Suction-Cup Drilling End Effector for Robot Stiffness Limits

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Solution Overview

Problem

Articulated robot arms used in aircraft assembly and maintenance have limited stiffness, causing drilling tools to move away from target locations during drilling operations, leading to inaccurate drilling, damage to components, and increased broken drill bits.

Innovation Solution

A drilling system that includes a drilling end effector with a chuck to hold a drilling tool, a nosepiece to surround the tool, and a camera to align the end effector with a pattern on the workpiece surface, ensuring accurate positioning of the drilling tool relative to the target location.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If articulated robot arms are used for drilling operations, then versatility and flexibility are improved, but stiffness deteriorates causing tool movement away from target locations

Engineering Contradiction:
ImproveversatilityVSAvoidstiffness
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

A suction cup is introduced as an intermediary component between the robot arm and the workpiece surface. The suction cup adheres to the workpiece surface and provides a stable mounting point for the drilling tool, compensating for the robot arm's limited stiffness and preventing tool movement away from the target location.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If secondary encoders are mounted on the robot arm to correct tool movement, then positioning accuracy is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvepositioning accuracyVSAvoidcomplexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The complex secondary encoder system is extracted and replaced with a simpler suction cup-based positioning approach. The suction cup adheres to the workpiece surface and provides passive stability, eliminating the need for complex active measurement and correction systems while maintaining positioning accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If laser tracking systems are used to correct tool movement, then positioning accuracy is improved, but cost and complexity increase due to calibration requirements and rigid fixturing

Engineering Contradiction:
Improvepositioning accuracyVSAvoidmanufacturing complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The expensive laser tracking system with rigid fixturing is replaced with a simple, inexpensive suction cup that can be easily manufactured and deployed. The suction cup provides sufficient positioning accuracy without requiring complex calibration procedures or expensive equipment.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Measurement precision

If normality sensors are added to correct tool movement, then positioning accuracy is improved, but cost and complexity increase

Engineering Contradiction:
Improvepositioning accuracyVSAvoidcomplexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The suction cup system is self-regulating and automatically maintains proper positioning through its adhesive connection to the workpiece surface. No additional sensors or active control systems are needed, as the suction cup inherently provides the necessary stability and positioning accuracy.

Inventive Principle:
Principle #25Self-service

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 effectively aligns the drilling tool with the target location, reducing the occurrence of inaccurate drilling, damage to components, and broken drill bits, while maintaining the cost and complexity of the drilling system.

Implementation Method 1

The at least one suction cup is configured to be engaged in physical contact with the workpiece surface and pulled under suction by the suction system such that the at least one suction cup adheres to the workpiece surface

Methodology Applied
Scientific EffectSuction: Suction

Data Source

PatentEP3862120B1Drilling end effector for drilling a workpiece
Publication Date: 2025.04.30 THE BOEING CO
  • EP3862120B1 patent drawingFigure 1
  • EP3862120B1 patent drawingFigure 2
  • EP3862120B1 patent drawingFigure 3

AI summary

A drilling end effector (106) is provided for drilling a workpiece (112) having a workpiece surface (110). The drilling end effector includes a chuck (118) configured to hold a drilling tool (122), and a nosepiece (128) configured to at least partially surround the drilling tool (122) when the drilling tool is held by the chuck. The nosepiece (128) includes an end portion (132). The nosepiece includes at least one suction cup and at least one suction feed line. The at least one suction cup is fluidly connected to the at least one suction feed line. The at least one suction feed line is configured to be fluidly connected to a suction system. The at least one suction cup is configured to be engaged in physical contact with the workpiece surface (110) and pulled under suction by the suction system such that the at least one suction cup adheres to the workpiece surface to thereby hold the end portion (132) of the nosepiece (128) on the workpiece surface (112).