TWI747151B - Robot manipulator motion compensation method - Google Patents

Abstract

A robot manipulator motion compensation method includes: providing a 3D sensor on a 3D motion object which has a high motion accuracy, and providing a tested element on a robot manipulator; synchronously driving the 3D motion object and the robot manipulator to move along a test path; using the 3D sensor to detect a position of the tested element when the 3D motion object arrives a selected path node on the test path, thereby obtaining an offset value between a sensor reference point and a tested reference point; outputting the offset value to a control instruction for error compensation of the robot manipulator, thereby keeping the sensor reference point and the tested reference point at a same three-dimensional position when the robot manipulator is controlled by the control instruction. As a result, the robot manipulator operated by the aforesaid method not only has a high motion accuracy, but also ensures good compatibility with the 3D motion object.

Description

Method of compensation for robot arm movement

The present invention relates to a method for compensating the movement of a mechanical arm, in particular to a method for compensating the movement of a mechanical arm with a three-dimensional moving object with higher accuracy for correction.

With the development of mechanical technology, mechanical arms that can imitate the functions of human arms and can be automatically controlled are widely used in various fields. However, in the processing process, errors in the movement of the robotic arm may gradually accumulate, resulting in a decrease in the accuracy of the movement of the robotic arm in space.

Therefore, the Republic of China Patent Publication No. I671606 provides a method of using a robotic arm selectable path compensation system, which mainly uses a laser tracker to track the actual position information of the robotic arm, and based on the actual measurement measured by the laser tracking device The position information is compared with the original input movement path of the robot arm, and when the difference is compared, a compensation path is generated, and the path error of the robot arm is quickly compensated by the laser tracking device to achieve the effect of quickly compensating the path.

However, when the robotic arm is used as an aid to the processing tool, such as changing the tool head of the processing tool, or placing/removing the processed parts, the movement of the robotic arm at this time needs to match the path of the processing tool. Compensation by the arm may reduce the degree of coordination between the robotic arm and the processing tool.

In this regard, the present inventor proposes a method for compensating the movement of a robotic arm, which includes: arranging a three-dimensional sensor on a three-dimensional moving object, the three-dimensional sensor having a sensing reference point, and setting a measured reference point on a robotic arm The tested part has a tested reference point, and the movement accuracy of the three-dimensional moving object in the three-dimensional space is greater than that of the robotic arm; the three-dimensional moving object and the robotic arm are synchronized to execute the same test path. , The three-dimensional sensor measures the test piece to obtain a displacement value between the sensing reference point and the tested reference point relative to each other; after starting the test path, select at least one path node in the test path , Read the displacement value of the path node; compensate the displacement value to a control instruction of the robotic arm, the control instruction controls the robotic arm to maintain the same three-dimensional position of the sensing reference point and the measured reference point .

Further, the three-dimensional sensor includes a frame and a three-digit scale. Each digital scale has a measuring needle. The measuring needles of the digital scale are arranged on a reference surface, and the measuring needles point to the sensor together. Measure the reference point.

Further, the three-dimensional sensor includes a frame and three laser rangefinders. The three laser ranges of the laser rangefinders have a reference plane, and each laser rangefinder has a laser direction. The laser direction of the laser rangefinder is on a reference surface, and the laser directions are collectively directed to the sensing reference point.

Further, the tested piece has an axis, the axis is perpendicular to the reference plane, and the distance between the boundary of the tested piece and the axis is gradually increased or decreased from the reference plane along the axis.

Wherein, the path node is an end point of the test path.

Wherein, the path node is a plurality of selection points between the together point of the test path and the end point.

Wherein, the test path is a three-dimensional path.

Wherein, the three-dimensional moving object is a processing machine, and the test path is an operation path of the robotic arm.

According to the above technical features, the following effects can be achieved:

1. The robot arm and the three-dimensional moving object with better accuracy execute the test path synchronously, and then the control command of the robot arm is compensated by the displacement value, which can ensure or even improve the robot arm and the three-dimensional moving object while maintaining the accuracy of the robot arm. The degree of coordination.

2. When the robot arm only needs to be accurate at the end point, the path node can be set only at the end point to ensure that the robot arm is accurate when it reaches the end point.

3. When the robot arm has a requirement for accuracy between the start point and the end point, the path node can be set at the multiple selection points between the start point and the end point to ensure that the robot arm has sufficient accuracy at each selection point.

4. Neither the three-dimensional sensor nor the test piece will affect the processing of the three-dimensional moving object and the robotic arm, and the processing procedure can be carried out directly without dismantling.

1: Three-dimensional moving objects

11: Support rod

2: Three-dimensional sensor

20: Sensing reference point

21: Frame

22: Digital scale

221: Measuring Needle

3: Robotic arm

4: the tested part

40: Tested reference point

A: Reference plane

d1: first distance

d2: second distance

d3: third distance

P: axis

[The first figure] is a schematic diagram of the implementation of the embodiment of the present invention.

[Second Figure] is a schematic flow diagram of an embodiment of the present invention.

[The third figure] is the first schematic diagram of the embodiment of the present invention in the implementation state, indicating that when the robot arm has no error, the sensing reference point and the measured reference point are coincident.

[Fourth Figure] is the second schematic diagram of the embodiment of the present invention in the implementation state, indicating that when the robot arm has an error, the sensing reference point is separated from the measured reference point.

[Fifth Figure] is a partial cross-sectional view 1 of the embodiment of the present invention in the implementation state, showing that the three-dimensional moving object and the robotic arm jointly execute the test path.

[Figure 6] is the second partial cross-sectional view of the embodiment of the present invention in the implementation state, showing that there is a displacement between the measured reference point and the sensing reference point.

[The seventh figure] is the third partial cross-sectional view of the embodiment of the present invention in the implementation state, showing that the displacement value is compensated back to the control command of the robot arm.

Based on the above technical features, the main effects of the method for compensating the movement of the robot arm of the present invention will be clearly presented in the following embodiments.

Please refer to the first to third figures, which disclose the method for compensating the movement of the robot arm according to the embodiment of the present invention, which includes the following steps: Step 1: Set up a three-dimensional sensor (2) on a three-dimensional moving object (1), and set a test piece (4) on a robot arm (3), adjust the robot arm (3) to make the receiver A tested reference point (40) of the test piece (4) coincides with a sensing reference point (20) of the three-dimensional sensor (2).

Please refer to the first, third and fourth figures, the three-dimensional moving object (1) can be a CNC processing machine, etc., whose movement accuracy in the three-dimensional space is greater than that of the robotic arm (3). The three-dimensional sensor (2) is installed on the movable part of the three-dimensional moving object (1). In the embodiment of the present invention, the three-dimensional sensor (2) is welded to the The tool head side of the three-dimensional moving object (1) does not affect the processing of the three-dimensional moving object (1), and the three-dimensional moving object (1) can be processed without removing the three-dimensional sensor (2). The three-dimensional sensor (2) includes a frame (21) and a three-digit scale (22). Each of the digital scales (22) has a measuring needle (221). The measuring needle (221) is arranged on a reference plane (A), and the measuring needles (221) are pointing to the sensing reference point (20) together. Taking the circular frame (21) as an example, the reference plane ( A) is the plane formed by the frame (21), the sensing reference point (20) is the center of the frame (21), and the digital scale (22) is set on the frame (21) at the same interval On the circumference, and each Since the measuring needle (221) points to the sensing reference point (20), the digital gauge (22) can be a thickness gauge or a pressure gauge, etc., and the measuring needle (221) contacts the measured reference point (20). Piece (4) to obtain the thickness value or pressure value. The three-dimensional sensor (2) can also be the frame (21) with three laser rangefinders. The laser rangefinders each emit a laser beam in a laser direction. The laser direction forms the reference plane (A), and the laser directions point to the sensing reference point (20), but this implementation is not shown in the drawing.

The tested part (4) has the tested reference point (40) and an axis (P) [the axis (P) please match the fifth figure], the axis (P) is perpendicular to the reference plane (A), the The distance between the boundary of the test piece (4) and the axis (P) is gradually increased or decreased from the reference plane (A) along the axis (P). Taking the spherical tested part (4) as an example, the tested reference point (40) is the center of the sphere of the tested part (4), and the axis (P) is connected to the tested reference point (40) While the diameters perpendicular to the reference plane (A) coincide, the distance between the boundary of the test piece (4) and the axis (P) decreases from the reference plane (A) along the axis (P). In addition to the spherical shape, the tested part (4) can also be in the shape of a cone or a rugby ball. The tested part (4) is welded to the robot arm (3), adjacent to the gripper of the robot arm (3), and it does not affect the processing of the robot arm (3), and there is no need to remove the tested part (4). ), the robotic arm (3) can directly process.

In step 1, after the robot arm (3) is adjusted correctly, as shown in the third figure, the measuring needle (221) will be attached to the surface of the tested part (4), and the tested reference point (40 ) And the sensing reference point (20) will overlap into one point; and when the tested reference point (40) and the sensing reference point (20) are separated as shown in the fourth figure, it means that adjustment is still required The mechanical arm (3) avoids wrong compensation of the mechanical arm (3).

Please refer to the second and fifth figures, and please match the fourth figure. Step 2: Make the three-dimensional moving object (1) and the robotic arm (3) execute the same test path simultaneously. After starting the test path, At least one path node is selected in the test path, and the three-dimensional sensor (2) measures the test piece (4) to obtain the A displacement value relative to each other between the sensing reference point (20) and the measured reference point (40). The test path is a three-dimensional path. In actual implementation, the test path can be directly an operation path of the robotic arm (3). The path node is an end point of the test path, or a plurality of selection points between the test path and the end point. The path node can be set according to different requirements. For example, the robot arm (3) only needs to be in the When picking and placing items at the end point, you can set the path node at the end point to ensure that the robotic arm (3) is accurate when reaching the end point; and when the robotic arm (3) needs to assist in performing the continuous operation path such as trimming , The path node can be set at the selection point between the starting point and the end point, and the number of the selection points can be increased to ensure that the robotic arm (3) is accurate on the required operation path .

Please refer to the second and sixth figures, and please match the fourth figure. Step 3: When the tested reference point (40) of the tested part (4) and the sensing of the three-dimensional sensor (2) When the three-dimensional position of the reference point (20) is different, and the three-dimensional coordinate of the displacement value is not (0,0,0), the three-dimensional sensor (2) can measure according to the digital scale (22) The change of the numerical value determines the displacement value of the test piece (4) in the three-dimensional space. The tested part (4) has a first distance (d1), a second distance (d2) and a third distance (d3). On the reference plane (A), the boundary of the tested part (4) and The distance of the axis (P) is the first distance (d1). The farther away from the reference plane (A), the shorter the distance between the boundary of the tested part (4) and the axis (P), that is to say The second distance (d2) will be smaller than the first distance (d1), and the third distance (d3) will be smaller than the second distance (d2).

Please refer to the fifth and sixth figures. In the fifth figure, after the measuring needle (221) is aligned with the tested part (4), the distance between the measuring needle (221) and the axis (P) will change Is the first distance (d1), and in the sixth figure, due to the error of the robotic arm (3), the position of the measuring needle (221) aligned with the test piece (4) changes, and the measuring needle (221) The distance from the axis (P) may be changed to the third distance (d3). The digital scale (22) is all set on the reference surface (A) formed by the frame (21), so the displacement value of the test piece (4) on the reference surface (A) can be directly determined by the The numerical value judgment of the digital scale (22), and in the direction perpendicular to the reference plane (A) Upward, that is, on the axis (P), since the distance between the measuring needle (221) and the axis (P) is changed from the first distance (d1) to the third distance (d3), the digital quantity The value of the table (22) will change, and the displacement value of the test piece (4) in the direction perpendicular to the axis (P) of the reference plane (A) can be calculated accordingly.

Please refer to the second and seventh diagrams, and please match the fourth diagram. Step 4: Compensate the displacement value to a control command of the robotic arm (3), and the control command controls the robotic arm (3) to make The three-dimensional positions of the sensing reference point (20) and the measured reference point (40) on the path node are kept consistent. With the assistance of the three-dimensional moving object (1), the accuracy of the mechanical arm (3) can be maintained while ensuring a good coordination degree between the mechanical arm (3) and the three-dimensional moving object (1).

Based on the description of the above-mentioned embodiments, when one can fully understand the operation and use of the present invention and the effects of the present invention, the above-mentioned embodiments are only the preferred embodiments of the present invention, and the implementation of the present invention cannot be limited by this. The scope, that is, simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the description of the invention, are all within the scope of the present invention.

1: Three-dimensional moving objects

11: Support rod

2: Three-dimensional sensor

21: Frame

22: Digital scale

221: Measuring Needle

3: Robotic arm

4: the tested part

Claims (8)

A method for compensating the movement of a mechanical arm includes: setting a three-dimensional sensor on a three-dimensional moving object, the three-dimensional sensor having a sensing reference point, and setting a test piece on a mechanical arm, the test piece having A tested reference point, the movement accuracy of the three-dimensional moving object in the three-dimensional space is greater than that of the robotic arm; the three-dimensional moving object and the robotic arm are synchronized to execute the same test path, in the test path, the three-dimensional sensor Measure the component under test to obtain a displacement value relative to each other between the sensing reference point and the tested reference point; after starting the test path, select at least one path node in the test path, and read the path node The displacement value; the displacement value is compensated to a control instruction of the robotic arm, and the control instruction controls the robotic arm to maintain the same three-dimensional position of the sensing reference point and the measured reference point. The method for compensating the movement of a mechanical arm according to claim 1, further, the three-dimensional sensor includes a frame and a three-digit scale, each digital scale has a measuring needle, and the measuring needle of the digital scale is set On a reference plane, and the measuring needles point to the sensing reference point. The method for compensating the movement of a mechanical arm according to claim 1, further, the three-dimensional sensor includes a frame and three laser rangefinders, each laser rangefinder has a laser direction, and the laser rangefinder The laser direction of the device is on a reference plane, and the laser directions are collectively directed to the sensing reference point. According to the method of claim 2 or claim 3 for the movement compensation of the mechanical arm, further, the test piece has an axis, the axis is perpendicular to the reference plane, and the distance between the boundary of the test piece and the axis is from the The reference plane gradually increases or decreases along the axis. The method for compensating the movement of a mechanical arm according to claim 1, wherein the path node is an end point of the test path. The method for compensating the movement of a mechanical arm according to claim 1, wherein the path node is a plurality of selection points between a point of the test path and an end point. The method for compensating the movement of a mechanical arm according to claim 1, wherein the test path is a three-dimensional path. The method for compensating the movement of a robotic arm according to claim 1, wherein the three-dimensional moving object is a processing machine, and the test path is an operation path of the robotic arm.

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