JP2003307404A - Method and apparatus for measuring shape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow detection of an angle in multiaxial direction when measuring the shape of an object to be measured. <P>SOLUTION: A ball 3 equipped with an operation rod 15 is rotatably housed in a case 11. A first magnet 21 is provided to a surface of the ball 3 on the side opposite to the operation rod 15, and a second magnet 23 is provided to a surface of the ball 3 which is perpendicular to the first magnet 21. First Hall elements 27 and 29 are provided to a first circuit board 25 on the case 11 side. The distance between the first magnet 21 and the first Hall elements 27 and 29 changes as the ball 3 rotates with its center as a first axis which is orthogonal to the plane of a figure 1. An rotational angle is detected according to the difference in voltage that occurs between the Hall elements 27 and 29. A pair of Hall elements are provided to the first circuit board 25 in the direction orthogonal to the plane of the figure 1 as well, by which the rotational angle of the ball 3 whose center is a second axis in the vertical direction of the figure 1 is detected. Further, the second magnet 23 is also provided with a pair of Hall elements, for detecting the rotational angle with its center being a third axis lateral in the figure 1. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape measuring method and a shape measuring apparatus for measuring a curved shape of an object to be measured.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Unexamined Patent Publication No. 2000-321.
As described in Japanese Patent No. 052, a plurality of angle detection units are rotatably connected to each other to form a shape measurement probe, and the shape measurement probe is attached along an object to be measured to obtain the shape of the object to be measured. Some measure change.

[0003]

However, the above-mentioned prior art can only detect the angle in the uniaxial direction when measuring the shape of the object to be measured. Therefore, for example, it is installed along the arm of an industrial robot. It is not possible to measure the shape of a cable, etc., and improvement is desired.

Therefore, an object of the present invention is to make it possible to detect an angle in a multi-axis direction when measuring the shape of an object to be measured.

[0005]

In order to achieve the above object, the invention according to claim 1 rotatably accommodates a spherical body having a magnetized portion in a case, and rotational displacement of the spherical body with respect to the case is This is a shape measuring method for measuring by detecting the magnetized portion by a magnetic detecting means.

According to a second aspect of the present invention, in the shape-side Aichi method of the first aspect, the magnetized portion is a first magnetized portion provided in the vicinity of the surface of the sphere, and the first magnetized portion is different from the first magnetized portion. , A second magnetized portion provided in the vicinity of the surface of the sphere at an angular position forming a substantially right angle, and the magnetic detection means,
A pair of first magnetic detectors for detecting a magnetic change due to the movement of the first magnetized portion due to rotation about a first axis passing through the center of the sphere; and a pair of first magnetic detectors orthogonal to the first axis of the sphere. A pair of second magnetic detectors for detecting a magnetic change due to the movement of the first magnetized portion due to rotation about a second axis passing through the center of the sphere, the first axis and the second of the sphere.
And a pair of third magnetic detectors for detecting a magnetic change caused by movement of the second magnetized portion due to rotation about a third axis that is orthogonal to each other and passes through the center of the sphere. .

According to a third aspect of the present invention, in the shape measuring method according to the second aspect, one end of the operating rod is fixed to the opposite side of the spherical body from the first magnetized portion, and the case and the operating rod are provided. A plurality of shape measuring instruments having a spherical body and the magnetic detecting means are provided, the other end of the operating rod is connected and fixed to the case of another shape measuring instrument, and the plurality of shape measuring instruments are connected to each other. The structure is attached along the cable and the shape of the cable is measured.

According to a fourth aspect of the present invention, a sphere having a magnetized portion, a case that rotatably accommodates the sphere, and a rotational displacement of the sphere with respect to the case are measured by detecting the magnetized portion. And a detection means.

According to a fifth aspect of the present invention, in the configuration of the fourth aspect, the magnetized portion is substantially perpendicular to the first magnetized portion provided near the surface of the sphere and the first magnetized portion. A second portion provided near the surface of the sphere at an angular position forming
The magnetism detecting means is configured to detect a magnetic change due to the movement of the first magnetized portion due to the rotation around the first axis passing through the center of the sphere. A detection unit and a pair of second magnets for detecting a magnetic change due to movement of the first magnetized portion due to rotation about a second axis that is orthogonal to the first axis of the sphere and passes through the center of the sphere. A magnetic change due to the movement of the second magnetized portion due to the rotation of the detection unit and the third axis passing through the center of the sphere orthogonal to the first axis and the second axis of the sphere. It is configured to have a pair of third magnetic detectors.

According to a sixth aspect of the invention, in the structure of the fifth aspect of the invention, one end of the operating rod is fixed to the side of the sphere opposite to the first magnetized portion, and the sphere is provided with the case and the operating rod. Also, a plurality of shape measuring instruments having the magnetic detecting means are provided, and the other end of the operating rod is connected and fixed to the case of another shape measuring instrument to connect the plurality of shape measuring instruments to each other.

According to a seventh aspect of the present invention, in the structure of the sixth aspect, the first magnetized portion is provided near the surface of the sphere opposite to the operation rod.

According to an eighth aspect of the invention, in the structure of the sixth or seventh aspect of the invention, elastic means for returning each shape measuring instrument unit to a predetermined position is provided between each shape measuring instrument unit. .

According to a ninth aspect of the present invention, in the structure of the eighth aspect, the elastic means presses the sphere exposed from the case.

[0014]

According to the invention of claim 1 or 4, since the magnetic detection means detects the magnetism of the magnetized portion according to the rotational displacement of the sphere, the rotational displacement of the sphere can be measured. It is possible to perform shape measurement even on an object to be measured whose shape changes.

According to the invention of claim 2 or 5, while the rotational displacement of the sphere about the first axis is detected by the first magnetic detection unit, the second magnetic detection unit detects the second displacement of the sphere.
The rotational displacement about the axis is detected, and the rotational displacement about the third axis of the sphere is detected by the third magnetic detection unit. Therefore, the shape measurement is performed on the DUT whose shape changes in the three axis directions. be able to.

According to the third or sixth aspect of the present invention, by connecting a plurality of shape measuring devices alone, it is possible to easily measure the shape of the cable in the three axial directions.

According to the seventh aspect of the present invention, the first magnetized portion and the second magnetized portion detect the first magnetized portion provided near the surface of the sphere opposite to the operating rod. , The rotational displacement of the sphere about the first axis and the second axis can be measured, respectively.

According to the eighth aspect of the invention, after the shape measuring work is completed, when the device is detached from the object to be measured, the individual shape measuring devices are returned to their original prescribed positions by the elastic means.

According to the ninth aspect of the present invention, since the spherical body is pressed by the elastic means, the play of the rotationally sliding portion between the spherical body and the case is absorbed, and the shape detection accuracy is improved.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a shape-side instrument unit 1 in a shape measuring apparatus showing an embodiment of the present invention.
This shape measuring device single body 1 has a spherical body 3 rotatably housed in a cylindrical case 5. The case 5 includes a first case 7, a second case 9, a third case 11 and a lid 13 from the left side in FIG.

The first case 7 and the second case 9 are divided into the left and right at the center of the sphere 3, and the first case on the left side in the figure.
A bolt (not shown) is inserted from the case 7 to fix them to each other. Then, concave curved surface portions 7a and 9a for rotatably supporting the spherical body 3 are formed on the inner surfaces of the first case 7 and the second case 9.

The flat portion 3 is provided on the left side portion of the sphere 3 in FIG.
a is formed, and one end of the operating rod 15 is fixed to the flat surface portion 3a. The operating rod 15 projects from the opening 7b of the first case 7 to the outside of the case.

Second case 9, third case 11 and lid 1
No. 3 is fixed to each other by inserting a bolt (not shown) from the lid 13 on the right side in the figure.

Here, with respect to the central axis when the sphere 3 rotates with respect to the case 5, the direction orthogonal to the paper surface in FIG. 1 is the first axis (X axis), and the vertical direction is the second axis (Y). And the left-right direction is the third axis (Z-axis). That is, by moving the tip of the operating rod 15 on the left side in the figure up and down, the spherical body 3 rotates about the first axis. Further, by moving the left end of the operating rod 15 in the drawing in the direction orthogonal to the paper surface, the spherical body 3 rotates about the second axis.
Further, by rotating the operating rod 15 about its axis, the spherical body 3 rotates about the third axis.

A protrusion 17 is provided on the upper portion of the spherical body 3, and the protrusion 17 includes the first case 7 and the second case 9.
It is inserted into the angle regulating hole 19 provided at the joint portion with. When the protrusion 17 is inserted into the angle regulating hole 19 having an inner diameter larger than the outer diameter of the protrusion 17, the rotational displacement operation of the spherical body 3 around the third axis is regulated. on the other hand,
The rotation displacement operation of the spherical body 3 about the first axis and the second axis is regulated by the operation rod 15 contacting the opening 7b of the first case 7.

A first magnet 21 as a first magnetizing portion is embedded in the end surface of the sphere 3 on the right side in FIG. 1, and the end surface of the sphere 3 on the lower side in FIG. , A second magnet 23 as a second magnetized portion is embedded. That is, the first magnet 21 and the second magnet 23 are provided on the surface of the sphere at angular positions that form an angle of approximately 90 degrees with each other.

A circular opening 9b and a circular board mounting recess 9c continuous with the opening 9b are formed in the second case 9 in a portion corresponding to the above-mentioned first magnet 21. . The board mounting recess 9c is continuously connected to the third
The case 11 is formed with a through hole 11a penetrating in the left-right direction in FIG.

A disk-shaped first circuit board 25 is accommodated and fixed in the board mounting recess 9c, and the first circuit board 25 has a position corresponding to the opening 9b and the first magnet 21.
1, a pair of first Hall elements 27 and 29 serving as a first magnetic detection unit are provided at upper and lower positions.

Here, when the sphere 3 rotates about the first axis orthogonal to the paper surface of FIG. 1, that is, the operating rod 15 moves to the position shown in FIG.
Moving up and down as indicated by arrow A in FIG.
1 approaches one of the first Hall elements 27 and 29 as indicated by arrow B. As a result, a voltage difference proportional to the rotation angle of the sphere 3 occurs between the two first Hall elements 27 and 29, and the rotation angle of the sphere 3 about the first axis is measured based on this voltage difference. It will be possible.

FIG. 3 is a sectional view taken along the line CC in FIG. 1. As shown in FIG. 3, the first circuit board 25 has the first magnet 21 at a position corresponding to the opening 9b. In contrast to Fig. 3
In the upper and lower positions in the second
Hall elements 31 and 33 are provided.

That is, the second Hall elements 31, 3
3 are arranged at intervals of 90 degrees along the circumferential direction of the circular first circuit board 25 between the first Hall elements 27 and 29. In the second Hall elements 31 and 33, when the spherical body 3 rotates about a second axis (vertical direction in FIG. 1) orthogonal to the plane of FIG. In the same way as shown in
By approaching either of the second Hall elements 31 and 33, a difference in voltage proportional to the rotation angle is generated between the two second Hall elements 31 and 33. The rotation angle around the two axes can be measured.

A circular opening 35 and a rectangular shape continuous with the opening 35 are formed at the joints between the first case 7 and the second case 9 at the portions corresponding to the second magnet 23. Each board mounting recess 37 is formed.
A rectangular second circuit board 39 is formed in the board mounting recess 37.
4 is accommodated and fixed in the second circuit board 39 at a position corresponding to the opening 35 and in the second magnet 23 in FIG. 4 as shown in FIG. At the upper and lower positions, the third Hall elements 41, 4 as a pair of third magnetic detectors are provided.
3 is provided.

In the third Hall elements 41, 43, when the sphere 3 rotates about the third axis in the horizontal direction in FIG. 4, the second magnet 23 causes the third Hall elements 41, 43 to rotate. By approaching either of them, a voltage difference proportional to the rotation angle is generated between the two third Hall elements 41 and 43,
The rotation angle of the sphere 3 about the third axis can be measured based on this voltage difference.

A groove 9d is formed on the surface of the second case 9 so as to be continuous with the above-mentioned board mounting recess 37. Further, in the joint portion of the second case 9 and the third case 11 so as to be continuous with the groove 9d,
A through hole 45 is formed, and the through hole 45 is formed in the board mounting recess 9c of the first case 9 and the second case 1 described above.
It communicates with the inside of the space 47 formed by one through hole 11a.

In this space 47, the main circuit board 49
The lead wire 51 drawn from the first circuit board 25 is connected to the main circuit board 49, and the lead wire 53 drawn from the second circuit board 39 is connected to the concave groove 9d and It is connected through the through hole 45. Further, the lead wire 55 is drawn out from the main circuit board 49 through the through hole 45.

FIG. 5 is a right side view of FIG. 4, in which a screw hole 13b is formed in the center of the lid 13, and an oval spring accommodating groove 13a is formed outside thereof. On the other hand, the operating rod 15 is formed with a male screw,
By screwing and fixing the tip of the operation rod 15 of the other shape measuring device single body 1 into the screw hole 13b, a plurality of shape measuring device single body 1 can be obtained.
Can be sequentially connected.

FIG. 6 is a perspective view showing a state in which the shape measuring instruments 1 are connected to each other. The shape measuring device 1 shown in FIG. 6 has a concave groove 11 a formed outside the case 11.
Are omitted for simplicity.

A restoring spring 57 as an elastic means is interposed between the above-mentioned shape measuring devices 1 alone. The restoring spring 57 has an oval shape so as to fit into the oval spring accommodating groove 13a. Due to the reaction force of the restoring spring 57, the shape measuring instruments 1 after the shape measurement return to their original linear positions as a whole. Further, the restoring spring 57 prevents mutual rotation of the shape measuring instruments 1 adjacent to each other in a state of being connected to each other, and presses the spherical body 3 at one end side thereof, so that the spherical body 3 and the case 11 are mutually prevented from being rotated. It absorbs the backlash of the rotating and sliding parts and improves the measurement accuracy.

Further, as shown in FIG. 5, a kerf 11a is formed over the entire length of the case 11 along its axial direction (direction orthogonal to the paper surface in FIG. 5). This kerf 11a is used as a mutual alignment between the first, second, and third cases 7, 9, 11 and the lid 13 when the shape measuring device 1 is assembled, and is also used after the shape measurement. It is used as a reference for attachment to the jig when calibrating the shape measuring device.

FIG. 7 shows an example in which the above-described shape measuring instrument single unit 1 is connected to each other and is attached to a cable 59 installed along an arm of an industrial robot, which is an object to be measured. ing.

A holder 61 is used for this attachment. The holder 61 includes a cable fixing portion 63 that covers the periphery of the cable 59, and a cylindrical case 11 of the shape measuring device single unit 1.
Measuring instrument fixing claw 65 that holds and holds a little over half of the circumference
Have and. The tip of the measuring device fixing claw 65 is inserted and fixed in the cut groove 11a of the case 11 described above.

The above-mentioned cable 59 has a diameter of 30 mm.
Approximately 50 mm with a maximum bending radius of 900 m
It is about m. On the other hand, since the shape measuring device 1 has a diameter of 32 mm and a bending radius of 400 mm at the maximum, the bending shape of the cable 59 described above can be sufficiently dealt with. Further, the detection angle of each rotation axis of the shape measuring instrument single body 1 is ± 15 °.

FIG. 8 is a system configuration diagram of the entire shape measuring device constituted by sequentially connecting a plurality of shape measuring devices 1 to each other. A lead wire 55 drawn from each shape measuring device 1 is shown.
Is connected to the power supply and amplifier unit 67. Further, the power supply and amplifier unit 67 is connected to the notebook computer 71 via the wiring 69.

In the notebook computer 71, the sphere 3 described above is used.
Relationship between the voltage difference between the first Hall elements 27 and 29 due to the rotational displacement of the first Hall element and the rotation angle about the first axis, the sphere 3
Of the voltage difference between the second Hall elements 31 and 33 due to the rotational displacement of the second Hall element and the rotation angle about the second axis, the sphere 3
The data indicating the relationship between the voltage difference between the third Hall elements 41 and 43 due to the rotational displacement and the rotation angle about the third axis are stored in advance in the built-in memory.

FIG. 9 shows the flow of data output from each shape measuring instrument single unit 1. The data (voltage value) detected by the shape measuring instrument single unit 1 is A / D converted by an A / D converter (not shown). After the D conversion, the voltage value is displayed on the display 75 while being stored in the memory 73. And
The rotation angle of each axis is calculated by the CPU 77 from the previously stored correlation data of the rotation angle and the voltage value and the detected voltage value, and the calculation result is the hard disk 79.
Memorized in.

FIG. 10 shows the relationship between the rotation angles corresponding to the voltage values on the first axis (X axis) and the second axis (Y axis) when the rotational displacement on the third axis (Z axis) is zero. Shows. The rotation angle on the X axis is shown by a solid line, and the rotation angle on the Y axis is shown by a one-dot chain line. Here, for both the X-axis and the Y-axis, the + side angle and the − side angle are asymmetric even if the voltage value (absolute value) is the same. It depends on the processing accuracy of each part such as the mounting state of the, the play of the spherical body 3 with respect to the case 11 (gap 0.1 mm), and the like.

The voltage values on the first axis (X axis) and the second axis (Y axis) as shown in FIG. 10 are set for each angle other than 0 ° for the rotation angle on the third axis (Z axis). Has a correlation of rotation angles corresponding to.

Next, the operation will be described. As shown in FIG. 11, when the spherical body 3 is rotationally displaced about the X axis (first axis), the distance between the first Hall elements 27 and 29 and the first magnet 21 changes, and the first Hall element 27, 29 moves. A difference occurs in the generated voltage between the elements 27 and 29. This voltage value (voltage difference)
Based on the above, the rotation angle about the X axis (first axis) is calculated from the relationship shown in FIG.

When the sphere 3 is rotationally displaced about the Y axis (second axis), the distance between the second Hall elements 31 and 33 and the first magnet 21 changes, and the second Hall element 3 is changed.
A difference occurs in the generated voltage between 1 and 33. Based on the voltage value (voltage difference), the rotation angle about the Y axis (second axis) is calculated from the relationship shown in FIG.

Further, when the spherical body 3 is rotationally displaced about the Z axis (third axis), the third Hall elements 41 and 43 are
The distance from the second magnet 23 changes, and the third Hall element 4
A difference occurs in the generated voltage between 1 and 43. Based on this voltage value (voltage difference), the rotation angle about the Z axis (third axis) is calculated from the relationship between the voltage value and the rotation angle.

In this way, a plurality of shape measuring instruments 1 capable of measuring rotational displacements in the three axial directions are sequentially connected, and the connected ones are attached along the cable 59 as shown in FIG. It is possible to measure the shape change of 59 in the multiaxial direction. In this case, by connecting a plurality of the shape measuring devices 1 alone, the rotation angles of the respective axes (X axis, Y axis, Z axis) are accumulated, and the shape change of the cable 59 is measured by the accumulated value. By measuring the change in the shape of the cable 59 in this way, it is possible to grasp the load applied to the cable 59.

Further, for example, the above-mentioned shape measuring device single unit 1
In the state in which 10 pieces are connected, one shape measuring device single unit 1 can measure the three-axis directions, so each shape measuring device single unit 1
By connecting so as to detect rotational displacements in mutually different directions, it is possible to measure the shape displacement in the 30-axis direction, which is optimal for shape measurement of the cable 59 installed in the robot arm.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a shape-side instrument alone in a shape measuring device showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between a Hall element and a magnet due to movement of a sphere.

FIG. 3 is a sectional view taken along the line CC of FIG.

FIG. 4 is a view on arrow D in FIG.

5 is a right side view of FIG. 4. FIG.

FIG. 6 is a perspective view showing a state in which the shape measuring instruments are connected to each other.

FIG. 7 is a perspective view showing an example in which the shape measuring instruments are connected to each other and attached to a cable.

FIG. 8 is a system configuration diagram of the entire shape measuring apparatus configured by sequentially connecting a plurality of single shape measuring apparatuses.

9 is an explanatory diagram showing a data flow in the system of FIG.

FIG. 10 is a correlation diagram between the voltage value and the rotation angle on the first axis (X axis) and the second axis (Y axis) when the rotation angle on the third axis (Z axis) is 0 degrees.

FIG. 11 is an explanatory diagram showing an angle detection operation by each Hall element with respect to a rotational displacement of a sphere on each axis.

[Explanation of symbols]

1 Shape Measuring Device Single Unit 3 Sphere 11 Case 15 Operation Rod 21 First Magnet (First Magnetized Part) 23 Second Magnet (Second Magnetized Part) 27, 29 First Hall Element (Magnetic Detection Means, First 1 magnetic detection part) 31, 33 2nd hall element (magnetic detection means, 2nd magnetic detection part) 41, 43 3rd hall element (magnetic detection means, 3rd magnetic detection part) 57 restoration spring (Elastic means) 59 cable

Claims (9)

[Claims] 1. A sphere having a magnetized portion is rotatably housed in a case, and a rotational displacement of the sphere with respect to the case is measured by detecting the magnetized portion by a magnetic detection means. Shape measurement method. 2. The first magnetized portion provided near the surface of the sphere, and the first magnetized portion,
A second magnetized portion provided in the vicinity of the surface of the sphere at an angular position that forms a substantially right angle, and the magnetic detection means includes the first magnetized portion associated with rotation about a first axis passing through the center of the sphere.
First pair for detecting magnetic change due to movement of the magnetized portion of the
And a pair of second magnetic detection units for detecting a magnetic change due to movement of the first magnetized portion due to rotation about a second axis that is orthogonal to the first axis of the sphere and passes through the center of the sphere. And a magnetic change due to the movement of the second magnetized portion due to rotation about a third axis that is orthogonal to the first axis and the second axis of the sphere and passes through the center of the sphere. The shape measuring method according to claim 1, further comprising a pair of third magnetic detectors for detecting. 3. A plurality of shape measuring device single bodies each having one end of an operating rod fixed to a side of the sphere opposite to the first magnetized portion and having the case, the sphere having the operating rod, and the magnetic detecting means. , The shape of this cable by connecting the other end of the operating rod to the case of another shape measuring device alone, and mounting the plurality of shape measuring devices connected to each other along the cable The shape measuring method according to claim 2, wherein 4. A sphere having a magnetized portion, a case that rotatably accommodates the sphere, and a magnetic detection unit that measures the rotational displacement of the sphere with respect to the case by detecting the magnetized portion. A shape measuring device characterized in that 5. The first magnetized portion provided near the surface of the sphere, and the first magnetized portion,
A second magnetized portion provided in the vicinity of the surface of the sphere at an angular position that forms a substantially right angle, and the magnetic detection means includes the first magnetized portion associated with rotation about a first axis passing through the center of the sphere.
First pair for detecting magnetic change due to movement of the magnetized portion of the
And a pair of second magnetic detection units for detecting a magnetic change due to movement of the first magnetized portion due to rotation about a second axis that is orthogonal to the first axis of the sphere and passes through the center of the sphere. And a magnetic change due to the movement of the second magnetized portion due to rotation about a third axis that is orthogonal to the first axis and the second axis of the sphere and passes through the center of the sphere. The shape measuring apparatus according to claim 4, further comprising a pair of third magnetic detection units for detecting. 6. One end of an operating rod is fixed to the side of the sphere opposite to the first magnetized portion, and a plurality of shape measuring devices each having the case, the sphere having the operating rod and the magnetic detecting means are provided. The shape measuring device according to claim 5, wherein the other end of the operation rod is connected and fixed to the case of another shape measuring device alone, and a plurality of shape measuring devices are connected to each other. 7. The shape measuring device according to claim 6, wherein the first magnetized portion is provided in the vicinity of the surface of the sphere opposite to the operation rod. 8. The shape measuring device according to claim 6, further comprising elastic means for returning each shape measuring device to a specified position between the respective shape measuring devices. 9. The shape measuring apparatus according to claim 8, wherein the elastic means presses the sphere exposed from the case.