Robotic Gripper With Switchable Mobility Limits for Flexible Fingers

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Solution Overview

Problem

Existing fluidic elastomer grippers face issues with undesirable deformation and loss of grip due to external forces, limiting their application in production and logistics processes where speed and stability are crucial.

Innovation Solution

A robotic gripper with a switchable mobility limiting mechanism for flexible fingers that restricts unwanted deformation during gripping and holding, allowing controlled bi-directional movements using a support structure with a switchable coupling element and pneumatic/hydraulic actuation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If fluidic elastomer grippers with elastic flexible fingers are used, then adaptability to object surfaces and gentle gripping are improved, but stability against external forces and resistance to unwanted deformation deteriorate

Engineering Contradiction:
Improveadaptability to object surfacesVSAvoidstability against external forces
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The support structure transitions from a static rigid configuration to a dynamic switchable structure. The mobility limiting mechanism can be activated or deactivated based on operational requirements, allowing the system to adapt its stiffness characteristics dynamically. This resolves the contradiction by providing high adaptability when the mechanism is deactivated and high stability when activated.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the physical parameter of structural stiffness by switching the mobility limiting mechanism between activated and deactivated states. This parameter change allows the same structure to provide both high adaptability (when flexible) and high stability (when rigid), resolving the fundamental contradiction between these two requirements.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If elastic flexible fingers are used, then positioning accuracy requirements are reduced and compensation for position deviations is improved, but resistance to rapid movements with high accelerations deteriorates

Engineering Contradiction:
Improvepositioning accuracy requirementsVSAvoidrapid movements with high accelerations
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The support structure dynamically adjusts its mobility characteristics through the switchable mobility limiting mechanism. During rapid movements, the mechanism can be activated to provide structural rigidity, enabling high accelerations without excessive deformation. During positioning phases, it remains deactivated to allow flexibility for compensation, thus resolving the contradiction between positioning tolerance and movement speed.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If bellows actuators are used for bi-directional movement, then gripping and releasing capabilities are improved, but torsional stiffness and resistance to finger twisting deteriorate

Engineering Contradiction:
Improvegripping and releasing capabilitiesVSAvoidtorsional stiffness
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The support structure acts as an intermediary between the bellows actuator and the flexible finger. It provides the necessary torsional stiffness to prevent unwanted twisting while allowing the bellows to perform its bi-directional actuation function. The switchable mobility limiting mechanism ensures that this intermediary structure does not interfere with the gripping motion but provides stability during holding and movement phases.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enhances gripping stability and reliability by preventing unwanted finger deformation, enabling secure handling of objects during movement and release, suitable for applications requiring speed and precision.

Implementation Method 1

These consist of an elastic sheath and a pressure chamber enclosed by the sheath. When the internal pressure is increased again the bellows expand and force the finger to bend. By generating negative pressure in the pressure chamber, the direction of motion can be reversed

Methodology Applied
Scientific EffectPneumatic pressure: Pressure Increase

Implementation Method 2

The robotic gripper with a switchable mobility limiting mechanism for flexible fingers that restricts unwanted deformation during gripping and holding, allowing controlled bi-directional movements using a support structure with a switchable coupling element and pneumatic/hydraulic actuation

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 3

When the internal pressure is reduced again to atmospheric pressure the bellows return to their original shape due to the elasticity of the material

Methodology Applied
Scientific EffectElasticity: Elastic Recovery

Data Source

PatentEP4316749B1Robotic gripper
Publication Date: 2025.09.10 HELMUT SCHMIDT UNIV UNIV DER BUNDESWEHR HAMBURG
  • EP4316749B1 patent drawingFigure 1
  • EP4316749B1 patent drawingFigure 2
  • EP4316749B1 patent drawingFigure 3

AI summary

To provide robotic gripper (100) comprising a base (10) and at least one flexible finger (11) and a support structure (12), wherein the at least one flexible finger (11) is connected to the base (10), wherein the at least one flexible finger (11) is configured for performing at least a bi-directional movement for gripping and releasing an object (13) that restricts undesired movements or deformations of the flexible finger (11) for example while gripping, holding and/or moving an object (13), without hindering or restricting the desired, necessary deformations it is proposed that that the support structure (12) comprises at least one switchable mobility limiting mechanism (14) configured for at least partially restricting the bi-directional movement of the at least one flexible finger (11) in a first direction (15).