Robot Gripping Posture Evaluation for Load and Stability Balance

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Solution Overview

Problem

Existing robotic systems face challenges in determining an appropriate gripping posture for workpieces, leading to excessive load on robots, which can cause operational stoppages and instability during transportation.

Innovation Solution

A gripping posture evaluation apparatus and program that derive and evaluate gripping postures based on load index and stability index values, repeatedly adjusting the posture to ensure optimal gripping and transportation stability, using a combination of a gripping posture deriver, load index calculator, stability index calculator, and evaluator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the gripping posture is determined based on gripping stability alone, then the workpiece can be transported stably, but the robot receives excessive load and cannot achieve appropriate gripping posture

Engineering Contradiction:
Improvegripping stabilityVSAvoidrobot operational reliability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The invention changes the evaluation parameters from only gripping stability to a combined evaluation of gripping stability and load index. The controller calculates both the stability index (indicating gripping stability) and load index (indicating robot load), and determines the gripping posture based on both parameters, thereby resolving the contradiction between stable transportation and robot operational reliability.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the gripping posture is determined through trial and error by an operator, then an optimal gripping posture can be obtained, but it may take a lengthy time depending on the skill of the operator

Engineering Contradiction:
Improvegripping posture optimizationVSAvoidteaching time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The invention enables the robot system to automatically determine the optimal gripping posture through self-evaluation using the calculated stability index and load index, without requiring operator intervention or trial-and-error teaching. The controller autonomously selects the appropriate gripping posture based on the evaluation results, eliminating time loss while achieving optimal gripping posture.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention replaces the manual trial-and-error process with an automated computational system. Instead of relying on operator skill and physical experimentation, the system uses algorithms to calculate stability and load indices, and automatically determines the optimal gripping posture, substituting mechanical/operator-based methods with computational automation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If a robot picks workpieces stacked randomly, then multiple optimal gripping postures must be taught for possible orientations, but this increases the complexity of the teaching process

Engineering Contradiction:
Improvehandling capability for various orientationsVSAvoidteaching process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention changes the approach from teaching multiple fixed gripping postures for different orientations to dynamically evaluating and determining appropriate gripping postures based on real-time calculation of stability and load indices. This allows the system to handle workpieces of various orientations and types without increasing teaching complexity, as the evaluation is performed automatically for each case.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3822048B1Gripping attitude evaluating device, and gripping attitude evaluating program
Publication Date: 2024.05.01 OMRON CORP
  • EP3822048B1 patent drawingFigure 1
  • EP3822048B1 patent drawingFigure 2
  • EP3822048B1 patent drawingFigure 3~4

AI summary

To evaluate an appropriate gripping posture for a target based on a load on a robot, a gripping posture evaluation apparatus (10) includes a gripping posture deriver (101) that derives a gripping posture in which a robot hand (H) in a robot (RB) grips a workpiece, a load index calculator (103) that calculates a load index value indicating a load to the robot (RB) gripping and transporting the workpiece with the hand (H) in the gripping posture derived by the gripping posture deriver (101), and a gripping posture evaluator (104) that evaluates the gripping posture by determining whether the gripping posture is appropriate based on the load index value calculated by the load index calculator (103). In response to the gripping posture evaluator (104) determining that the gripping posture is inappropriate, derivation of a new gripping posture by the gripping posture deriver (101), calculation of a load index value by the load index calculator (103), and evaluation by the gripping posture evaluator (104) are repeated.