JP2005147673A - Three-dimensional coordinates measuring probe and three-dimensional coordinates measuring system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a probe proper for measuring continuous line such as ridgeline and a three-dimensional coordinates measuring system using the probe. <P>SOLUTION: A spherical probe body 10 is notched with two semicircles notching planes crossing with an angle θ(=120 degrees) on a center line passing the center G of the sphere 14 as a cross line to make nearly 2/3 of a sphere. Positions separating each notching planes of the two semicircles are made reference ridgelines 11a and 11b, which are made inclined planes 12a to 12d declining toward the direction parting from the reference ridgelines 11a and 11b. The probe body 10 is rotatable around the axis 9 and so measurement is made by manually moving the probe along the cross point of the reference ridgelines 11a and 11b attaching the edge of the outline of a panel part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a probe used for three-dimensional coordinate measurement and a three-dimensional coordinate measurement apparatus using the probe, and more particularly to a probe suitable for measuring the three-dimensional coordinates of a panel edge portion which is the outline of a thin panel component. And a three-dimensional coordinate measuring apparatus using the probe.

The thing of patent document 1 is known as a thing regarding this kind of three-dimensional coordinate measuring apparatus. In the technique described in Patent Document 1, an articulated three-dimensional measuring machine having a multi-degree of freedom (infinite degree of freedom) similar to the form of an articulated industrial robot is used as a base, and a pressure-sensitive type is attached to the tip of the arm. A probe (contact) is attached, the probe is manually brought into contact with the measurement object using the degree of freedom of the arm, and a signal at the moment of contact is captured. Then, the position of the probe, that is, the three-dimensional position in the X, Y, and Z directions at this time can be obtained by inverse matrix calculation based on the rotation angle position of the rotation sensor provided in each joint. The probe can be arbitrarily selected from, for example, a spherical shape, a flat bottom shape, a tapered shape, and a needle shape according to the shape of the measurement object and the convenience of the operator. .
JP-A-8-261745

  However, in such a conventional technique, since the degree of freedom of operation of the base CMM is high, the measurer can freely move the probe to an arbitrary position, such as a corner or a ridge line. In the case of a measurement point that needs to be contacted with a point, it is difficult to accurately apply a spherical or needle-like probe, and there is a limit to improvement in measurement accuracy.

  In addition, in order to accurately measure the corners and ridgelines, after measuring several points on the surface forming the corners and ridgelines, to calculate the required three-dimensional position of the corners and ridgelines by calculation Therefore, the number of measurement points is increased and the measurement time is increased, and software for calculation is required, resulting in an increase in cost.

  In addition, even when measuring a continuous line such as a ridge line, it is assumed that each point constituting the ridge line is measured, and the probe cannot be moved continuously along the ridge line. In addition to the huge measurement time required for the measurement, the measurement point once measured is measured again, or the measurement point to be measured is skipped. Even when such a continuous line is measured, there is a limit in improving the measurement accuracy.

  The present invention has been made paying attention to such a problem, and is intended to provide a probe suitable for measuring a continuous line such as a ridge line.

  According to the first aspect of the present invention, as a probe structure of a three-dimensional coordinate measuring apparatus, a spherical probe body is divided into two semicircular shapes intersecting at a predetermined angle with a center line passing through the center of the sphere as an intersection line. It is a spherical shape with approximately two-thirds of a notch with a notch surface, and with respect to the two semicircular notch surfaces, the position that bisects each notch surface is the reference ridge line, and the slope is downward from the reference ridge line. It is characterized by being an inclined plane.

  In this case, as described in claim 2, it is desirable that the probe main body be rotatably supported by the holder with a shaft portion positioned on an extension of the center line of the sphere as a rotation center. As described in 3, the shaft portion is set on an extension line of one of the reference ridge lines that bisect the semicircular cutout surface.

  The invention according to claim 4 is the invention of the three-dimensional coordinate measuring apparatus itself, which is a multi-joint type robot, and a manual type three-dimensional measuring machine provided with a rotation sensor at each joint part. The coordinate measuring probe according to claim 1 is detachably attached to the tip of the arm of the coordinate measuring machine.

  Therefore, in the invention described in claim 1, as described in claim 4, the probe is detachably mounted on the arm tip of a manual CMM. In this case, as described above, the angle formed by the two semicircular cutout surfaces is 120 degrees, and the two cutout surfaces are separated from the reference ridgeline with the position that bisects the cutout surface as the reference ridgeline. Since it is an inclined plane that is inclined downward in the direction, each notch surface has a reference ridgeline, and both of these reference ridgelines intersect at the center of the sphere that is the basic shape of the probe Will be.

  Therefore, when measuring a continuous line such as a ridgeline, the measurer can easily make point contact by simply placing the corner portion of the probes between the reference ridgelines on the ridgeline to be measured. Therefore, the three-dimensional coordinates of the point contact portion can be measured directly and instantaneously.

  For example, when the probe is placed on the ridge line to be measured, the probe is continuously moved along the ridge line in the form of so-called scanning measurement, while the measurement software is used together with the measurement pitch set in advance. If the probe is moved only by that time, the three-dimensional coordinate value of the measurement point is automatically taken in each time. Alternatively, for example, a push button switch for instructing the acquisition is provided in the vicinity of the probe, and the three-dimensional coordinate value of the measurement point is acquired every time when the operator presses the push button switch.

  Further, if the spherical surface of the probe body is used as necessary, a so-called spherical probe that has been widely used can be used for three-dimensional measurement other than the ridge line.

  According to the first and fourth aspects of the invention, for example, when measuring an edge portion that is an outline of a panel component having a three-dimensional shape, that is, when measuring a continuous line such as a ridgeline, Can be made to make point contact simply by placing the corner part between the reference ridge lines on the ridge line to be measured, so that the three-dimensional coordinates of the point contact part can be measured directly and instantaneously. This makes it possible to significantly reduce the measurement time and improve the measurement accuracy.

  FIG. 1 is a diagram showing a schematic configuration of a three-dimensional coordinate measuring apparatus including a three-dimensional coordinate measuring probe according to the present invention.

  As shown in the figure, the three-dimensional coordinate measuring device is formed with a manual three-dimensional measuring machine 1 in the form of an articulated robot (articulated manipulator) as a mother machine, and functions as the mother machine. A probe 3 is detachably attached to the tip of the arm 2 of the measuring machine 1 and the joints 4a, 4b, 4c, and 4d of the three-dimensional measuring machine 1 are rotated with the joints 4a to 4d. A rotation sensor (not shown) for detecting the rotation position of each arm is incorporated. The coordinate measuring machine 1 is connected with a data processing device 5 configured with a personal computer via a controller 6, and the data processing device 5 is in either an automatic recording mode or a manual recording mode of measurement data. Measurement software that can be used is also pre-installed. As will be described later, the measurement data at the measurement point with which the probe 3 is brought into contact is taken into the data processing device 5 as three-dimensional coordinate values in the X, Y, and Z directions specified by the current position data of each rotation sensor. Will be.

  The probe 3 is provided with a push button switch 7 for giving a data recording instruction when recording data in the manual recording mode.

  FIG. 2 shows details of the probe 3. The probe 3 includes a cylindrical holder 8 that is directly and detachably attached to the arm 2 of the coordinate measuring machine 1, and a shaft portion with respect to the holder 8. 9 and a deformed spherical probe main body 10 that is rotatably mounted via 9. Note that a precision rotation mechanism such as a high-precision bearing (not shown) is interposed between the holder 8 and the shaft portion 9 so that the probe body 10 can smoothly rotate about the axis of the shaft portion 9 as the rotation center. Has been.

  As shown in FIGS. 3 and 4 in addition to FIG. 2, the probe body 10 has a spherical shape of the probe body 10 at a predetermined angle with a center line passing through the center of the sphere as an intersecting line, in this example, about 120 degrees. By being cut out with two semicircular cutout surfaces intersecting at an angle (inner angle) θ, it is formed as a substantially spherical solid sphere. Then, as the two half-circular cutout surfaces, the positions dividing the cutout surfaces into two are the convex reference ridgelines 11a and 11b, and inclined planes 12a to 12d that are inclined downward in the direction away from the reference ridgelines 11a and 11b. As a result, the probe main body 10 has a quadrant-shaped four inclined planes 12a to 12d and a convex ridge line 11a that is divided into the quadrant-shaped four inclined planes 12a to 12d in a portion other than the spherical surface 14. 11b and concave ridgelines 13a and 13b. The two convex reference ridgelines 11a and 11b coincide with the center line passing through the center G of the spherical surface 14, and the intersection of the convex ridgelines 11a and 11b and the concave shapes 13a and 13b is a spherical surface. 14 coincides with the center G.

  Since the probe body 10 has a spherical shape and a special shape as described above, as shown in FIGS. 3 and 4, when measuring the edge E on the upper surface side which is the outline of the panel component P made of a thin plate. If the probe body 10 is applied to the edge portion E so as to receive the edge portion E of the panel part P at the corner portion formed by the convex reference ridge lines 11a and 11b, the two points at the center G of the spherical surface 14. It is possible to contact. In other words, the intersection between the reference ridgelines 11a and 11b and the ridgelines 12a and 12b is not only the center G of the spherical surface 14 of the probe body 10, and the diameter of the spherical surface 14 is known, so that the convex reference ridgeline 11a, In a state where the edge E of the panel part P is applied to the intersection formed by 11b, the probe body 10 and the panel part P are relatively moved while maintaining the state, and the central coordinate value of the spherical surface 14 is continuously or By capturing at predetermined intervals, the three-dimensional shape of the edge E can be measured and specified.

  Here, the deformed spherical probe body 10 and the shaft portion 9 are integrally formed in advance, but the shaft center of the shaft portion 9 is positioned on the same axis as the one reference ridge line 11a, that is, It is set so that the shaft center of the shaft portion 9 is positioned on the extension line of one reference ridge line 11a. The groove angle θ of the probe body 10 may be 90 degrees or more since the edge portion E is 90 degrees. However, the workability is improved so that the edge section E is brought into contact with the center G of the spherical surface 14 quickly. Considering this, the angle is set to about 120 degrees.

  According to the three-dimensional coordinate measuring apparatus configured as described above, for example, as shown in FIG. 5, when measuring the three-dimensional shape of the edge E of the peripheral edge of the panel, which is the outline of the thin panel component P, FIG. As shown in FIG. 6, the pitch of measurement points (pitch between adjacent measurement points) P is input and set as an arbitrary value (step S1 in FIG. 6), and the automatic recording mode and the manual recording mode are used as the data recording mode. 1 is selected (step S2), and the measurement is performed while the probe 3 touched to the edge E is manually moved along the edge E by the so-called scanning method (steps S3 and S8). .

  In this case, the method of applying the probe body 10 and the edge portion E is as shown in FIGS. 3 and 4, and the coordinate value (X, Y) of the center G of the spherical surface 14 of the current probe body 10 at that time. , Each coordinate value in the Z direction) is calculated in real time based on the current position data of the rotation sensors provided in the joint portions 4a to 4d (see FIG. 1) of the coordinate measuring machine 1. The current coordinate value of the center G of the spherical surface 14 of the probe body 10 represents the three-dimensional coordinate value of the corresponding edge portion E, and the three-dimensional coordinate value is always in the data processing device 5 of FIG. It has been captured.

  The above-mentioned automatic recording mode is a mode in which all data taken in the data processing device 5 can be recorded in time series regardless of whether or not the push button switch 7 attached to the probe 3 is operated in principle. In this way, by setting the pitch P of the measurement point in advance, every time the probe 3 moves by the pitch P of the measurement point, the current three-dimensional coordinate value of the edge E, that is, the current probe The coordinate values (coordinate values in the X, Y, and Z directions) of the center G of the spherical surface 14 of the main body 10 are stored (recorded) (steps S6 and S7). However, even if the data between the last acquisition position that is a specific measurement point and the next acquisition position that is the next measurement point is acquired, it is not saved. That is, as shown in step S4 of FIG. 6, the distance L from the previous data capture position to the current position is always known, and the current position data at that time is stored on the condition that L = P. Is done. Therefore, the stored data in this automatic recording mode is always point sequence data at an equal pitch as shown in FIG. However, as a matter of course, it is possible to make the span of the point sequence data dense by setting the value of the measurement pitch P small.

  On the other hand, in the manual recording mode, only when the measurer moves the probe 3 and presses the push button switch 7 attached to the probe 3 (step S9 in FIG. 6), the current position data at that time is stored. (Steps S10 and S7). That is, in this manual recording mode, it is possible to measure while increasing or decreasing the span of the point sequence data as shown in FIG. This increases the number of point sequence data by increasing the span of the point sequence data in a portion where the shape change is relatively small, while decreasing the span of the point sequence data in a portion where the shape change is relatively large. Therefore, it becomes possible to measure more precisely and accurately in a portion where the shape change is relatively large.

  As described above, according to the present embodiment, the three-dimensional coordinate value of a continuous line such as a ridge line can be measured very easily and accurately. Of course, it is also possible to measure a three-dimensional shape other than the ridgeline using the spherical surface 14 of the probe body 10 as necessary.

Explanatory drawing which shows schematic structure of the three-dimensional coordinate measuring apparatus containing the probe for three-dimensional coordinate measurement which concerns on this invention. The principal part expansion perspective view of the probe for a three-dimensional coordinate measurement shown in FIG. The perspective view which shows the measurement state with the probe for three-dimensional coordinate measurement shown in FIG. (A) is a view in the direction of arrow a in FIG. 3, and (b) is a view in the direction of arrow b in FIG. Explanatory drawing which shows the relationship between the measurement state in the probe for three-dimensional coordinate measurement shown in FIG. 2, and the point sequence data obtained by it. The flowchart which shows the measurement process sequence in the three-dimensional coordinate measuring apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Three-dimensional coordinate measuring device 2 ... Arm 3 ... Probe 4a-4d ... Joint part 5 ... Data processing device 7 ... Pushbutton switch 8 ... Holder 9 ... Shaft part 10 ... Probe body 11a, 11b ... Reference ridgeline 12a-12d ... Inclination Plane 13a, 13b ... Ridge line 14 ... Spherical surface G ... Center of spherical surface

Claims (4)

The spherical probe body is approximately two-thirds spherical with two semicircular cutout surfaces intersecting at a predetermined angle with the center line passing through the center of the sphere as an intersection line,
A probe for measuring a three-dimensional coordinate system, characterized in that, with respect to two semicircular cutout surfaces, a position that bisects each cutout surface is defined as a reference ridgeline, and an inclined plane that is inclined downward in a direction away from the reference ridgeline.   The probe for three-dimensional coordinate measurement according to claim 1, wherein the probe body is rotatably supported by the holder with a shaft portion positioned on an extension of the center line of the sphere as a rotation center.   The probe for three-dimensional coordinate measurement according to claim 2, wherein the shaft portion is set on an extension line of any one of the reference ridge lines that bisect the semicircular cutout surface.   The three-dimensional coordinate measuring probe according to claim 1, wherein the probe is a multi-joint type robot and a manual three-dimensional measuring machine provided with a rotation sensor at each joint is used as a mother machine. A three-dimensional coordinate measuring device, wherein the is detachably mounted.

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