, the visual device 28 records the initial placement position of the object 32, that is, the initial placement position is photographed in Figure 41. In this way, the robot arm 10 moves in the manner of the embodiments shown in FIGS. 2 to 9 to complete a robot arm teaching. That is, the teaching method of the robot arm 10 includes several steps.

Refer to Figure 10, which is a schematic diagram of the robot arm tool offset to pick up and place objects according to the present invention. When the robot arm 10 replaces the tool 29 or suffers a collision, the robot arm 10 or the tool 29 is deflected. As shown in the figure, the position where the tool 29 picks up and places the object 32 is shifted to the right edge of the upper surface of the object 32 . Therefore, the robot arm 10 controls the tool 29 to extract the object 32 according to an offset pick-and-place point 35, and because the position of the extracted object 32 is offset, the placement of the object 32 is offset to an offset position, for example, placed to Compared with the position on the left side of the environment area 34 in the eighth figure, the object 32 is picked up and placed based on the initial pick-and-place point 33 to approximately the center of the environment area 34 . In addition, the initial pick-and-place point 33 and the offset pick-and-place point 35 are different positions, and the initial placement position is different from the offset placement position.

Please refer to Figure 11, which is a schematic diagram of the robot arm vision device of the present invention obtaining the offset position of an object. As shown in the figure, after the object 32 is placed at the offset position, the visual device 28 is used to obtain the offset position of the object 32 (ie, the offset position is captured in Figure 42). The visual device 28 is coupled to the control device 11 and transmits image data to Control device 11 to perform correction. That is, a computing device provided in the control device 11 can calculate the difference between the initial placement position (as shown in Figure 9) and the offset position of the object 32, and the control device 11 obtains a compensation amount based on the difference. Therefore, the control device 11 compensates a positioning posture of the robot arm 10 according to the compensation amount, where the positioning posture may include compensating a tool end value, so the compensation amount Offsets of the robot arm or tool 29 can be corrected. The offset of the tool 29 may be a positional offset or a rotational offset.

Therefore, the control of the robot arm 10 of the present invention includes a teaching method and a correction method. The teaching method includes, in addition to picking and placing the object 32 based on the initial picking and placing point 33 in the eighth figure and recording the initial placement position of the object 32 in the ninth figure. It also includes tool corrections in Figures 3 to 5, visual guidance in Figure 6, and pick and place point guidance in Figure 7. Afterwards, after encountering a collision during the task or causing a deviation due to device replacement, you only need to run the eighth picture (such as the tenth picture) again to pick and place the object 32 and the ninth picture (such as the eleventh picture) to record the position of the object 32. Complete offset correction. In other words, when the robot arm 10 is in working condition and needs to be recalibrated and taught, it is only necessary to re-run the eighth and ninth embodiments in Figures, without re-running the movements of the third to seventh embodiments, which saves a lot of time. recalibration and teaching schedule. Based on the above, the teaching method of the present invention includes picking and placing the object to the initial placement position, recording the initial placement position of the object and completing the robot arm teaching; the correction method of the present invention includes picking and placing the object to the offset based on the offset pick-and-place point. Position and, obtain the offset position of the object for correction. Therefore, the present invention uses the non-deviated vision to correct the deviation tool, so that the robot arm can quickly return to the working state.

The above are only used to conveniently illustrate the embodiments of the present invention. The scope of the present invention is not limited to these embodiments. Any changes made according to the present invention shall not deviate from the spirit of the present invention. Scope of invention patent application.

10: Robot arm

20: base

21:First joint

22:First axis arm

23:Second joint

24: Second axis arm

25:Third joint

26:Third axis arm

27: Tool end

28:Visual installation

29:Tools

30:Working area

32:Object

34:Environmental area

35: Offset pick and place point

Claims (7)

A teaching method for a robot arm, which includes: picking up and placing an object to an initial placement position; recording the initial placement position of the object to correct the offset of a tool to the robot arm; and completing a robot arm teaching. A teaching method for a robot arm, which includes: installing a tool to the robot arm; setting a calibration target; controlling the tool in different postures to align the robot arm with the calibration target to complete a tool calibration; picking up and placing the object to the initial position place the object; record the initial placement position of the object to correct the offset of the tool to the robot arm; and complete teaching of the robot arm. The teaching method of the robot arm described in item 1 of the patent application scope includes: moving a visual device above the object, identifying an object feature of the object, and completing a visual teaching to pick and place the object to the initial position. Put the location. For example, the teaching method of the robot arm described in item 3 of the patent application scope includes: determining an initial pick-and-place point based on the characteristics of the object, and the initial pick-and-place point is used to pick and place the object. A method for calibrating a robot arm, which includes: picking and placing an object to an offset position based on an offset pick and place point; and obtaining the offset position of the object to correct the offset of a tool to the robot arm. The correction method of the robot arm described in item 5 of the patent application scope includes: using a visual device to obtain the offset position of the object; and setting up a computing device to calculate an initial placement position and the offset position of the object a one-position difference; and obtain a compensation amount based on the position difference; and compensate a positioning posture of the robot arm based on the compensation amount. As described in claim 6 of the patent application, the correction method of the robot arm, wherein compensating the positioning posture of the robot arm includes compensating a tool end value to correct the offset of a tool.