JPH0543551Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a wireless communication device, and more specifically, it is used for remote control of automatic guided vehicles in FA (factory automation) systems that aim to automate production sites. The present invention relates to a wireless communication device that prevents failure of communication due to interference caused by reflected waves of transmitted radio waves.

[Prior art]

In FA systems, automated guided vehicles may be remotely controlled in large indoor spaces, but the radio waves transmitted indoors may be reflected off walls, causing interference between the transmitted radio waves and the reflected waves, resulting in weak parts of the indoor area. May produce electric field regions. Therefore, if the position where the automatic guided vehicle is stopped is in a weak electric field region, there is a problem that wireless communication continues to fail and control of the automatic guided vehicle by wireless communication becomes impossible midway through. This problem also occurs outdoors due to reflections from buildings. A mobile communication device capable of resolving such an inability to perform wireless communication is disclosed in, for example, Japanese Patent Laid-Open No. 112211/1983. However, this mobile communication device transmits a digital signal from the mobile station, counts the response time from the base station, and if there is no response within a certain period of time, changes the height of the mobile station's antenna and retransmits the digital signal. However, there is a problem in that it requires complex control on the mobile station side to enable communication.

(Purpose) The present invention aims to establish communication by constantly and repeatedly moving the position of the antenna within a predetermined range during communication time, thereby eliminating or breaking out of the stationary weak electric field region. The purpose is to provide a new wireless communication device that can achieve the following.

〔composition〕

A wireless communication device according to the present invention is a wireless communication device equipped with an antenna for performing wireless communication.
The antenna is provided so that its position can be changed within a predetermined range, and is provided with a drive device for changing the position, and during communication time, the antenna is constantly and repeatedly moved within the predetermined range by the drive device. It is characterized by being configured.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The wireless communication device according to the present invention will be described in detail below with reference to drawings showing embodiments. Figure 1 is an external perspective view of a wireless communication device according to the present invention (hereinafter referred to as the proposed device). It will be established in In Fig. 1, 1 is a communication device main body, and this communication device main body 1 has, for example, a carrier frequency of 440MHz, a communication time of 100msec, and a communication interval.
Control data is transmitted to a communication device of an automatic guided vehicle (not shown) in 1 sec, and the automatic guided vehicle is configured to receive data from the communication device, and is connected to the central control device. Reference numeral 2 denotes a disc-shaped base, and a bearing 2a is mounted at the center of the base 2.
The rotary shaft cylinder 3, whose base end is fitted into the bearing 2a, is erected so as to be freely rotatable. At the upper end of the rotating shaft tube 3, a rotating disk 4 made of an insulating material and having a radius slightly longer than one wavelength (68 cm) of the carrier frequency of 440 MHz is fixedly fixed with its center position coincident with the rotating shaft tube 3. installed.

And near the periphery of the rotating disk 4, that is, the rotating disk 4
A small-diameter rod-shaped whip antenna (hereinafter referred to as antenna) 5 is erected at a position radially away from the center of the antenna by one wavelength of the carrier frequency of 440 MHz. One end of a transmitting/receiving cable 6 made of a coaxial cable is connected to the base of the antenna 5.
This transmitting/receiving cable 6 is inserted through a cable insertion hole 4a opened at the center of the rotating disk 4, passed through the inside of the rotating shaft cylinder 3, and led out from a cable pull-out hole 3a formed at the base of the rotating shaft cylinder 3. It is connected to the output terminal of the main body 1. The portion of the transmitting/receiving cable 6 near the cable insertion hole 4a is lifted upward by the tip of a cable support member 7 made of wire attached to the upper surface of the rotating disk 4, so that the rotation of the rotating disk 4 is connected to the transmitting/receiving cable. 6 so that it is smooth without being hindered. A driven pulley 8 is attached to the lower side of the rotary shaft cylinder 3, and a reversible motor 9 is disposed on the base 2 apart from the rotary shaft cylinder 3. A drive belt 11 is stretched between the driven pulley 8 and a drive pulley 10 attached to a rotating shaft 9a of a reversible motor 9, and the rotating disk 4 is rotated by the drive of the reversible motor 9. ing. That is, the reversible motor 9 and the driven pulley 8
With the drive pulley 10 and drive belt 11,
A drive device 12 is configured to rotationally drive the rotating disk 4. The reversible motor 9 is connected by a lead wire 13 to an output terminal of a motor control circuit (not shown) provided in the communication device main body 1, so that the reversible motor 9 is driven when the communication device main body 1 is in operation. It's summery. Furthermore, when the reversible motor 9 is driven, the rotary disk 4 rotates once every 10 seconds, and the reversible motor 9 rotates once at the position where it has rotated once.
The robot rotates in the opposite direction, rotates once in the opposite direction in 10 seconds, and repeats this action. Radio waves are emitted from the antenna 5 when the communication device body 1 communicates, and radio waves are received by the antenna 5 during reception.

The wireless communication device configured in this manner emits radio waves containing control data for the automatic guided vehicle from the antenna 5 by turning on the power switch SW of the communication device main body 1, and is installed on the automatic guided vehicle (not shown). The communication device receives these radio waves and controls the movement of the automatic guided vehicle according to the content of the radio waves. During this time, the reversible motor 9 is driven and the rotary disk 4 repeats forward and reverse rotations, and the upright position of the antenna 5 is moved moment by moment on the plane. Therefore, the distance between the antenna position, which is the transmitting position, and the predetermined receiving position changes within a length range of approximately two wavelengths of the transmitted radio waves.
In other words, the nodes of the standing radio waves within the factory move in conjunction with the antenna 5, and the weak electric field region changes moment by moment. Since communication is performed at 1-second intervals, there are 10 reception chances within one rotation of the rotating disk 4, and even if the automatic guided vehicle is stopped in a weak electric field region at the start of transmission, there will be a slight time delay. When it enters the strong electric field region, communication is established.

Conversely, even when the communication device on the automatic guided vehicle side transmits, the position of the antenna 5 changes every moment, so communication is established regardless of the position of the automatic guided vehicle.

FIG. 2 shows another embodiment of the present invention with a different drive device, and the same parts as those in FIG. 1 are given the same reference numerals. In FIG. 2, a rectangular base 2 has two support legs 2 placed at the center of its longitudinal direction and facing each other in the width direction.
0,20 are erected, and these supporting legs 20,2
At the upper end of 0, there is an antenna guide plate 2 parallel to the base 2.
1 is installed. An elongated hole 21a having a length corresponding to one wavelength of the carrier wave is provided at the center of the antenna guide plate 21. Bearing mounting plates 22, 22 are attached to the lower surface of both longitudinal ends of the antenna guide plate 21, and bearings 23, 23 are fitted to the bearing mounting plates 22, 22, respectively. And both bearings 2
A feed screw shaft 24 is rotatably supported across the shafts 3 and 23. The feed screw shaft 24 is provided with an antenna mounting member 25 made of a prismatic insulator that is screwed onto the screw, and the antenna 5 is made to stand up by inserting a hollow hole 21a into the antenna mounting member 25. The base of the is fixedly attached.

Further, the rotating shaft of the reversible motor 9 is connected to one end of the feed screw shaft 24 via an appropriate speed reduction mechanism. A drive device 12 is constituted by the reversible motor 9, the feed screw shaft 24, and the antenna mounting member 25. In this wireless communication device, the feed screw shaft 24 is rotated by driving the reversible motor 9.
The antenna mounting member 25 is moved by the feed screw shaft 24 in its length direction. Therefore, the antenna 5 is guided by the elongated hole 21a, and its mounting position reciprocates linearly on a plane within its length range, so that the antenna 5 operates in the same way as the wireless communication device shown in FIG.

In addition, in the above-mentioned embodiment, the antenna 5 for the communication device main body 1 on the central control unit side, which is fixed, is moved, but conversely, the antenna of the communication device on the automatic guided vehicle side can be moved. You can also use it as It goes without saying that the present invention may also be applied to dedicated transmitter and receiver devices.

Further, the shape of the antenna and the driving device are not limited to those of the above-described embodiments. In addition, although the upright position of the antenna is moved within the range of 1 or 2 wavelengths of the transmitted radio wave on a plane, it is of course possible to move it within the range of 1/2 wavelength or 1/4 wavelength. be. Furthermore, if the antenna 5 and the transmission cable 6 shown in FIG. 1 are connected by attaching a slip ring to the rotary shaft cylinder 3, the rotary disk 4 can be continuously rotated in one direction.

〔effect〕

As detailed above, the present invention constantly and repeatedly moves the antenna position within a predetermined range during communication time without checking whether the communication status is good or not, and changes the electric field strength at the reception position moment by moment. , it is possible to establish communication with the receiving position when communication is started.

Further, there is no need for a control device that performs complicated control such as checking whether the communication status is good or bad in order to establish communication, and thus costs can be reduced.

Therefore, for example, when controlling an automatic guided vehicle in a PA system by wireless communication, an excellent effect of enabling communication at low cost can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an external perspective view of a wireless communication device according to the present invention, and FIG. 2 is an external perspective view showing another embodiment of the wireless communication device according to the present invention. DESCRIPTION OF SYMBOLS 1... Communication device main body, 3... Rotating shaft cylinder, 4... Rotating disk, 5... Antenna, 6... Transmission/reception cable, 9... Reversible motor, 12... Drive device, 20
...Feed screw shaft, 25...Antenna mounting member.

Claims (1)

[Scope of utility model registration request] In a wireless communication device equipped with an antenna for performing wireless communication, the antenna is provided so that its position can be changed within a predetermined range, and includes a drive device for changing the position, and during communication time, A wireless communication device characterized in that the antenna is configured to be constantly and repeatedly moved within the predetermined range by the drive device.