JP3055714B2 - Photoelectric switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detecting light emitting element for projecting a pulse light having a predetermined period into a detecting area, a detecting light receiving element for receiving incident light from within the detecting area, and a detecting element for detecting the light. The present invention relates to a photoelectric switch having control means for detecting an object in the detection area according to a light receiving signal from a light receiving element.

[0002]

2. Description of the Related Art Conventionally, as this kind, for example,
A light emitting element projects pulse light into a predetermined detection area, detects the light that is reflected by an object in the detection area and is incident on the light receiving element, and detects the light in the detection area based on the received light signal. There is a configuration that detects the presence or absence of an object.

[0003] Such a photoelectric switch is mounted, for example, on an automatic guided vehicle moving in a factory or the like, and is used for detecting whether there is an obstacle in the traveling direction to prevent an accident due to a collision.

[0004]

Generally, in such a photoelectric switch, an object detection condition for changing an object detection distance or a width of a detection area or the like in accordance with a use condition. There is provided an adjustment unit for changing the value, and for example, there is an adjustment unit which is adjusted by an adjustment volume provided on the main body side.

However, in the case of a configuration in which a volume is provided on the main body, when the photoelectric switch is incorporated in an automatic guided vehicle, the volume may be hidden inside the apparatus and cannot be directly operated, making adjustment work difficult. It may be. Therefore, it is conceivable to dispose the volume near the light emitting and receiving element that is installed in a state where it is exposed to the outside so that the adjustment operation is easy even when the volume is incorporated in the automatic guided vehicle. During operation, there is a high possibility that an operator's hand or the like enters the detection area. In such a case, there is a problem that the adjustment becomes difficult and correct adjustment cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a photoelectric switch which can easily perform an object detection condition such as sensitivity adjustment or change of a detection area from the outside in a detection state. To offer.

[0007]

According to the present invention, there is provided a detecting light emitting element for projecting a predetermined period of pulse light into a set detecting area, and a detecting light receiving element for receiving incident light from within the detecting area. And a control unit for detecting an object in the detection area according to a light receiving signal from the light receiving element for detection. A remote operation unit for transmitting a command signal for instructing a change of the object detection condition is provided. The remote operation unit includes an adjustment light receiving element for receiving light from the detection light emitting element, and an An adjusting light emitting element for outputting a signal, and adjusting means for adjusting an output timing of a command signal by the adjusting light emitting element so as to be different from a light receiving timing of the adjusting light receiving element. On the side, a discriminating means for discriminating the received signal by the detecting light-receiving element into a signal synchronized with the other signal to the pulse light of the detection light emitting element is provided, said control means,
It is characterized in that the object detection condition is changed in accordance with the command signal included in the received light signal discriminated by the discriminating means.

[0008]

According to the photoelectric switch of the present invention, the main body emits pulse light having a predetermined period toward the detection area by the light emitting element for detection, and when there is an object in the detection area, the pulse light is emitted. The reflected light is incident on the light receiving element for detection, and the presence or absence of an object is detected by the control means. Then, when changing the object detection condition, a command signal is transmitted by the remote control unit. First, the adjusting light receiving element receives the pulse light from the detecting light emitting element, and the adjusting means supplies a command signal to the adjusting light emitting element at an output timing different from the light receiving timing of the adjusting light emitting element. Output as an optical signal. On the main body side, the control means changes the object detection condition based on the command signal discriminated by the discrimination means from the light reception signals from the detection light receiving element.

Thus, the remote control unit can remotely control the change of the detection condition of the object by using the command signal by the optical signal to the main body unit. For example, it is possible to adjust the detection sensitivity or change the detection area. Can be easily performed while the main body is being detected.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is applied to a collision preventing photoelectric switch mounted on an automatic guided vehicle will be described below with reference to FIGS.

FIG. 2 shows the overall arrangement, showing the use state of the main unit 1 and the handy terminal 2 as a remote control unit. The handy terminal 2 receives a light pulse projected toward the device and outputs a command signal.

FIG. 1A schematically shows an electrical configuration of the main body 1. In the light receiving circuit 3, a photodiode (hereinafter referred to as PD) 4 as a light receiving element for detection is connected to an input terminal, and a discriminating circuit 5 as discriminating means is connected to an output terminal thereof. An output terminal of the discrimination circuit 5 is connected to a binarization circuit 7 via an amplification circuit 6, and an output terminal of the binarization circuit 7 is connected to a microcomputer 8 as control means. The amplification degree adjustment terminal C of the amplification circuit 6 is connected to the microcomputer 8. The other output terminal of the discrimination circuit 5 is connected to an adjustment amplifier circuit 9 for amplifying the command signal.
0 is connected to the microcomputer 8.
The binarization circuits 7 and 10 output an "H" level signal when a signal of a predetermined level or more is input.

The light emitting circuit 11 has an output terminal connected to a light emitting diode (hereinafter, referred to as an LED) 12 as a light emitting element for detection, and drives the LED 12 at a predetermined frequency. An output terminal of the light emitting circuit 11 is connected to the microcomputer 8 while being connected to the discriminating circuit 5.
A signal indicating the frequency of light emission is output. A program for judging the detection of an object is stored in the microcomputer 8 in advance, and an output terminal of the microcomputer 8 is connected to an output circuit 13 for outputting a judgment result.

Next, in FIG. 1B showing the electrical configuration of the handy terminal 2, a microcomputer 14 as an adjusting means is provided with a photodiode (hereinafter referred to as a terminal PD) as an adjusting light receiving element via a light receiving circuit 15. ) 16 is connected, and a light emitting diode (hereinafter referred to as a terminal LE) serving as an adjustment light emitting element via a light emitting circuit 17.
D) 18. An operation circuit 19 is connected to the microcomputer 14, and a signal corresponding to an operation is input from the operation circuit 19.

Next, the operation of this embodiment will be described with reference to FIG.

Now, during operation of the main body 1, a command signal is given by the handy terminal 2 from within the detection area to adjust the detection sensitivity of the main body 1 as a condition for detecting an object, that is, an amplifier circuit. The case where adjustment is performed so as to reduce the amplification degree of No. 6 will be described. FIG.
(A) to (k) show the output states of the signals S1 to S11 (see FIG. 1) in each part of the main body 1 and the handy terminal 2.

First, in the main body 1, the light emitting circuit 11
Supplies a pulse signal S1 to the LED 4 at a predetermined cycle, whereby the LED 12 projects a pulse light toward the detection area. Here, each pulse of the pulse signal S1 in the light projecting circuit 11 is sequentially set to P1 to P7 from the left as shown in FIG. On the main body 1 side, other signals will be described in correspondence with the respective pulses P1 to P7.

Handy terminal 2 for sensitivity adjustment
Is placed in the light projecting area of the LED 12, the pulse light from the LED 12 is incident on the terminal PD 16 of the handy terminal 2. Thus, the light receiving circuit 15 receives the light receiving signal S9 corresponding to each of the pulses P1 to P7 of the pulse signal S1.
(See FIG. 3 (i)) to the microcomputer 14. The respective pulses of the light receiving signal S9 at this time are referred to as pulses Q1 to Q7, corresponding to the respective pulses P1 to P7 of the above-described pulse signal S1. And Handy Terminal 2
On the side, other signals will be described in correspondence with each of the pulses Q1 to Q7.

When an object exists in the detection area, the LED
The pulse light from the light source 12 is reflected and incident on the PD 4, and the light receiving circuit 3 corresponds to the pulses P2 to P7 of the pulse signal S1.
3a (see FIG. 3 (b)).
Will be included.

Now, the operation circuit 1 of the handy terminal 2
9, the microcomputer 14 of the handy terminal 2 operates the operation signal S11 from the operation circuit 19 when the operation is performed to reduce the detection sensitivity of the object by the main body 1.
(See FIG. 3 (k)), and a command signal is generated accordingly. At this time, if the input timing of the operation signal S11 is, for example, after the pulse Q3 is input from the light receiving circuit 15, as shown in FIG. Q4
Is output to the light projecting circuit 17 as a command signal S10 (see FIG. 3 (j)) immediately after the is input.

That is, the command signal S10 is the light receiving signal S9
Are output at a timing different from the light receiving timing of each of the pulses Q4 to Q7. This command signal S10
Are output within a time that falls within each pulse of the light receiving signal S9. With this, the terminal LED
From 18, a command signal is output to the main body 1 as an optical signal.

On the other hand, on the main body 1 side, the LED 4 receives a light signal from the terminal LED 18 in a state of receiving reflected light from an object in the detection area. As a result, as shown in FIG. 3B, the output signal S2 from the light receiving circuit 3 becomes a signal including the command signal from the handy terminal 2 in addition to the detection pulse a of the object after the output of the pulse P4. .

When the light receiving signal S2 from the light receiving circuit 3 is input, the discriminating circuit 5 outputs a signal S3 synchronized with the output timing of the pulse signal S1 supplied from the light projecting circuit 11 (FIG. c)) and other signals S that are not.
4 (see (d) in the figure) and the synchronized signal S
3 to the amplifying circuit 6 and another signal S4 corresponding to the command signal to the adjusting amplifying circuit 9.

In the amplifier circuit 6, a given signal S
3 is given to the binarization circuit 7 as an output signal S5 (see FIG. 3 (e)) amplified by the set amplification degree, and the binarization circuit 7 compares the input signal with a predetermined level. , "H" level or "L" level binary signal S6
(See FIG. 3 (f)). The microcomputer 8 outputs a signal to the output circuit 13 by judging the detection of the object in response to this.

On the other hand, the other signal S4 discriminated by the discrimination circuit 5 is supplied to the microcomputer 8 as a binarized signal S7 (see FIG. 3 (g)) via the amplifying circuit 9 and the binarizing circuit 10. . The microcomputer 8 operates the handy terminal 2 based on the given binary signal S7.
Of the sensitivity adjustment command signal from the amplifier circuit 6 and a control signal S8 (FIG. 3 (h)) for decreasing the amplification
See).

As a result, the amplification degree of the amplifier circuit 6 is reduced, and the amplitude of the output signal S5 after the pulse P5 gradually decreases. Therefore, the object is at the same position,
Even if the level of the reflected light is the same, the detection state can be changed to the non-detection state by lowering the level of the output signal S5 of the amplifier circuit 6. That is, the detection distance is adjusted so as to substantially change to the short distance side.

On the contrary, it is also possible to output a command signal from the handy terminal 2 to the main body 1 so as to change the detection distance to the long distance side.

The sensitivity adjustment data changed and set as described above may be stored in a non-volatile memory such as an EEPROM or a RAM backed up by a battery. In this case, after the power is turned off, However, the setting data can be saved, and it is not necessary to perform the setting each time.

According to the present embodiment, a command signal is transmitted from the handy terminal 2 to the main body 1 to adjust the sensitivity as an object detection condition. Since there is no need for direct operation, the degree of freedom of the installation condition of the main body 1 is improved, and the operation for changing the detection condition is simplified.

Since the command signal from the handy terminal 2 is transmitted while the pulse light is output from the main body 1, the main body 1 can be easily detected while performing the object detecting operation. Can be changed.

In the above embodiment, the sensitivity was adjusted by changing the amplification degree of the amplifier circuit 6.
The present invention is not limited to this. For example, as shown by a broken line in FIG. 1, the microcomputer 8 may change the comparison level of the binarization circuit 7 to change the object detection condition.

In the above embodiment, the discriminating means is constituted by the discriminating circuit 5. However, the present invention is not limited to this.
In the microcomputer 8, the discrimination program may be used to perform discrimination in synchronization with the pulse signal of the light emitting circuit 11.

FIGS. 4 and 5 show a second embodiment of the present invention. Hereinafter, only parts different from the first embodiment will be described. This embodiment is applied to a collision prevention sensor mounted on an automatic guided vehicle or the like. When an object in a traveling direction enters a detection area, the object is detected and stopped or a course change is performed. In this case, the case where the detection area is changed as the change of the object detection condition is applied.

In FIG. 4, the input terminal of the discrimination circuit 5 is connected to a light receiving circuit 21a via a setting switch 20a and a PD 22a as a detecting light receiving element connected thereto, and receives light via a setting switch 20b. Circuit 21
b and PD22b, which is a light receiving element for detection, connected thereto
Is connected. Then, the setting switches 20a, 20
b has a control terminal for performing on / off switching, and the control terminal is connected to the microcomputer 8 respectively. The output terminal of the light emitting circuit 11 has L
Instead of the ED 12, an LED group 23 formed by connecting six LEDs is connected.

When the pulse signal S1 is given from the light projecting circuit 11, the LED group 23 projects pulse light so as to diffuse not only at the front but also at a wide angle. On the other hand, the PD 4 is set to receive light from a predetermined area in front, the PD 22a receives light from a predetermined area on the right side of the PD 4, and the PD 22b receives light from a predetermined area on the left side of the PD 4. It is arranged and configured.

Such a main body 23 is mounted on an automatic guided vehicle V (see FIG. 5) and arranged so as to detect an object in the traveling direction. The automatic guided vehicle V is set so as to travel along paths A, B or C having different widths as shown in FIGS. 5 (a), 5 (b) or 5 (c). In the vicinity of the changing points of the passages A to C, instead of the handy terminal 2 in the first embodiment, an optical terminal 24 as a remote control unit is provided.
a and 24b are provided. This optical terminal 24
A and 24b are configured to transmit a command signal when the automatic guided vehicle V approaches.

According to the above configuration, the setting switches 20a and 20b of the main body 23 are set to be in an off state when the automatic guided vehicle V travels in the narrow passage C. The main body unit 23 detects an object using a detection area Ec in a narrow traveling direction as a detection range.

When the automatic guided vehicle V approaches the passage B on the left side, the main body 23 receives a command signal for changing the detection area from the optical terminal 24b provided in the vicinity thereof. This command signal is input to the microcomputer 8 in the same manner as in the first embodiment. The microcomputer 8 operates the setting switch 20b to set the detection area Eb slightly wider on the left side in accordance with the given command signal.
To a control signal. Accordingly, the light incident on the PD 22b from the front left side is also input to the microcomputer 8, and the detection of an object corresponding to the width of the passage B can be performed.

Similarly, when the automatic guided vehicle V approaches the wide passage A on both sides, a command signal for changing the detection area is received from the optical terminal 24a to the main body 23. As a result, the microcomputer 8 sets the setting switch 20
a is set to the ON state and changed to the detection area Ea. Thus, it is possible to detect an object corresponding to the wide passage A.

According to such a second embodiment, the first embodiment
In the same manner as in the embodiment, the object detection condition can be remotely controlled.

FIG. 6 shows a third embodiment of the present invention. The difference from the above embodiments is that the frequency of the pulse signal S1 by the light emitting circuit 11 is changed as a change of the object detection condition. is there. The present embodiment is effective, for example, in a case where a plurality of automatic guided vehicles come and go when the main body is mounted on an automatic guided vehicle for use.

In FIG. 6, the light emitting circuit 11 of the main body 25 is provided.
Is configured such that the frequency of the pulse signal can be changed and output in a plurality of stages, and a change setting terminal thereof is connected to the microcomputer 8. The main body 25 is mounted on, for example, an automatic guided vehicle, and receives a command signal from an optical terminal (not shown). And the first
When the microcomputer 8 receives the command signal from the optical terminal in the same manner as in the embodiment, the microcomputer 8 gives a signal for changing the frequency to the light projecting circuit 11 to change the output frequency of the pulse signal.

Thus, for example, when another automatic guided vehicle using a pulse signal of the same frequency approaches,
By detecting this by the optical terminal, the frequency of the pulse signal of the main body 25 mounted on one of the automatic guided vehicles can be changed, and erroneous detection between each other can be prevented.

FIG. 7 shows a fourth embodiment of the present invention.
For example, this is a case where the present invention is applied to an unmanned transport system in a factory or the like. That is, the main body 26 is mounted on the automatic guided vehicle V, and an optical terminal 27 as a remote control unit is provided at a key point in the passage of the automatic guided vehicle V. The optical terminal 27 exchanges information with the main body 26 by performing various communications as described below.

FIG. 7A shows a case where the path D is curved rightward in front, and when the automatic guided vehicle V approaches, a command signal is output from the optical terminal 27. Here, if the detection area on the right side is activated when the automatic guided vehicle V makes a right turn, the wall surface of the passage D will be detected.
Invalidates the right detection area in response to a command signal from the optical terminal 27.

FIG. 7 (b) assumes that when the automatic guided vehicle V makes a left turn at the intersection of the path E, for example, there is another automatic guided vehicle V 'on its path. In this case, in order to avoid a collision with the automatic guided vehicle V, the optical terminal 27 moves straight ahead and turns left at the next intersection.
6 is supplied with a command signal.

In this case, for example, the optical terminal 2
Reference numeral 7 denotes a main body unit which stores information on the power consumption state of the automatic guided vehicle.
, And if necessary, change the course to replenish the battery.

FIG. 7C shows a case where a mirror object M is left in the vicinity of the automatic guided vehicle V in the traveling direction or the like, and a command signal is sent to the main body 26 by the optical terminal 27 and the mirror object M is transmitted from the mirror object M. This is to invalidate the detection of the reflected light. In this case, for example, a command signal such as invalidating the left side of the detection area or decreasing the detection sensitivity is given, and the traveling speed of the automatic guided vehicle V is reduced to instruct the vehicle to run slowly.

According to this embodiment, the main body 26
Since various command signals can be exchanged and information can be exchanged between the optical terminal 27 and the optical terminal 27, an excellent unmanned transport system can be formed.

[0050]

As is apparent from the above description, according to the photoelectric switch of the present invention, the remote operation unit uses the optical signal which does not affect the pulse light for object detection. Since the change of the detection condition of the object is remotely controlled, it is possible to easily adjust the detection sensitivity, change the detection area, and the like while detecting the main body.

[Brief description of the drawings]

FIG. 1 is an electrical configuration diagram showing a first embodiment of the present invention.

FIG. 2 is an external view showing an overall arrangement state.

FIG. 3 is a time chart showing an output state of a signal of each unit.

FIG. 4 is a view corresponding to FIG. 1, showing a second embodiment of the present invention;

FIG. 5 is a diagram for explaining an operation of changing a detection area.

FIG. 6 is a view corresponding to FIG. 1, showing a third embodiment of the present invention.

FIG. 7 is an operation explanatory view showing a fourth embodiment of the present invention.

[Explanation of symbols]

Reference numerals 1, 23, 25, and 26 denote a main body unit, 2 denotes a handy terminal (remote operation unit), 3, 21a and 21b denote light receiving circuits,
4, 22a and 22b are PDs (detection light receiving elements), 5 is a discrimination circuit (discrimination means), 6 is an amplification circuit, 7 is a binarization circuit,
8 is a microcomputer (control means), 9 is an amplification circuit, 10 is a binarization circuit, 11 is a light emitting circuit, and 12 is an LED
(Light emitting element for detection), 12 'is a group of LEDs (light emitting element for detection), 14 is a microcomputer (adjustment means), 15
Is a light receiving circuit, 16 is an adjusting PD (adjusting light receiving element), 1
7 is a light emitting circuit, 18 is an adjusting LED (adjusting light emitting element), 19 is an operation circuit, 20a and 20b are setting switches, and 24a, 24b and 27 are optical terminals (remote operation unit).

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01V 8/12 G01B 11/00

Claims (1)

(57) [Claims] 1. A detecting light emitting element for projecting a pulse light having a predetermined period into a set detecting area, a detecting light receiving element for receiving incident light from the detecting area, and a detecting light receiving element. And a control unit for detecting an object in the detection area in accordance with the light receiving signal, wherein a command signal for instructing the main unit to change an object detection condition by the control unit is provided. A remote control unit for transmitting, the remote control unit is provided with an adjusting light receiving element for receiving light from the detecting light emitting element, an adjusting light emitting element for outputting the command signal by an optical signal, and Adjusting means for adjusting the output timing of the command signal by the adjusting light emitting element so as to be different from the light receiving timing of the adjusting light receiving element. A discriminating means for discriminating between a signal synchronized with the pulse light of the detecting light emitting element and another signal is provided, and the control means controls an object according to the command signal included in the received light signal discriminated by the discriminating means. A photoelectric switch configured to change a detection condition.