Modular Robotic Finger Cable Guidance for Precision Control

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Solution Overview

Problem

Existing robotic hands face challenges in achieving precise movements and fine handling of objects due to mechanical nonlinearities and high actuation requirements, which result in bulky and heavy designs that hinder fine fingertip control.

Innovation Solution

A robotic finger design featuring a base with two independent non-parallel hinges, actuators, and cable-guiding mechanisms that minimize friction and maximize mechanical efficiency, allowing for precise control and force transmission, enabling the creation of a modular and anthropomorphic hand with adjustable dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high actuation requirements are implemented to achieve precise movements, then control precision is improved, but device complexity and size increase resulting in bulky and heavy designs

Engineering Contradiction:

Improvecontrol precisionVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The robotic finger is divided into modular components including multiple phalanges (proximal, intermediate, distal), independent hinge units, and separate cable transmission systems. Each hinge is controlled by dedicated actuators, allowing independent optimization of each segment's control precision without increasing overall system complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Cable transmission systems act as intermediaries between actuators and hinges, enabling precise force transmission without direct mechanical connections. The cables transmit actuator forces through the phalanges to control hinge movements, achieving high control precision while keeping actuators external to the finger structure

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If high actuation requirements are implemented to achieve precise movements, then control precision is improved, but the design becomes bulky and heavy

Engineering Contradiction:

Improvecontrol precisionVSAvoidweight

Core Design Contradiction:

Measurement precisionVSWeight of moving object

Solution Approach 1:

Actuators are extracted from the finger structure and positioned externally in the wrist or forearm. Only lightweight cable transmission elements remain within the finger, dramatically reducing the weight of the moving finger components while maintaining precise control capabilities through the external actuators

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The cable transmission system uses flexible cable elements instead of rigid mechanical linkages. These thin, flexible cables transmit actuator forces through the finger with minimal weight, enabling precise control without adding significant mass to the moving finger components

Inventive Principle:

Principle #30Flexible shells and thin films

3Ease of manufacture

If mechanical nonlinearities are present in the hinge system, then ease of manufacture is improved, but movement precision and fine handling capability deteriorate

Engineering Contradiction:

Improveease of manufactureVSAvoidmovement precision

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

Tactile sensors are integrated at the fingertip to provide feedback on contact forces and object properties. This feedback enables real-time adjustment of cable tensions and hinge positions, compensating for mechanical nonlinearities in the hinge system and maintaining high movement precision during fine handling operations

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts cable tensions and actuator forces based on task requirements and sensor feedback. By changing the tension parameters in the cable system, the finger can compensate for hinge nonlinearities and maintain precise control across different movement ranges and loading conditions

Inventive Principle:

Principle #35Parameter changes

4Measurement precision

If cable-guiding mechanisms are added to minimize friction, then movement precision is improved, but device complexity increases

Engineering Contradiction:

Improvemovement precisionVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The cable guidance function is merged with the existing hinge and phalange structures. Guide elements are integrated into the hinge assemblies and phalange connections, providing friction reduction and movement precision without adding separate, independent guidance mechanisms that would increase overall device complexity

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS10384343B2Modular robotic finger for grasping and dexterous handling

Publication Date: 2019.08.20 CENT NAT DE LA RECH SCI (C N R S)

AI summary

The invention concerns a device forming a robotic finger comprising a base (100) forming a palm, at least one knuckle (500, 700, 900) articulated on the base (100) about two separate joints (200, 400) non-parallel to each other, at least two actuators (110, 120, 130, 140) and cable-linking means (112, 122) respectively linking the two actuators (110, 120) to drive elements of said two joints (200, 400), characterized in that the device comprises guide means (150, 151, 152) designed to guide the cables involved in the control of each joint (400, 600, 800) located after the first joint (200) on the base (100), in a common plane passing through the axis (202) of said first joint (200).