JPH022729A - Wireless optical communication system - Google Patents

Abstract

PURPOSE:To obtain an optical communication system with a simple constitution and with low power consumption by emitting light by automatically selecting the optimum light emitting element corresponding to the position of a master to a slave out of plural light emitting elements provided on the light transmission equipment of the slave at the time of performing data communication between the master and a remote slave by using an optical signal. CONSTITUTION:An optical axis adjusting function not shown in figure is operated, and a parallel signal is sent from a microcomputer 6 to a select circuit 15, and one of plural light emitting diodes LED2 provided on the slave B is designated. The information of the signal is sent from the circuit 15 to a driving circuit 14, and a designated LED2 is set at an available state. Following that, an address for the slave B and the identification numbers (1-5) of the LED2 from the computer 6 are sent to the circuit 14 via a serial data line 17, and the optical signal is generated from the designated LED2, and the intensity of a reception signal is decided by repeating such operation, and the optimum identification number is transferred to a control unit 5, then, components and the number of them in a warehouse are detected.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a wireless optical communication system that performs data communication using optical signals between a base unit and a slave unit located far away, and is applicable to, for example, a picking system. Regarding the technology used.

[Conventional technology]

In general, in a wireless optical communication system, the light emitting element and the light receiving element each have their own unique effective angles, so in order to perform bidirectional communication in the best possible condition with few errors, the light emitting element and the corresponding light receiving element must be placed at each other. must be located within the effective angle of If the parent unit and slave unit are in a fixed one-to-one positional relationship, it is sufficient to first adjust the orientation of the light-emitting element and light-receiving element.
If at least one of the parent unit and slave unit moves, or if there are multiple slave units, the orientation of the light-emitting element and light-receiving element cannot be fixed from the beginning. need to be adjusted so that they face each other.

This can be achieved by (1) using a light-emitting element with a wide effective radiation angle and high output, or a light-receiving element with a wide effective light-receiving angle and high sensitivity.

■ A device is installed on the light-emitting element and the light-receiving element to change their orientation, and the device is activated when communicating.
There is a method of controlling the light emitting element and the light receiving element so that they face each other.

(2) There is a method of expanding the range of effective angles by arranging a plurality of light-emitting elements and light-receiving elements facing different directions and using all of them.

■ There is a method that shares the above methods (■ to ■).

In a wireless communication system that adopts the method of ■,
A picking system disclosed in Japanese Unexamined Patent Publication No. 186624/1983 is known. In this prior art, - number of master units are mounted on the ceiling of a warehouse, and slave units are provided on each component shelf of a picking box installed on the floor. The satellite type optical transmitter/receiver installed in the communication repeater of the parent unit is equipped with multiple light emitting diodes as light emitting elements and multiple photodiodes as light receiving elements, and the optical transmitter/receiver of each slave unit is also equipped with multiple light emitting diodes as light emitting elements and multiple photodiodes as light receiving elements. A plurality of light emitting diodes and photodiodes are provided. Then, in the base unit, the optical signals sent to each slave unit are emitted from all the light emitting diodes of the satellite type optical transmitter/receiver, and the optical signals sent to the base unit are emitted from all the photodiodes of the satellite type optical transmitter/receiver. This is how you receive it. Furthermore, in the slave device, optical signals to be sent to the parent device are emitted from all light emitting diodes of the optical transmitter/receiver.

[Problem to be solved by the invention]

However, each of the above-mentioned methods has the following problems.

The method (2) uses high-performance light-emitting elements and light-receiving elements, which not only increases costs, but also makes it impossible to significantly expand the effective radiation angle of the light-emitting elements. Moreover, since it consumes a lot of power, the power supply capacity must be increased, making it unsuitable for transportation.

Method (2) allows communication over a wide range, but it requires difficult control, which requires an electronic control device and a driving machine, making the device complex, heavy, and bulky. Requires capacity power supply. The cost is also quite high.

In the method (2), inexpensive light emitting elements and light receiving elements can be used, but current must be simultaneously supplied to a plurality of light emitting elements and light receiving elements, and a large capacity power source is required. Not suitable for transportation.

Focusing on these points, the present invention aims to construct a wireless communication system that has a relatively simple structure, is inexpensive, and consumes little power.

[Means to solve the problem]

In order to solve the above objectives, an optical transmitter that performs wireless optical communication with an optical transmitter/receiver of a base unit includes a plurality of light emitting elements that emit optical signals to the optical transmitter/receiver of the base unit, and an optimal state for the optical transmitter/receiver. and means for selecting a light emitting element that emits an optical signal received by the light emitting device.

Preferably, this means automatically selects the light emitting element according to the received information sent back from the optical transmitting/receiving device of the base unit.

In addition, in an optical receiver that performs wireless optical communication with the optical transmitter/receiver of the base unit, there are multiple light receiving elements that receive optical signals from the optical transmitter/receiver of the base unit, and a light receiver that receives the optical signals in an optimal state. Means for automatically selecting the elements is provided.

Furthermore, as one of the preferred embodiments of the present invention, an optical transmitting/receiving device can be configured by including the optical transmitting device and the optical receiving device.

The method for adjusting the optical axis of the optical transmitting/receiving device is to sequentially emit optical signals from a plurality of light emitting elements of the child device, and receive the optical signals with the optical receiving device of the parent device, so that the optical signals are received in an optimal state. After determining the optical signal and identifying the light emitting element that is emitting this signal, the optical transmitter of the base unit emits the result as an optical signal, and the optical signal from the base unit is received by the optical receiver of the slave unit. death,
There is a method of automatically setting the optimum light emitting element for transmission based on this.

Furthermore, it is convenient to apply the wireless optical communication system to a system in which at least one of the base unit and the slave unit is mobile.

[For production]

The optical transmitting device sequentially emits optical signals from a plurality of light emitting elements to the optical transmitting and receiving device. Then, it selects which light-emitting element emits an optical signal that is optimally received by the optical transmitting/receiving device of the base unit, and uses the selected light-emitting element to transmit the optical signal.

The optimum light emitting element can be automatically selected according to the received information sent back from the optical transmitting/receiving device of the base unit.

The optical receiving device receives the optical signal from the optical transmitting/receiving device of the base unit with multiple light receiving elements, automatically selects the light receiving element that can receive the signal in the optimal condition from among them, and uses the selected light receiving element. and receive optical signals.

When an optical transmitting/receiving device is configured by including the optical transmitting device and the optical receiving device, a light emitting element optimal for emitting an optical signal to the optical transmitting/receiving device of the base unit, and a light receiving element optimal for receiving the optical signal. It becomes possible to select and communicate.

In the method for adjusting the optical axis of an optical transmitting/receiving device according to the present invention, first, optical signals are sequentially emitted from a plurality of light emitting elements of a slave device. After receiving these optical signals, the base unit's optical receiver determines which optical signal is received in the optimal condition, identifies the light-emitting element that is emitting this signal, and sends the result to the base unit's optical receiver. It is emitted as an optical signal from a transmitting device. The optical transmitter/receiver of the child device then receives the returned optical signal and automatically sets the light emitting element for transmission based on it.

〔Effect of the invention〕

The present invention has the following effects.

(a) Optimum transmission is possible with low power consumption because only the best one with the least transmission error is selected from a plurality of light emitting elements and used.

(b) Optimum reception is possible with low power consumption because only the best one with few reception errors is selected from among the plurality of light receiving elements and used.

(C) In addition to being able to use low-power consumption light-emitting elements and low-sensitivity and inexpensive light-receiving elements, there is no need for control to direct the light-emitting elements and light-receiving elements toward the communication partner, simplifying the structure and reducing costs. It's cheap.

(d) These optical transmitting devices and optical receiving devices, or optical transmitting/receiving devices constructed of them, have a simple structure, a small power supply capacity, and are lightweight, so they are ideal for installation in a moving body.

〔Example〕

Hereinafter, embodiments of a picking system to which the present invention is applied will be described based on the drawings.

As shown in Figure 4, two picking boxes (IA) and (1B) are installed facing each other on the floor of the warehouse. These picking boxes (LA), (IB
), as shown in Fig. 3, is a box-shaped parts shelf (2) for storing parts etc. arranged in 8 rows horizontally and 5 rows vertically, and the upper plate (2a ), the handset (B) is attached individually. And these picking boxes (LA)
, in the middle of (IB)! There are multiple cordless handsets (
A single master device (A) is provided to control the devices B).

The master device (A) has a host computer (3) in the warehouse, a communication repeater (4) that corresponds to an antenna for bidirectional data communication with the slave device (B), and a communication relay device (4) interposed between these. and a control unit (5). The host computer (3) stores the address for identifying each slave unit (B) and the quantity of parts stored in each parts shelf (2), and manages inventory data in the warehouse. It supervises the entire system by giving picking instructions.

The control unit (3) converts the data sent from the host computer (3) into a serial signal for transmission and sends it to the communication repeater (4), or sends it to the slave unit (B).
It is a so-called interface that converts the serial signal returned from the computer via the communication repeater (4) into data and transfers it to the host computer (3). The communication repeater (4) includes a satellite optical transmitter and a satellite optical receiver. The satellite type optical transmitter modulates the serial signal sent from the control unit (5) into an infrared light signal and emits it into space, and the satellite type optical receiver device modulates the serial signal sent from the control unit (5) into an infrared light signal and emits it into space. The optical signal is demodulated into a serial signal and transferred to the control unit (5).

As shown in FIG. 2, the slave unit (B) includes an optical transmitter and an optical receiver for the base unit (A), a one-chip microcomputer, and a display unit (7) that displays communication results. It is equipped with a key for manually editing and correcting data (8), a power switch (SW), a reset box (9), etc. The optical transmitting device modulates the serial signal sent from the microcombinator (6) into an infrared optical signal and emits it into space, and the optical receiving device modulates the serial signal sent from the microcombinator (6) into an optical signal using infrared rays and emits it into space. is demodulated into a serial signal and sent to the microcomputer (6). The microcomputer (6) is
The number of parts on the parts shelf (2) that each slave unit (B) is responsible for is managed. Analyzes the input signal to identify the address, and when the address matches its own address, displays quantity data, for example, the quantity to be taken out from the parts shelf (2) or the quantity to be supplied to the parts shelf (2). (7) for the operator to recognize. Furthermore, when the address setting is changed or the number of parts is modified, the data is sent as a serial signal to the optical transmitter.

Perform various other tasks based on the program.

The display section (7) is provided with a 4-digit 7-segment light emitting diode (10), and can digitally display necessary information in numbers or alphabets from 8 to F. The key (8) is a hexadecimal key, and is used by on-site workers when inputting the actual number of parts when taking out or replenishing parts, correcting the quantity of remaining parts, and changing address settings.

In this way, in the picking system, the main unit (A)
and picking box (IA), each child machine (1B) (
B) Effective two-way communication allows for efficient parts inventory management.

The satellite optical transmitter of the communication repeater (4) includes:
Of the 16 light emitting diodes (LBDI) that emit infrared rays, each of the 8 light emitting diodes (LEDI) is
As a group, the light emitting diodes are arranged radially at intervals of 20 degrees as shown in FIG.
) are arranged in an overlapping manner at approximately 20 degree intervals as shown in FIG. and two groups of light emitting diodes (Ll), (L
2) to each picking box (IA), (I
B) It is placed towards.

These light emitting diodes (LBDI) are connected to the control unit (5) via a driver circuit (11) for modulation signal insertion and switching, as shown in FIG. This allows optical signals to be emitted simultaneously at a wide angle to all slave units (5) based on the serial signal. In addition, each light emitting diode (LEDI) is an inexpensive low power consumption type,
Its effective radiation angle is about 40 degrees.

The satellite type optical receiving device of the communication repeater (4) includes 2
Between the two light emitting diode groups (Ll) and (L2), three light emitting diodes are arranged radially at intervals of about 30 degrees as shown in Figure 8.
(12).

These light receiving units (12) employ a plurality of highly sensitive photodiodes and have an effective light receiving angle of about 90 degrees. Then, one of the light receiving units (12) can receive optical signals emitted from all the optical transmitting devices with high sensitivity.

As shown in FIG. 9, the optical transmitter of the handset (B) has five light emitting diodes (LED2) that emit infrared rays arranged radially at intervals of approximately 30 degrees. Communication repeater (4) is activated by either LED (2).
) to emit optical signals. An optical receiver is provided near the optical transmitter to receive the optical signal from the communication repeater (4). This optical receiving device consists of a light receiving unit (12) similar to the light receiving unit (12) of the communication repeater 4).A light emitting diode (LED2) used in each slave unit (B) and Light receiving unit (13)
has almost the same performance as that used in the communication repeater (4).

In this picking system, when emitting an optical signal, the handset (B) does not emit light from five light emitting diodes (LED2) at the same time, but uses a communication repeater (4) within the effective radiation angle.
One light emitting diode (LIED) that can accommodate
2) is designed to emit light. In other words, the handset (B) is equipped with an optical axis adjustment function, and the five light emitting diodes (LED2) located at the position where the emitted optical signal is received by the communication repeater (4) are the strongest. By selecting one of the diodes (LED2), it is possible to minimize transmission errors while consuming low power.

Next, the front shaft adjustment function will be explained.

As shown in FIG. 1, a drive circuit (14) is connected to each light emitting diode (LED2) of the slave device (B), and a select circuit (14) is connected to this drive circuit (14).
5) is connected. Also, this select circuit (15)
The microcomputer (6) is connected to the microcomputer (6) via a control bus (16).

The drive circuit (14) drives the selected light emitting diode (
This is for supplying a specified current to L[ED2) to cause it to emit light, and is also directly connected to the microcomputer (6) via the serial data line (17). The selection circuit (15) is a so-called decoder, and selects one light emitting diode (LED2) based on a parallel signal sent from the microcomputer (6) via the control bus (16).

Specifically, when the optical axis adjustment function is activated, the microcomputer (6) sends a parallel signal to the select circuit (15), and specifies the light emitting diode (LED2) to emit light based on this parallel signal. This information is sent from the select circuit (15) to the drive circuit (14),
Enables the specified light emitting diode (LED2). Next, the microcomputer (6) sends the light emitting diode (LE) specified as the address of the slave unit (B).
D2)'s identification number (1 to 5) is the serial data line (
17), a serial signal is sent to the drive circuit (14), and a designated light emitting diode (LED2) modulates it into an optical signal and emits it as an optical signal. When this is completed, specify the next light emitting diode (LED2) and repeat the same process. That is, each light emitting diode (LED2) sequentially transmits the address and the designated identification number of the light emitting diode (LED2) as an optical signal.

The optical signals emitted from the light emitting diodes (LED2) are received one after another by the satellite type optical receiver of the communication repeater (4), and the strength of the signals is determined.The address and identification number most suitable for communication are determined by the serial signal. The signal is demodulated and sent to the control unit (5). The data is then transferred from the control unit (5) to the host computer and stored. When the host computer completes storage, it returns the address and identification number data to the control unit (5). Control unit (5)
modulates the returned data into a serial signal and sends it to the satellite optical transmitter of the communication repeater (4).

The optical signal emitted from the satellite optical transmitter of the communication repeater (4) is received by the optical receiver of each slave unit (B), and is addressed by the microcomputer (6) of each slave unit (B). is identified.

When the address matches its own, the identification number sent at the same time is stored in the microcomputer (6). From then on, this handset (8) will emit an optical signal using the light emitting diode (L, 602) corresponding to the identification number.

In this picking system, the handset (B) is placed on the parts shelf (2
), the transmitting light emitting diode (Lε02) can be set by adjusting the optical axis once when the handset (B) is positioned. For example, in Figure 3,
The leftmost and topmost slave unit (of the picking box (IA))
In B), the light emitting diode (LED2) with identification number 5 is set on the far right in Figure 9, and the light emitting diode (LED2) on the far right and bottom is set.
In B), the second light emitting diode (LED2) from the left in FIG. 9 and having the identification number 2 is set.

In this embodiment, a light emitting diode is used as a light emitting element, and a light receiving unit having a photodiode is used as a light receiving element, but the present invention is not limited thereto.

In carrying out the invention, a picking box (IA),
The layout of (IB) is free, and the picking boxes (IA>, (1B) may be arranged in the same direction as shown in FIG. 10).

Furthermore, by applying the optical axis adjustment function to the satellite type optical transmitter of the communication repeater (4), it is possible to set the light emitting diode (LEDI) that emits the optimal optical signal for each slave unit (B). You can also do it.

Further, the optical axis adjustment function may be applied to the optical receiving device of the handset (B) or the satellite type optical receiving device.

Furthermore, the present invention can be implemented even when at least one of the base unit (A) and the slave unit (B) moves freely. In that case, the optical axis adjustment function will automatically operate immediately before communication.
Optimum light emitting diodes and light receiving units are set at any time to correspond to the positional relationship between the master unit (A) and slave unit (B).

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings show an embodiment of the wireless optical communication system according to the present invention, in which Figure 1 is a block circuit diagram of a slave unit, Figure 2 is a perspective view of the exterior of the slave unit, and Figure 3 is the position of the base unit and slave unit. Figure 4 shows the arrangement of the picking boxes, Figure 5 shows the relationship.
The figure shows the arrangement of the light emitting elements of the base unit, Figure 6 shows the arrangement of the light emitting elements and light receiving elements of the base unit, Figure 7 is the block circuit diagram of the base unit, and Figure 8 shows the light reception of the base unit. A diagram showing the arrangement of elements,
FIG. 9 is a diagram showing the arrangement of the light emitting elements of the handset;
The figure shows a modification of the arrangement of the picking boxes. (12)...Light receiving element, (A)...Main unit, (B)...Group/Slave unit, (LEO2)...Light emitting element.

Claims (1)

[Claims] 1. In an optical transmitter that performs wireless optical communication with the optical transmitter/receiver of the base unit (A), a plurality of light emitting elements (LED2) that emit optical signals to the optical transmitter/receiver of the base unit (A); , means for selecting a light emitting element (LED 2) that emits an optical signal that is received in an optimal state for the optical transmitter/receiver. 2. The optical transmitting device according to claim 1, wherein the means automatically selects the light emitting element (LED 2) according to the received information returned from the optical transmitting/receiving device of the base unit (A). 3. In an optical receiving device that performs wireless optical communication with the optical transmitting and receiving device of the base unit (A), a plurality of light receiving elements (12) that receive optical signals from the optical transmitting and receiving device of the base unit (A), and the optical signals. A light-receiving element (12) that receives the light in an optimal state.
An optical receiving device comprising means for automatically selecting a. 4. The optical transmitter according to claim 1 or 2, and claim 3
An optical transmitting/receiving device comprising the optical receiving device described above. 5. In a method for adjusting the optical axis between a base unit and a slave unit that perform two-way wireless communication, [1] sequentially emitting optical signals from multiple light emitting elements (LED2) of the slave unit; [2] emitting those optical signals [3] Identify the light emitting element (LED2) that is emitting this signal, and send the result to the base unit (A). (A) to emit an optical signal from the optical transmitter/receiver to the handset; [4] to send an optical signal from the optical transmitter of the master (A) to the handset (B);
), and automatically setting an optimal light-emitting element (LED2) for transmission based on the received information. 6. The optical axis adjustment method for an optical receiver according to claim 4, wherein at least one of the base unit (A) and the slave unit (B) is movable.