Cable-Driven Robotic Hand with Idler Pulleys

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Solution Overview

Problem

Conventional robotic hands are complex, large, and cumbersome due to their complex mechanical drive mechanisms and high number of degrees of freedom, which results in a large form factor and limited ability to grasp objects of different sizes and shapes effectively.

Innovation Solution

A robotic hand design featuring a modular structure with cable-driven fingers, each composed of three rotatably coupled phalanges, and an actuating mechanism that allows for independent control of each finger, enabling flexible grasping capabilities through a combination of tendons and idler pulleys, reducing the complexity of the mechanical drive mechanism while maintaining high mobility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional robotic hands use multiple degrees of freedom with complex mechanical drive mechanisms, then finger movement capability is improved, but device complexity and form factor increase

Engineering Contradiction:

Improvefinger movement capabilityVSAvoidmechanical drive mechanism complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical drive mechanisms with a cable-driven system. Instead of using multiple motors and mechanical linkages for each degree of freedom, the invention uses tendons and cables that can be actuated from the base to control finger movements. This substitution dramatically reduces mechanical complexity while maintaining multi-degree-of-freedom finger movement capability, directly resolving the contradiction between adaptability and device complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If conventional robotic hands increase the number of cables and actuators to achieve good finger movement, then finger mobility is improved, but weight and form factor increase

Engineering Contradiction:

Improvefinger mobilityVSAvoidrobotic hand weight

Core Design Contradiction:

Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The patent merges multiple actuation functions into a single cable-driven system. Instead of having separate actuators for each finger and degree of freedom, the invention uses a integrated cable network where tendons can control multiple fingers simultaneously. This merging reduces the total number of actuators and cables needed, thereby reducing weight while maintaining finger mobility.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces idler pulleys as intermediary elements in the cable system. These pulleys allow a single cable to control multiple degrees of freedom by routing the cable through strategic positions. The idler pulleys act as mediators that multiply the effect of each actuator, enabling complex finger movements without requiring proportional increases in actuator数量, thus reducing overall system weight.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If conventional robotic hands use complex mechanical drive mechanisms, then grasping precision is improved, but ease of manufacture decreases

Engineering Contradiction:

Improvegrasping precisionVSAvoidmanufacturing complexity

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent segments the robotic hand into modular components: finger assemblies with integrated cable routing, base actuators, and idler pulley stations. Each finger can be manufactured and tested independently before assembly. The cable-driven mechanism allows for standardized tendon and pulley components that can be mass-produced. This segmentation significantly improves ease of manufacture while maintaining grasping precision through modular adjustability.

Inventive Principle:

Principle #1Segmentation

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 design achieves a lightweight and versatile robotic hand capable of forming both precision and power grasps, adapting to various object sizes and shapes with reduced mechanical complexity and increased mobility, allowing for efficient object manipulation.

Implementation Method 1

Each of the fingers may include a tendon configured to generate a force that acts on one of the two phalanges, causing the phalanx to rotate from a flexed state to an extended state

Methodology Applied

Scientific EffectTension: Tension

Implementation Method 2

combining tendons and idler pulleys, reducing the complexity of the mechanical drive mechanism

Methodology Applied

Scientific EffectPulley: Pulley

Data Source

PatentUS20220143841A1Robotic hand

Publication Date: 2022.05.12 FUTRONICS NA CORP

AI summary

A robotic hand includes a baseplate, a finger having multiple phalanges that are rotatably coupled to one another, a first of the phalanges having a first end rotatably coupled to the baseplate and a second end and a second of the phalanges rotatably coupled to the second end about an axis of rotation, an actuating mechanism mounted on the baseplate, the actuating mechanism configured to actuate rotation of the plurality of phalanges, and a tendon having opposite ends that are respectively attached to the second of the phalanges and the baseplate. The second of the phalanges has an engagement portion arranged around the axis of rotation, and the tendon is wrapped around a portion of the engagement portion to generate a force acting on the second end of the first of the phalanges, causing the first of the phalanges to rotate from a flexed state to an extended state.