Light Rotary Joint for Robot Arm Miniaturization

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Solution Overview

Problem

Existing industrial robots face challenges in miniaturizing joint portions due to the presence of electric wiring, which hinders the reduction of size and increases the risk of damage from excessive deformation.

Innovation Solution

The implementation of a light rotary joint that replaces electric wiring with optical wiring within the joint portion, utilizing a tubular light guide path configuration to maintain connectivity and reduce light loss, allowing for bi-directional communication and efficient routing of both optical and electric wiring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If electric wiring is disposed through a joint of a multi-joint arm, then electrical connection is achieved, but the joint cannot be miniaturized

Engineering Contradiction:

Improvejoint sizeVSAvoidwiring complexity

Core Design Contradiction:

Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent replaces electric wiring with optical wiring (light guides) to transmit signals through the joint portion. This substitution allows for thinner, more flexible light guide paths compared to traditional electric wiring, enabling the joint to be miniaturized while maintaining signal transmission capability between the first and second arms.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Length of moving object

If electric wiring passes through the joint portion, then electrical connection is maintained, but the joint portion increases in size

Engineering Contradiction:

Improvejoint dimensionVSAvoidwiring volume

Core Design Contradiction:

Length of moving objectVSQuantity of substance

Solution Approach 1:

The patent extracts the wiring function from traditional electric cables and implements it through separate light guide paths. By taking out the wiring requirement and replacing it with optical transmission, the joint portion can be designed with reduced dimensions while still achieving the necessary connection function between arms.

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of operation

If the joint portion is rotated, then arm movement is achieved, but electric wiring suffers from excessive deformation and damage

Engineering Contradiction:

Improvearm rotatabilityVSAvoidwiring durability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent replaces mechanical electric wiring with optical light guide paths that are less susceptible to deformation damage during joint rotation. The light guides can accommodate the rotational movement between first and second arms without the same vulnerability to excessive deformation that plagues traditional electric wiring, thereby improving reliability during dynamic operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Use of energy by moving object

If traditional electric wiring is used in the joint, then power and signal transmission is achieved, but light propagation efficiency decreases due to deformation

Engineering Contradiction:

Improvesignal transmission efficiencyVSAvoidlight loss

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent substitutes electric wiring with optical light guide paths that maintain consistent light propagation efficiency even during joint rotation. The light guides are designed to minimize deformation and associated light loss, ensuring efficient signal transmission between arms while accommodating the rotational movement required for arm operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This configuration enables the miniaturization of joint portions, enhances the reliability of the robot by reducing damage and light propagation inefficiencies, and improves communication speed and precision.

Implementation Method 1

a light rotary joint that is provided between the first light guide path and the second light guide path inside the joint portion and that optically connects the first light guide path and the second light guide path to each other

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

the first light guide portion includes a diffusing material which diffuses light

Methodology Applied

Scientific EffectLight diffusion: Diffusion

Data Source

PatentUS10099390B2Robot

Publication Date: 2018.10.16 SEIKO EPSON CORP

AI summary

A robot includes: a first arm that has a first light guide path, a second arm that has a second light guide path, a joint portion that has a rotation axis and connects the first arm and the second arm to each other so as to be rotatable about the rotation axis and a light rotary joint that is provided between the first light guide path and the second light guide path inside the joint portion and that optically connects the first light guide path and the second light guide path to each other. In addition, the light rotary joint has a first light guide portion which is fixed to the first light guide path and has a tubular shape about the rotation axis and an end portion of the second light guide path on the light rotary joint side faces the first light guide portion.