JPH03154814A - Displacement measuring instrument with output correcting function - Google Patents

Abstract

PURPOSE:To realize a displacement measuring instrument with a output correcting function which takes an accurate measurement even if the surface state of a body to be measured is changed by generating reference data for correction in a calibration mode according to the kind of an object to be measured and correcting a measured value in measurement mode with the reference data. CONSTITUTION:The instrument is constituted of a detector 1 which irradiates the body with light and detects its reflected light and a control part 20 which corrects its detection signal, and the control part 20 is constituted of an amplifying arithmetic part 2 and a correcting arithmetic part 3 and is equipped with a mode changeover switch 12 which switches the measurement mode and calibration mode. In the calibration mode, the quantities of actual positive-directional and negative-directional displacement from a zero-point position and the outputs of the amplifying arithmetic part 2 corresponding to the actual displacement quantities are stored as reference data for correction in an EEPROM 7 previously by using an instrument for adjustment. When a measurement is taken actually in the measurement mode, the measured value is compared with the reference data for correction and corrected, so even if the surface state of the object is changed, the measurement is performed accurately.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a device that non-contactly measures the amount of displacement of an object using light such as a laser. The present invention relates to a displacement measuring device having a function of correcting changes in linearity and deviations in zero point position.

[Conventional technology]

Conventionally, a fuse with two output ends was used to detect the position of a light spot.
A power output device (PSD) consisting of an odd double ode is used. In this position detection element, the ratio of output currents at the two output terminals changes depending on the position of the light spot, and this is used to determine the position of the light spot. When such a position detection element is used to irradiate light onto an object to be measured from a predetermined position, the position at which the reflected light is received changes depending on the displacement of the object, and it is difficult to determine at which position the reflected light is received. A reflective displacement meter is used to measure the displacement of an object. The position detection element used in such a reflection type displacement meter measures the position by the ratio of two output currents, so it is not originally affected by the amount of incident light, but in reality it is not affected by the amount of incident light. If the amount of reflected light changes depending on the surface condition of the object being measured, the ratio of the two output currents will inevitably change, and the linearity and zero point position of the output will change. Therefore, depending on the level of the amount of reflected light, the detector The gain of the amplifier that amplifies the output from the position detection element is manually or automatically switched to an appropriate value to stabilize the linearity of the output and the zero point position.

[Issues to be solved by -]

By the way, even if you correct it by switching the gain of the amplifier, when the amount of reflected light is very large, or conversely, near the limit when the amount of reflected light is always small, the linearity and zero point position will be affected.
There are cases where it is not possible to obtain the same accuracy as under good measurement conditions, and this is especially difficult when the object to be measured has a wide variety of surface conditions depending on its quality, such as refractory bricks. The meter could not be used for firebricks, etc.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a displacement measuring device with an output correction function that can accurately correct even when the surface condition of the object to be measured changes and can easily measure the object. do.

[Means to solve the problem]

The displacement measuring device with an output correction function of the present invention includes a detection section that irradiates light onto an object and detects the reflected light, and a control section that corrects the detection signal.
It is equipped with a mode switching means for switching between measurement mode and calibration mode, a storage means for storing reference data for correction, and a selection means for selecting and reading out the reference data for correction. The present invention is characterized in that the value of the detection signal is stored as correction reference data, and the measured value obtained by switching to the measurement mode is corrected using the correction reference data.

C action] The present invention uses an adjustment device in advance in the cali-play shiran mode to calculate the zero point position, the actual displacement amount in the (+) direction and the (-) direction from the zero point position, and the amplification calculation for each actual displacement amount. The output from the unit is stored in the EEPROM as reference data for correction, and when switching to measurement mode and actually measuring, the measured value is compared with the reference data for correction and the result is calculated. By displaying the determined value and outputting it to the outside, even if the surface condition of the object to be measured changes, it can be accurately corrected and measurements can be made easily.

〔Example〕

Examples will be described below.

FIG. 1 is a block diagram showing a schematic configuration of a displacement measuring device according to the present invention. In FIG. 1, l is a detector, 2 is an amplification calculation section, 3 is a correction calculation section, 4 is an A/D converter, and 5 is a ROM, 6 is RA
M, 7 is EEPROM, 8 is external output interface, 9 is external output connector, IO is CPU, 11 is correction data selection switch, 12 is mode changeover switch, 1
3 is a switch, 14 is a switch ink face, 15 is a display, 16 is a display interface, 17 is a measurement surface,
18 is a light projection center line, 19 is a projection/light receiving surface, and 20 is a control section.

This measuring device is composed of a detector 1 and a control section 20, and the control section 20 is composed of an amplification operation section 2 and a correction operation section 3. The detector l and the amplification calculation section 2 are constructed by using a commercially available general-purpose analog output type optical non-contact displacement meter, incorporating a correction calculation section 3 for correcting the analog output, and after the correction processing. It is designed to be displayed and output externally.

The detector 1 and the amplification calculation unit 2 can be of an analog output type or a digital output type by changing the input part of the correction calculation unit 3.

The correction calculation unit 3 includes an A/D converter 4 that converts the analog output from the amplification calculation unit 2 into a digital signal, a ROM 5 that stores a CPU processing program, a RAM 6 that temporarily stores data during correction processing, and a correction It has an EEPROM 7 for storing reference data used for the measurement, an interface 8 for outputting the corrected measurement value to the outside, and a connector 9 thereof, and a CPU 101 for controlling each element. A switch 11 to select according to the type of measurement, a switch 12 for switching between measurement mode and calibration mode, a switch 13 for calibration mode, an interface 14 between each switch and CPU10, a display 15 for displaying the corrected measured value, and a display. 15 and an interface 16 for cpulo.

In such a configuration, first, before measurement, the actual displacement amount and the output from the amplification calculation section 2 at each actual displacement amount are created as reference data for correction using an adjustment instrument (not shown). do.

The user presses the calibration side button of the mode changeover switch 12 on the front panel of the control unit 20 that houses the amplification calculation unit 2 and correction calculation unit 3, and then selects the type of measurement target using the correction data selection switch 11. After that, press the calibration mode switch 13,
0 is displayed on the display 15, and in this state, the displacement meter is set in the adjustment tool so that the light emission center line 18 of the detector 1 is perpendicular to the measurement surface 17 of the object to be measured.

Next, use an adjustment tool to adjust the distance between the measurement surface 17 and the light emitting/receiving surface 19 so that it is close to the reference distance of the displacement meter. When it is desired to match the zero point position, the distance between the measurement surface 17 and the light emitting/receiving surface 19 is matched to the reference distance with the necessary accuracy, and that position is set as the true reference distance, that is, the zero point position.

When the calibration mode switch 13 is pressed again, the A/D converted value of the output from the amplification calculation section 2 at that time is stored in the data storage area of the zero point position in the EEPROM 7 for storing reference data for correction, and the The next reference data creation position stored in the ROM 5 is displayed.

In this way, in the calibration mode, a method is adopted in which the position from which the next correction reference data is created is indicated, and the position from the true reference distance is indicated on the display 5, simplifying the operation. It is now possible to

When the next correction reference data creation position is displayed, the adjustment tool sets the distance between the measurement surface 17 and the light emitting/receiving surface 19 of the detector l to the true displacement position that is displaced from the true reference distance by the displayed value. When the calibration mode switch 13 is pressed, the A/D converted value of the output from the amplification calculation section 2 at that time is stored in a predetermined data storage area in the EEPROM 7, and the display 15 displays the value for the next correction. The reference data creation position is displayed.

Thereafter, similar operations are repeated, and the true displacement from the true reference distance and the A/D converted value of the output from the amplification calculation section 2 at that time are created and stored as correction reference data according to the type of measurement target. be done. The number and interval of reference data creation positions are set in the correction calculation section 3 according to the specifications and required accuracy of the detector 1 and the amplification calculation section 2 to be used.

When the creation of the reference data for correction is completed in this way, measurement becomes possible. Note that since the correction reference data is stored in the EEr'ROM, it can be rewritten as appropriate.

Next, a correction method during measurement will be explained.

Press the measurement side button of the mode changeover switch 12 on the front panel of the control unit 20, select the one corresponding to the surface to be measured from the reference data selection switch 11, and receive the detection signal from the detector 1 during actual measurement. is the amplification calculation section 2
The signal is inputted to the correction calculation section 3 via the A/D converter 4, and taken into the CPU10 through the A/D converter 4. The CPU 10 searches the reference data based on the obtained value, and searches for two values closest to the measured value among values larger and smaller than the measured value.

That is, the value obtained by measurement is as, the correction reference data is the closest value greater than or equal to the measured value as al, the closest value less than or equal to the measured value is a'=, and from the true reference distance corresponding to a'l. The distance of A+, the true criterion I corresponding to am! Assuming that the distance from the distance is A, the value A. corrected by the measurement value correction calculation section 3 is derived by the following equation.

The results are output to the display 15 and external output interface 8. Note that in the above correction method, the correction was performed linearly by the ratio of the two sets of values of the reference data obtained in the calibration mode and the measured value, but it is also possible to use various correction methods such as curve correction.

As an example, a light source: a laser diode with a wavelength of 7 Bon-, a spot diameter at a reference distance? 0.4X 1゜4■
, reference path 111: 40mm, measurement range: 1s semi-distance fl.

Peng, resolution? 12bit, response: 20m5ec A/D transformer, CPU: Z80A, / -1=
IJ-:RO? 132j [B.

When the displacement diameter of the present invention was configured with R18KB, EERROMo, and 5KB, resolution of 410 μm, 927 retweet error: ±20 μm, response: 50 m5ec, and output voltage ±5V/±10− were obtained.

Next, the measurement characteristics of the displacement meter according to the present invention will be explained in comparison with a conventional reflective optical non-contact displacement meter having the same specifications.

FIG. 2 is a diagram showing errors with respect to each displacement of the present invention and a conventional example when measuring white shaped refractories after firing.

For white measurement objects, -
According to Figure 2, in the present invention, the measurement target is 10.02 to 0.01 m.
, the conventional example has an error of -0.02 to 0.05-, showing approximately the same linearity.

FIG. 3 is a diagram showing errors for each displacement of the present invention and a conventional example when measuring a dark brown shaped refractory after firing.

In general, black-colored measurement objects are said to have a small amount of reflected light from the measurement surface in a reflective optical displacement meter, and have a large measurement error.
01 to 0.01m, and the conventional example had an error of -0.19 to 0.1m, which shows that the linearity of the conventional machine has changed considerably compared to the case shown in Figure 2. The present invention shows linearity equivalent to that obtained when measuring a white shaped refractory after firing.

〔Effect of the invention〕

As described above, according to the present invention, reference data for correction is created in the calibration mode according to the type of measurement target, and the measured values obtained in the measurement mode are corrected using the reference data. Objects to be measured in various states can be measured with high precision using the displacement needle of the present invention by switching the correction reference data selection button. Further, in the present invention, commercially available devices with simple structures and functions can be used for the detection section and the amplification/operation section, so that they can be constructed at low cost.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the schematic configuration of the displacement measuring device of the present invention, Figure 2 is a diagram showing comparative measurement results of the present invention and the conventional method for fired products of white shaped refractories, and Figure 3 is dark brown. FIG. 3 is a diagram showing a comparison result between the present invention and a conventional example of fired products of shaped refractories. l...Detector, 2...Amplification calculation section, 3...Correction calculation section, 7...EEPROM, 10-...CPU, 11
. . . Correction data selection switch, 12 . . . Mode changeover switch, 15 . . . Display device, 19 .

Claims (5)

[Claims] (1) Consisting of a detection section that irradiates light onto an object and detects the reflected light, and a control section that corrects the detection signal, the control section includes a mode switching means for switching between measurement mode and calibration mode, and a correction section. A storage means for storing reference data and a selection means for selecting and reading correction reference data are provided, and each actual displacement and the value of a detection signal for each actual displacement are stored in advance as correction reference data in a calibration mode, A displacement measuring device with an output correction function, characterized in that a measurement value obtained by switching to a measurement mode is corrected using reference data for correction. (2) The displacement measuring device with an output correction function according to claim 1, wherein the storage means comprises an EEPROM. (3) Correction using reference data is characterized by correction using a reference value that is closest to the measured value obtained in the measurement mode and is larger than the measured value, a smaller reference value, and an actual displacement corresponding to these values. A displacement measuring device with an output correction function according to claim 1. (4) The displacement measuring device with an output correction function according to claim 1, wherein when in the carburetion mode, a position at which correction reference data will be created next is displayed. (5) The displacement measuring device with an output correction function according to claim 1, wherein the reference data for correction is created and stored for each type of object to be measured.