Robotic Tool Coupling With Impedance Switching for Precise Engagement

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Solution Overview

Problem

Vehicle manufacture requires skilled operators to work in un-ergonomic, restricted areas for long periods, leading to increased likelihood of manufacturing defects, variance in process completion time, and cost due to various hard-to-quantify process variables such as operator skill, tool placement accuracy, and tool serviceability, which existing solutions have failed to adequately address.

Innovation Solution

A tool engagement coupling system utilizing a robotic arm linked to a tool engagement coupler, capable of operating in multiple axes and switching between impedance modes to achieve precise positioning of tools on workpieces, with stiff and compliant modes allowing for accurate and flexible movement, guided by a locator with a predetermined shape, enabling precise tool engagement within a spatial tolerance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a robotic arm is used to automate tool positioning, then operator skill dependency and manufacturing defects are reduced, but positioning precision and adaptability to restricted spaces become challenging

Engineering Contradiction:
Improvemanufacturing defect reductionVSAvoidtool placement accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The robotic arm operates in multiple impedance modes (stiff and compliant) that can be dynamically switched based on the task and distance from the work position. This dynamic adaptability allows the system to maintain high positioning precision during approach while providing compliance during engagement, resolving the contradiction between automation reliability and manufacturing precision

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the impedance parameter (stiffness) of the robotic arm based on the operational phase. By adjusting the stiffness parameter dynamically, the system achieves both accurate positioning when far from the workpiece and compliant engagement when close, thereby maintaining precision while benefiting from automation reliability

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the robotic arm operates in stiff mode for accurate positioning, then placement accuracy improves, but flexibility and compliance in restricted spaces deteriorate

Engineering Contradiction:
Improvetool placement accuracyVSAvoidcompliance in restricted spaces
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The system dynamically switches between stiff and compliant impedance modes based on the operational requirements. During the approach phase, stiff mode provides accurate positioning, while during engagement in restricted spaces, compliant mode provides the necessary flexibility and adaptability, thus resolving the contradiction between precision and adaptability

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If the robotic arm operates in compliant mode for flexibility, then adaptability to restricted spaces improves, but positioning accuracy and stability deteriorate

Engineering Contradiction:
Improveflexibility in restricted spacesVSAvoidpositioning accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The system uses dynamic impedance mode switching where compliant mode is activated during the approach phase to navigate restricted spaces with flexibility, then transitions to stiff mode during the final positioning phase to ensure accurate and stable tool placement, thereby resolving the contradiction between adaptability and precision

Inventive Principle:
Principle #15Dynamics

4Manufacturing precision

If multiple impedance modes are implemented, then system adaptability and precision improve, but device complexity increases

Engineering Contradiction:
Improvetool positioning accuracyVSAvoidimpedance mode control system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system implements multiple impedance modes by changing the stiffness parameter of the robotic arm based on the operational phase and distance from the work position. This parameter-based approach allows the system to achieve high precision and adaptability through a relatively simple control mechanism that switches between predefined impedance states, thereby minimizing the increase in device complexity

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4397454A1A tool engagement coupling system and associated method
Publication Date: 2024.07.10 BAE SYSTEMS PLC
  • EP4397454A1 patent drawingFigure 1
  • EP4397454A1 patent drawingFigure 2
  • EP4397454A1 patent drawingFigure 3

AI summary

There is provided a tool engagement coupling system configured to engage a tool engagement coupler with a locator located relative to a workpiece at a working position of a tool, the system comprising: a robotic arm linked to the tool engagement coupler and moveable in multiple axes relative to the workpiece to position the tool engagement coupler at the working position via the locator; wherein the robotic arm operates in one or more impedance modes the or each of which is configured to give rise to a different stiffness in one or more of the axes of motion of the tool engagement coupler.