JP2595342B2 - Laser measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a laser measuring apparatus, and in particular, a measurement object (work) that flows continuously by conveyor conveyance, extrusion, and the like.
The present invention relates to a laser measuring device for measuring dimensions such as a diameter of a laser beam based on scanning of a laser beam.

[Conventional technology]

In a conventional laser measuring apparatus, as shown in FIG. 5, a work 30 (for example, a needle pin) is continuously moved between a light projecting unit 10 and a light receiving unit 20 of a laser beam. In some cases, dimensions and the like are measured based on scanning of the laser beam L.

The laser measuring device has an edge detection sensor 40, and when the edge detection sensor 40 detects the position of the tip of the work 30, the diameter of the work 30 is measured.

[Problems to be solved by the invention]

However, the above-mentioned conventional laser measuring device requires a separate edge detection sensor 40, which increases the cost, and also requires that the mounting position of the edge detection sensor 40 be set every time the work length changes. There is a problem that it does not. Further, it is difficult for the edge detection sensor 40 to detect the edge of the work that flows continuously (when the rear end of the preceding work comes into contact with the front end of the following work).

The present invention has been made in view of such circumstances, and provides a laser measuring apparatus capable of measuring a dimension of a predetermined position of a measurement object without requiring another sensor for detecting an edge or the like of the measurement object. The purpose is to:

[Means to solve the problem]

In order to achieve the above object, the present invention provides a laser measurement method in which an object to be measured is continuously moved between a light projecting part and a light receiving part of a laser beam, and the dimension of the object is measured based on the scanning of the laser beam. In the apparatus, setting means for setting in advance a set value different from the original dimension of the object to be measured by a certain value or more,
A comparing unit that compares the measured value with a preset set value and outputs the comparison result; and whether the measured object is transferred to a predetermined reference position based on an output of the comparing unit. And a means for starting the original dimension measurement of the measured object after the measured object moves by a predetermined amount after the measured object reaches the reference position.

[Action]

According to the present invention, the dimensions of a continuously moving object to be measured are sequentially measured based on laser beam scanning, and a predetermined reference position such as an edge position of the object to be measured is detected from the measured value. That is, a set value different from the original dimension of the measured object by a certain value or more is set in advance, and the set value is compared with the sequentially measured values. Based on the comparison result, the measured object is moved to a predetermined reference position. Is determined. Then, after the measurement object moves by a predetermined amount after reaching the reference position, the original dimension measurement of the measurement object is performed.

〔Example〕

Hereinafter, a preferred embodiment of a laser measuring apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an overall configuration diagram of a laser measuring device according to the present invention. As shown in FIG.
The measuring section 100 mainly includes a light emitting section including a semiconductor laser 102, a polygon mirror 104, a collimator lens 108, and a light receiving section including a light receiving lens 110, a light receiving element 112, and the like. I have.

The laser light oscillated from the semiconductor laser 102 in the light emitting section is reflected by a polygon mirror 104 rotating at a constant speed and then emitted as a parallel light by a collimator lens 108. That is, the light emitting part is a polygon mirror
A laser beam is emitted so as to scan a predetermined scanning area for one surface of each 104.

The laser light projected as described above is
The light is condensed on the light receiving element 112 via 110, and is photoelectrically converted here. Therefore, the measured object (work) 120 is placed in a predetermined scanning area.
Is positioned, the laser beam is cut off according to the outer shape of the work 120, and the light receiving element 112 outputs an electric signal corresponding to the brightness of the light. Reference numerals 114 and 116 denote glass windows for protecting the lens, respectively, and 118 denotes a light receiving element for synchronization which outputs a signal for each scan.

On the other hand, the controller unit 200 mainly includes a central processing unit (CPU) 202, a clock pulse generator 204, a counter 206,
It comprises a gate circuit 208, an edge detector 210, a storage device 220 and the like.

The controller unit 200 includes the light receiving element 112 of the measuring unit 100.
The dimension is measured by calculating the length of time during which the shadow of the laser beam that scans the workpiece 120 is generated based on the electric signal applied from the computer.

That is, the edge detector 210 outputs a pulse signal to the gate circuit 208 at the time of rising and falling of the electric signal according to the brightness of the light applied from the light receiving element 112.

When a pulse signal is applied from the edge detector 210, the gate circuit 208 opens the gate during that time.

The clock pulse generator 204 outputs a high-speed clock pulse to the gate circuit 208, and the counter 206 counts this clock pulse and outputs a signal indicating the counted value to the CPU 202. The CPU 202 calculates the length of time during which the shadow of the work 120 is generated based on the count value of the counter 206 at the time of scanning each edge position of the work 120 input from the gate circuit 208, thereby obtaining the dimension (outside) of the work 120. Diameter).
Since the laser beam scans the work 120 at a constant speed, the length of time during which the shadow of the work 120 is generated corresponds to the outer diameter of the work 120. In addition, multi-sided polygon mirror 1
The outer diameter of the work 120 is measured for each surface of 04, that is, for each scan. Usually, a plurality of predetermined times of measurement are performed, and the average value is taken to improve the measurement accuracy. .

The measured value measured in this way is displayed on the data display unit 214.
Will be displayed.

 Next, details of the measurement of the work diameter will be described.

FIG. 2 is a configuration diagram of a main part of the controller unit 200 shown in FIG. In the figure, the setting device 250 includes a work 120
For example, a value smaller than the outer diameter of by about 0.1 mm is preset as a set value, and this set value is applied to the input A of the comparator 252. On the other hand, the other input B of the comparator 252 has 1
A measurement of the workpiece 120 for each scan is added.

The comparator 252 compares the above two inputs. When the measured value is larger than the set value (A ≦ B), the comparator 252 outputs an H level signal to the gate circuit 254, and when the measured value is smaller than the set value (A > B), an H level signal is output to the gate circuit 256. A pulse signal STOP (see FIG. 4 (A)) generated for each scan is applied to the other inputs of the gate circuits 254 and 256, and the gate circuits 254 and 256 satisfy the AND condition of two inputs each. Then, L level pulse signals OK and NG are output (see FIGS. 4B and 4C).

The pulse signal OK is applied to the set input S of the flip-flop 262 and to the gate circuit 260 via the inverter 258. The pulse signal NG is applied to the reset input R of the flip-flop 262 via the gate circuit 264 and the inverter 266. Then, the flip-flop 262 is set when the pulse signal OK falls, and reset when the pulse signal NG falls,
Q (see FIG. 4 (D)) is a one-shot circuit 268.
Is added to

One-shot circuit 268 outputs an L-level pulse signal to set input S of flip-flop 270 when the input signal falls, flip-flop 270 is set by the pulse signal, and outputs an H-level signal from output terminal Q to a gate circuit. The signal is output to 260 (see FIGS. 4 (E) and 4 (F)). The flip-flop 270 inputs a pulse signal for starting measurement of the original work diameter output from an inverter 278 described later to a reset input R, and is reset when the pulse signal falls (FIG. 4 ( F),
(H)).

The counter 272 is reset when a signal for resetting the flip-flop 262 or an output signal when the flip-flop 270 is reset is applied through the gate circuit 274, and when a pulse signal is applied from the gate circuit 260, the pulse is reset. The number is counted (see FIG. 4 (G)).
The output of the fourth bit QD among the output bits QA, QB, QC, and QD of the counter 272 is applied to the gate circuit 276.

The pulse signal STOP is applied to the other input of the gate circuit 276, and the gate circuit 276 outputs an L-level pulse signal when the AND condition is satisfied. This L-level pulse signal is inverted via the inverter 278, and is output as a pulse signal to start measuring the original work diameter.

As described above, the flip-flop 270 is reset by this pulse signal, and the counter 272 is accordingly reset.
Is also reset, the inverter 278 outputs one pulse signal.

Next, the operation of the circuit shown in FIG. 2 will be described with reference to FIG. 3 and FIG.

As shown in FIG. 3, the workpiece 120 is sent out continuously and at a predetermined speed to the laser measuring device shown in FIG. The end face of the work 120 is chamfered.

Now, consider a case where the chamfered portion of the work 120 is scanned by the laser light. In this case, the pulse signal NG is output from the gate circuit 256 because the measured value for each scan is smaller than the set value set by the setter 250. This pulse signal NG is output from the gate circuit 264 and the inverter 2
In addition to the reset input R of the flip-flop 262 through 66, the flip-flop 262 is reset, and the reset input R of the counter 272 through the gate circuit 274 to reset the counter 272 (FIG. 4C).
(See (D) and (G)).

Thereafter, when the measured value for each scan becomes equal to or greater than the set value (time t ₁ ) as the workpiece 120 moves, a pulse signal OK is output from the gate circuit 254, and the flip-flop 262 is set by the pulse signal OK. (Fig. 4 (B),
(D)).

When the flip-flop 262 is set, a pulse is output from the one-shot circuit 268, and the pulse sets the flip-flop 270 (FIG. 4E).
(F)). When the flip-flop 270 is set, the counter 272 can count.

When the count value of the counter 272 reaches a predetermined value (8 in this embodiment), the output of the fourth bit QD becomes H level (FIG. 4 (G)). Is added to Then, at time t _2, the pulse signal STOP is applied to the other input of the gate circuit 276,
The AND condition is satisfied, and the gate circuit 276 outputs the pulse signal (L
Level signal). This pulse signal is
It is inverted at 278 and output as a pulse signal for starting the measurement of the original work diameter (see FIG. 4 (H)).

That is, when the measured value is equal to or greater than the set value, since it is not at the position where the chamfered part of the work 120 has been removed yet, it is further scanned a predetermined number of times, and when it is surely at the work outer diameter position, Measurement is performed a predetermined number of times, and an average value thereof is taken to measure the original work diameter.

On the other hand, a plurality of portions of the workpiece 120 in the case of measuring the outer diameter of the flip-flop 262 via the gate circuit 264 and an inverter 26 a Pasuru signal STAT at time t ₃ after a predetermined time from the time t ₂ of the first measurement Add to reset input R (4th
FIG. (I).

The flip-flop 262 is reset by the above signal input, and thereafter a pulse signal applied to the set input S
Set by OK. And flip-flop 26
When 2 is set, the one-shot circuit 2
From 68, a pulse is output to the set input S of the flip-flop 270, and the flip-flop 270 is set again.

As a result, the counter 272 starts counting again, and after an elapse of a predetermined time, when the H level signal is output from the fourth bit QD, a pulse for starting the measurement of the original work diameter from the inverter 278 in the same manner as described above. A signal is output.

In the same manner, work diameters at a plurality of positions of the work 120 are measured. The measurement end time t ₄ varies depending on the number of measurement points of the workpiece 120. Further, even after the measurement is completed, scanning by laser light is executed to start measurement of the next work.

Then, the pulse signal NG is obtained by scanning the chamfered portion of the work.
There the output flip-flop 262 is reset (time t _5), the subsequent pulse signal OK is outputted flip-flop 262 is set (time t _6). Thus, in the same manner as described above, the measurement of the diameter of the next work is started at time t ₆ after a predetermined time has elapsed by count in counter 272.

In the present embodiment, after the flip-flop 270 is set, the work diameter is measured after a predetermined time has elapsed by counting by the counter 272.However, the present invention is not limited to this. For example, a means for detecting the moving amount of the work may be provided. After the flip-flop 270 is set, the work diameter may be measured when the work moves by a predetermined amount.

Needless to say, the measurement according to the present invention can be applied even when the front and rear ends of each work are moving away from each other. Further, in the present embodiment, the chamfered portion at the end of the work is detected, and the diameter of the predetermined position of the work is measured with reference to the position of the chamfered portion. The dimension of an arbitrary position of the stepped work may be measured with reference to the position. In this case, the set value is used to detect the step on the stepped workpiece.
Set the value to the middle value of the workpiece diameter before and after the step.

〔The invention's effect〕

As described above, according to the laser measuring apparatus according to the present invention, a predetermined reference position such as an edge of an object to be measured is detected based on the dimension measuring function of the apparatus itself, so that the reliability of detecting the reference position is high. Further, another sensor for detecting the edge of the measured object or the like is not required. Further, it is possible to measure a dimension at an arbitrary position separated from the reference position of the object by a predetermined distance, and to easily cope with a case where the length of the object changes.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing one embodiment of a laser measuring device according to the present invention, FIG. 2 is a main portion configuration diagram of a control unit shown in FIG. 1, and FIG. 3 is a laser measuring device according to the present invention. FIG. 4 is a plan view showing an example of a measured object, FIG. 4 is a timing chart of signals of respective parts in FIG. 2, and FIG. 5 is a plan view showing an example of a conventional laser measuring apparatus. 100: measuring unit, 200: controller unit, 250: setting unit, 252: comparator, 262, 270: flip-flop, 2
72 …… Counter.

Claims (1)

(57) [Claims] 1. A laser measuring apparatus for continuously moving a measured object between a laser beam projecting portion and a light receiving portion and measuring a dimension of the measured object based on scanning of the laser beam. Setting means for presetting a set value different from the original dimension to be measured by a certain value or more, and comparing means for comparing the measured value with a preset value and outputting the comparison result Means for judging whether or not the measured object has been transferred to a predetermined reference position based on an output of the comparing means; and after the measured object has reached the reference position, measurement is performed after the measured object has moved by a predetermined amount. Means for starting an original dimension measurement of an object.