JPH0989543A - Method for positioning underwater inspecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a destined position without using an inclination angle by measuring a traveled distance using a bathometer, calculating the length of the linearly traveled distance along the direction of Y-axis, and computing the length of the linearly traveled distance along the direction of X-axis. SOLUTION: An underwater inspection robot 4 is moved from a preset initial position on a vertical wall 24 and along a vertical plane consisting of horizontal (X-axis) and vertical (Y-axis) directions, and is advanced toward a destination. Every sampling time, the distance Ii linearly traveled along the direction of X-axis is calculated from the value of a number-of-revolution counter, and the distance Yi traveled along the direction of Y-axis, obtained when a value measured by a bathometer 20 is converted into a y-coordinate from the initial position (zero point), is calculated. From the previously calculated difference between Yi -1 and Yi , the length yi of the distance Yi in the direction of Y-axis is calculated, and the length xi =(Ii <2> -yi <2> )<1/2> of the distance Xi in the direction of X-axis is calculated. The present position Pn is obtained from the integrated value Xn =Σ<n> xi of the distance Yn and the length xi calculated from the values measured by the bathometer 20. Therefore, the present position of the robot 4 can be detected with accuracy without use of an inclination angle θi which often results in computing errors.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of positioning an inspection device which moves along a vertical wall provided in water.

[0002]

2. Description of the Related Art The dead reckoning method is widely known as a method for measuring and grasping a current position on a plane by measuring a moving direction and a moving distance from a known initial position. FIG. 8 is a diagram for explaining the dead reckoning method. With the initial position as the origin (0 point), the horizontal X-axis and the vertical Y-axis are set, and the inclination θi with respect to the X-axis and the linear movement distance li in this direction are used. The point Pi represented is sequentially obtained, and the X coordinate Xn and the Y coordinate Yn of the current position Pn are obtained from the following equations.

Xn = l1COS θ1 + l2COS θ2 + ... + lnCOS θn ... (1) Yn = l1SIN θ1 + l2SIN θ2 + ... + lnSIN θn ... (2)

The inspection device is provided with wheels symmetrically with respect to the center line in the moving direction, and the moving distance li is obtained from the number of rotations. The following three methods are often used to measure the tilt angle θi. It is obtained from the difference in the rotational speeds of the left and right wheels described above. In the case of a wall, it is calculated from the difference between the direction of gravitational acceleration and the traveling direction. The direction is calculated by integrating the initial value and the angular velocity using a gyro.

[0005]

The linear movement distance li can be accurately measured even by a relatively small device, but there are problems in measuring the inclination θi. That is, in the method of (1), the measurement error is large due to the fluctuation and slippage of the contact point of the wheel. In the method (1), a measurement error may occur depending on the moving acceleration of the inspection device. Although the method is accurate, the device is large and expensive, and it is necessary to separate the influence of the rotation of the earth, which requires complicated calculation. Further, since the position inspection device measures the current position with reference to the reference point (initial position), the home position is frequently returned. Therefore, a high-accuracy sensor for finding the home position is required. It took a lot of time.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for detecting a moving position without using the inclination angle θi. Another object is to provide a method for approximately correcting the moving position. Moreover, it aims at providing the method of performing origin return quickly.

[0007]

In order to achieve the above object, in the invention of claim 1, the moving directions θi and θi with respect to the horizontal direction (X-axis direction) from the known initial position of the inspection device traveling on the vertical wall in water. The linear moving distance li in the direction is measured, and the moving distance Xj = Σ ^j licos θi in the X-axis direction and the vertical (Y-axis direction) moving distance Yj = Σ ^j lisin θi are set as the moving position of the Pj point (j ≧ i). In the positioning method of the underwater inspection apparatus that determines the above, Yi is measured from a water depth gauge, the length yi of li in the Y-axis direction is obtained, and the length of li in the X-axis direction xi = √ (li ² −yi ² ) To calculate Xj = Σ
Calculate ^j xi.

If Yi and Yi -1 are measured by a water depth meter, yi is obtained as the difference, and xi is obtained from li and yi. Xj is obtained as the integrated value of xi. Yj is measured by a water depth gauge. As a result, the current position Pj can be obtained without using θi.
Problems such as measurement error due to i can be eliminated. It should be noted that Σ ^j represents that 1 to ^j are integrated.

According to the second aspect of the present invention, the horizontal direction (X-axis direction) from the known initial position of the inspection device traveling on the underwater vertical wall.
The moving direction θi with respect to and the linear moving distance li in the θi direction
Is measured, and the moving distance in the X-axis direction Xj = Σ ^j licos θ
i, vertical direction (Y-axis direction) movement distance Yj = Σ ^j lisin
In the positioning method of the underwater inspection apparatus that determines the moving position (j ≧ i) of the Pj point as θi, Yi is measured by a water depth gauge, and a circle centering on the initial position and passing through the Pi point and a straight line Y =
An intersection point Pi ′ with Yi is obtained, and the Pi point is replaced with this intersection point Pi ′.

Assuming that the correct position of the point Pi is on the circumference passing through the Pi point with the initial position as the center, Yi can be obtained fairly accurately by the depth gauge, so the intersection Pi 'with the straight line Y = Yi is X. It can be approximated to represent a position containing only an axial error. As a result, it is possible to remove the error in the Y-axis direction among the errors caused by θi. The error can be reduced by performing such correction a plurality of times until reaching the current position Pj. The accuracy is lower than that of the invention of claim 1, but the calculation can be performed quickly.

According to the third aspect of the present invention, the depth gauge is a hollow material provided vertically, for example, a pressurized air supply source and a pressure measuring device for the pressurized air are connected to the upper side of a pipe, and the water pressure is measured at the lower end of the hollow material. The pressure at which the discharge air pressure is balanced is measured by the pressure measuring device, and the depth of the hollow material is measured from this.

Since the pressurized air pressure is balanced with the water pressure at the lower end of the hollow material when air is discharged from the lower end of the hollow material, the water depth at the lower end of the hollow material is measured by measuring the pressure of the pressurized air. be able to. This method is simple, but it can be measured with high accuracy.

In the invention of claim 4, the X-axis direction is the position of a known member provided in parallel with the Y-axis as the initial position, and the Y-axis direction is the measured value of the depth gauge.

Since the Y-axis direction can be accurately measured by using the measurement value of the water depth gauge, it is not necessary to return to the origin. Therefore, the measurement accuracy can be maintained only by returning to the origin in the X-axis direction. The purpose of returning to the origin is to find the reference point and measure the movement distance from it, so that it is possible to return to the nearest reference point. The reference in the X-axis direction may be any member whose position is known in parallel with the Y-axis. In this way, it is sufficient to return to the origin only in the X-axis direction, so the time required for the return is reduced,
In addition, since it is easier to detect a line than to detect a point, the number of sensors to be detected is reduced.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a system for implementing the present invention. The present invention detects the position of an inspection device moving on a vertical wall in water. The case of a pressure vessel used for nuclear power generation as a vertical wall will be described as an example, but the present invention can be applied to any vertical wall in water (for example, a tank wall of a hull). The system comprises an underwater inspection robot system 1, a data collection and processing device 2 for processing this data, and a remote control monitoring system 3 for operating and monitoring the underwater inspection robot. The underwater inspection robot system 1 includes an underwater inspection robot 4 which moves on a vertical wall, and a hose including a signal line for supplying pressurized air and electric power to the underwater inspection robot 4 and rewinding and rewinding of a cable including an electric wire. It is composed of a cable processing device 5 for performing cable processing, a controller 6 for controlling the underwater inspection robot 4 and the cable processing device 5, and a calibration water tank 7 for calibrating a depth gauge provided in the underwater inspection robot 4. ing. The remote control surveillance system 3 displays a rod-shaped surveillance camera device 8 equipped with a light source for illumination and a surveillance camera at its tip, a camera and a light source controller 9 for controlling the surveillance camera device 8, and an image captured by the camera. Monitor 10
Consists of.

FIG. 2 shows the construction of the underwater inspection robot,
(A) shows a planar structure, (B) shows the YY cross section of (A). Drive wheels 13 are provided in front of the vehicle body 12 and at symmetrical positions with respect to the center line C, and behind wheels 14 on the center line C are provided on the rear side and on which the direction can be freely changed. The drive wheel 13 is provided with a rotation counter 15 that counts the number of rotations.
The inclination θi can be measured from the difference in the number of rotations. When the moving distance li is obtained, the average value of the left and right rotation speed counters 15 may be used. Thrusters 16 are provided on the left and right of the vehicle body 12 and serve as propulsion units when moving in water.
When it adheres to, the water inside is discharged to generate an adsorption force.

A circular top plate 17 having an opening for the thruster 16 is provided on the top of the vehicle body 12, and a skirt 18 is provided around the top plate 17 to cover the vehicle body 12. A seal 19 made of a flexible material such as rubber is provided around the tip of the skirt 18, and when the underwater inspection robot 4 adheres to the vertical wall 24, the thruster 16 discharges the water inside to attract the water. To occur. The top plate 17 is provided with a water depth gauge 20 for measuring the depth of the underwater inspection robot 4 and a sensor 21 for detecting a reference position. A hose for pressurized air supplied to the water depth gauge 20, an electric wire for supplying electric power to the drive wheel 13 and the thruster 16, and a cable 22 which is an electric wire for control and measurement are connected to the vehicle body 12.

FIG. 3 is a diagram for explaining the operation of the water depth gauge 20. The water depth gauge 20 is provided at the underwater inspection robot 4 and the reference water depth position, and the water depth gauge provided at the reference water depth position is referred to as a reference water depth gauge 25. The pressurized air is supplied from the pressurized air source 26 to the water depth gauge 20 and the reference water depth gauge 25 through the solenoid valve unit 27 and the pressurized air hoses 23 provided in the respective units. A pressure gauge 28 is connected to each pressurized air hose 23 to measure the pressure of the pressurized air supplied. The water depth gauge 20 and the reference water depth gauge 25 may be those having an opening through which pressurized air is discharged into the water, and for example, as shown in the drawing, a pipe 34.
When using, the water pressure and the air pressure are balanced at the opening of the pipe 34. By correcting the pressure loss of the pressurized air hose 23, the pressure gauge 28 indicates the pressure at the opening portion, so that the water depth at the opening portion, that is, the position of the water depth gauge can be measured. In order to measure the depth position of the water depth gauge 20, the difference between the measured values of the water depth gauge 20 and the reference water depth gauge 25 is obtained. This makes it possible to offset the effects of changes in water level and changes in water temperature.

4A and 4B are views for explaining the origin return in the X-axis direction. FIG. 4A is a vertical sectional view, and FIG. 4B is an XX sectional view of FIG. In the vicinity of the vertical wall 24 of the pressure vessel, there is a shroud 31 for housing the core portion, and a plurality of cylindrical jet pumps 32 are vertically arranged around this shroud 31. Since the position of the jet pump 32 is fixed, the jet pump 32 is set to the X-axis, that is, the horizontal reference position. The center position of the cylinder is taken as the reference position of the jet pump 32 in the X-axis direction, and this center position is measured by the sensor 21. The sensor 21 is composed of a light emitting element and a light receiving element, and the underwater inspection robot 4 irradiates the jet pump 32 while traveling horizontally and receives the reflected light, and the received light data is collected and processed by the data processing and processing device 2
Then, the center position of the cylinder is calculated and the distance between the center position of the cylinder and the underwater inspection robot 4 in the X-axis direction is calculated. Reference numeral 33 indicates irradiation light.

FIG. 5 is an explanatory diagram for calculating the center position of the jet pump 32 in the X-axis direction. The horizontal axis represents the traveling distance of the underwater inspection robot 4 in the horizontal direction (X-axis direction), and the vertical axis represents the amount of reflected light. The center of a predetermined threshold value of reflected light is set as the center of the cylinder. The current position can be accurately obtained from the distance between the center of the cylinder and the underwater inspection robot 4 in the X-axis direction.

Next, the position measuring method of the first embodiment will be described using the above-mentioned apparatus. FIG. 6 is a diagram for explaining the position measuring method according to the first embodiment. From the predetermined initial position on the vertical wall 24, the underwater inspection robot 4 is moved along a vertical plane in the horizontal direction (X-axis direction) and the vertical direction (Y-axis direction) to proceed to the target position. Li is obtained from the value of the rotation counter 15 every sampling time, and Yi is obtained by converting the measured value of the water depth gauge 20 into the value of the Y coordinate from the initial position (0 point). From the difference between Yi -1 and Yi obtained previously, y
i is calculated, and xi = √ (li ² −yi ² ) is calculated. The current position Pn is Yn and x calculated from the measured value of the depth gauge 20.
It can be obtained from the integrated value Xi of i = Σ ⁿ xi. Σ ⁿ
Indicates an integrated value from 1 to n. This method does not use the tilt angle θi with many measurement errors, and the position in the vertical direction is measured by the water depth gauge 2.
Underwater inspection robot 4 with high accuracy
The current position of can be detected. Further, when measuring the next position, the origin return need only be performed in the X-axis direction, so that it can be completed in a short time.

Next, the position measuring method of the second embodiment will be described using the above-mentioned device. FIG. 7 is a diagram for explaining the position measuring method according to the second embodiment. The present embodiment reduces the error in the Y-axis direction by adding the data of the water depth gauge to the dead reckoning method described in FIG. That is, the moving direction θi in the horizontal direction (X-axis direction) from the known initial position and the linear moving distance li in the θi direction are measured, and the moving distance Xn = Σ ⁿ licos θi in the vertical direction (Y-axis direction) is measured. ) The moving position (n ≧ i) of the Pn point is determined as the moving distance Yn = Σ ⁿ lisin θi, but Y is set at the Pi point.
i is measured by a water depth meter, an intersection point Pi ′ of a circle passing through the point Pi and the straight line Y = Yi centered at the initial position is obtained, and the point Pi is replaced with the intersection point Pi ′.

Assuming that the correct position of the point Pi is centered on the initial position and on the circumference passing through the point Pi, Yi can be obtained fairly accurately by the water depth gauge 20, so that the straight line Y = Yi.
The intersection point Pi ′ with and can be approximated to represent the position including only the error in the X-axis direction. As a result, it is possible to remove the error in the Y-axis direction among the errors caused by θi. The error can be reduced by performing such correction a plurality of times until reaching the current position Pn. In the case of the first embodiment, since Yi is measured for each point Pi, an accurate position can be obtained, but measurement and calculation take time. On the other hand, in the case of the second embodiment, since the measurement of Yi is small, the measurement can be performed quickly.

[0024]

As is apparent from the above description, according to the present invention, the position in the Y-axis direction is measured by the water depth meter for each sampling position, and the moving distance li for each sampling position is changed to the length in the X-axis direction for each sampling position. Is calculated and integrated to measure the current position in the X-axis direction. Since the inclination angle θi having a large error is not used, the current position of the inspection device can be accurately detected. Further, by adding the depth gauge data to the conventional dead reckoning method, the error in the Y-axis direction can be reduced. Further, since the origin return in the Y-axis direction is not necessary, the return time can be shortened, the number of sensors for detecting the origin or the reference point and the grade can be reduced, and the device can be downsized and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a system for implementing the present invention.

FIG. 2 shows a configuration of an underwater inspection robot, (A) shows a planar structure, and (B) is a sectional view taken along line YY of (A).

FIG. 3 is a diagram illustrating a configuration of a water depth gauge.

FIG. 4 is a diagram illustrating origin return in the X-axis direction,
(A) is a longitudinal sectional view and (B) is a sectional view taken along line XX of (A).

FIG. 5 is an explanatory diagram for calculating the center position of the jet pump 32 in the X-axis direction.

FIG. 6 is a diagram illustrating the first embodiment.

FIG. 7 is a diagram illustrating a second embodiment.

FIG. 8 is a diagram illustrating a conventional dead reckoning method.

[Explanation of symbols] 1 underwater inspection robot system 2 data collection and processing device 3 remote control monitoring system 4 underwater inspection robot 12 vehicle body 13 drive wheel 14 follower wheel 15 revolution counter 16 thruster 17 top plate 18 skirt 19 seal 20 water depth gauge 21 sensor 22 cable 23 pressurized air hose 24 vertical wall 25 reference depth gauge 26 pressurized air source 27 solenoid valve unit 28 pressure gauge 31 shroud 32 jet pump 33 irradiation light 34 pipe

Front page continuation (72) Inventor Katsumi Kai 3-1-1, Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries Co., Ltd. Toni Technical Center

Claims (4)

[Claims] 1. A moving direction θ with respect to a horizontal direction (X-axis direction) from a known initial position of an inspection device which travels on an underwater vertical wall.
The linear moving distance li in the i and θi directions is measured, and the moving distance Xj in the X-axis direction is Xj = Σ ^j licos θi, and the vertical (Y-axis direction) moving distance is Yj = Σ ^j lisin θi. In the positioning method of the underwater inspection apparatus for determining ≧ i), Yi is measured by a depth gauge, the length yi of li in the Y-axis direction is obtained, and the length of li in the X-axis direction xi = √ (li ²
-Yi ² ) is calculated to calculate Xj = Σ ^j xi. 2. A moving direction θ with respect to a horizontal direction (X-axis direction) from a known initial position of an inspection device that travels on an underwater vertical wall.
The linear movement distance li in the i and θi directions is measured, and the movement distance Xj in the X-axis direction is Xj = Σ ^j licos θi, and the vertical movement distance (Y-axis direction) is Yj = Σ ^j lisin θi. In the positioning method of the underwater inspection apparatus for determining ≧ i), Yi is measured from a water depth meter, and Pi is centered on the initial position.
The intersection point Pi ′ between the circle passing through the point and the straight line Y = Yi is calculated, and Pi
A method of positioning an underwater inspection apparatus, characterized in that a point is replaced with this intersection Pi '. 3. The water depth meter has a pressurized air supply source and a pressure measuring device for the pressurized air connected to an upper side of a hollow member provided vertically, and a pressure at which a water pressure and a discharge air pressure are balanced at a lower end of the hollow member. The method for positioning an underwater inspection apparatus according to claim 1 or 2, wherein the pressure measuring device measures the depth of the hollow material. 4. The X-axis direction is the position of a known member provided in parallel with the Y-axis as the initial position, and the Y-axis direction is the measured value of the water depth gauge. A method for positioning the underwater inspection apparatus described.