Cable Spool Gravity Compensation for Crawler Vehicles

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Solution Overview

Problem

Existing automated systems for maintaining large structures like aircraft fuselages and wind turbine blades face challenges in maintaining vacuum adherence and locomotion on non-level surfaces due to high gravitational forces, leading to increased complexity, cost, and performance risks, particularly with dirt, grease, or debris on the surface.

Innovation Solution

A gravity-compensating system using a cable spool to generate tensile force counteracting gravitational forces, allowing crawler vehicles to adhere and move on non-level surfaces with reduced suction forces and power consumption, by winding a portion of the cable to exert a tensile force opposing gravity, enabling efficient movement and maintenance operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If higher suction flow (vacuum adherence) is used to maintain crawler vehicle position on non-level surfaces, then adherence force is improved, but device complexity and system cost increase

Engineering Contradiction:
Improveadherence forceVSAvoidsystem complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent applies a cable spool mechanism that winds a cable to generate a tensile force counteracting the gravitational force on the crawler vehicle. This anti-gravity force compensates for the component of weight acting parallel to the inclined surface, thereby reducing the vacuum adherence force required to prevent slippage. The cable spool system acts as a mechanical counterweight that dynamically balances gravitational effects.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The patent introduces a cable as an intermediary element between the crawler vehicle and the support structure. The cable transmits the gravitational load from the crawler vehicle to the cable spool mechanism, which is anchored to a stable support structure. This intermediary cable system allows the crawler vehicle to operate on inclined surfaces without requiring the vacuum adherence system to directly counteract the full gravitational force.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If higher suction flow is used to prevent slippage on contaminated surfaces, then reliability is improved, but use of energy increases

Engineering Contradiction:
Improveslippage preventionVSAvoidelectrical power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The cable spool mechanism provides a mechanical counterbalance to gravitational forces, specifically counteracting the component of weight parallel to the inclined surface. By providing this anti-gravity force through cable tension, the system reduces the energy demand on the vacuum adherence system, allowing it to operate at lower power levels while maintaining sufficient adherence to prevent slippage on contaminated surfaces.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

3Speed

If higher locomotion power is used to move crawler vehicle in vertical directions, then speed is improved, but device complexity increases

Engineering Contradiction:
Improvelocomotion speedVSAvoidsystem complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The cable spool system acts as a mechanical counterweight that compensates for gravitational forces during vertical or near-vertical locomotion. By providing an upward tensile force through the cable, the system reduces the net force that the crawler vehicle's drive system must generate, enabling vertical movement without requiring excessively high locomotion power or complex additional mechanisms.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

4Stability of the object's composition

If higher adherence force is used to maintain position on inclined surfaces, then stability is improved, but object-affected harmful factors increase due to surface damage risk

Engineering Contradiction:
Improveposition stabilityVSAvoidsurface damage
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The cable spool mechanism provides a mechanical counterbalance to gravitational forces, reducing the normal force that the crawler vehicle's vacuum system must exert on the surface. By sharing the load through cable tension, the system maintains position stability on inclined surfaces while reducing the adhesive stress on the surface, thereby minimizing the risk of surface damage.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system reduces the electrical power consumption and cost of crawler vehicles while maintaining effective adherence and movement on non-level surfaces, enhancing safety and reducing maintenance time and labor by allowing efficient scanning and inspection operations.

Implementation Method 1

a cable spool (not onboard the tool-equipped crawler vehicle) is rotated to wind a portion of the cable from which the vacuum-adhered crawler vehicle is suspended to generate a tensile force that counteracts a gravitational force

Methodology Applied
Scientific EffectTension: Tension

Implementation Method 2

the crawler vehicle is in contact with and 'adhered' to a non-level surface by suction or vacuum forces

Methodology Applied
Scientific EffectVacuum: Vacuum

Data Source

PatentEP3599175B1Gravity compensation for self-propelled robotic vehicles crawling on non-level surfaces
Publication Date: 2021.05.19 THE BOEING CO
  • EP3599175B1 patent drawingFigure 1A~1B
  • EP3599175B1 patent drawingFigure 2A~2B
  • EP3599175B1 patent drawingFigure 3A~3C

AI summary

Apparatus and methods for providing gravity compensation to a cable-suspended, vacuum-adhered, tool-equipped crawler vehicle traveling along and following the contour of a non-level surface during the execution of an automated maintenance operation. One technical feature shared by multiple embodiments of the gravity-compensating systems is that a cable spool is operated to wind a portion of the cable from which the vacuum-adhered crawler vehicle is suspended to generate a tensile force that counteracts a gravitational force being exerted on the crawler vehicle during movement. Rotation of the cable spool may be driven by a motor or by a tensioning spring.