Robotic Finger Assemblies with Variable Durometer Compliant Elements

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Solution Overview

Problem

Existing robotic grippers with rigid components fail to effectively grasp objects if they cannot make contact, limiting their ability to perform tasks intended for human-like gripping and manipulation.

Innovation Solution

A robotic compliant jaw gripper with fingers comprising phalanges that include a compliant element, allowing for variable pressure application and conformation to object shapes, driven by a preload unit that adjusts the durometer of the compressible material, enabling differential force distribution and adaptability to various shapes and sizes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If rigid components are used to drive the fingers, then the mechanical structure is simple and strong, but the fingers cannot conform to object shapes and fail to grasp objects effectively

Engineering Contradiction:

Improveability to conform to object shapesVSAvoidstructural strength

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The patent employs flexible compliant elements including elastomeric materials, springs, and bellows structures within the finger assemblies. These flexible components allow the rigid phalanges to conform to irregular object shapes while maintaining structural integrity through the combination of rigid and compliant elements.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent utilizes compliant elements with variable stiffness characteristics that can change their mechanical properties based on loading conditions. The springs and elastomeric materials provide progressive compliance, allowing the finger to adapt its effective stiffness to match the object being grasped, thereby achieving both conformity and structural strength.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If compliant elements are added to enable conformation to objects, then the ability to grasp irregular objects improves, but the device complexity increases

Engineering Contradiction:

Improveability to grasp irregular objectsVSAvoidmechanical structure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The finger is divided into multiple phalanges (proximal, intermediate, distal) with compliant elements positioned at specific segments. This segmentation allows independent compliance control at different finger regions, enabling complex grasping of irregular objects while keeping each segment's complexity manageable.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The compliant elements including springs and elastomeric materials are nested within the finger structure, with bellows mechanisms providing compact volume for compliance. This nesting approach integrates multiple functional elements (structural support, compliance, actuation) into a unified compact assembly, reducing overall device complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Adaptability or versatility

If variable pressure application is implemented through preload units, then the grip strength adaptability improves, but the control system complexity increases

Engineering Contradiction:

Improvegrip strength adaptabilityVSAvoidcontrol system complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The compliant elements including springs and elastomeric materials provide passive compliance and variable pressure distribution automatically based on the object's geometry and required grip force. This self-adjusting mechanism eliminates the need for complex active control systems, sensors, and actuators while achieving adaptive grip strength.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The preload units and compliant elements create a dynamically adaptable grip system where the contact pressure and force distribution automatically adjust to the object's shape and size. The mechanical compliance provides real-time adaptation without electronic control, reducing system complexity while maintaining high adaptability.

Inventive Principle:

Principle #15Dynamics

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

The robotic gripper achieves effective grasping of both regular and irregular objects by conforming to their shapes, providing haptic feedback and adaptable grip strength, reducing cognitive burden on operators and enhancing teleoperation capabilities.

Implementation Method 1

a phalange contacts a compliant element as the finger applies pressure against the object

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 2

The compliant element of the robotic compliant jaw gripper is compressible

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 3

a preload unit configured to change the durometer of the compliant element

Methodology Applied

Scientific EffectPreload: Spring

Data Source

PatentUS10099388B1Robotic finger assemblies

Publication Date: 2018.10.16 TELEFACTOR ROBOTICS LLC

AI summary

A robotic compliant jaw gripper includes one or more fingers, wherein each finger comprises a plurality of phalanges configured to grasp an object, wherein an internal compliant element is compressed, or wherein a proximal phalange contacts a compliant element as the finger applies pressure against the object; and a preload unit is configured to change the durometer of the compressible element.