Robotic Gripper Jaw Elasticity for Intuitive Holding Force Teaching

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Solution Overview

Problem

Current methods for programming industrial robots to hold objects effectively lack the ability to intuitively determine and apply a precise holding force, especially for delicate objects that require manual adjustment to avoid damage.

Innovation Solution

A method utilizing reversibly elastically deformable gripper jaws that absorb and store external closing force as a spring force, allowing direct tactile feedback for users to teach the gripping force to a robot system without numeric input, with force or torque sensors measuring the gripping force for precise measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional programming methods are used to teach holding force, then the robot can be programmed to hold objects, but the process is complex and lacks intuitive force feedback for delicate objects

Engineering Contradiction:
Improveintuitive teaching of holding forceVSAvoidprogramming complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent implements force feedback by measuring the closing force applied by the user during teaching and transmitting this force information back to the robot controller. This allows the robot to intuitively learn the desired holding force through direct tactile interaction, eliminating complex programming while providing natural force feedback for handling delicate objects

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces a force sensor as an intermediary device that mediates between the user's manual closing action and the robot's control system. The sensor captures the analog closing force and transmits it to the controller, serving as a bridge that enables intuitive teaching without requiring complex programming interfaces

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If rigid gripper jaws are used, then the structure is simple and strong, but the gripper cannot provide tactile feedback for precise force teaching

Engineering Contradiction:
Improveforce measurement accuracyVSAvoidgripper jaw rigidity
Core Design Contradiction:
Measurement precisionVSStrength

Solution Approach 1:

The patent changes the physical parameter of the gripper jaws from rigid to elastically deformable. This allows the jaws to deform under closing force, providing tactile feedback that can be measured by force sensors. The elastic deformation enables precise force measurement while maintaining sufficient structural strength for gripping operations

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If elastic gripper jaws are used to provide tactile feedback, then force teaching becomes intuitive, but the gripper structure becomes more complex

Engineering Contradiction:
Improvetactile feedback for force teachingVSAvoidgripper structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent employs elastically deformable gripper jaws that function as flexible structural elements. These jaws provide tactile feedback through their deformation characteristics while maintaining a relatively simple overall gripper structure. The flexibility is achieved through material selection and geometric design rather than complex mechanical mechanisms

Inventive Principle:
Principle #30Flexible shells and thin films

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

Enables rapid and precise teaching of a holding force to a robot manipulator, allowing for gentle handling of fragile objects without damage, with accurate force transmission and minimal material fatigue, providing intuitive and efficient object handling.

Implementation Method 1

the gripper has reversibly elastically deformable gripper jaws... so that the connection points shift relative to the contact points under elastic deformation of the gripper jaws

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3946845B1Teaching a holding force for an object in a robotic gripper
Publication Date: 2023.05.03 FRANKA EMIKA GMBH
  • EP3946845B1 patent drawingFigure 1~2
  • EP3946845B1 patent drawingFigure 3

AI summary

The invention relates to a method for teaching a holding force for holding an object (9) by means of a gripper (5) of a robot manipulator (3), said gripper (5) having gripper jaws (7) which can be elastically deformed in a reversible manner, wherein the method has the steps of: - closing (S1) the gripper (5) until the gripper jaws (7) contact the object (9) at contact points (15) of the gripper jaws (7), - externally applying (S2) a desired closing force at connection points (13) of the gripper jaws (7) to gripper jaw bearings (11) such that the connection points (13) move relative to the contact points (15), thereby elastically deforming the gripper jaws (7), - actuating (S3) a gripper drive (17) in order to maintain the current position of the connection points (13) and terminating the closing force externally applied onto the connection points (13), and - ascertaining and storing (S4) the value of a gripping force or a gripping torque, wherein the gripping force or the gripping torque is produced by the elastic deformation of the gripper jaws (7) and is exerted onto the connection points (13) by the gripper jaws (7).