JP2013234951A - Three-dimensional measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-dimensional measuring apparatus capable of preventing reduction of measurement accuracy.SOLUTION: The three-dimensional measuring apparatus includes: a measuring probe 2 for measuring a measuring object; a multi-joint arm having a plurality of links connected in series through joint parts to movably support the measuring probe 2 against external force in a three-dimensional space; an operation detection device 5 attached to either one of the measuring probe 2 and the multi-joint arm to detect operation of the multi-joint arm and output operation information concerned with the operation; and a control device 6 for entering a measurement result by the measuring probe 2 and calculating a measurement value. The control device 6 includes a measurement result determination part 61A for determining whether the measurement result by the measuring probe 2 is to be entered or not based on the operation information.

Description

  The present invention is configured so that a measurement probe can be directly moved by a hand, and based on the measurement result of the measurement probe, a three-dimensional coordinate value of an arbitrary point on the measurement object is calculated, and the measurement target The present invention relates to a three-dimensional measuring apparatus that measures a three-dimensional shape, surface property, etc. of an object.

2. Description of the Related Art Conventionally, a three-dimensional measuring apparatus having a plurality of articulated arms having a plurality of links connected in series via joint portions and supporting a measurement probe in a three-dimensional space so as to be movable with respect to an external force. It is known (see, for example, Patent Document 1).
The measurer measures the object to be measured while holding the articulated arm directly in his hand and moving the measurement probe.

JP 2000-28302 A

By the way, when measuring an object to be measured while operating the articulated arm and moving the measurement probe, it is desirable that the moving speed of the measurement probe is constant considering the measurement accuracy.
That is, for example, the measurement result of the measurement probe when the measurement probe is moving at the first speed and the measurement when the measurement probe is moving at the second speed that is the same speed as the first speed. The probe measurement result is a measurement result measured under the same measurement conditions. For this reason, if the measurement of the three-dimensional shape, surface property, etc. of the object to be measured is performed based on each three-dimensional coordinate value (each measurement value) calculated from each measurement result, the measurement accuracy is good.

On the other hand, when a sudden acceleration occurs in the measurement probe and the second speed is higher than the first speed, the measurement result at the first speed, the measurement result at the second speed, Is a measurement result measured under different measurement conditions. For this reason, if measurement of the three-dimensional shape, surface property, etc. of the object to be measured is performed based on each three-dimensional coordinate value calculated from each measurement result, the measurement accuracy decreases.
Here, at the time of measuring the object to be measured, an abnormal operation of the articulated arm is assumed such as the measurer wobbling or the measurer releasing his hand from the articulated arm.
When an abnormal operation as described above occurs, a rapid acceleration is generated in the measurement probe, so that there is a problem that the measurement accuracy decreases as described above.

  The objective of this invention is providing the three-dimensional measuring apparatus which can prevent the fall of a measurement precision.

  The three-dimensional measurement apparatus of the present invention has a measurement probe for measuring an object to be measured and a plurality of links connected in series via joints, and the measurement probe is subjected to external force in a three-dimensional space. An articulated arm that is movably supported, and an operation detection device that is provided on at least one of the measurement probe and the articulated arm, detects an operation of the articulated arm, and outputs operation information related to the operation And a control device that takes in the measurement result from the measurement probe and calculates a measurement value, and the control device determines whether to take in the measurement result from the measurement probe based on the operation information. A result judging unit is provided.

In the present invention, the three-dimensional measurement apparatus includes the above-described motion detection device and the control device having the above-described measurement result determination unit.
Thus, the measurement result determination unit can determine whether the operation of the articulated arm is a normal operation or an abnormal operation based on the operation information output from the operation detection device. If the measurement result determination unit determines that the operation is normal, the measurement result of the measurement probe is captured. On the other hand, if the measurement result determination unit determines that the operation is abnormal, the measurement result of the measurement probe is not captured.
Therefore, the control device does not include the measurement results of the measurement probe during abnormal operation, and measures the three-dimensional shape, surface properties, etc. of the measurement object based on the measurement result of the measurement probe during normal operation. This can be performed, and a reduction in measurement accuracy can be prevented.

In the three-dimensional measurement apparatus of the present invention, it is preferable that the measurement probe is a laser probe that irradiates the object to be measured with laser light and detects the laser light reflected by the object to be measured.
By the way, as a measurement probe, the laser probe which irradiates a measured object with a laser beam and detects the laser beam reflected by the measured object can be illustrated.
In the abnormal operation described above, the laser beam reflected by the object to be measured cannot be detected well. That is, when a laser probe is employed as the measurement probe, the above-described decrease in measurement accuracy is particularly observed.
In the present invention, since the measurement probe is composed of a laser probe, it is possible to suitably achieve the effect of preventing the above-described decrease in measurement accuracy.

In the three-dimensional measurement apparatus of the present invention, it is preferable that the control device includes an irradiation control unit that controls an irradiation state of the laser light of the laser probe based on the operation information.
In this invention, a control apparatus is provided with the irradiation control part mentioned above.
As a result, the irradiation control unit, like the measurement result determination unit, is based on the operation information output from the operation detection device, and the operation of the articulated arm is a normal operation or an abnormal operation. Can be determined. When the irradiation control unit determines that the operation is normal, the irradiation control unit continues the irradiation of the laser light from the measurement probe. On the other hand, if the irradiation control unit determines that the operation is abnormal, it stops the irradiation of the laser light from the measurement probe.
Therefore, unnecessary irradiation of the laser beam at the time of abnormal operation can be stopped.

In the three-dimensional measurement apparatus of the present invention, it is preferable that the motion detection device is an acceleration sensor that detects an acceleration during movement of the articulated arm.
By the way, the articulated arm is usually provided with an angle detection device such as an angle sensor for detecting a relative angle between the linked links. And a control apparatus calculates the three-dimensional coordinate value of the arbitrary points on a to-be-measured object based on the measurement result by a measurement probe, the relative angle of the links detected by the angle detection apparatus, etc.
Here, as an operation of the articulated arm, for example, it is conceivable to detect based on a relative angle detected by an angle detection device such as the angle sensor described above.
However, usually, a plurality of joints are provided, and in association therewith, a plurality of the angle detection devices described above are also provided. Complex calculations are required based on each relative angle. Therefore, there is a risk that the processing load for determining the operation of the articulated arm will increase.
In the present invention, the motion detection device is composed of an acceleration sensor.
As a result, the motion of the articulated arm can be easily detected without performing a complicated calculation only by detecting the acceleration when the articulated arm is moved by the acceleration sensor.

The figure which shows the structure of the three-dimensional measuring apparatus in this embodiment. The figure which shows the structure of the articulated arm in this embodiment. The block diagram which shows the control structure of the three-dimensional measuring apparatus in this embodiment. The flowchart explaining operation | movement of the three-dimensional measuring apparatus in this embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[Configuration of three-dimensional measuring device]
FIG. 1 is a diagram showing a configuration of a three-dimensional measuring apparatus 1 in the present embodiment.
The three-dimensional measuring apparatus 1 is configured so that a measurement person can directly move the measuring probe 2 by hand, and the measurement result (measurement data) obtained by the measuring probe 2 is taken in, so that the three-dimensional shape and surface of the object to be measured are obtained. Measure properties.
As shown in FIG. 1, the three-dimensional measuring apparatus 1 includes a measuring probe 2, an articulated arm 3, an angle sensor 4 (see FIG. 3), and an acceleration sensor 5 (see FIG. 3) as a motion detecting device. And a control device 6.

[Configuration of measurement probe]
In the present embodiment, the measurement probe 2 is composed of a laser probe that irradiates a measurement object with laser light and detects the laser light reflected by the measurement object.
The measurement probe 2 includes a laser light source 21 (see FIG. 3) that emits laser light, and an optical element (not shown) that diffuses the laser light emitted from the laser light source 21 into a line shape and irradiates the object to be measured. A CCD (Charge Coupled Device) camera 22 (see FIG. 3) for detecting a line-shaped laser beam reflected by the object to be measured, and an exterior casing 23 (FIG. 1) constituting the exterior.

[Configuration of articulated arm]
FIG. 2 is a diagram showing a configuration of the articulated arm 3.
The articulated arm 3 is configured to support the measurement probe 2 and to be able to move the measurement probe 2 with respect to external force (operation by the measurer) in the three-dimensional space.
As shown in FIG. 2, the multi-joint arm 3 includes a columnar column 3A, columnar first to sixth links 3B to 3G, first to sixth joint portions 3H to 3M, and a probe head 3N. With.
The column 3A is fixed to a work table or the like along the vertical axis Ax1 (FIG. 2).
The first joint 3H connects the column 3A and one end of the first link 3B in a state where the first link 3B is along the vertical axis Ax1.
And the 1st link 3B becomes rotatable centering on the vertical axis Ax1 with respect to the support | pillar 3A by being connected with the support | pillar 3A by the 1st joint part 3H.

The second joint portion 3I connects the other end of the first link 3B and one end of the second link 3C.
The first and second links 3B and 3C are connected to each other by the second joint portion 3I, so that the first and second links 3B and 3C can be relatively rotated about the horizontal axis Ax2 (FIG. 2).
The third joint portion 3J connects the other end of the second link 3C and one end of the third link 3D in a state in which the center axes Ax3 (FIG. 2) coincide with each other.
The second and third links 3C and 3D can be relatively rotated about the central axis Ax3 by being connected to each other by the third joint portion 3J.
The fourth joint 3K connects the other end of the third link 3D and one end of the fourth link 3E.
The third and fourth links 3D and 3E are connected to each other by the fourth joint portion 3K, so that the third and fourth links 3D and 3E can relatively rotate about the axis Ax4 (FIG. 2) orthogonal to the central axis Ax3.

The fifth joint 3L connects the other end of the fourth link 3E and one end of the fifth link 3F in a state in which the center axes Ax5 (FIG. 2) coincide with each other.
The fourth and fifth links 3E and 3F are connected to each other by the fifth joint portion 3L, so that the fourth and fifth links 3E and 3F can relatively rotate about the central axis Ax5.
The sixth joint 3M connects the other end of the fifth link 3F and one end of the sixth link 3G.
The fifth and sixth links 3F and 3G are connected to each other by the sixth joint portion 3M, so that the fifth and sixth links 3F and 3G can relatively rotate about the axis Ax6 (FIG. 2) orthogonal to the central axis Ax5.
As described above, the articulated arm 3 is configured to be operable with six axes.
The probe head 3N is attached to the other end of the sixth link 3G and detachably supports the measurement probe 2.

[Configuration of angle sensor]
Although not specifically shown, the angle sensor 4 is attached to the first to sixth joint portions 3H to 3M, respectively.
The six angle sensors 4 detect relative rotation angles of the first to sixth links 3B to 3G connected to each other by the first to sixth joint portions 3H to 3M.
For example, the angle sensor 4 provided in the first joint portion 3H detects a relative rotation angle about the vertical axis Ax1 between the support 3A and the first link 3B.

[Configuration of acceleration sensor]
Although not specifically shown, the acceleration sensor 5 is attached to the probe head 3N and detects the operation of the multi-joint arm 3 (acceleration of the probe head 3N).
In addition, since the acceleration sensor 5 is a well-known technique, it abbreviate | omits about detailed description.

[Configuration of control device]
FIG. 3 is a block diagram showing a control structure of the three-dimensional measuring apparatus 1.
As shown in FIG. 3, the control device 6 includes a control device main body 61 having a CPU (Central Processing Unit) and a hard disk, an input device 62 composed of a mouse and a keyboard, and a display device 63 such as a display. Prepare.
Based on the measurement data of the measurement probe 2 (image data detected by the CCD camera 22) and the detection value (rotation angle) of the angle sensor 4, the control device main body 61 has a three-dimensional shape and surface properties of the object to be measured. Etc. are measured.
As shown in FIG. 3, the control device main body 61 includes a measurement result determination unit 61A, an irradiation control unit 61B, an arithmetic processing unit 61C, a shape analysis unit 61D, and a memory 61E.

The measurement result determination unit 61 </ b> A determines whether or not to take in the measurement data of the measurement probe 2 and the detection value of the angle sensor 4 based on the detection value (acceleration) of the acceleration sensor 5.
The irradiation control unit 61B controls the irradiation state of the laser light of the measurement probe 2 (laser light source 21) based on the detection value (acceleration) of the acceleration sensor 5.
The arithmetic processing unit 61C determines the three-dimensional coordinate value of an arbitrary point on the object to be measured based on the measurement data taken by the measurement probe 2 and the detection value of the angle sensor 4 based on the determination by the measurement result determination unit 61A. (Measurement value) is calculated.
Then, the arithmetic processing unit 61C stores the calculated three-dimensional coordinate value in the memory 61E.
The shape analysis unit 61D calculates surface shape data of the object to be measured based on the three-dimensional coordinate values stored in the memory 61E, and performs shape analysis to obtain errors, distortions, and the like of the calculated surface shape data of the object to be measured. Do.

[Operation of CMM]
Next, the operation of the three-dimensional measuring apparatus 1 will be described with reference to the drawings.
FIG. 4 is a flowchart for explaining the operation of the three-dimensional measuring apparatus 1.
In the following, for convenience of explanation, a line-shaped laser beam is emitted from the measurement probe 2 and the articulated arm 3 is operated by a measurer to scan the line-shaped laser beam on the object to be measured. The operation of the three-dimensional measuring apparatus 1 when in operation will be described.
First, the measurement result determination unit 61A constantly monitors the detection value of the acceleration sensor 5, and determines whether or not the acceleration of the probe head 3N based on the detection value is equal to or greater than a predetermined threshold (step ST1).

When the measurement result determination unit 61A determines “Y” in step ST1, that is, when it is determined that the operation of the articulated arm 3 is an abnormal operation, the measurement data of the measurement probe 2 and the angle sensor are measured. The detection value of 4 is not captured.
In addition, the irradiation controller 61B stops the irradiation of the laser beam from the measurement probe 2 (laser light source 21) (step ST2).
And the control apparatus main body 61 complete | finishes the measurement of a to-be-measured object.

On the other hand, the measurement result determination unit 61A determines that “N” is determined in step ST1, that is, the movement speed of the probe head 3N is substantially equal and the operation of the articulated arm 3 is a normal operation. In this case, the measurement data of the measurement probe 2 and the detection value of the angle sensor 4 are captured (step ST3).
After step ST3, the arithmetic processing section 61C, based on the taken measurement data of the measurement probe 2 and the detected value of the angle sensor 4, as shown below, an arbitrary point (measurement object) on the measurement object. The three-dimensional coordinate value of the laser light irradiated on the line is calculated (step ST4).

First, the arithmetic processing unit 61C determines the position of the measurement probe 2, the laser light source, based on the detected values (respective rotation angles) of the angle sensor 4 and the lengths of the first to sixth links 3B to 3G. The irradiation angle of the laser beam from 21 and the angle of the CCD camera 22 are calculated.
Then, the arithmetic processing unit 61C uses the triangulation principle based on the position of the measurement probe 2, the irradiation angle of the laser beam, and the angle of the CCD camera 22 to capture the measurement data (image data) of the measurement probe 2. A three-dimensional coordinate value of each point (point on the object to be measured) of the line pattern of the laser beam included is calculated.
In addition, the arithmetic processing unit 61C stores the calculated three-dimensional coordinate value in the memory 61E (step ST5).

After step ST5, the control device main body 61 determines whether or not the measurement end condition is satisfied (step ST6).
For example, the measurement end condition can be a case where the articulated arm 3 is operated by the measurer and the measurement probe 2 is moved by a predetermined distance.
If the determination is “N” in step ST6, the control device main body 61 proceeds to the process of step ST1 again. Then, only when the acceleration of the probe head 3N is less than a predetermined threshold, the control device main body 61 performs the three-dimensional coordinate values of arbitrary points on the object to be measured until the measurement end condition is satisfied, according to steps ST3 to ST5. Continue to calculate.

On the other hand, if it is determined as “Y” in step ST6, the control device main body 61 proceeds to step ST2, stops the irradiation of the laser beam from the measurement probe 2, and ends the measurement of the object to be measured. To do.
Then, after the measurement of the object to be measured is completed, for example, according to the operation of the input device 62 by the measurer, the shape analysis unit 61D determines the object to be measured based on the three-dimensional coordinate value stored in the memory 61E. Surface shape data is calculated and shape analysis is performed.

According to this embodiment described above, the following effects are obtained.
In the present embodiment, the three-dimensional measurement apparatus 1 includes an acceleration sensor 5 and a control device 6 having a measurement result determination unit 61A.
Accordingly, the measurement result determination unit 61A can determine whether the operation of the articulated arm 3 is a normal operation or an abnormal operation based on the detection value of the acceleration sensor 5. When the measurement result determination unit 61A determines that the operation is normal, the measurement result determination unit 61A takes in the measurement data of the measurement probe 2. On the other hand, if the measurement result determination unit 61A determines that the operation is abnormal, it does not capture the measurement data of the measurement probe 2.
Therefore, the control device 6 does not include the measurement data of the measurement probe 2 at the time of abnormal operation, and based on the measurement data of the measurement probe 2 at the time of normal operation, the three-dimensional of an arbitrary point on the object to be measured A coordinate value is calculated, and surface shape data of the object to be measured can be calculated based on the three-dimensional coordinate value. That is, it is possible to prevent a decrease in measurement accuracy such as the three-dimensional shape and surface properties of the object to be measured.
Moreover, since the measurement probe 2 is composed of a laser probe, the effect of preventing the above-described decrease in measurement accuracy can be suitably achieved.

Furthermore, the control device 6 includes an irradiation control unit 61B.
As a result, the irradiation control unit 61B operates normally or abnormally on the articulated arm 3 based on the detection value of the acceleration sensor 5, similarly to the measurement result determination unit 61A. Can be determined. When the irradiation control unit 61B determines that the operation is normal, the irradiation control unit 61B continues the irradiation of the laser light from the measurement probe 2. On the other hand, the irradiation control unit 61B stops the irradiation of the laser light from the measurement probe 2 when determining that the operation is abnormal.
Therefore, unnecessary irradiation of the laser beam at the time of abnormal operation can be stopped.

Moreover, the acceleration sensor 5 is employ | adopted as an operation | movement detection apparatus which concerns on this invention.
As a result, the motion of the multi-joint arm can be easily detected without complicated calculations by simply detecting the acceleration during movement of the multi-joint arm 3 with the acceleration sensor 5.

Note that the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within a scope in which the object of the present invention can be achieved are included in the present invention.
In the above embodiment, the measurement probe 2 is not limited to the laser probe described in the above embodiment. For example, a contact probe having a probe that contacts the object to be measured, an image probe using a CCD camera or an image sensor. May be adopted.
In the above-described embodiment, the multi-joint arm 3 includes six links and joints and is configured to be operable by six axes. However, the present invention is not limited to this, and is configured to include other numbers of links and joints. You may comprise so that it can operate by five axes or seven axes.

In the above-described embodiment, the acceleration sensor 5 is used as the motion detection device. However, the configuration is not limited to this, and other configurations, for example, the motion of the articulated arm 3 may be detected using the angle sensor 4. It doesn't matter.
In the above-described embodiment, the motion detection device according to the present invention is provided in the articulated arm 3. However, the present invention is not limited thereto, and a configuration provided in the measurement probe 2 (exterior housing 23) may be employed.

  The present invention is configured so that a measurement probe can be directly moved by a hand, and based on the measurement result of the measurement probe, a three-dimensional coordinate value of an arbitrary point on the measurement object is calculated, and the measurement target The present invention can be used in a three-dimensional measuring apparatus that measures the three-dimensional shape and surface properties of an object.

DESCRIPTION OF SYMBOLS 1 ... Three-dimensional measuring apparatus 2 ... Measuring probe 3 ... Articulated arm 3B-3G ... Link 3H-3M ... Joint part 5 ... Acceleration sensor (motion detection apparatus)
6 ... Control device 61A ... Measurement result judgment unit 61B ... Irradiation control unit

Claims (4)

A measurement probe for measuring an object to be measured;
A multi-joint arm having a plurality of links connected in series via a joint, and supporting the measurement probe movably with respect to an external force in a three-dimensional space;
An operation detection device that is provided on at least one of the measurement probe and the articulated arm, detects an operation of the articulated arm, and outputs operation information related to the operation;
A control device that takes in the measurement result by the measurement probe and calculates the measurement value,
The control device includes:
A three-dimensional measurement apparatus comprising: a measurement result determination unit that determines whether or not a measurement result obtained by the measurement probe is captured based on the operation information. The three-dimensional measuring apparatus according to claim 1,
The measurement probe is
A three-dimensional measuring apparatus, characterized by being a laser probe that irradiates the object to be measured with laser light and detects the laser light reflected by the object to be measured. The three-dimensional measuring apparatus according to claim 2,
The control device includes:
A three-dimensional measurement apparatus comprising: an irradiation control unit that controls an irradiation state of the laser beam of the laser probe based on the operation information. In the three-dimensional measuring apparatus in any one of Claims 1-3,
The motion detection device includes:
A three-dimensional measuring apparatus, wherein the three-dimensional measuring apparatus is an acceleration sensor that detects an acceleration during movement of the articulated arm.

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