JPH075251A - In-pipe robot position measurement method - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a method capable of easily and accurately measuring the position of a work robot working in a pipe from the ground. [Structure] Radio waves of a predetermined frequency are transmitted from the open end of the tube 1. When the radio wave comes into contact with the robot in the pipe and is reflected, the reflected radio wave is received at the same position as the transmission point. Next, the elapsed time from the transmission to the reception is detected, this elapsed time is substituted into a predetermined calculation formula, and the position from the radio wave transmission point to the robot in the pipe is measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-pipe robot position measuring method capable of accurately measuring the position of a work robot moving in a pipe such as a gas pipe from the ground.

[0002]

2. Description of the Related Art In a pipe such as a gas pipe buried in the ground, moisture may cause corrosion or foreign matter such as earth and sand may enter. In order to detect such a condition and repair it early, a conventional self-propelled robot equipped with a camera was sent into the pipe, and while moving, the inside condition of the pipe was photographed, and the photographed screen was observed for abnormalities. There has been known a method for determining the presence or absence of the above (Japanese Patent Laid-Open No. 59-147).
260 publication). Then, when an abnormality in the pipe is found from the image from this robot, the pipe is excavated, the pipe in that portion is taken out, and repairs such as replacement are performed. Therefore,
In order to carry out the repair work, it is necessary to accurately detect the location where the robot shows an abnormality such as corrosion. Therefore, conventionally, a rotary encoder is provided on the wheel of the robot, the moving amount of the robot in the pipe is measured by the rotary encoder via the wheel, and the numerical value is read to detect the moving amount, or the cable connected to the robot. It was attempted to measure how much the robot was pulled in by the robot at the insertion port, and to know to what extent the robot is currently entering the pipe (Japanese Patent Laid-Open No. 61-278475).

[0003]

However, in the case where the rotary encoder is incorporated in the wheel, slip occurs especially when the wheel crosses the groove, and an error is accumulated in the measured value. Regarding this, some measures are taken by using a plurality of measurement wheels, but there are problems such as matching a plurality of data from each wheel and requiring a sensor in the robot itself. In addition, a device in which the position of the robot is measured from a cable connected to the robot has a problem that the accurate distance cannot be measured because the cable is bent in the pipe.

[0004]

In order to solve the above problems and to easily and reliably detect the position of a robot moving in a hollow metal tube from the ground, the present invention adopts the following method. That is, a radio wave of a predetermined frequency is transmitted from the transmitter on the ground to the inside of the pipe and applied to the robot inserted in the pipe. The robot measures the elapsed time until the radio wave is reflected by the robot, returns to the ground again, and is received by the receiver, and the distance to the robot is calculated from this elapsed time.

[0005]

It is known that when a radio wave having a predetermined frequency determined from the inside diameter of the tube is transmitted into the tube, the internal attenuation is small and the intensity can be transmitted to a distant place without decreasing the intensity. Therefore, when this radio wave is transmitted to the inside of the pipe, it is transmitted to a distant place, and is reflected by hitting a robot located on the way. Since the reflected radio waves return inside the pipe and are received by the receiver on the ground, the distance from the ground device to the robot can be measured by measuring the time interval from transmission to reception and converting it into a distance.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the in-pipe robot position measuring method of the present invention will be described below.

FIG. 1 shows a measuring device used in such a pipe robot position measuring method. This measuring device 2 includes a transmitter 4,
The receiver 6 and the antenna 8 connected to them, the arithmetic unit 10, the display unit 12, the storage unit 14 connected to the arithmetic unit 10, and the like. The robot 20 is inserted for inspection inside the pipe 1, which is a gas pipe.

The transmitter 4 has a frequency = light speed / {1.706.
The radio wave having a frequency equal to or higher than the value obtained by x .., can be transmitted from the antenna 8. Thus, a radio wave having a frequency equal to or higher than the frequency obtained from the above equation has a property of propagating inside the pipe with a small attenuation if the pipe has an inner diameter substituted into the calculation formula. For example, the pipe 1 has an inner diameter of about 105 mm.
If it is a 100 A tube, the radio wave will have a frequency of 1.67 GHz or higher.

The receiver 6 receives the radio wave received by the antenna 8, and together with the radio wave transmitted from the transmitter 4, the arithmetic unit 10
Send to. The arithmetic device 10 detects the time interval between the transmitted radio wave and the received radio wave, substitutes the time interval into a predetermined formula, and calculates the distance to the robot 20. The storage device 14 stores a reception result obtained in a state where the robot 20 is not inserted in the tube 1 in advance, and is used as a comparison target with a reflection when the robot 20 actually receives the reflection. The display device 12 is a device that displays the distance to the robot 20 and the like calculated by the arithmetic device 10. Further, the display device 12 can be connected to a monitor 36 (which will be described later) of the robot 20 so that the distance value can be displayed together with the image in the tube taken by the robot 20.

Next, the robot 20 will be described. The robot 20 is driven by a radio control system, and includes a traveling drive device, a camera, a lighting device, a receiver, a transmitter, an antenna and the like (none of which are shown). Further, the robot 20 may be provided with a metal plate that reflects radio waves in the rear or the like, or a transponder may be mounted.
FIG. 2 shows the operating device 24 of the robot 20. As shown in FIG. 2, the operating device 24 includes an instruction box 26 for instructing the robot 20 to move forward and backward, a transmitter 28 for issuing an instruction from the instruction box 26, an antenna 30 connected to the transmitter 28, and an antenna 30. Receiver 32 to be connected, receiver 32
It is composed of a VTR 34, a monitor 36 and the like connected to the.

Then, the robot 20 is inserted into the tube 1 through its opening, and the traveling drive device is operated by radio instructions from the command box 26 to advance inside the tube 1. While proceeding, the inside of the camera is photographed by the equipped camera, and the video signal is transmitted from the transmitter. This video wave passes through the pipe 1 and is received by the antenna 30 and is received by the receiver 32.
The video is recorded on the VTR 34 and the image is displayed on the monitor 36.

In this way, when the robot 20 photographing the inside of the pipe 1 reaches a location such as corrosion and the fault location is shown in the image, the transmitter 4 of the inspection apparatus 2 transmits the signal of the predetermined frequency. An electric wave is transmitted as a pulse from the antenna 8. The radio wave travels through the pipe 1 and hits the robot 20,
It reflects and returns to the antenna 8. The reflected radio wave received by the antenna 8 is amplified and then sent to the arithmetic unit 10. A process for binarizing a signal in which a signal above a certain level is 1 and a signal below that level is 0 is binarized. At the same time, it is compared with the radio wave transmitted from the transmitter 4, and if necessary, it is compared with the information stored in the storage device 14, and the time from transmitting the radio wave to returning is spent. Detect the time taken. Then, from this elapsed time, the distance from the antenna 8 to the robot 20 is calculated by the calculation formula 1/2 (light speed × measurement time) and displayed on the display device 12.

As described above, according to the in-pipe robot position measuring method of the present embodiment, the position of the robot 20 working in the pipe 1 is measured by measuring the time until radio waves are transmitted from the ground and reflected by the robot. Since it is calculated by using the above method, it is possible to measure a very accurate position. Therefore, it is possible to correctly identify the location where an abnormality occurs and repair is required. Moreover, since a mechanism for adding the traveling distance of the robot 20 is not required for measurement, the system itself of the robot 20 can be simplified. Even if you measure several points in a row,
Since the measurement is performed at each point individually, no error is accumulated. Furthermore, the measurement can be performed in a very short time.

In the above embodiment, the case of the gas pipe has been described, but the in-pipe robot position measuring method of the present invention is not limited to the gas pipe. Further, the robot 20 is controlled by radio, but the present invention is not limited to this, and a cable may be connected. Even in this case, the position of the robot can be measured accurately and easily. Further, when the robot is a radio-controlled robot, the position measuring device may be incorporated in a device for operating the robot. By doing so, the antenna and the like can be shared, and the system can be further simplified.

[0015]

According to the in-pipe robot position measuring method of the present invention, a radio wave having a predetermined frequency is transmitted into the pipe, and the reflected wave reflected by the robot inserted for the inspection in the pipe and returned is received. , The distance to the robot is calculated by measuring the time until returning, so it is possible to measure a very accurate position. Therefore, it is possible to correctly identify the location where an abnormality occurs and repair is required. Further, since the robot does not need a mechanism for adding the traveling distance, the robot system itself can be simplified. Even when several points are continuously measured, the error is not accumulated at all because the measurement is performed individually at each point. Furthermore, the position of the robot in the pipe can be measured in a very short time.

[Brief description of drawings]

FIG. 1 is a diagram showing a measuring apparatus for carrying out a measuring method of the present invention.

FIG. 2 is a diagram showing a robot.

[Explanation of symbols]

 1 Tube 2 Measuring Device 4 Transmitter 6 Receiver 10 Computing Device 12 Display Device 14 Storage Device 20 Robot 24 Operating Device 26 Command Box 28 Transmitter 30 Antenna 32 Receiver 34 VTR 36 Monitor

Claims (1)

[Claims] 1. A radio wave having a predetermined frequency is transmitted from the ground into a pipe into which a robot for pipe work is inserted, and the radio wave reflected by the radio wave coming into contact with the robot in the pipe is used as a transmission point of the radio wave. The distance from the point of transmission of the radio wave to the robot in the pipe is detected by receiving the time at the same point, detecting the elapsed time from the time the radio wave is transmitted to the time of reception, and substituting the elapsed time into a predetermined calculation formula. In-pipe robot position measuring method, characterized in that