Robot Arm Deflection Compensation During Gripper Release

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Solution Overview

Problem

Conventional robot control methods face malfunctions due to inappropriate switching of compensation amounts during deflection compensation after a workpiece is brought into a non-gripping state, risking damage to the workpiece or collision with the workbench.

Innovation Solution

A robot control method that compensates for arm deflection by gradually decreasing the compensation amount while transitioning from a gripping to a non-gripping state, using multiple compensation amounts that change linearly or in curved shapes, and adjusting the acceleration within allowable limits to prevent unintended arm movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the compensation amount is switched immediately after the opening command is output, then the deflection compensation is performed timely, but the workpiece may be damaged by being pressed against the workbench due to delay in hand opening

Engineering Contradiction:
Improvedeflection compensation accuracyVSAvoidworkpiece safety
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by waiting for a predetermined time after the opening command is output before switching the compensation amount. This ensures the hand has sufficient time to open completely before the compensation amount changes, preventing the workpiece from being pressed against the workbench while maintaining timely deflection compensation

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the compensation amount is waited to be switched after a predetermined time, then the workpiece safety is improved, but the arm acceleration becomes large causing the arm to move excessively and possibly contact the workbench

Engineering Contradiction:
Improveworkpiece safetyVSAvoidarm acceleration
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent applies dynamics by changing the compensation amount gradually rather than switching it abruptly. The compensation amount is adjusted incrementally over time after the hand opens, which reduces arm acceleration and prevents excessive movement that could cause collision with the workbench, while still achieving the necessary deflection compensation

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies parameter changes by modifying the compensation amount parameter gradually instead of making an abrupt change. The compensation amount is adjusted in small steps over a predetermined time period, which controls the arm's acceleration and prevents harmful movements while maintaining workpiece safety

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4681890A1Robot control method
Publication Date: 2026.01.21 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP4681890A1 patent drawingFigure 1
  • EP4681890A1 patent drawingFigure 2
  • EP4681890A1 patent drawingFigure 3

AI summary

When workpiece (W) is brought into a non-gripping state after deflection compensation of robot arm (10) is performed in a gripping state of workpiece (W), the deflection compensation of robot arm (10) is performed in a non-gripping state of workpiece (W). Here, the deflection compensation of robot arm (10) in the non-gripping state of workpiece (W) is performed while a compensation amount is changed to gradually decrease, while hand (18) is moved from a first teaching point to a second teaching point.