In-Pipe Robot Wheel Pivot Structure for Axis Alignment

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Solution Overview

Problem

Conventional in-pipe robots experience instability while traveling in pipes, often roll around the pipe axis, and are limited in their ability to perform multiple operations due to misalignment of the rotation axis with the pipe center, leading to unintended cutting or inadequate photography.

Innovation Solution

The in-pipe robot features a chassis with side frames, first and second wheel bodies, and a rotary actuator, where intermediate wheels are raised to contact the pipe wall, ensuring the rotation axis aligns with the pipe center, allowing stable travel and efficient operation for both drilling and inspection tasks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional in-pipe robot uses four wheels for traveling, then the robot can move in the pipe, but the traveling becomes unstable and the robot rotates around the pipe axis

Engineering Contradiction:
Improvetraveling stabilityVSAvoidoperation difficulty
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The robot divides its wheel system into two separate wheel bodies (first wheel body and second wheel body) instead of using a conventional four-wheel configuration. Each wheel body has traveling wheels and intermediate wheels that can be independently positioned, allowing stable contact with the pipe inner wall and preventing unwanted rotation during travel

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The wheel bodies are designed to be rotatable relative to the chassis, with elevating means that can raise and lower the intermediate wheels to contact the pipe wall. This dynamic adjustment capability allows the robot to adapt to different pipe diameters and maintain stable positioning, resolving the instability issue of conventional fixed wheel configurations

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the rotation axis deviates from the pipe center axis due to different pipe diameters, then the robot can adapt to various pipe sizes, but the drilling blade cuts unintended parts or the camera fails to photograph as intended

Engineering Contradiction:
Improvepipe diameter adaptabilityVSAvoiddrilling precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The invention replaces conventional mechanical positioning methods with a sensor-based detection system. A sensor detects the position of the pipe center axis, and this information is transmitted to a controller that automatically adjusts the rotation axis position to coincide with the detected pipe center, ensuring precise drilling and photography operations regardless of pipe diameter variations

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system implements a feedback loop where the sensor continuously monitors the pipe center axis position, and the controller adjusts the rotation axis accordingly. This closed-loop control ensures that the rotation axis remains aligned with the pipe center, maintaining drilling precision and photography quality across different pipe diameters

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If conventional in-pipe robot is designed for single purpose (drilling or inspection), then the design can be simplified, but one robot cannot be used for multiple purposes

Engineering Contradiction:
Improvemulti-purpose capabilityVSAvoidrobot structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The robot is designed with a universal chassis structure that can accommodate different functional attachments. The wheel bodies, elevating means, and rotary actuator system provide a stable platform that can support both drilling blades and camera systems, allowing a single robot to perform multiple functions including drilling, cutting, and inspection operations

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3792544B1In-pipe robot
Publication Date: 2023.06.07 SHONAN GOSEI JUSHI SEISAKUSHO KK
  • EP3792544B1 patent drawingFigure 1
  • EP3792544B1 patent drawingFigure 2
  • EP3792544B1 patent drawingFigure 3

AI summary

An in-pipe robot is provided with a rotary actuator 30 that rotates the drilling blade 21 in the circumferential direction of an existing pipe. A wheel body 50 provided with a traveling wheel 52 on both sides and a wheel body 70 provided with a traveling wheel 72 on both sides are supported between side frames 43 of a chassis via pins 54 and 74. The other ends of both the wheel bodies are rotatably coupled around an axle 63 of an intermediate wheel 65 as a pivot. When both the wheel bodies rotate, the intermediate wheels and the rotary actuator move above a horizontal line passing through the pin center. Each pin is disposed at the midpoint of a line connecting the center of the traveling wheel and the center of the intermediate wheel so that the rotation axis v1 of the rotary actuator coincides with the pipe center axis of the existing pipe.