JPH02116706A - displacement measuring device - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a displacement measuring device using an optical position detection element.

[Conventional technology]

Conventional literature on this type of displacement measuring device includes: (1) Application of PSD in position measurement: Kurasawa, O.: Precision Machinery, 51/4/1985, p.68 (2) Laser displacement meter and its application: Yorio Ikenaga 2 Automation Technology, 19-11, P4
3:1987, etc., and (3) Japanese Patent Application Laid-Open No. 61-88087 regarding application to laser processing equipment.

These are triangular sensors using optical position detection elements (eg PSD). A method for non-contact measurement of the displacement of an object using the #Jffi method and an example of its application are shown.

[Problem to be solved by the invention]

With conventional technology, changes in the output of the photodetector due to differences in reflection characteristics due to the surface properties of the object to be measured are either included in the error range or the intensity of the spot light to be irradiated is adjusted. None of them only provide an adjustment circuit, but do not correct the detected position by taking into account differences in reflection characteristics, and none of them deal with changes in the detection position due to differences in reflection characteristics. do not have.

However, depending on the degree of accuracy required of the displacement measuring device, this change in output may become a factor that makes it impossible to satisfy the required accuracy.

The present invention has been made in view of the above circumstances, and its first object is to determine the "displacement-output" of the optical position detection means for each type of IIFJ treasure.

It is an object of the present invention to provide a displacement (nl) determination device that can automatically perform correction by storing characteristics and determining the type of an object to be measured, and can perform displacement 11 determination with high accuracy.

A second object of the present invention is to attach a material that makes the reflection characteristics uniform to the object to be measured, and to keep the reflection characteristics constant for all objects to be measured, thereby reducing the "displacement".
It is an object of the present invention to provide a displacement measuring device that has uniform output characteristics and can measure displacement with high accuracy.

[Means and effects for solving the problem] In order to achieve the above-mentioned first object, the present invention provides a light position detection means that outputs an electrical signal corresponding to the position of an imaged light spot, and Changes in the "displacement-output" characteristics due to differences in the reflection characteristics of the surface of the fixed object detected by the detection means are calibrated and stored in advance for each type of object to be measured, and the type of object to be measured is determined at the time of measurement. By doing so, the configuration includes a processing means for outputting a correction value.

Then, by determining the type of object to be measured, correction is automatically performed based on the stored contents of the "displacement-output" characteristics of the optical position detection means for each type of object to be measured.

Moreover, in order to achieve the above-mentioned second object, the present invention has the following features:
A material attachment means for applying a material to the surface of the object to be measured to make the reflection characteristics uniform; a detection means for converting the displacement of the object to position information on an optical position detector; and a detection means for converting the displacement of the object to position information on an optical position detector; The structure includes a processing means for converting the signal into an electrical signal and outputting it to the outside as an electrical signal.

Then, a material that makes the reflection characteristics uniform was attached to the treasure to keep the reflection characteristics constant for all objects to be measured, thereby making the "displacement-output" characteristics uniform.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

As shown in FIG. 1, the displacement measuring device is equipped with a detection head 1 which is a detection means. P.S.D.

CCD, etc.) 4-.

The output side of the optical position detector 4 is connected to the input side of the processing circuit 5, and the processing circuit 5 is configured to receive input for determining the fixed object 1111, and the processing circuit 5 has a memory. 6 are connected, and these constitute a processing means. The memory 6 stores the outputs of the optical position detector 4 for various objects to be measured based on calibration results or external data.

Next, the operation will be explained.

With respect to the displacement from a previously known reference position A,
The output value of the optical position detector 4 is stored in the memory 6 by the processing circuit 5 as a calibration value depending on the type of the object to be measured.
(The format of memory can be decided arbitrarily).

During actual Δ-1 regularization, the type of the object to be measured 14111 is first identified, and the processing circuit 5 retrieves the data of 7% of the object to be measured of the same type from the memory 6 according to the output of the optical position detector 4, and calculates the displacement. Calculate quantities.

The calculation result is output as an electric signal value that corresponds one-to-one with the displacement amount port. The slope of this correspondence is arbitrary and may be determined depending on the required accuracy or ease of handling the data.

The conversion calculation into the displacement amount in the processing circuit 5 is performed by hardware or software using the triangular 311 ffi method and an approximation formula according to the required accuracy. The optical position detector 4 may be selected from one-dimensional PSD, CCD linear sensor, etc. depending on the required characteristics.

The identification of the type of object to be measured may be input manually at the operator's discretion, or may be performed using an appropriate sensor. As for the processing means, if there are only a few types of objects to be measured, the memory 6 may not be used, and arithmetic circuits may be prepared in hardware according to the types, and correction calculations may be performed by selecting the circuits.

As described above, according to the present invention, the conventional optical position detector 4
The displacement n1 constant determined by the triangulation method can be highly accurate without being influenced by the surface properties of the object to be measured.

Furthermore, if the -degree calibration is performed, corrections can be made for the same type of object to be measured according to the memory contents, which is effective in factory lines where random objects to be inspected are flowing.

Note that in the present invention, a similar change in output can be obtained with respect to the inclination of the surface of the object to be measured, that is, a change in inclination, so that inclination measurement can be performed using the same means as the above-mentioned displacement n1 constant. Therefore, it can be expected to be applied to fields such as three-dimensional measurement to measure the shape of an object, or three-dimensional processing that always faces the physical property and maintains a constant distance.

FIG. 2 shows another embodiment of the invention. In this embodiment, by coating or spraying a material (for example, MgO, etc.) that increases the diffuse reflectance on the surface of the object to be measured, the reflection characteristics are kept constant for all objects to be measured. output"
To make the characteristics uniform and to measure displacement with high accuracy.

That is, a material that makes the reflection characteristics uniform is coated or sprayed using the sprayer 7 on the surface of the object 7I-1.

Next, the detection head 1 converts the displacement of the object n1 into position information on the optical position detector 4, and sends it to the processing circuit 5.

The processing circuit 5 converts the position information from the optical position detector 4 into a displacement amount and outputs it to the outside as an electrical signal.

If there is a problem if the material applied (or sprayed) remains on the surface of the object A111 after the measurement, it is removed by a remover 8.

Note that the above series of procedures may be combined with a device that transports the object to be measured.

Furthermore, the thickness of the material applied (or sprayed) on the surface of the object to be measured needs to be controlled in the case of measurements that require precision.

As described above, according to the present invention, the displacement measurement by the triangulation method using the optical position detector 4 can be made highly accurate because the reflection characteristics are kept constant without being affected by the surface properties of the object to be measured. .

Further, since the material applied or sprayed increases the diffuse reflectance, the z1 difference becomes small even if the object 4p1 constant C is inclined.

Furthermore, since a function for attaching and removing a material for diffuse reflection is only added to the displacement determining device using the optical position detector 4, the accuracy can be improved with a simple modification.

〔Effect of the invention〕

As described in detail above, the displacement measuring device according to the present invention includes an optical position detecting means that outputs an electrical signal corresponding to the position of an imaged optical spot, and a surface of a workpiece detected by the optical position detecting means. Changes in “displacement-output” characteristics due to differences in reflection characteristics of /I? The present invention is characterized by comprising a processing means for main storing calibration information for each type of constant object and outputting a correction value by determining the type of the object to be measured during measurement.

Therefore, by determining the type of object to be measured, the "displacement-output" characteristics of the optical position detection means for each type of object to be measured are automatically corrected based on the stored contents, and displacement measurement can be performed with high precision. Can be done.

The present invention also provides a material adhering means for adhering a material that makes the reflection characteristics uniform on the surface of an object to be measured, a detecting means for converting the displacement of the object to position information on an optical position detector, and a detecting means. The apparatus is characterized in that it includes a processing means for converting the position information into a displacement amount and outputting it to the outside as an electric signal.

Therefore, by attaching a material that makes the reflection characteristics uniform to the object to be measured and keeping the reflection characteristics constant for all objects to be measured, the "displacement-output" characteristic can be made uniform and the displacement δ91 can be determined with high precision. Can be done.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the configuration of one embodiment of the present invention, and FIG. 2 is an explanatory diagram of the configuration of another embodiment of the invention. 1 is a detection head, 2 is a light projection source, 4 is an optical position detector, 5 is a processing circuit, and 6 is a memory.

Claims (2)

[Claims] (1) An optical position detection means that outputs an electrical signal corresponding to the position of the imaged optical spot, and a "displacement" caused by the difference in reflection characteristics of the surface of the object to be measured detected by this optical position detection means.
Displacement measurement characterized by comprising a processing means for calibrating and storing changes in output characteristics for each type of object to be measured in advance and outputting a correction value by determining the type of object to be measured during measurement. Device. (2) A material attachment means for applying a material to the surface of the object to be measured to make the reflection characteristics uniform, a detection means for converting the displacement of the object to position information on the optical position detector, and position information from the detection means. 1. A displacement measuring device comprising processing means for converting the amount of displacement into an amount of displacement and outputting it to the outside as an electrical signal.