3D Workpiece Holding Point Selection to Prevent Nearby Part Attraction

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Solution Overview

Problem

Existing workpiece holding technologies face challenges in handling a variety of workpieces, as they require pre-created 3D models and can inadvertently attract nearby workpieces due to the attractive force, leading to unwanted holding of multiple pieces simultaneously.

Innovation Solution

A workpiece holding apparatus and method that uses 3D information acquisition, candidate calculation, and control mechanisms to select a holding point that avoids attracting other workpieces within a predetermined range affected by the attractive force, ensuring only the intended workpiece is held by determining candidate holding points and assessing the presence of other workpieces using 3D vision and control systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the holding means attracts and holds workpieces using attractive force, then the workpiece can be held securely, but other nearby workpieces may also be attracted and held together unintentionally

Engineering Contradiction:
Improveholding reliabilityVSAvoidunintentional attraction of other workpieces
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by evaluating the attraction effect locally around each candidate holding point. The control unit calculates whether other workpieces are present within a predetermined range (attractive force range) from each candidate holding point, and selects a holding point where no other workpieces are present. This local evaluation ensures that the attractive force is applied only to the intended workpiece without inadvertently attracting nearby workpieces.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies preliminary action by acquiring 3D information of all workpieces before selecting a holding point, and performing candidate holding point selection based on this advance information. The control unit determines candidate holding points and evaluates the presence of other workpieces within the attractive force range before actually applying the attractive force, thereby preventing unintentional attraction of other workpieces.

Inventive Principle:
Principle #10Preliminary action

2Stability of the object's composition

If the highest height position is used as the holding point, then the workpiece can be held stably, but there is a possibility that other workpieces near the highest height position will also be attracted

Engineering Contradiction:
Improveholding stabilityVSAvoidattraction of other workpieces near highest position
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

Instead of universally using the highest height position as the holding point (which may cause harmful attraction of nearby workpieces), the patent applies local quality by evaluating each candidate holding point individually. The control unit checks whether other workpieces are present within the predetermined range from each candidate holding point, and selects a holding point that provides both stability and isolation from other workpieces.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the workpiece surface into multiple candidate holding points and evaluates each point independently based on the presence of other workpieces within the attractive force range. This segmentation allows selection of a holding point that maximizes stability while minimizing the risk of attracting other workpieces.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If 3D model pattern is created in advance for each workpiece, then pattern matching can be performed accurately, but it is impossible to handle a wide variety of workpieces

Engineering Contradiction:
Improvepattern matching precisionVSAvoidworkpiece variety handling
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies preliminary action by acquiring 3D information of workpieces in advance using a 3D measurement device, and storing this information for later use. This preliminary acquisition of geometric information allows the system to handle various workpieces without requiring pre-created 3D model patterns for each specific workpiece type, thereby improving versatility while maintaining measurement precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses copying by creating a digital 3D representation (copy) of the workpiece geometry through 3D measurement. This digital copy is stored and used for candidate holding point selection, eliminating the need for physical 3D model patterns and enabling the system to handle a wide variety of workpieces by simply measuring and storing their geometric information.

Inventive Principle:
Principle #26Copying

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

Effectively prevents other workpieces from being attracted and held together with the intended workpiece, allowing for precise and independent handling of multiple workpieces in a 3D space by selecting optimal holding points based on presence and distance criteria.

Implementation Method 1

holding means for attracting and holding each workpiece in turn from among a plurality of workpieces placed in a 3D (three-dimensional) space

Methodology Applied
Scientific EffectAttractive force: Magnetic Field

Data Source

PatentEP4148374B1Workpiece holding apparatus, workpiece holding method, program, and control apparatus
Publication Date: 2024.07.31 TOYOTA JIDOSHA KK
  • EP4148374B1 patent drawingFigure 1
  • EP4148374B1 patent drawingFigure 2
  • EP4148374B1 patent drawingFigure 3

AI summary

A workpiece holding apparatus include holding means for attracting and holding each workpiece in turn from among workpieces placed in a 3D space; first information acquisition means for acquiring 3D information of workpieces; candidate calculation means for calculating, based on the acquired 3D information of the workpieces, candidate holding points, the candidate holding points being, when the holding means holds each of the workpieces in turn, candidates for a holding point of that workpiece; second information acquisition means for acquiring information about each of other workpieces present within a predetermined range from each of the candidate holding points on the workpieces; and control means for selecting one of the candidate holding points based on the information about the workpiece acquired by the second information acquisition means, and controlling the holding means so that the holding means holds the workpiece at the selected candidate holding point.