Force-Sensed Tool Gap Measurement in Structural Assemblies

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Solution Overview

Problem

Current methods for measuring gaps between structural components, such as in aircraft manufacturing, are time-consuming, labor-intensive, and prone to errors, particularly when using feeler gauges, and are difficult to access in fully-assembled structures.

Innovation Solution

A system and method using force sensors coupled to a tool or end effector to detect differences in forces as the tool operates on components, determining the gap distance based on these force variations, allowing real-time, accurate measurement of gaps without additional processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If feeler gauges are used to measure gap width, then measurement can be performed, but the process is time-consuming and labor-intensive

Engineering Contradiction:

Improvegap width measurementVSAvoidmeasurement speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces the manual mechanical feeler gauge system with an automated optical measurement system. The optical sensor non-contactively measures the gap between components while the drill operates, eliminating the need for manual insertion and removal of feeler gauges. This substitution of mechanical measurement with optical measurement resolves the contradiction by maintaining measurement capability while dramatically improving productivity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If feeler gauges are used to measure gap width, then measurement can be performed, but errors in measurements can occur

Engineering Contradiction:

Improvegap width measurementVSAvoidmeasurement accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces manual mechanical measurement with automated optical sensing. The optical sensor objectively measures gap dimensions without human intervention, eliminating measurement errors caused by operator technique, gauge wear, or contamination. This substitution enhances reliability by providing consistent, repeatable measurements that are not subject to human error.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If feeler gauges are used to measure gap width, then measurement can be performed, but accessibility is difficult in fully-assembled structures

Engineering Contradiction:

Improvegap width measurementVSAvoidaccessibility to gap

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent integrates the measurement function into the drilling tool itself, making the drill multi-functional. The drill both creates the hole and simultaneously measures the gap between components during operation. This integration resolves the accessibility problem because the measurement is performed from the same location where drilling occurs, eliminating the need for separate access to measure gaps in fully-assembled structures.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Manufacturing precision

If shimming process is performed to compensate for gaps, then load capabilities can be satisfied, but additional time and processes are required

Engineering Contradiction:

Improvegap compensationVSAvoidassembly cycle time

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent performs gap measurement during the drilling operation itself, before final assembly steps. By measuring the gap while the drill is still in position, the system enables preliminary identification of gap issues that can be addressed immediately. This preliminary measurement action prevents the need for subsequent shimming operations, thereby maintaining manufacturing precision while reducing overall assembly cycle time.

Inventive Principle:

Principle #10Preliminary action

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

Enables efficient, accurate, and reliable gap measurement during tool operations, reducing time and labor, minimizing accessibility limitations, and eliminating human error, while integrating with automated processes for improved quality control.

Implementation Method 1

A control unit is configured to receive one or more force signals from one or more force sensors coupled to one or both of a tool or an end effector. The one or more force signals are indicative of one or more forces exerted in relation to the tool or the end effector as the tool operates on a first component and a second component.

Methodology Applied

Scientific EffectForce detection: Force

Data Source

PatentUS12366446B2Systems and methods for evaluating a gap between structural components

Publication Date: 2025.07.22 THE BOEING CO

AI summary

A system and a method include a control unit configured to receive one or more force signals from one or more force sensors coupled to one or both of a tool or an end effector. The one or more force signals are indicative of one or more forces exerted in relation to the tool or the end effector as the tool operates on a first component and a second component. The control unit is further configured to detect a difference in the one or more forces as an operative portion of the tool passes through a gap between the first component and the second component. The control unit is further configured to determine a distance of the gap based on the difference in the one or more forces.