JPH01246091A - Initial setting for arm length of swing type machine - Google Patents

Abstract

PURPOSE:To reduce a required time for measuring an arm length of a robot and facilitate measuring the arm length by applying three-point measurement and simple calculation. CONSTITUTION:A reference position 23 is positioned at a set position so as to position a second rotation axis 13 on one side of a line C connecting the reference position 23 near the forward end part of a second arm 17 with a first rotation axis 7. Then the reference position 23 is positioned at a set position to position the second rotation axis 13 at a symmetrical position on the other side of the line C, so an angle beta0 formed by a supported reference line X1 of the second rotation axis 13 to the first arm 11 is determined, and the initial position of the reference position 23 is set. Next, the reference position is positioned and fixed at a position D apart from a set position for a predetermined length L to position the second rotation axis 13 on one side of the line C, and the coordinates of the reference position at the position D are determined, so the lengths of the first arm 11 and the second arm 17 are measured, thereby the initial setting for the first arm 11 and the second arm 17 are performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for initializing the arm length of a swing type machine such as a robot or a three-dimensional measuring device.

(Prior Art) Conventionally, as a swing type machine, for example, a robot is known. The robot has two rotation axes and two arms and can move freely in the X and Y axis directions.

In a swing-type robot, the reference position must be set to the initial position when moving the tool grip provided at the tip of the robot. Since the two arms of a robot are constantly subject to thermal displacement depending on the environment of the location, especially the environmental temperature, when the robot is used, the arm length must be measured and the arm length must be initialized.

The initial position setting of the reference position and the initial setting of the arm length were performed by measuring multiple points and setting parameters.

(Problem to be Solved by the Invention) However, in the method for initializing the arm length of the robot described above, the reference position of the tool gripping portion is measured at multiple points, and the initial position of the reference position is determined based on the measurement data from the multiple points. The arm length was then measured and the arm length was initialized.

Therefore, the measurement time and calculation time due to multi-point measurement are very long, and in the past, it took a considerable amount of time and trouble to measure the arm length.

The purpose of the present invention, in order to improve the above-mentioned problems, is to shorten the time required to measure the arm length of a robot based on three-point measurement and a simple calculation method, and to easily measure the arm length of a robot at any environmental temperature. The object of the present invention is to provide a method for initializing the arm length of a swing-type machine.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above object, the present invention has a first arm attached to a rotatable first rotating shaft supported on a base, and a first arm attached to the first arm. A method for initializing an arm length of a swing-type machine, wherein a second arm is attached to a supported rotatable second rotating shaft, and a tool gripping portion is provided at the tip of the second arm. The reference position is positioned at a preset position so that the second rotation axis is located on one side of the straight line C connecting the base position near the base and the first rotation axis, and the first rotation axis is positioned at the virtual origin. The angle α1 made by the first arm with respect to the virtual X axis and the angle β1 made by the second arm with respect to the virtual reference fax+ are determined with the second rotation axis as the virtual origin, and then the second rotation is made to a symmetrical position on the other side of the straight line C. After the axis has moved to the desired position, the reference position is again positioned at the set position, and the angle β formed by the second arm with respect to the movement position of the virtual reference line X1 accompanying the movement of the second rotation axis is determined.
2, and the obtained monthly β1. The initial position of the reference position is set by determining the angle β0 formed by the virtual reference line X1 of the second rotation axis with respect to the first arm from β2, and further, the second rotation axis is positioned on one side of the straight line C. The lengths of the first arm and the second arm are measured by positioning and fixing the reference position at a position a certain length away from the set position and determining the coordinates of the reference position at that position. This is an arm length initial setting method for a swing type machine, which is characterized by setting the initial length of the second arm.

(Function) By adopting the arm length initial setting method of the swing type machine of the present invention, the second rotation axis is located on one side of the straight line C connecting the reference position near the tip of the second arm and the first rotation axis. The reference position is positioned at a predetermined setting position so as to be located, and the angle α1 of the first arm with respect to the virtual The angle β1 formed by the second arm with respect to Xt is determined. Next, after the second rotating shaft is moved to a symmetrical position on the other side of the straight line C, the reference position is again positioned at the set position, and the virtual reference line XI is moved as the second rotating shaft moves. The angle β formed by the second arm with respect to the moving position of
2, and the obtained monthly β1. The initial position of the reference position is set by determining the angle β0 formed by the virtual reference line X1 of the second rotation axis with respect to the first arm from β2.

Further, by positioning and fixing the reference position at a position a certain distance away from the set position so that the second rotation axis is located on one side of the straight line C, and determining the coordinates of the reference position at that position, The lengths of the first arm and the second arm are measured, and the lengths of the first arm and the second arm are initialized.

Since the lengths of the first arm and the second arm can be measured simply and easily and accurately by measuring three times, the measurement time is shortened and troublesomeness is eliminated. therefore,
When installing a swing-type machine, the arm length is accurately measured each time the arm length is initialized, even if the local environment, especially the ambient temperature, is constantly changing, so the accuracy of the swing-type machine is guaranteed.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

Examples of swing-type machines include robots and three-dimensional measuring devices, and in this embodiment, a swing-type three-dimensional measuring device will be described.

Referring to FIGS. 1 and 2, a base 5 is erected at one corner on the surface plate 3 of the swing type three-dimensional measuring device 1, at the upper right corner in FIG.

A rotatable first rotating shaft 7 is supported at one end on the base 5. A first encoder 9 for detecting rotation of the first rotating shaft 7 is provided above the first rotating shaft 7 .

A first arm 11 is attached to the first rotating shaft 7, and a rotatable second rotating shaft 13 is supported at the tip of the first arm 11. A second encoder 15 that detects the rotation of the second rotation shaft 13 is provided at the bottom of the second rotation shaft 13.
is provided.

A second arm 17 is attached to the tip of the second rotating shaft 13, and a Z-axis column 19 that is vertically movable is supported at the tip of the second arm 17. A linear scale for detecting the vertical movement length of the Z-axis column 19 is attached to the second arm 17 so as to extend in the vertical direction.

A tool gripping section 21 is provided at the bottom of the biaxial column 19, and a detachable measurement probe 23 is attached to the tool gripping section 21. The center of the measurement probe 23 is the reference position.

A counterbalance 25 is provided on the first arm 11 toward the right side in FIG.
Since the balance has been adjusted, the first arm 11 can rotate smoothly.

With the above configuration, when the workpiece is placed on the surface plate 3 and each measurement point of the workpiece is measured, the first arm 11 is moved to the base 5 by the operator holding and moving the upper part of the measurement probe 23 by hand. The second arm 17 rotates horizontally relative to the first arm 11, and the second arm 17 rotates horizontally relative to the first arm 11. Further, the Z-axis column 19 moves vertically relative to the second arm 17. As a result, the measurement probe 23 is moved in the X, Y, and Z axis directions to measure each measurement point on the workpiece.

Therefore, the movement of the measurement probe 23 in X, Y and Z
The work is performed extremely smoothly in the axial direction, improving work efficiency. Furthermore, the installation area is small and the measurement range can be widened.

In the swing-type three-dimensional measuring device 1, when the operator holds the upper part of the measuring probe 23 in his hand and starts measurement work, it is necessary to set the initial position of the measuring probe 23.

That is, in FIG. 3, virtual X and Y coordinate axes are taken with the position of the first rotating shaft 7 as the virtual origin.

A straight line connecting the first rotating shaft 7 and the measuring glove 23 is designated as C, and the measuring glove 23 (
A reference position) is positioned and fixed at a preset position on the surface plate 3 using a hole H1 of a fixing jig 27 comprising holes H1 and H2 maintained at an accurate distance apart. Note that the fixing jig 27 is made of, for example, ceramic that does not change depending on the environmental temperature.

As a result, the angle α formed by the first arm 11 with respect to the virtual X-axis
1 is determined by the first encoder 9. Further, the angle β formed by the second arm 17 with respect to the virtual reference line XI with the second rotating shaft 13 as the virtual origin is determined by the second encoder 15. Furthermore, the first arm 11. The lengths of the second arms 17 are determined in advance as A and B, and the lengths of the first arms 1
If the angle formed by the virtual reference line X1 is β0 with the second rotation axis 13 relative to the extension line extending from 1 as the virtual origin, then the coordinate position (X+, V+
) is expressed as follows.

X l =ACO8α1 +Bcos (α1+β1
+β0)V + =Asin tB +Bs1n (
al + β1 + β0)...(1) In the above formula (+), A, B, α1, and β1 are set or known in advance, so once β0 is determined, the values of × and so can be found. It will be done.

After the measuring glove 23 is removed from the hole H+ of the fixing jig 27, the second rotating shaft 13 is moved to a symmetrical position on the other side of the straight line C, for example, above the straight line C in FIG. With the shaft 13 positioned above the straight line C, the measurement probe 23 is again positioned and fixed in the hole H1 of the fixing jig 27 at the set position. This state is shown by the two-dot chain line in FIG.

That is, the first arm 11 rotates from the position indicated by the solid line to the position indicated by the two-dot chain line. Thus, the angle α2 formed by the first arm 11, indicated by the two-dot chain line, with respect to the virtual X-axis is detected by the first encoder 9.

The second arm 17 rotates from the position indicated by the solid line to the position indicated by the two-dot chain line. Thus, the second encoder 15 detects the angle β2 formed by the second arm 17, indicated by the two-dot chain line, with respect to the position to which the virtual reference line X of the virtual origin of the second rotating shaft 13 has moved. Moreover, since the quadrilateral shown in FIG. 3 is a parallelogram, the angle formed by the second arm 17 shown by the solid line with respect to the extension line of the first arm 11 shown by the solid line is
It is equal to the angle formed by the second arm 17 shown by the two-dot chain line with respect to the extension line of the first arm 11 shown by the two-dot head line.

That is, βI+β0=β2−β0 holds true.

Therefore, β0-1(β1-β2)/2...(2)
becomes.

By substituting the value of β0, which cannot be determined by the equation (2), into the equation (1), the initial position of the stagnation probe 23 is set. Note that the movement of the measuring glove 23 in the Z-axis direction is caused by the movement of the two-axis column 19 and the movement of the second arm 1.
This is done by detecting with a linear scale extending in the vertical direction of 7.

Based on this initial position setting of the measurement probe 23, various workpieces placed on the surface plate 3 are measured.

Therefore, since the initial position of the measurement probe 23 is set by moving the measurement probe 23 twice, the time required to set the initial position is shortened and the initial position can be set easily.

Next, the first arm 11. The lengths A and B of the second arm 17 vary from machine to machine, and also vary depending on the environment of the place to be measured, such as the environmental temperature. Arm 17 length A, B
It is necessary to check in advance.

First, when the initial position of the measuring glove 23 is set,
Since the position of the measurement probe 23 indicated by the solid line and the position of the measurement probe 23 indicated by the two-dot chain line are the same, the following equation holds true.

ACO3al +Bcos (αl + β1 ten β0) ten people 0os a2 + BeO2 (a2 + β2
+β0) From the above formula, find the ratio of A and B, A (CO3(21CO8a2) = B [CQS
(α2 + β2− βo ) −cos (α
1 + β 1 + βo)], and when further organized, it becomes.

Next, the first arm 11. To confirm the length of the second arm 17, move the measuring arm 23 to the position of the hole H2 of the fixing jig 27 shown in FIG. The angle α3 formed with the arm 11 is detected by the first encoder 9. Further, the angle β3 between the second arm 17 shown by the dotted line and the virtual reference line X1 with the second rotating shaft 13 as the virtual origin is
Detected by 5.

Therefore, the value of the coordinates (X+, Vl) is determined from the above equation (+) as follows: X H=ACO3al +BCOS (α1 +εI)
y +=Asin al +Bs1n (at
−1−ε+ ) −(4), where ε1=β
1+β0 Also, the value of the coordinate (X2.V2) is: X 2 =ACO8α3 +BCO3(α3+ε2)V
2 = ASin cx3; B51n (B3 +
ε2 ) =・(5), however, ε2=β3+β0 The distance between the coordinates (Xl, V+) and the coordinates (X2.Y2) is L
Therefore, (X2-XI)2+(Vz-V2>2=L2...
(6) holds true.

Xl+Vl calculated using equations (4) and (5) in the above equation (6),
Substituting the value of X2 + y2 and organizing it, a A2 +b B2 +CAB=L2 =-
<7).

Here, from equation (3), A=K - B, and by substituting this value into equation (7) above, a K2 B2-! -b B2 +c KB2 =L2
Therefore, B=L/a +K A=K −L/ a +
...(8).

However, a, b and C are α eyes, α3. It is a trigonometric function formula including ε turtle and ε3, and is a constant.

Thus, the first arm 11. Lengths A and B of the second arm 17
can be simply and easily measured by moving the measuring glove 23 three times, so that it is confirmed before starting the measurement of each measuring point on the workpiece. Therefore, even if the swing type three-dimensional measuring device 1 is not always installed in a constant temperature room, but is installed in a place where the environmental temperature changes, for example, the first arm 11. By accurately and quickly checking the lengths A and B of the second arm 17, accurate measurement data can be obtained.

Note that the present invention is not limited to the above-mentioned embodiments,
By making appropriate changes, it can be implemented by Mr. B in the pond.1 For example, in this example, a swing-type three-dimensional measuring device was used as an example, but it can also be applied to swing-type robots and other swing-type machines. It is also applicable to

[Effects of the Invention] As can be understood from the description of the embodiments above, according to the present invention, since the configuration is as described in the claims, the reference near the tip of the second arm The reference position is positioned at a predetermined setting position so that the second rotation axis is located on one side of a straight line C connecting the position and the first rotation axis, and then the second rotation axis is positioned at a symmetrical position on the other side of the straight line C. The initial position setting of the reference position is set by positioning the reference position at the set position so that the two rotational axes are located.

Further, by positioning and fixing the reference position at a position a certain length away from the set position so that the second rotation axis is located on one side of the straight line C, and determining the coordinates of the reference position at that position, The length of the first arm and the second arm can be easily and accurately measured.
You can make initial settings for the arm. Therefore, when installing a swing type machine, the arm length is accurately measured and the arm length is initially set even if the environment, especially the environmental temperature, is constantly changing, so the accuracy of the swing type machine can be guaranteed.

[Brief explanation of the drawing]

FIG. 1 is a front view of a swing type three-dimensional measuring device according to an embodiment of the present invention, and FIG. 2 is a plan view of FIG. 1. FIG. 3 is an explanatory diagram for setting the initial position of the reference position. 1... Swing type three-dimensional measuring device 3... Surface plate 5... Base 7... First rotating shaft 11... First arm 13... Third rotating shaft 17... Second Arm 21...Tool grip part 23...Measurement probe (reference position)

Claims (1)

[Claims] A first arm is attached to a rotatable first rotating shaft supported on a base, a second arm is attached to a rotatable second rotating shaft supported by the first arm, and the tip of the second arm is attached to a rotatable first rotating shaft supported on a base. In a method for initializing an arm length of a swing-type machine having a tool grip, a second rotation axis is provided on one side of a straight line C connecting a reference position near the tip of the second arm and the first rotation axis. The reference position is positioned at a predetermined setting position so that the first rotation axis is the virtual origin, and the angle α_1 of the first arm with respect to the virtual The angle β_1 made by the second arm with respect to The angle β_2 formed by the second arm with respect to the movement position of the virtual reference line
The initial position of the reference position is set by determining the angle β_0 formed by the virtual reference line Preferably a certain length L from the set position
The lengths of the first arm and the second arm are measured by positioning and fixing the reference position at a position D that is separated by the distance D, and determining the coordinates of the reference position at that position D. A method for initializing the arm length of a swing-type machine, which is characterized by setting the arm length.