Externally Driven Joint Structure With Modular Link Coupling

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Solution Overview

Problem

Existing joint structures for robots, particularly exoskeletal robots and robot arms, face limitations due to built-in actuators that restrict size, shape, and drive direction, while externally-driven joint structures lack modularity for general-purpose use.

Innovation Solution

A modular externally-driven joint structure featuring a shaft member and rotatable members with coupling portions for linking with external actuators, allowing for flexible link mechanism formation and compact design, including the use of encoders for rotational angle detection and radial bearings for enhanced rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If joint structures have a built-in actuator, then they can be directly driven, but their size becomes relatively large and their shape and drive direction are limited

Engineering Contradiction:
Improvedirect drive capabilityVSAvoidjoint structure size
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The actuator is extracted from the joint structure itself and placed externally. The joint structure becomes a passive mechanism that is driven by external actuators, removing the bulky motor housing and drive components from the joint assembly, thereby significantly reducing its size and volume.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A drive transmission mechanism serves as an intermediary between the external actuator and the joint structure. This mediator transmits the driving force from the external actuator to the joint, enabling direct drive capability without requiring the actuator to be built into the joint itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If joint structures are individually designed for each use situation, then they are optimal for specific applications, but they lack modularity for general-purpose use

Engineering Contradiction:
Improveapplication-specific optimizationVSAvoiddesign variety
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The joint structure is designed with universal coupling portions that can interface with different types of link members and actuators. The standardized interface allows a single joint design to be used across multiple applications and configurations, achieving general-purpose usability without sacrificing adaptability through the modular coupling system.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The joint structure is segmented into modular components including the main body, coupling portions, and interface elements. This segmentation allows the joint to be assembled in different configurations and combined with various link members, providing application-specific optimization while maintaining a standardized base design for modularity.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If externally-driven joint structures are designed for general-purpose use, then they can be modularized, but they may lack application-specific optimization

Engineering Contradiction:
Improvemodular designVSAvoidapplication-specific performance
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The joint structure incorporates dynamic adjustment capabilities through its coupling portions, allowing the configuration and characteristics of the joint to be adapted based on the specific application requirements. The modular coupling system enables the same basic joint design to be optimized for different uses by changing the attached components rather than redesigning the entire joint.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3415283B1Externally-driven joint structure
Publication Date: 2021.06.09 ATR ADVANCED TELECOMM RES INST INT
  • EP3415283B1 patent drawingFigure 1
  • EP3415283B1 patent drawingFigure 2
  • EP3415283B1 patent drawingFigure 3

AI summary

Provided is a modularized externally-driven joint structure that can be used for general purposes. An aspect of the present invention is directed to an externally-driven joint structure (1) including: a shaft member (13) that extends in an axial direction; and a plurality of rotatable members (11 and 12) that are arranged along the axial direction, and are coupled with each other by the shaft member in an axially rotatable manner. Each of the rotatable members includes a pair of face portions (122) that face each other in the axial direction, a side wall portion (113 or 123) that is arranged along the outer circumferential edges of the pair of face portions, and at least one coupling portion (21) that is arranged at the face portions or the side wall portion, and is coupled with a link member (31) constituting a link of a robot.