JPS62228905A - Distance measuring instrument - Google Patents

Abstract

PURPOSE:To measure the distance of an object to be measured with high accuracy by providing an observation part to photodetect reflected light at peripheral plural places of a projection part to irradiate the projection light and photodetecting the reflected light with the intense reflected light. CONSTITUTION:The projection light 15 is irradiated on the object 13 to be measured from the projection part 25 and at the same time, a motor 35 is driven to turn a measuring header 23. The photodetected position of the reflected light 17 on the photodetection surface of an optical detecting element 31 and the intensity of the reflected light 17 at the photodetected position are made electrical signals and inputted to a measurement controller 39. This measurement controller 39 drives the motor 35 and turns the measuring header 23 and stops the measuring header 23 at the position where the intensity of the reflected light of the reflected light incident on the observation part 27 is made maximum. In this way, the reflected light with the intense reflected light is photodetected and the photodetected position of the reflected light can be accurately detected by the optical detecting element 31.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a distance measuring device that measures the distance to a measured object by irradiating light onto the measured object.

(Prior Art) A conventional distance measuring device 1 includes a measuring head 3, a laser beam projection section 5, and an observation section 7. The observation section 7 includes an imaging lens 9 and a photodetector element 11. sea 11
Projection light 15 irradiated onto the measurement object 13 from the light projection section 5 is reflected by the surface of the measurement object, and the reflected light 17 passes through the imaging lens 9 and is received by the photodetection element 11. Based on the light-receiving position on the light-receiving surface of the photodetector 11, the distance to the object 13 is measured according to the triangular ril principle.

(Problem that 1 Mei attempts to solve) By the way, in general, the intensity of the reflected light 17 is
) In order to receive the large reflected light of . However, as shown in FIGS. 2 and 3, the projected light 15 may be irradiated to a position that deviates significantly from the normal line 19 and forms a small angle (projection angle α) with the surface of the measurement object 13. In this case, the reflected light intensity 1β varies greatly depending on the angle (reflection angle β) with the surface of the measurement object 13, as shown by curve B in FIG. The reflected light near the surface of the object 13 is the smallest. Therefore, if the reflected light 17 passing through the imaging lens 9 in FIG. 3 is the reflected light 17B near the surface of the measurement object 13 shown in FIG. The detection element 11 may not be able to accurately detect the light receiving position.

Here, since the position of the observation section 7 of the distance measuring device 1 is fixed, when the projected light 15 is irradiated onto the measurement object 13 from a position with a small projection angle α, the light is received by the vA measurement section 7. The reflected light may become reflected light 17B with a small reflected light intensity Iβ. Therefore, in such a case, the photodetecting element 11 may not be able to accurately detect the light receiving position n, and there is a possibility that the distance to the object 13 may not be measured.

Furthermore, since the reflected light intensity Iβ is generally greatly influenced by the surface condition of the object to be measured 13, some of the reflected light 17 interferes with the surface condition of the object to be measured 13. Even when the observation unit 27 receives the reflected light 17 that has interfered in this way, the light receiving position cannot be accurately detected on the light receiving surface of the photodetecting element 11, and it may be difficult or impossible to measure the distance to the object 13. There is.

Furthermore, depending on the distance of the measurement object 13, the lens angle of the imaging lens 9 may not be appropriate. example.

For example, when the object to be measured 13 is at the position indicated by the two-dot chain line in FIG. The reflected light intensity Iβ of the reflected light 17 may become small. As a result, in this case as well, the light-receiving position may not be accurately detected by the photodetecting element 11, and the distance to the object 13 may not be accurately measured.

This invention was made in consideration of the above facts,
It is an object of the present invention to provide a distance measuring device that can measure the distance of an object with high precision by receiving reflected light having a large reflected light intensity.

[Structure of the invention]

(Means for Solving the Problems) The present invention includes a projection unit that irradiates a surface of a measurement object with projection light;
an observation section that receives reflected light from the surface of the object to be measured through an imaging lens and a light detection element, and measures the distance of the object based on the receiving position of the reflected light in the light detection element. In the distance measuring device, the observation section is installable at a plurality of locations around the projection section, and the observation section receives the reflected light at a position where the intensity of the reflected light is large.
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(Function) Therefore, according to the distance measuring device according to the present invention, even when the angle between the surface of the object to be measured and the projected light (projection angle) is small, the reflected light with a large reflected light intensity is received and the light is detected. The element can accurately detect the receiving position of reflected light.

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

FIG. 1 is a block diagram showing a first example of a distance measuring device according to the present invention.

A projection section 25 and an observation section 27 are arranged in the measurement header 23 of the distance measurement device 21 .

The projection section 25 includes a semiconductor laser element and a projection light lens, both not shown, and is provided so that the projection light 15 from the semiconductor laser element passes through the projection light lens and can be irradiated onto the object 13 to be measured.

Semiconductor laser elements are elements that can emit laser beams with wavelengths that are not interfered with by natural light, and this allows the S of measurement to be
The signal-to-noise ratio (SN ratio) is improved.

The observation section 27 includes an imaging lens 29 and a photodetection element 31. A portion of the reflected light 17 reflected by the measurement object 13 is incident on the imaging lens 29 . This imaging lens 2
9 is equipped with a narrow band filter, which cuts out natural light and allows only reflected light 17 to pass through 1! I'm starting to get it. This improves the S/N ratio of measurement. Further, the photodetecting element 31 receives reflected light 17 that has passed through the imaging lens 29 on its light receiving surface. Then, the light receiving position and amount of the reflected light (reflected light intensity Iβ) are detected.

Now, a rotating shaft 33 is formed in the measurement header 23. The axis of this rotating shaft 33 is provided to coincide with the projection light 15 irradiated from the projection section 25 .

A motor 35 is connected to the rotating shaft 33.
, the measurement header 23 is rotated around the projection light 15 via the rotation shaft 33 . Therefore, due to this rotation of the measurement header 23, the observation sections 27 are installed at a plurality of positions around the projection section 25. Even when the measurement header 23 rotates, the relative positions of the projection section 25 and observation section 27 remain unchanged.

Further, the photodetecting element 31 is electrically connected to three measurement control devices via a terminal, for example, a step terminal 37.

This measurement i, IJ tl device 39 is connected to the motor 35 as well. The measurement ai control device 39 receives the light receiving position of the reflected light 17 on the light receiving surface of the photodetecting element 31 and the reflected light intensity ■ρ of the reflected light 17 at the light receiving position as an electric signal.

The function of the measurement control device 39 is to rotate the measurement header 23 by driving the motor 35, and rotate the measurement header 23 at the position where the reflected light intensity ■β of the reflected light incident on the observation section 27 is maximum. It is to stop it. Furthermore, the measurement control device 39 calculates the distance from the light reception position of the reflected light 17 at this stop position to the measurement object 13 based on the principle of the triangular side a, and outputs the value to the outside.

Next, the effect will be explained.

At the same time that the projection light 15 is irradiated from the projection section 25 to the measurement object 13, the motor 35 is driven to rotate the measurement header 23. Therefore, for example, the projection light 1 from the projection section 25
5 deviates from the normal line 19 of the measurement object 13 and is irradiated onto the measurement object 13 at a position with a small projection angle α, the observation unit 27
As shown in the figure, reflected light 17 having a reflection angle β within the range of γ to (2β−γ) can be received. The reflection angle is (2β
The reflected light 17B at the position -γ) has a small reflected light intensity because it is near the surface of the measurement object 13, but the reflected light 17G at the position where the reflection angle is γ is close to the normal line 19, so the reflected light intensity is large. . Therefore, the measurement control device 39
receives reflected light 17G (two points 5r1f in Figure 1)
The rudder 23 is stopped for measurement at position j). and,
The measurement control device 39 detects from the light receiving position of the reflected light 17 received by the light receiving surface of the photodetecting element 31 at this stop position.
The distance to the measurement object 13 is calculated.

Therefore, even when the projection angle α is small, the reflected light can be received at a position where the reflected light intensity Iβ is large, so that the receiving position of the reflected light 17 on the light receiving surface of the photodetecting element 31 can be accurately detected. As a result, the distance measurement viscosity can be improved.

Further, even if interference or the like occurs in the reflected light 17 depending on the surface condition of the measurement object 13, by rotating the measurement header 23, the reflected light 17 can be received at a position where there is no interference. Therefore, regardless of the surface condition of the measurement object 13,
The distance to the measurement object 13 can be measured using a high-precision melon.

Because of the above effects, if this distance measuring device is attached to the tip of a robot, three-dimensional distance can be measured without contact.

Next, a second embodiment will be explained.

In the first embodiment, the measurement header 23 rotates and the observation section 27
are installed at multiple positions around the projection section 25, but in this second embodiment, the projection section 25 and the i! l measurement section 27
The observation unit 27 is placed on a table so as to be slidable. Furthermore, instead of the motor 35, a two-dimensional scanner is used as a driving device for the W measurement section 27, and the observation section 27 is slid on the table by this scanner, and the projection section 27 is moved by the scanner.
An observation section 27 is installably provided around 5. In this case as well, like 1! The measurement control device 39 is controlled by a measurement control device 39 that inputs a signal from the photodetector element 31. Therefore, also in the case of the second embodiment, since the observation section 27 can be installed around the projection section 25, the observation section 27 can receive the reflected light 17 with a large reflected light intensity Iβ.
Distance measurement accuracy can be improved.

The third embodiment is 1. A single observation section 27 is not movable around the projection section 25, but a plurality of observation sections 27 are fixedly installed around the projection section 25. In this case, the observation section 27 may be installed at an equal distance from the projection section 25, or at an unequal distance. In such a third embodiment, among the reflected lights 17 received by the plurality of observation units 27, the reflected lights 15 with a large reflected light intensity are
A signal is input from the l measurement section 27 that receives the light to the measurement υ control device 39, and the distance to the measurement object 13 is calculated by the measurement control device 39 based on this signal. can be measured.

In particular, when a plurality of observation sections 27 are installed at unequal distances from the projection section 25, the range in which the reflected light 17 with a large reflected light intensity ■β is received is expanded, which further improves distance measurement accuracy. can be improved.

In addition, in the first to third embodiments, the imaging lens 29
Although a fixed type lens has been described, it may be provided so that the imaging lens 29 can be rotated as shown by arrow A in FIG. 1 to change the lens angle. This rotation of the imaging lens 29 is achieved by driving a servo motor or the like, for example.
The rotation of the imaging lens is stopped at a position where the lens surface of the imaging lens 29 is perpendicular to the reflected light 17. Specifically, while the imaging lens 29 is rotating, the measurement control device 39 causes the servo motor etc. to stop at the position where the reflected light intensity Iβ of the reflected light 17 received by the photodetecting element 31 becomes maximum. output a signal,
The rotation of the imaging lens 29 is stopped. By rotating the imaging lens 29 in this way, the reflected light 17 can be efficiently incident on the imaging lens 29 even when the measurement object 13 is located at a long distance or a short distance, and the distance Il ! The distance measuring range of the measuring device can be expanded.

Alternatively, the imaging lens 29 may not be rotated, but a plurality of imaging lenses 29 having different lens angles may be installed. At this time, a plurality of photodetecting elements 31 are provided corresponding to each lens, or one photodetecting element 31 is configured to be slidable. Even when using two of these multiple imaging lenses,
Similarly to the case where the lens angle of the imaging lens 29 is variable, the distance measuring range of the distance measuring device can be expanded.

〔Effect of the invention〕

As described above, according to the distance measuring device according to the present invention,
Observation sections that receive reflected light can be installed at multiple locations around the projection section that irradiates the projection light, and the observation section is configured so that the reflected light can be received at positions where the intensity of the reflected light is large. The angle between the measured object or surface and the projected light (projection angle)
Even if the blade is small, it can receive reflected light with a large reflected light intensity, and the photodetector can accurately detect the receiving position of the reflected light, making it possible to measure the distance of the object with high precision. be effective.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a distance measuring device according to the present invention, FIG. 2 is a diagram showing the relationship between projected light and reflected light, and FIG. 3 is a block diagram showing a conventional distance measuring device. be. 13... Measurement object, 15... Projection light, 17... Reflected light, 21... Distance measuring device, 25... Projection unit, 27
...11 measurement section, 29-...imaging lens, 31...
Photodetection element, 33... Rotating shaft, 35... Motor, 3
9...Measurement control device, 1, G...Reflected light intensity.

Claims (1)

[Claims] 1. A projection unit that irradiates the surface of the object to be measured with projected light, and an observation unit that receives the reflected light from the surface of the object through an imaging lens and a photodetector, In the distance measuring device that measures the distance of the object based on the receiving position of the reflected light in the photodetecting element, the observation section is installably installed at a plurality of locations around the projection section, and the observation section is installed at a plurality of locations around the projection section. A distance measuring device characterized in that the distance measuring device is configured such that reflected light can be received by the observation section at a certain position. 2. The distance measuring device according to claim 1, wherein the observation section is rotatably provided around the projection section. 3. The distance measuring device according to claim 1, wherein a plurality of observation sections are installed around the projection section. 4. The distance measuring device according to any one of claims 1 to 3, wherein the imaging lens of the observation section is configured to have a variable lens angle. 5. The distance measuring device according to any one of claims 1 to 3, wherein the observation section is provided with a plurality of imaging lenses having different lens angles.