JP3176045B2 - Touch signal probe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a touch signal probe suitable for measuring a shape of a three-dimensional measuring machine or a machine tool, and more particularly to a vibrating touch signal probe having a low measuring force and a high sensitivity. Things.

[0002]

2. Description of the Related Art A height gauge (one-dimensional measuring machine), a three-dimensional measuring machine, a contour measuring machine and the like are known as measuring machines for measuring the shape and dimensions of an object to be measured. In order to perform coordinate detection and position detection in that case, a touch signal probe that detects contact with an object to be measured is used for the measuring device. As a detection principle of the touch signal probe, a substantially cylindrical stylus having a contact portion at its tip that comes into contact with an object to be measured, a vibrating means for vibrating the stylus, and a stylus when the contact portion comes into contact with the object to be measured. Detecting means for detecting a change in a vibration state due to contact is provided, and when the vibration detected by the detecting means attenuates to a detection trigger level, a contact trigger signal is transmitted, and a coordinate value at that time is read.

[0003] It is desired to use a stylus in order to widen the application range of the vibrating touch signal probe. Therefore, as shown in FIG. 5, the applicant has arranged the stylus in a cross shape. We are developing an excitation type touch signal probe. In the touch signal probe shown in FIG. 5, a block-shaped stylus support 51 is attached to a probe support 50, and vibrating means are respectively provided on installation protrusions 52 projecting from four corners of the upper and lower surfaces of the stylus support 51. And a piezo-electric element 53 serving as a detecting means, and symmetrical first and second styluses 54, which coincide with each other in the X-axis and Y-axis directions, are disposed at the center positions of the respective side surfaces. In the touch signal probe having this structure, the entire vibrator including the stylus support body 51 and the plurality of styluses 54 constitutes a single vibrating system, so that simple, easy to assemble and stable resonance characteristics can be obtained.

In the cross-shaped touch signal probe shown in FIG. 5, the piezoelectric element 53 uses a wiring pattern of a conventional straight ultrasonic touch sensor. In other words, a part of one piezoelectric element 53 is used as a vibration electrode 53A, and the remaining part is used as a detection electrode 53B, and these electrodes 53A and 53B are used as stylus 5 facing each other.
4 are aligned with the longitudinal direction. Further, the piezoelectric element 53 is connected to a vibration circuit and a control circuit shown in FIG. In FIG. 6, a vibration circuit includes a drive circuit 55 for applying a vibration current to the vibration electrode 53A,
5 connected to a power supply 56. The control circuit includes an amplitude-DC level conversion circuit 57 that converts the amplitude of the detection signal detected by the detection electrode 53B into a DC level,
And a touch trigger signal generation circuit 58 for generating a touch trigger signal from the signal output from the amplitude-DC level conversion circuit 57.

[0005]

In the touch signal probe shown in FIG. 5, the vibration electrode 5
Since there are both 3A and the detection electrode 53B, the vibration detection direction of the vibrator is only one axis direction. In this direction, sufficient detection performance can be ensured, but in the direction intersecting this direction, the detection performance is low. There is a problem that the detection performance becomes insufficient and the detection performance varies for each stylus. Also,
A plurality of detection signals detected from the two piezoelectric elements 53 are sent to the amplitude-to-DC level conversion circuit 57, and as shown in FIG. Is analog-added to the detection signal S2 detected by the piezoelectric element 53 of FIG.

The detection signal S is, as shown in FIG.
Since the detection signals S1 and S2 are added in an analog manner, the behavior of the added detection signal S is leveled and the waveform immediately after the contact is dull. In FIG. 8, when only the individual detection signal S1 is subjected to amplitude-to-DC level conversion, the detection delay time from when the signal S1 starts to be attenuated to the detection trigger level of the touch trigger signal for the first time is t1. signal
When only S2 is subjected to amplitude-DC level conversion, it takes a detection delay time t2 from when the signal S2 is first attenuated to the detection trigger level of the touch trigger signal from the start of contact. On the other hand, the detection signal S obtained by adding these detection signals S1 and S2 is
When the signal S is subjected to amplitude-to-DC level conversion, the detection delay time t from when the signal S first attenuates to the detection trigger level of the touch trigger signal after the start of contact is the sum of the detection signals S1 and S2 of the systems where the detection signal S is different. As a result, the waveform immediately after the contact becomes dull, and it takes longer than t1 and t2.

In addition, since the signal S to be detected is one system, when the behavior of the signal waveform changes as shown in FIG. 9, the detection trigger level does not reach the initial behavior, and the subsequent The response time is greatly reduced until the time is reached. FIG. 9 shows an error factor in the case where the measurement is repeatedly performed.
Although the detection delay time from the start of contact to the first decay to the detection trigger level of the touch trigger signal is t, even if the signal is of the same system, its waveform may fluctuate during repeated measurement, The detection signal S 'whose waveform oscillates has a detection delay time t'. This time difference (t'-
t) becomes a variation error of the detection delay time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a touch signal probe capable of shortening a detection delay time, improving a variation in detection capability between styluses, and eliminating a measurement error.

[0009]

Therefore, according to the present invention, a plurality of detecting means are arranged corresponding to a plurality of styluses, respectively, and a plurality of detection signals respectively obtained by these detecting means are independently combined without being combined with each other. It is intended to achieve the above-mentioned object by being used. Specifically, the touch signal probe of the present invention has a stylus support provided on the probe support, and a contact portion which is formed to project radially from the stylus support and which comes into contact with the contacted portion at the tip. A vibrator configured to include a plurality of styluses, and vibrating means disposed on the stylus support and vibrating the stylus at a frequency substantially equal to a natural frequency of the vibrator;
A detecting unit that is disposed on the stylus support and detects a state of vibration that changes with the contact when the contact unit comes into contact with the object to be measured, and performs an arithmetic processing on a detection signal detected by the detecting unit. And a control means for generating a contact trigger signal by means of a stylus support, wherein the plurality of the detecting means are arranged on the stylus support so as to respectively correspond to the plurality of styluses, and the control means comprises the plurality of styluses. The detection of a change in the vibration state caused by the contact of the contact portion with the contacted portion can be performed on any of the plurality of styluses by independently using the plurality of detection signals obtained by the detection means without being combined with each other. And the contact portion does not depend on the contacted portion from any direction.

In the present invention having this configuration, for the purpose of measurement, the touch signal probe is moved to bring the contact portion into contact with the object to be measured. At this time, the vibrator is vibrated by vibrating means to form a resonance state. I do. When the contact portion of the stylus comes into contact with the contacted portion in a state where the vibrator resonates, the detection signal detected by the detection unit changes, and the detection signal is arithmetically processed by the control unit to generate a contact trigger signal. In the present invention, vibration and detection are performed simultaneously in all directions of the stylus,
Even if the contacted part comes into contact with any of the contact parts of the plurality of styluses, detection can be performed under the same conditions. Therefore, it is possible to cancel the variation in the detection performance for each stylus. In addition, since the detection signals detected by the respective detection units are separately processed without being added, the detection signals from the respective detection units do not influence each other. This allows
A sharply changing signal can be detected without dulling, and the detection delay time can be reduced.

Here, in the present invention, the control means individually performs signal processing on a plurality of detection signals independently obtained by the plurality of detection means, and performs a separate contact trigger for each processing system. A signal is generated, and the first contact signal among the individual contact trigger signals generated from all processing systems is taken out and used as a total contact trigger signal, so that the contact of the contact portion with the contacted portion is started. The detection delay time until the generation of the total contact trigger signal does not depend on any of the plurality of styluses, and may depend on the contact portion coming into contact with the contacted portion from any direction. There may be no configuration.

In this configuration, of the plurality of contact trigger signals generated by independently processing signals in the respective signal systems, the contact trigger signal generated fastest is used as the final one contact trigger signal. Even when the waveform of the detection signal for each system changes during measurement, the detection delay time of the sensor is always minimized, and the detection delay time can be reduced. In other words, if the measurement is repeated, the detection signal of the shortest system for generating the contact trigger signal is determined, but even if the signal waveform of that system changes,
Then, the detection signal of the system with the shortest arrival time immediately generates the contact trigger signal, so that the detection delay time of the sensor is always minimized.

Further, the plurality of detecting means are independently arranged on one surface of the stylus support, and the vibrating means is
A plurality of stylus supports may be arranged on the other surface opposing the stylus with the stylus interposed therebetween in correspondence with the detection means. In this configuration, the detecting means and the vibrating means are respectively opposed to each other with the base end of the stylus interposed therebetween. Therefore, the detecting means and the vibrating means are arranged close to each other with the base end of the stylus interposed therebetween. Thus, the stylus can be reliably vibrated by the vibrating means in the vicinity of the stylus, and the change in the vibration state can be reliably detected by the detecting means.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. 1 to 4 show one embodiment of the present invention. FIG. 1 is an exploded perspective view of the touch signal probe according to the present embodiment, and FIG. 2 is a perspective view of the touch signal probe. In these figures, a touch signal probe 1 has a substantially block-shaped stylus support 3 through which a columnar tip 2A of a probe support 2 penetrates at the center, and radially extend along the X-axis and the Y-axis of the stylus support 3, respectively. A vibrator 5 including four styluses 4 protruding from the vibrator; a vibrating piezoelectric element 6 disposed on an upper surface of the stylus support 3;
A configuration including a piezoelectric element for detection 7 arranged on the lower surface of the stylus support 3, a vibration circuit 8 connected to the piezoelectric element 6 for vibration, and control means 9 connected to the piezoelectric element 7 for detection Have been.

The center of the stylus support 3 is X,
A substantially rectangular parallelepiped block having a plane that is coincident with the origin of the Y and Z axes and that is perpendicular to the Z axis and has a square shape, and is installed at four corners of two upper and lower planes perpendicular to the Z axis. Projection 3
The piezoelectric elements 6 and 7 are bonded to A. The stylus 4 includes a main body 4A formed in a substantially columnar shape, and a substantially spherical contact portion 4B provided at the tip of the main body 4A. The contact portion 4B can contact a contacted portion (not shown). It is. The main body 4A of the stylus 4 has a structure in which the base end is fixed to the stylus support 3 by bonding, welding, or the like.

The vibrating piezoelectric element 6 is formed in a flat plate shape having a square planar shape, and is arranged in a plane orthogonal to the Z axis. The piezoelectric element 6 is formed with four vibrating electrodes 6A as vibrating means, and these vibrating electrodes 6A are arranged at positions corresponding to the base ends of the four styluses 4. ing. A circular notch 6B is formed at the center of the piezoelectric element 6 so as not to interfere with the columnar tip 2A of the probe support 2.
The detecting piezoelectric element 7 is formed in a flat plate shape having a square planar shape, and is disposed in a plane orthogonal to the Z axis. On the piezoelectric element 7, four detection electrodes 7A as detection means are formed separately, and these detection electrodes 7A are arranged at positions corresponding to the base ends of the four styluses 4. . A circular notch 7B is formed at the center of the piezoelectric element 7 so as not to interfere with the columnar tip 2A of the probe support 2.

That is, the four detection electrodes 7A are independently arranged on the upper surface of the stylus support 3, and the excitation electrodes 6A
Are independently arranged on the lower surface facing the upper surface of the stylus support 3 and the base end of the stylus 4 in correspondence with the detection electrodes 7A. FIG. 3 shows a specific configuration of the excitation circuit 8 and the control means 9. In FIG. 3, a vibrating circuit 8 vibrates the stylus 4 at a frequency substantially coincident with the natural frequency of the vibrator 5, and the vibrating circuit 8 applies vibration to the four vibrating electrodes 6 A of the vibrating piezoelectric element 6 respectively. A drive circuit 10 for applying an exciting current, and a power supply 11 for driving the drive circuit 10
It is composed of

The control means 9 generates the contact trigger signal S by independently using a plurality of detection signals obtained by the four detection electrodes 7A without combining them with each other. 7A, four amplitude-to-DC level conversion circuits 12 for converting the amplitudes of the detection signals respectively detected to DC levels, and contact trigger signals SA, Four contact trigger signal generating circuits 13 that generate SB, SC, and SD, and individual contact trigger signals SA, SB, SC, and SD generated from all processing systems of these contact trigger signal generating circuits 13 A logical operation circuit 14 which takes out a signal and makes it a total contact trigger signal S.

The logic operation circuit 14 generates the contact trigger signals SA, SB, SC, and SD sent from the contact trigger signal generation circuit 13.
Among these, a signal having the shortest time from the start of contact of the measurement unit to the measurement target to the arrival of the detection trigger level is selected, and a final contact trigger signal S is issued, that is, as shown in FIG. When repeatedly measuring, assuming that the signal having the shortest detection time among the contact trigger signals SA, SB, SC, and SD is SA, the time from the start of contact of the detection signal SA to the detection trigger level is tA. . When the behavior of the waveform of the detection signal SA changes to the signal SA ′, the time from the start of contact to the detection trigger level is tA ′ longer than tA. On the other hand, if the signal having the second shortest detection time among the contact trigger signals SA, SB, SC, and SD is SB, the time from the start of contact of the detection signal SB to the detection trigger level is tB (tA <tA < tB <tA ′), and the detection time only needs to be delayed by (tB−tA) compared to tA, which has the fastest detection time. That is, even if the behavior of the signal waveform changes and the timing of reaching the detection trigger level is delayed, the detection signal of the next or the next fastest system will generate the total contact trigger signal S.

Therefore, in the present embodiment, the vibration constituted by including the stylus support 3 and the four styluses 4 which are formed to project radially from the stylus support 3 and have the contact portions 4B at the tips, respectively. Vibrator 5, vibrating means 6 </ b> A disposed on stylus support 3 and vibrating stylus 4 at a frequency substantially equal to the natural frequency of vibrator 5, and a contact portion disposed on stylus support 3 and Detecting means 7A for detecting a state of vibration which changes with the contact when the object 4B comes into contact with an object to be measured, and control means for arithmetically processing a detection signal detected by the detecting means 7A to generate a contact trigger signal 9 and the detecting means 7A is 4
Since four stylus supports 3 are arranged on the stylus support 3 so as to correspond to the respective styluses 4, vibration and detection can be simultaneously performed in all longitudinal directions (X-axis direction and Y-axis direction) of the stylus 4, Contact portion 4B of four styluses 4
No matter which one of the contacted parts comes into contact, detection can be performed under the same conditions. Therefore, it is possible to cancel the variation in the detection performance for each stylus 4.

Further, the control means 9 comprises four detection means 7
A is used independently of the plurality of detection signals obtained by each of the contact portions 4A without being combined with each other.
The detection of the change in the vibration state due to the contact with the contacted portion does not depend on any of the four styluses 4, and depends on the contact portion 4B coming into contact with the contacted portion from any direction. Each detection means 7
Since the detection signals detected by A are separately processed without being added, the detection signals from the respective detection means 7A do not influence each other. As a result, a sharply changing signal can be detected without dulling, and the detection delay time can be reduced.

Further, in this embodiment, the control means 9
Performs signal processing individually on the four detection signals independently obtained by the four detection means 7A to generate individual contact trigger signals SA, SB, SC, SD for each processing system, Individual touch trigger signals generated from all processing systems
By detecting the first-arrival signal from SA, SB, SC, and SD and using it as a total contact trigger signal, detection from the start of contact of the contact portion to the contacted part until the generation of the total contact trigger signal S The delay time does not depend on any of the four styluses 4, and the contact portion 4B does not depend on the contacted portion from any direction. Of the plurality of contact trigger signals SA, SB, SC, and SD generated by signal processing independently in the system, repeat measurement is performed so that the contact trigger signal SB that occurs the fastest is the final contact trigger signal S. In this case, even if the detection signal for each system changes, the detection delay time of the sensor is always minimized, and the detection delay time can be reduced.

Further, the four detecting means 7A are independently disposed on the lower surface of the block-shaped stylus support 3,
The vibrating means 6A is provided on the upper surface opposed to the lower surface of the stylus support 3 with the stylus 4 interposed therebetween in correspondence with the detecting means 7A.
Since the individual parts are arranged, the detecting means 7A and the vibrating means 6A are respectively opposed to each other with the base end of the stylus 4 interposed therebetween. Therefore, the detecting means 7A and the vibrating means 6A
And the stylus 4 can be disposed close to each other with the base end of the stylus 4 interposed therebetween.
A can reliably apply the vibration, and the change in the vibration state can be reliably detected by the detection means 7A.

Since the detecting means 7A is formed by dividing one detecting piezoelectric element 7 into four pieces, the detecting means 7A is attached to the stylus support 3 by bonding one piezoelectric element 7 thereto. Since it is only necessary to perform the same operation, the attaching work of the detecting means 7A can be easily performed. Similarly, the vibration means 6A is 1
Since the detection piezoelectric elements 7 are divided into four parts, the vibration means 6A can be attached to the stylus support 3 by bonding one piezoelectric element 6 or the like. 6A can be easily attached.

Further, since the stylus support 3 is formed in a rectangular parallelepiped in which a plane orthogonal to the Z axis is a square, the center position of the stylus support 3 is easily matched with the origin of the X, Y, Z axes. Therefore, the assembling work of the touch signal probe can be easily performed. Further, the stylus 4 is a pair of a first stylus fixed along the X-axis and symmetrically arranged with respect to the origin, and a pair of a second stylus fixed along the Y-axis and symmetrically arranged with respect to the origin. Thus, a cross-shaped stylus in which the stylus 4 extends from the four side surfaces of the stylus support 3 in the X axis and the Y axis, respectively, can be provided.

The present invention is not limited to the above embodiments, but includes the following modifications as long as the object of the present invention can be achieved. For example, in the above-described embodiment, the vibrating unit 6A is configured by dividing one piezoelectric element 6 into four parts. However, in the present invention, each of the four vibrating units may be configured by one piezoelectric element. Or
Another actuator may be used instead of the piezoelectric element.
Similarly, the detection means 7A is configured by dividing one piezoelectric element 7 into four parts.
It may be composed of a single piezoelectric element, or another actuator may be used instead of the piezoelectric element.

Further, although the four styluses 4 are provided along the X axis and the Y axis, one stylus may be provided along the X axis and the Y axis, or the stylus 4 may be provided along the Z axis direction. Is also good. When one stylus 4 is provided along each of the X axis and the Y axis, it is preferable to provide a balancer on the side where the stylus 4 is not provided so as to keep the stylus 4 in vibration balance. Also, stylus support 3
The piezoelectric elements 6 and 7 may have a planar circular shape.

[0028]

As described above, according to the touch signal probe of the present invention, it is possible to shorten the detection delay time, improve the variation in the detection capability between styluses, and eliminate the measurement error.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a touch signal probe according to an embodiment of the present invention.

FIG. 2 is a perspective view of the touch signal probe.

FIG. 3 is a block diagram illustrating a configuration of a vibration unit and a control unit of the touch signal probe.

FIG. 4 is a graph showing a relationship between time and a DC level converted amplitude amount in the embodiment.

FIG. 5 is an exploded perspective view of a touch signal probe described as a background art.

FIG. 6 is a block diagram illustrating a configuration of a vibration circuit and a detection circuit of a touch signal probe described as a background art.

FIG. 7 is a diagram showing a schematic configuration of a detection circuit of a touch signal probe described as a background art.

FIG. 8 is a graph showing a relationship between time and a DC level-converted amplitude in a touch signal probe described as a background art.

FIG. 9 is a graph showing the relationship between time and the DC level-converted amplitude when repeated measurement is performed in the touch signal probe described as the background art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Touch signal probe 2 Probe support 3 Stylus support 4 Stylus 4B Contact part 5 Vibrator 6A Vibration means (vibration electrode) 7A Detection means (detection electrode) 9 Control means

────────────────────────────────────────────────── ─── Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01B ⁷ /00-7/34 102 G01B 5/00-5/30 G01B 21/00-21/32

Claims (3)

(57) [Claims] 1. A stylus support provided on a probe support, and a plurality of styluses each protruding radially from the stylus support and having a contact portion at a tip end for contacting a contacted portion. A vibrator configured, vibrating means disposed on the stylus support and vibrating means for vibrating the stylus at a frequency substantially equal to a natural frequency of the vibrator; and vibrating means disposed on the stylus support Detecting means for detecting a state of vibration that changes with the contact when the contact portion makes contact with an object to be measured, and control means for performing arithmetic processing on a detection signal detected by the detecting means to generate a contact trigger signal A touch signal probe comprising: a plurality of the detecting means arranged on the stylus support so as to respectively correspond to the plurality of styluses; The control means uses the plurality of detection signals respectively obtained by the plurality of detection means independently without combining with each other, thereby detecting the change in the vibration state caused by the contact of the contact portion with the contacted portion. A touch signal probe which does not depend on any of the styluses, and does not depend on which direction the contact portion contacts the contacted portion from any direction. 2. The touch signal probe according to claim 1, wherein said control means individually performs signal processing on a plurality of detection signals independently obtained by said plurality of detection means, respectively, to process each processing system. By generating an individual contact trigger signal for each of the individual contact trigger signals generated from all the processing systems, by taking out the first-arrived signal and forming a total contact trigger signal, The detection delay time from the start of contact to the generation of the total contact trigger signal does not depend on any of the plurality of styluses, and the contact portion contacts the contacted portion from any direction. A touch signal probe characterized in that it does not depend on the touch signal probe. 3. The touch signal probe according to claim 1, wherein the plurality of detecting means are independently arranged on one surface of the stylus support, and the vibrating means is provided on the stylus support. A touch signal probe, wherein a plurality of touch signal probes are arranged corresponding to the detection means on one surface and the other surface facing the stylus.