JPH08320309A - Method and apparatus for underwater inspection - Google Patents

Abstract

PURPOSE: To detect a small crack or the like easily and surely by a remote operation. CONSTITUTION: In a robot body 11, a skid 22 which is provided with a slip preventive member 24 on the rear surface is installed at the lower part. When a vertical propeller 20 is driven, the skid 22 is pushed to a fixation part or the like, and the robot body 11 can be fixed. An arm 26 which can be turned to the horizontal direction and the up-and-down direction is attached to the tip part of the skid 22. Then, a hand 42 which is provided with a probe 38 for testing of an eddy current and with a scanning mechanism 40 used to scan the probe 38 is attached to the tip of the arm 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for inspecting an object to be inspected existing in water, and more particularly to an underwater inspection method and an apparatus suitable for detecting flaws in a water turbine of a hydroelectric power generation facility.

[0002]

2. Description of the Related Art A water turbine of a hydroelectric power plant is subjected to a large amount of water pressure and rotates at a high speed, so that high stress is likely to occur at the root portion of the blade of the runner. May damage the wings. For this reason, in hydroelectric power generation facilities, water turbines are regularly inspected. In the conventional turbine inspection work, after draining the water in the draft tube that forms the drainage channel of the turbine, the worker enters the draft tube from the manhole provided on the side of the draft tube and visually inspects it. I was trying to do it.

However, since such an inspection work requires a worker to enter the draft tube, it not only requires drainage work in the draft tube, but also requires attachment and detachment of scaffolds for inspection, which is long. Requires preparatory work. Moreover, the inspection work is not only dangerous work at a high place, but also a visual inspection by a worker,
The inspection requires a lot of time. Therefore, the applicant of the present application has proposed a water wheel inspection device using an underwater robot so that a manual inspection work can be eliminated and a quick inspection can be performed (JP-A-5-288686).

In this water turbine inspection device, an underwater robot equipped with an underwater television camera is launched into the draft tube from a manhole opened in the draft tube, a laser beam is used to indicate a target position, and the television camera sets the position. While checking, the underwater robot is guided to the target position, and the image taken by the TV camera is displayed on the image device to check the state of the water turbine.

[0005]

However, the above inspection device using the underwater robot detects a small crack in the water turbine because the image taken by the TV camera is displayed on the image device to inspect the state of the water turbine. Not only is it difficult to do, but it is often difficult to distinguish between dust and cracks on the turbine.

The present invention has been made to solve the above-mentioned drawbacks of the prior art, and an object thereof is to make it possible to easily and surely detect a small crack or the like by remote control.

[0007]

In order to achieve the above object, an underwater inspection method according to the present invention is an underwater robot capable of navigating underwater, in which water is ejected above the robot by a propulsion device of the robot. It is configured to perform inspection such as flaw detection and the like by pressing and fixing it to a fixed object in water and bringing the sensor provided in the underwater robot into contact with the inspection area of the inspection object and slidingly scanning.

Further, the underwater inspection apparatus according to the present invention is provided in a robot body for navigating underwater, and ejects water above the robot body to tightly fix the legs of the robot body to an underwater fixed object or the like. And a contact type sensor such as a flaw detection probe, an arm attached to the robot body for holding the sensor in contact with an inspection target, and a scanning mechanism section for moving the sensor held by the arm. . The leg portion provided at the bottom of the robot body may be provided with a slip prevention member on the lower surface. As the anti-slip member, rubber having a large friction coefficient can be used. Further, the arm is formed to be bent and rotatable in the horizontal direction and the vertical direction. As the sensor, a probe for an eddy current test, an ultrasonic sensor for detecting the thickness of an object to be inspected or an internal defect, a displacement sensor for detecting a surface shape, or the like can be used.

[0009]

According to the present invention constructed as described above, the vertical moving propulsion device of the body of the underwater robot is driven to eject water above the robot body, and the robot body is fixed by pressing it against an underwater fixed object or an object to be inspected. Then, the inspection area around it is slidably scanned by the contact sensor attached to the arm to inspect for flaws and the like. Therefore, it is possible to easily and accurately detect a small crack, distinguish dust from a crack, change a surface shape, an internal defect of an inspection target, a change in thickness, and the like. Furthermore, since the sensor is slidably scanned by the scanning mechanism, it is not necessary to operate the entire arm when scanning the sensor, and control is easy and scanning can be performed with a small amount of energy. Also, if slip prevention is attached to the lower surface of the leg part, it is possible to prevent the robot body from slipping when the robot body is pressed against a fixed object etc. by the propulsion device, and perform stable sliding scanning of the sensor. It is possible to perform accurate inspection. If rubber is used as the slip prevention member, the inspection target will not be damaged even if the robot main body is stopped on the inspection target via the legs.
By making the arm bendable and rotatable, it is possible to scan a wide range while the robot body is stopped.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the underwater inspection method and apparatus according to the present invention will be described in detail with reference to the accompanying drawings. FIG.
FIG. 3 is a side view of the underwater inspection apparatus according to the embodiment of the present invention.

In FIG. 1, an underwater inspection apparatus 10 has a robot body 11 composed of a pressure-resistant cylindrical watertight container. In the case of the embodiment, the robot main body 11 is formed to have a size that allows it to enter the water turbine of the hydraulic power generation facility, and has a transparent dome portion 12 made of acrylic resin or the like on the front side (right side in FIG. 1). I have it. A television camera 14 attached to a pan head is arranged in the dome 12, and the front state of the robot body 11 is imaged.
As will be described later, it can be displayed on the monitor display section.

On both sides of the robot body 11, the body 11
A horizontal thruster 16 for moving the robot forward or backward, a lateral thruster 18 for laterally moving the robot body 11,
A vertical propulsion device 20 is provided for raising and lowering the robot body 11 and for pressing and fixing the robot body 11 to, for example, a runner of a water turbine for a generator or an arbitrary position of a draft tube as described later. Further, a pair of skids 22, which are legs to be brought into contact when fixing the main body 11 to the runner or the draft tube, are attached to the lower portion of the robot main body 11. The skid 22 has an anti-slip member 24 formed on the lower surface with a member having a large friction coefficient such as rubber.

One skid (eg right skid)
An arm 26 is provided above the tip of 22. The arm 26 has a first arm 28 and a second arm 30, and the shoulder joint 32 allows the entire arm 26 to pivot horizontally. In addition, the first arm 28
Can be rotated in the vertical direction with respect to the shoulder joint 32 by the joint 34.
In the above, the first arm 28 can be rotated in the vertical direction. Then, at the tip of the second arm 30,
A hand 42 having a plurality of eddy current test probes 38, which are sensors, and a scanning mechanism section 40 for linearly scanning the probes 38 is attached.

The hand 42, as shown in FIG.
It is fixed to an output shaft 46 of a gear motor 44 provided in the arm 30 so that it can rotate around the axis of the second arm 30. The hand 42 is provided with a wrist motor 48 that rotates the scanning mechanism 40 in a direction orthogonal to the paper surface of FIG. 2, and a scanning motor 50 that moves the probe 38 in the left-right direction of FIG. Wrist motor 48
Is arranged so as to be orthogonal to the second arm 30, a gear 54 is fixed to the output shaft 52, and the gear 54 is fixed to one end of a shaft 56 arranged parallel to the wrist motor 48. It meshes with the gear 58. The scanning mechanism 40 is attached to the shaft 56 via a bracket 60, and the shaft 56 is driven by driving the wrist motor 48.
So that the scanning mechanism 40 can be swung around the shaft 56.

The scanning motor 50 is arranged parallel to the wrist motor 48, and a gear 64 is fixed to the output shaft 62.
Further, a screw shaft 72 is rotatably attached to the front side of a motor case 66 accommodating the scanning motor 50 in parallel with the scanning motor 50 via brackets 68 and 70.
The gear 64 provided on the scanning motor 50 is
It meshes with a gear 74 fixed to one end of the shaft 2, and the rotational driving force of the scanning motor 50 is transmitted to the screw shaft 72 via the gear 74 so that the screw shaft 72 can be rotated. Further, a probe unit 78 in which a plurality of probes 38 are integrated is attached to the screw shaft 72 via a nut member 76. Further, as shown in FIG. 3, a guide bar 80 is attached to the motor case 66 above the screw shaft 72 via brackets 68 and 70. The guide bar 80 is parallel to the screw shaft 72 and
The nut member 76 penetrates and blocks the rotation of the nut member 76.

In the probe unit 78, five probes (coils) 38 and two dummy coils 82 for preventing a decrease in the sensitivity of the end probe are arranged in a zigzag pattern, which are shown in FIG. It is inserted in the holder 86 so as to be movable in the axial direction (front-back direction) as indicated by an arrow 84. Further, a stopper 90 is attached to the probe 38 and the dummy coil 82, and a base 88 to which a holder 86 is attached is attached.
A coil spring 92 compressed between the stopper 90 and the stopper 90 biases the probe and the dummy coil in a direction projecting from the holder 86, so that the probe 38 can be reliably inspected even if the inspection target has a curved surface or unevenness. It is designed so that it can be brought into contact with an object.

As shown in FIG. 5, the inspection apparatus thus constructed is connected to the control unit 104 provided in a control room such as on the ground via cables 100 to 102. These cables 100 to 102 are integrated and have a so-called neutral buoyancy, in which an appropriate floating body is attached to a portion that is pulled out into water and the specific gravity is adjusted to be approximately the same as the specific gravity of water. The control unit 104 includes a video recording unit 106 and a monitor display unit 108, and also includes a robot control device 110 and an arm control device 112. In addition, the control unit 104 includes the robot body 1
1, the joystick device 114 for remotely operating the arm 26 and the arm operating device 116 are connected, and an eddy current test (E
The CT) analysis device 118 can be connected.

In the embodiment constructed as described above,
For example, when inspecting a water turbine of a hydraulic power generation facility, the underwater inspection device 10 is arranged in a manhole of a draft tube, and water in the trough tube is introduced into the manhole via a water injection pipe or the like. When the manhole is filled with water, the manhole cover is released, and the joystick device 114 is operated to operate the propulsion devices 16, 18, 20 provided on the robot body 11.
To drive the underwater inspection device 10 into the draft tube. Then, while watching the image of the television camera 14 displayed on the monitor display unit 108, the underwater inspection device 10 is guided to the lower part of the runner above the draft tube by using the laser guiding device or the tracking device.

When the robot body 11 reaches the lower portion of the runner 120 as shown in FIG.
Is placed upward along the runner 120, and the direct thruster 20
Is driven to spout water above the robot body 11, and the skid 22 is pressed against the inner surface of the runner,
Is fixed to the inner surface of the runner and maintained in that state. After that, the television camera 1 displayed on the monitor display unit 108
While watching the image from 4, the arm operation device 116 is operated to bring the probe 38 provided at the tip of the arm 26 into contact with a predetermined inspection position such as the root of the wing. Next, the operation motor 50 is driven to rotate the screw shaft 72, and the probe 38 of the probe unit 78 slides and scans along the screw shaft 72. At this time, even if a reaction force is applied from the water turbine due to the sliding of the probe 38, the robot body 11 can move because it is pressed and fixed to the runner 12 and the draft tube which is the fixing portion by the vertical propulsion device 20. Absent.

On the other hand, the probe 38, when sliding on the surface of the water turbine, generates a high-frequency magnetic field to generate an eddy current on the surface of the water turbine. Then, the secondary electromotive force due to the eddy current is detected by the probe 38 and input to the eddy current test analysis device 118. The eddy current test analysis device 118 uses the probe 38.
Of the probe 38 and the position signal of the probe 38 from the control unit 104, the presence of a scratch or the like is detected from the change in the secondary electromotive force, and the position coordinate is calculated to calculate the size of the scratch or the like to the control unit 104. Output.

When the probe 38 moves from one end side to the other end side of the scanning mechanism section 40, the arm 26 and the hand 42.
3 is operated to move the operation mechanism section 40 in the vertical direction in FIG. 3 by a predetermined amount, and the scanning motor 50 is reversely rotated to scan the probe 38 in the reverse direction to return it to the initial position. Thereafter, when the inspection of the range covered by the arm 26 and the hand 42 is completed in the same manner, the robot main body 11 is moved and the robot main body 11 is stopped at an appropriate position, and the inspection of the water turbine is performed in the same manner as described above. continue.

As described above, in the embodiment, since the eddy current test probe 38 is slidably scanned on the water wheel by remote control, even a small scratch can be easily found, and dust and scratches can be easily detected. The distinction can be made easily. Moreover, it is not necessary to drain the water inside the draft tube or build a scaffold inside the draft tube, making it easy to inspect the turbine.
Can be done quickly. Furthermore, in the example,
Since the probe 38 is made to scan by the scanning motor 50, the arm 26 is scanned when the probe 38 is scanned.
It is not necessary to drive the whole of the device, control is easy, and scanning can be performed with a small amount of energy. Further, in the embodiment, since the slip prevention member 24 made of rubber is attached to the lower portion of the skid 22, the robot body 11 slides and moves when the robot body 11 is pressed against the draft tube by the vertical propulsion device 20. This can be prevented, and the probe 38 can be stably and reliably scanned. Since the anti-slip member is made of rubber, it is possible to prevent the draft tube from being scratched.

In the above-described embodiment, the case where the sensor is the eddy current test probe 38 has been described. However, an ultrasonic sensor for measuring an internal defect or a thickness of an inspection object or a surface shape of the inspection object. A displacement sensor or the like may be used to detect the. Further, in the above-described embodiment, the case where the invention is applied to the inspection of the water turbine of the hydroelectric power generation facility has been described, but the invention can also be applied to, for example, the inspection of the bottom of the ship or the inspection of the underwater pier. In particular, in the embodiment, since water is jetted above the robot body by the vertical propulsion device 20 and the robot body 11 is pressed against a fixed object or the like to be fixed, even in a place where there is a flow. The robot body 11 can be fixed easily and surely, and the inspection can be surely executed.

[0024]

As described above, according to the present invention, the propulsion device is driven to eject water above the robot main body to make the main body of the underwater robot become the underwater inspection object itself or a fixed object around it. Since it is pressed and fixed, and the inspection area around it is operated by a contact type sensor to inspect for flaw detection, etc., small cracks are detected, dust and cracks are distinguished, surface shape changes, internal defects of the inspection target, Easy to change the thickness, etc.
Can be accurately detected. Moreover, since the sensor is moved by the scanning mechanism unit, it is not necessary to drive the entire arm when scanning the sensor, control is easy, and scanning can be performed with a small amount of energy. Also, if you attach a slip prevention member to the lower surface of the leg, when the robot body is pressed against the inspection target or fixed object by the propulsion device,
It is possible to prevent the robot body from slipping, and it is possible to perform stable inspection. Furthermore, bend the arm,
By being rotatable, it is possible to scan a wide range without moving the robot body.

[Brief description of drawings]

FIG. 1 is a side view of an underwater inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing details of a scanning mechanism portion provided at a tip portion of an arm according to an embodiment.

FIG. 3 is a front view of the probe unit according to the embodiment.

4 is a sectional view taken along the line AA of FIG.

FIG. 5 is an explanatory diagram showing an example of an inspection system including the underwater inspection device according to the embodiment.

FIG. 6 is an explanatory diagram of a usage example of the inspection apparatus according to the embodiment.

[Explanation of symbols]

 10 Underwater Inspection Device 11 Robot Main Body 14 TV Camera 16 Horizontal Propulsion Device 18 Horizontal Propulsion Device 20 Vertical Propulsion Device 22 Leg (Skid) 24 Anti-Slip Member 26 Arm 38 Sensor (Eddy Current Test Probe) 40 Scanning Mechanism Unit 42 Hand 50 Scanning motor 72 Screw shaft

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Makoto Konosu 5-6-4 Tsukiji, Chuo-ku, Tokyo Mitsui Engineering & Ships Co., Ltd. (72) Toshihiko Sekimoto 5-6-4 Tsukiji, Chuo-ku, Tokyo Mitsui Shipbuilding Co., Ltd. (72) Inventor Hisao Ohno 1-3-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Tokyo Electric Power Company (72) Inventor Osamu Iwai 2-4 Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Toshiba Keihin Office

Claims (4)

[Claims] 1. An underwater robot capable of navigating underwater is fixed by jetting water above the robot by a propulsion device of the robot and pressing it against a fixed object in the water, and a sensor provided on the underwater robot is an object to be inspected. The in-water inspection method is characterized by inspecting for flaw detection and the like by making contact with the inspection area of and slidingly scanning. 2. A propulsion device provided on a robot body that navigates underwater, spraying water above the robot body to closely fix the legs of the robot body to an underwater fixed object, and a contact-type sensor such as a flaw detection probe. And an arm attached to the robot body for holding the sensor in contact with an inspection target,
An underwater inspection apparatus comprising: a scanning mechanism unit that moves the sensor held by the arm. 3. The underwater inspection apparatus according to claim 2, wherein the leg portion is provided with a slip prevention member on a lower surface thereof. 4. A robot body equipped with a propulsion device for navigating in water, and vertically moving the robot body, and jetting water above the robot body to fix the robot body to an underwater fixed object or the like. A vertical propulsion device, a contact type sensor such as a flaw detection probe, a bendable and rotatable arm attached to the robot body for bringing the sensor into contact with an object to be inspected, and the sensor held by the arm linearly. An underwater inspection apparatus comprising: a moving scanning mechanism section; and a leg section provided on the robot body and provided with an anti-slip member on a lower portion thereof.