JPH0319513B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an article detection device using a light projector/receiver for detecting the presence or absence of articles and the amount of the article loaded.

In recent years, computer systems are being introduced to make factories and warehouses unmanned. For example, when trying to control an unmanned crane that transports and takes out goods using a computer, as shown in FIG. Articles such as products manufactured in step 1 are loaded onto a crane 3 and transported from the factory 1 to the warehouse 2. In the warehouse 2, when the goods are seamless pipes, racks 6 for storing seamless pipes 5 are installed in multiple stages on both sides along the traveling rail 4, as shown in FIGS. 2 and 3. . Forks 7 are attached to both sides of the main body of the crane 3, and the seamless pipe 5 is conveyed via the forks 7.
Further, the crane 3 moves up and down via the support column 3a.
Here, the crane 3 is controlled by a computer system, which stores the position where the crane 3 stops in front of each rack 6 in the storage device of the computer system, and also stores the storage state of the seamless pipe 5 in each rack 6. By memorizing
It becomes possible to select a rack 6 that can accommodate the seamless pipe 5 newly transported from the factory 1 by the crane 3. However, if the computer system that controls the above operation malfunctions and another seamless pipe 5 is stored in the rack 6 that has already stored a predetermined number of seamless pipes 5, the seamless pipe may become unloaded, resulting in a serious accident. Connect. Therefore seamless pipe 5
A detector is required to check the presence or absence of the seamless pipe 5 on the rack 6 and the amount thereof before storing the seamless pipe 5 in the rack 6.

The configuration of a conventional detector used for this purpose will now be described.

In FIG. 4, 8 is a detector mounted on a part of the crane 3, and 9, 9, . When the crane 3 equipped with this detector 8 stops at a predetermined position, a light emitting element such as a light emitting diode installed inside each light emitting/receiving section 9 is directed toward a reflecting plate 10 arranged behind the detected position. Light such as infrared rays is projected. Seamless pipe 5 on the optical path
If the light is not present, the light is reflected by the reflecting plate 10, and the reflected light is detected by a light receiving element such as a phototransistor installed in the light projecting/receiving section 9. However, if the seamless pipe 5 is present on the optical path of the light emitted from the light emitting/receiving section 9,
The light that has reached the circumferential surface of the pipe 5 is not reflected and is not detected by the light receiving element. Therefore, by detecting the presence or absence of the reflected light, the presence or absence of the seamless pipe 5 on the rack 6 and its amount can be detected.

However, with this conventional configuration, the presence or absence of the seamless pipes 5 and the amount thereof cannot be detected unless the light is emitted at 1/2 or less of the minimum diameter of the various seamless pipes 5 housed in the rack 6. A large number of light emitting/receiving sections 9 must be installed inside the device 8, which complicates the configuration and increases costs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the conventional art, and aims to provide an apparatus that can detect the presence or absence of an article as well as its position by providing only one light emitting/receiving section.

In order to achieve this object, the article detection device of the present invention includes a reflecting plate disposed behind the detection range, and a light projecting/receiving section having a light projecting element and a light receiving element with optical axes in the same direction. , a driver circuit that instantly turns on the light emitting element every time it receives the control pulse t, an amplifier that amplifies the output of the light receiving element that receives the reflected light, and a synchronous detection that passes the output of the amplifier at the timing that the control pulse t is received. A determination circuit that compares the output of the amplifier that has passed through the synchronous detection circuit with a predetermined level, determines the presence or absence of an article at each timing of generation of the control pulse t, and outputs the result. After the control pulse t is received by the drive motor and its motor drive circuit, the reflection direction with respect to the optical axis of the light emitting/receiving section is radially dispersed and changed by one pitch angle, and a reset control pulse f is applied. It consists of a rotating reflector that returns the reflection direction to the origin position after receiving the light, and a plurality of plane mirrors arranged in an arc shape corresponding to each optical axis that is radially dispersed by one pitch angle from the rotating reflector. , an intermediate reflecting mirror that changes each optical axis to be parallel to the reflecting plate, the control pulse t that determines the timing of detecting the presence or absence of an article by projecting and receiving light and the timing of one-pitch rotation of the rotary reflecting mirror, and a reset timing. The above-mentioned control pulse f is outputted at a predetermined period, and detection data on the presence or absence of an object is received from the determination circuit for all optical axes from the intermediate reflecting mirror to the reflecting plate, and based on this detection data, the detected range is determined. The present invention is characterized by comprising: a control unit that calculates and determines the presence or absence of articles and their distribution; and a display unit that displays the calculation and determination results of the control unit.

The present invention will be described below with reference to one embodiment.

Reference numeral 11 shown in FIG. 5 is an article detection device mounted on the crane 3, etc., and 12 emits light from a light emitting element such as an infrared light emitting diode, and detects the presence or absence of reflected light using a light receiving element such as a phototransistor. A light emitting/receiving section to detect, 13 is its driver circuit, 14 is rotatably arranged on the optical axis of the light emitting/receiving section 12, and is a rotating device that radially disperses and changes the reflection direction with respect to the optical axis of the light emitting/receiving section 12. A reflector, 15 is a driving motor thereof, 16 is a motor drive circuit, and 17 is a mirror that directs each optical axis reflected from the rotating reflector 14 in parallel to a reflector 10 placed behind the detection range. It is an intermediate reflecting mirror that changes the Note that a single arc-shaped reflector (not shown) can be used as the intermediate reflector 17, but it is also possible to use a plurality of plane mirrors 17a, 17a, . . . arranged and fixed in an arc shape as shown in FIG. is practical.

Next, an example of a control circuit for this article detection device 11 will be explained.

In the control circuit 18 shown in FIG. 6, 12 is the light emitting/receiving section consisting of a light emitting element 19, a light receiving element 20, etc., 13 is the driver circuit for driving the light emitting element 19, 15 is the driving motor, and 16 is the driving motor. The motor drive circuit 21 is an amplifier that amplifies the output of the light receiving element 20, and 22 outputs control pulses t and f to control the light emitting/receiving section 12 and the driving motor 15, and also detects the presence or absence of articles and their loading amount. 23 is a synchronous detection circuit that detects the detection signal output from the amplifier 21 using a control pulse t; 24
25 is a determination circuit that determines whether the synchronous detection output exceeds a predetermined level and outputs the result to the control section 22; and 25 is a display section that displays the presence or absence of articles detected and output by the control section 22 and the loaded amount.

In the above configuration, the control unit 22 controls the control pulse t
Each time a single output of
9 lights up instantly. This pulsed light is transmitted through the rotating reflector 1
4. One of the intermediate reflecting mirrors 17, and the reflecting plate 10
projected in the direction. If there is no article 5 on this optical axis and it is not blocked, this pulsed light will be reflected by the reflecting plate 10, and will pass along the same optical axis to one of the same intermediate reflecting mirrors as mentioned above and the rotating reflecting mirror 14. The light returns to the light emitting/receiving section 12 via the light emitting and receiving section 12. In other words, the presence or absence of the article is detected by the light receiving element 20 of the light emitting/receiving section 12 . This detection output is passed through an amplifier 21 to a synchronous detection circuit 23.
Here, the signal is synchronously detected using the same control pulse t, and is input to the control section 22 via the determination circuit 24. The control pulse t is simultaneously output to the motor drive circuit 16, and the motor drive circuit 16 rotates the drive motor 15 by a predetermined amount every time the article detection operation for one optical axis is completed. The direction of reflection relative to the optical axis of the light emitting/receiving section 12 is rotated by one pitch angle. As a result, the plane mirror 17a of the intermediate reflecting mirror 17
The adjacent ones become effective, and the height of the optical axis toward the reflector 10 slides by a fixed pitch.

In this state, when the next control pulse t occurs,
The light emitting/receiving operation of the light emitting/receiving section 12 is performed with respect to this changed optical axis. And after this, rotating reflector 1
4 is rotated by one pitch angle.

Thereafter, the above operation is repeated every time the control pulse t is generated, and eventually each plane mirror 17 of the intermediate reflecting mirror 17
The object detection operation is performed by the light projecting/receiving section 12 for all optical axes extending in parallel toward the reflecting plate 10 from a, 17a, . . . , and the results are left in the control section 22 as detection data. The control unit 22 calculates and determines the presence or absence of the article 5 and its loading amount based on this detection data, and causes the display unit 25 to display the results.

When one detection operation is completed in this way,
The control section 22 sends a control pulse f to the motor drive circuit 16 to perform a reset operation to return the rotary reflecting mirror 14 to its original position.

In the above embodiment, it is better to make the light emitting axis and the light receiving axis of the light emitting/receiving section 12 coincide with each other.
4. Although the intermediate reflecting mirror 17 and the reflecting plate 10 can be made smaller, they do not necessarily have to be made the same size.

The intermediate reflecting mirror 17 according to the present invention can be used in combination with a plurality of plane mirrors 17a, 17a, . . . instead of using a single reflecting mirror having an arc-shaped reflecting surface. When divided in this way, the manufacturing cost is greatly reduced, and since it is possible to attach and adjust each sheet one by one, maintenance management is easy and the practical value is high.

Furthermore, although the above embodiment describes the case of detecting stacked articles, the present invention is effective for all detection applications in which detection is possible using a plurality of parallel optical axes. be.
For example, when articles are placed randomly within a predetermined length, the presence or absence of articles can be detected along with their distribution.

As explained above, according to the present invention, an intermediate reflector, which is composed of a rotating reflector and a plurality of plane mirrors and is inexpensive and easy to install and adjust, is disposed between the light emitting/receiving section and the reflecting plate, and is controlled by the control section. Since the presence or absence of an object is detected sequentially for all optical axis positions while rotating the rotating reflector one pitch angle at a time, only one light emitting/receiving section is used to detect the presence or absence of an object, its position and amount. Can be detected while understanding. Therefore, the article detection device can be provided at low cost.

[Brief explanation of the drawing]

Figure 1 is a schematic plan view of an article storage system using an unmanned crane, Figure 2 is a front view illustrating its storage operation, Figure 3 is a perspective view showing how articles are placed, and Figure 4 is a projection and reception of light. FIG. 5 is a side view showing an article detection device according to an embodiment of the present invention, and FIG. 6 is a block diagram showing its control circuit. 5...Goods, 6...Rack, 10...Reflector,
11... Article detection device, 12... Light emitting/receiving unit, 14
... Rotating reflecting mirror, 17... Intermediate reflecting mirror, 17a...
...Plane mirror.

Claims (1)

[Claims] 1. A reflector placed behind the detection range; a light emitting/receiving section having a light emitting element and a light receiving element with optical axes in the same direction; A driver circuit that instantaneously turns on the light, an amplifier that amplifies the output of the light receiving element that receives the reflected light, a synchronous detection circuit that passes the output of the amplifier at the timing when the control pulse t is received, and an amplifier that has passed through the synchronous detection circuit. A determination circuit that compares the output with a predetermined level and determines the presence or absence of an article at each generation timing of the control pulse t and outputs the output; A drive motor and its motor drive circuit, which is rotatably arranged on the optical axis of the light emitting and receiving section. After receiving the control pulse t, the reflection direction relative to the optical axis of the light emitting/receiving section is dispersed and changed radially by one pitch angle, and after receiving the reset control pulse f, the reflection direction is set to the origin. It consists of a rotating reflector that returns to its position, and a plurality of plane mirrors arranged in an arc shape in correspondence with each optical axis that is radially dispersed by one pitch angle from the rotating reflector, and each optical axis is directed toward the reflector. The control pulse t, which determines the timing of detecting the presence or absence of an object by emitting and receiving light and the timing of one-pitch rotation of the rotary reflector, and the control pulse f, which determines the reset timing, are set at a predetermined period. At the same time, it receives detection data on the presence or absence of an object from the determination circuit for all optical axes from the intermediate reflector to the reflection plate, and calculates the presence or absence of an object in the detection range and its distribution based on this detection data. - An article detection device comprising: a control unit that performs determination; and a display unit that displays calculation and determination results of the control unit.