JP3237042B2 - Touch 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 probe, and more particularly to a touch probe used in a three-dimensional coordinate measuring machine.

[0002]

2. Description of the Related Art In a three-dimensional coordinate measuring machine, a touch probe is used in a portion which directly accesses and contacts a work.

FIG. 6 shows a conventional touch probe. The touch probe 100 includes a fixing unit 200 and a work detection unit 300. The fixing unit 200 receives a detection signal from the work detection unit 300 and outputs the signal to a measuring device main body (computer) (not shown).
And a connecting member 202. A work detection unit 300 is provided at the tip of the connecting member 202. The work detector 300 is connected to the connecting member 20 via the support member 400.
2, five styluses 501 to 505 that are in direct contact with the object to be measured (work) and detect the contact are mounted on the support member 400. The contact signal is sent from the probe main body 201 to the measuring instrument main body side as described above, and the measuring instrument main body obtains the coordinate position of the workpiece based on the contact signals from the styluses 501 to 505.

When measuring a workpiece, five styluses 50 are used.
One stylus is selected from 1 to 505, and access to the work is performed. On the measuring instrument main body side, the position of one specific stylus among the five styluses 501 to 505 is recognized in absolute coordinates, and the positional relationship between the five styluses 501 to 505 is determined in advance. Since it is known, if it is known from which stylus the transmitted contact signal is, the coordinate position of the work can be obtained.

By the way, in the conventional touch probe 100, the operation of notifying the main body of the measuring instrument which stylus the transmitted contact signal is from is performed by the operator. Had to be specified.

[0006]

However, the operation of designating the stylus number before measurement is a complicated and time-consuming operation for the operator. In particular, in a measurement procedure teaching operation in automatic measurement, it is necessary to store stylus numbers in the order of measurement, so that a stylus number is designated each time measurement is performed. For this reason, the operator must always proceed with the measurement work while being conscious of which stylus is currently selected, which is extremely complicated for the operator.

Further, if a stylus other than the designated stylus erroneously comes into contact with the work, the coordinate position is obtained assuming that the contact signal is from the designated stylus, and an erroneous measurement result is output. As a result, there is a problem that the reliability of the measurement data is reduced.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a touch probe capable of performing a measurement operation smoothly and improving the reliability of measurement data.

[0009]

According to a first aspect of the present invention, there is provided a touch probe, comprising: a plurality of styluses disposed on a probe main body so as to maintain a predetermined positional relationship; A touch probe that includes a contact detection unit that outputs a contact detection signal when it comes into contact with an object to be measured; and a determination unit that determines which stylus of the plurality of styluses has contacted based on the contact detection signal. ing.

According to a second aspect of the present invention, there is provided a touch probe, comprising: storage means for storing coordinate position data of each of the plurality of styluses; and a probe center based on the stylus coordinate position data determined by the determination means. Correction means for correcting the coordinates.

Further, the touch probe according to the third aspect of the present invention has a stylus selecting means for validating only coordinate position data acquired by a specific stylus among the styluses determined by the determining means.

[0012]

According to the first aspect of the present invention, as described above,
Since there is provided a discriminating means for discriminating which stylus of the plurality of styluses has contacted based on the contact detection signal from the stylus, the stylus that has contacted the measurement object can be automatically discriminated.

According to the second aspect of the present invention, relative positional relationship data of a plurality of styluses is stored in advance, and the relative positional relationship data is used as coordinate position data acquired by the stylus determined this time. By performing the correction, the data can be converted into coordinate position data using a stylus as a reference, so that the coordinate position of the measurement target can be automatically and accurately determined.

Further, according to the third aspect of the present invention, since there is provided a stylus selecting means for validating only the coordinate position data acquired by a specific stylus, it is determined whether the contact detection signal is from the specified stylus. It is possible to automatically determine whether or not a contact detection signal from an unspecified stylus is mistakenly recognized as being from the specified stylus, and prevent measurement.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an entire configuration of a touch probe according to one embodiment of the present invention. The touch probe accesses and contacts the measurement object (work),
A touch probe main body 1 for outputting the contact signal; an arithmetic control unit (measuring machine main body) 10 for instructing a measurement operation by the touch probe main body 1 and processing the measurement result to obtain a coordinate position of a work; And

FIG. 2 is a side view showing the touch probe main body 1. The touch probe main unit 1 includes a fixing unit 2 and a work detection unit 3. The fixing unit 2 receives a detection signal from the work detection unit 3 and converts the signal into an arithmetic control unit 10.
Output to the side. The work detection unit 3 is connected to a lower end of the fixed unit 2.

The work detector 3 comes into direct contact with the work,
Five styluses 5a to 5e for detecting the contact (FIG. 2)
The middle stylus 5e is hidden and cannot be seen), and the support member 3 for supporting the five styluses 5a to 5e in a predetermined positional relationship.
a. The contact signals of the styluses 5a to 5e are sent from the probe body 2 to the arithmetic and control unit 10 via five signal lines. Although there are five styluses in this embodiment, any number may be used.

FIG. 3 is a sectional view showing the stylus. Since the styluses 5a to 5e have the same structure,
Here, only the stylus 5a will be described, and description of the other styli 5b to 5e will be omitted.

The stylus 5a is composed of a piezoelectric element 52 and a rod-shaped feeler 53 connected to the piezoelectric element 52 via a flange 54. Feeler 53
Consists of a rod 53a connected to the flange 54 and a tip ball 53b provided at the tip of the rod 53a.

The flange 54 is fixed to a support member 56,
The support member 56 is detachably attached to the support member 3a of the work detection unit 3.

The piezoelectric element portion 52 includes an upper portion 52a and a lower portion 52.
The piezoelectric element 57 is sandwiched between the upper part 52a and the lower part 52b. Further, the piezoelectric element 57
It is divided into two layers by the electrode plates 58 and 59. Then, the electrode 59 and the electrodes 58, 58 short-circuited to each other.
When a high-frequency voltage is applied between the piezoelectric element part 52 and the feeler 53, the piezoelectric element part 52 and the feeler 53 act as an ultrasonic vibration horn as a whole and vibrate in the axial direction. In the vibrating state, the tip ball 53
When b touches the work, it reacts sensitively to the contact by an electric circuit (not shown), and a contact signal at that time is sent to the arithmetic control unit 10 side.

The arithmetic control unit 10 shown in FIG. 1 includes a contact detecting circuit (contact detecting means) 11 for outputting various signals to the arithmetic control unit 10, a factor determining circuit (determining means) 12, a counter latch circuit 13, The interrupt generation circuit 14 and the input permission / prohibition switch circuit 15 are connected. Further, a measuring device control circuit 16 is connected to the arithmetic control unit 10, and the measuring device control circuit 16 receives a control signal from the arithmetic control unit 10 and outputs the signal to the touch probe main body 1. The touch probe main body 1 performs a measurement operation based on the control signal.

When any one of the five styluses 5a to 5e comes into contact with the work, the contact signal is transmitted through a signal line corresponding to the contacted stylus to the contact detecting circuit 11 and the factor determining circuit 12. Sent to The contact detection circuit 11 detects the contact signal and sends the detection signal to the arithmetic and control unit 10, the factor determination circuit 12, the counter latch circuit 13, and the interrupt generation circuit 14, respectively.

The factor discriminating circuit 12 includes the contact detecting circuit 1
When the detection signal is received from the stylus 1, the stylus number is recognized, the stylus number is stored, and the data can be read into the arithmetic and control unit 10.

When the counter latch circuit 13 receives the detection signal, it latches the counter coordinates and enables the arithmetic control unit 10 to read data. Further, upon receiving the detection signal, the interrupt generation circuit 14 sends an interrupt signal to the arithmetic control unit 10 and causes the arithmetic control unit 10 to start processing.

The input permission / prohibition switch circuit 15 is connected to a stylus selection switch (stylus selection means) 20, and uses the information on the stylus selected (specified) by the stylus selection switch 20 as a switch signal as a switch signal. Output to Arithmetic control unit 10
Makes only the contact signal from the stylus corresponding to the switch signal the target of the coordinate position calculation. The stylus selection switch 20 includes five switches 21a to 21e corresponding to the styli 5a to 5e and an all stylus switch 22 for selecting all the styli 5a to 5e.
Are provided. These switches are configured as alternate switches.

A stylus relative amount storage circuit 17 is connected to the arithmetic and control unit 10. The stylus relative amount is a relative coordinate value indicating a relative positional relationship between the styluses 5a to 5e, and is necessary for converting a counter coordinate value of an arbitrary stylus into a coordinate value of a reference stylus. The stylus relative amount storage circuit 17 stores the stylus relative amount in advance.

Next, the processing performed by the arithmetic control unit (correction means) 10 when an interrupt signal is received will be described with reference to the flowchart of FIG.

FIG. 4 is a flowchart showing a processing procedure executed in the operation control unit of the touch probe according to the present invention. Upon receiving the interrupt signal, the arithmetic control unit 10 first reads the counter coordinates (measurement machine coordinates) latched at that time into the counter latch circuit 13, and stores the read coordinate values in the position [x, y, z].
And release the latch (step S1).

Next, the stylus number of the stylus to which the contact signal has been sent is read from the cause determination circuit 12 (step S2).

The input permission / prohibition switch circuit 15
Is read, and the currently permitted stylus is recognized by the stylus number (step S3).

Next, it is determined whether or not the permitted styli are all styli, that is, whether or not the stylus selection switch 20 has pressed all the stylus switches 22 (step S4). here,
When all the stylus switches 22 are not pressed and one or a plurality of styluses among the styluses 5a to 5e are selected, the stylus number determined by the factor determination circuit 12 and the input permission / prohibition switch circuit 15 Then, it is determined whether the number matches the stylus number permitted by the user (step S5). If the two do not match, it is determined that the contact signal detected this time is not from the designated stylus, and a predetermined error process is executed.

On the other hand, when the stylus number determined by the factor determination circuit 12 matches the stylus number permitted by the input permission / prohibition switch circuit 15 (when the determination result in step S5 is Yes), and when all styluses are detected. When the switch 22 is pressed (when the determination result in step S4 is Yes), the counter coordinate value input to the arithmetic and control unit 10 is determined to be normal, and is first stored in the stylus relative amount storage circuit 17 in advance. The relative coordinate value inc [x, y, z] of the corresponding stylus is read from the relative coordinate value indicating the relative positional relationship between the styluses (step S6). Then, the count coordinate value position [x, y, z] read in step S1 and the relative coordinate value inc [x, y,
z] is added and corrected, and converted into a coordinate position using a stylus as a reference (step S7). Thereby, the coordinate position of the work is automatically and accurately determined.

Next, the above-described processing procedure will be described with reference to an actual measurement operation example.

FIG. 5 is an explanatory diagram for explaining the processing procedure based on an actual measurement operation. Here, a case is assumed in which, among the five styluses 5a to 5e, four styluses 5b to 5e projecting in the horizontal direction are used to access the cylindrical work 30 and make contact with the work 30.

When the measurement is performed using these four styluses 5b to 5e, in order to make the contact signals from the styluses 5b to 5e effective, the switches 21b to 21e of the stylus selection switch 20 must be pressed beforehand. Alternatively, all the stylus switches 22 are pressed in advance. In this state, for example, when the stylus 5b contacts the workpiece 30,
The arithmetic control unit 10 automatically recognizes that the contact signal is from the stylus 5b, and takes in the counter coordinate value at that time as a valid one. Similar processing is performed when measurement is performed using the other styluses 21c, 21d, and 21e. In this case, the measurement order by the styluses 5b to 5e may be in any order.

When the stylus 5e is erroneously measured while the switches 21b to 21e of the stylus selection switch 20 are pressed in advance, the arithmetic control unit 10 sends the contact signal from the designated stylus. If not, the counter coordinate value at that time is not taken as invalid, and an error can be displayed to notify the operator, for example.

In the stylus selection switch 20, when both the switches 21a and the like and all the stylus switches 22 are pressed, either of them may be given priority.

In the measurement by the conventional touch probe, first, the operator performs a selection operation (designation operation) of the stylus 5b, and then performs a measurement by the stylus 5b.
Subsequently, the same operation is performed with the styluses 5c, 5d, and 5e.
Do about. As described above, in the measurement using the conventional touch probe, it is necessary to select the corresponding stylus before each measurement using the stylus, and the measurement is very complicated. The selection only needs to be performed once using the stylus selection switch 20, and the subsequent measurement may be performed with the stylus in any order, so that the measurement can be performed very smoothly.

In the conventional touch probe, if the measurement is performed with a stylus other than the selected stylus, the measurement result becomes valid. Therefore, an incorrect counter coordinate value is adopted. For example, as described above, the counter coordinate value is invalidated, erroneous measurement can be prevented, and as a result, the reliability of the measurement data can be improved.

[0042]

As described above, according to the touch probe of the first aspect of the present invention, the stylus in contact with the object to be measured can be automatically determined. The operation of selecting a stylus becomes unnecessary, and the measurement can be performed smoothly.

According to the touch probe of the second aspect of the present invention, by correcting the coordinate position data by the current stylus using the relative positional relationship data, it can be converted into the coordinate position data by the reference stylus. , The coordinate position of the measurement object can be automatically and accurately obtained.

Further, according to the touch probe of the third aspect of the present invention, it is possible to automatically determine whether or not the contact detection signal is from a specified stylus, so that a contact detection signal from an unspecified stylus is provided. Can be prevented from being erroneously recognized as being from the specified stylus, and the reliability of the measurement data can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a touch probe according to one embodiment of the present invention.

FIG. 2 is a side view showing a touch probe main body.

FIG. 3 is a sectional view showing a stylus.

FIG. 4 is a flowchart showing a processing procedure executed in an arithmetic control unit of the touch probe according to one embodiment of the present invention.

FIG. 5 is an explanatory diagram for describing a processing procedure based on an actual measurement operation.

FIG. 6 is a perspective view showing a conventional touch probe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Touch probe main body 5a, 5b, 5c, 5d, 5e Stylus 10 Operation control part 11 Contact detection circuit 12 Factor discrimination circuit 13 Counter latch circuit 14 Interrupt generation circuit 15 Input permission / prohibition switch circuit 17 Stylus relative amount storage circuit 20 Stylus selection Switch 21a, 21b, 21c, 21d, 21e Switch 22 All stylus switch

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A 50-126255 (JP, U) JP-A 62-3005 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01B 7/00 G01B 21/00

Claims (3)

(57) [Claims] 1. A touch probe comprising: a plurality of styluses disposed on a probe body so as to maintain a predetermined positional relationship; and a contact detection unit that outputs a contact detection signal when the stylus comes into contact with an object to be measured. 5. The touch probe according to claim 1, further comprising a determination unit configured to determine which stylus of the plurality of styluses has contacted based on the contact detection signal. 2. A storage device for storing coordinate position data of each of the plurality of styluses, and a correcting device for correcting probe center coordinates based on the stylus coordinate position data determined by the determining device. The touch probe according to claim 1, wherein 3. The touch according to claim 1, further comprising a stylus selection unit that validates only coordinate position data acquired by a specific stylus among the styluses determined by the determination unit. probe.