Tactile-Sensing End Effector for Grasp Position Shift Correction

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Solution Overview

Problem

Existing end effector devices, such as slide type chucks, struggle with correcting position shifts of grasped objects during assembly, leading to inefficiencies in fitting operations.

Innovation Solution

An end effector device equipped with a palm and fingers, each with a tactile sensor unit capable of detecting external forces in three axial directions, determines position shifts and corrects them by controlling the drive device to move the palm in the opposite direction, ensuring accurate fitting into a recess.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If contact force between all fingers and the grasped part is not uniform, then the slide type chuck cannot correct the position shift of the grasped part, but adding position shift correction capability increases device complexity

Engineering Contradiction:
Improveposition shift correctionVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The tactile sensor unit provides real-time feedback on contact forces between fingers and the grasped part. The control unit processes this feedback information to detect position shifts and automatically adjusts finger positions to correct them, creating a closed-loop control system that enables position shift correction without requiring complex mechanical adjustment mechanisms

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system uses its own tactile sensing capability to detect position shifts and automatically corrects them through the control unit's processing and actuation, making the system self-correcting without requiring external intervention or additional complex correction mechanisms

Inventive Principle:
Principle #25Self-service

2Manufacturing precision

If the slide type chuck controls contact force to be uniform, then accurate insertion operation is enabled, but this requires highly accurate sensing and control which increases device complexity

Engineering Contradiction:
Improveinsertion accuracyVSAvoidsensing and control complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The tactile sensor unit continuously monitors contact forces between each finger and the grasped part, providing real-time feedback to the control unit. This feedback enables the system to detect and correct position shifts by adjusting individual finger positions, achieving uniform contact force and accurate insertion without requiring overly complex sensing and control mechanisms

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system independently controls each finger's contact force and position based on individual tactile sensor feedback. This segmented control approach allows precise adjustment of each finger to achieve uniform contact force distribution, enabling accurate insertion operations while keeping the overall system complexity manageable through modular control

Inventive Principle:
Principle #1Segmentation

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 device effectively corrects position shifts of grasped objects relative to a fitting recess, enhancing the accuracy and efficiency of assembly operations.

Implementation Method 1

a tactile sensor unit capable of detecting external forces in at least three axial directions

Methodology Applied
Scientific EffectForce detection: Force

Data Source

PatentEP3831549B1End effector device
Publication Date: 2025.08.13 OMRON CORP
  • EP3831549B1 patent drawingFigure 1
  • EP3831549B1 patent drawingFigure 2~3
  • EP3831549B1 patent drawingFigure 4~5

AI summary

The end effector device includes an end effector including a palm and a plurality of fingers, a drive device, a position shift direction determination unit and a position shift correction unit. Each finger includes a tactile sensor unit capable of detecting external forces in at least three axial directions. The drive device drives the palm and each finger. The position shift direction determination unit determines in which direction the object being grasped is position-shifted with respect to the fitting recess based on a detection result detected by the tactile sensor unit in a case where at least one of the external forces detected by the tactile sensor unit is a specified value or more. The position shift correction unit moves the palm in a direction opposite to a position shift direction of the object being grasped determined by the position shift direction determination unit, and corrects a position shift of the object being grasped with respect to the fitting recess.