Robot Joint Unit with Shared Rotor for Dual Angle Sensing

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Solution Overview

Problem

Existing joint units in robot arms face challenges in reducing size while maintaining multiple angle detection mechanisms, as simply arranging these mechanisms leads to increased thickness and prevents size reduction.

Innovation Solution

A joint unit configuration that shares an associated rotating body for both angle detection mechanisms, allowing for reduced size while maintaining multiple detection capabilities, utilizing a decelerator and strain generating portion to integrate these mechanisms efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple angle detection mechanisms are simply continuously arranged, then detection capability is improved, but thickness in axial direction increases

Engineering Contradiction:
Improveangle detection capabilityVSAvoidthickness in axial direction
Core Design Contradiction:
Measurement precisionVSLength of stationary object

Solution Approach 1:

The patent places the second angle detection mechanism inside the first angle detection mechanism, with both mechanisms sharing the same axial space. The associated rotating body serves as a common component for both mechanisms, allowing one detection mechanism to be nested within another, thereby maintaining multiple detection capabilities without increasing axial thickness.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The associated rotating body serves dual purposes: it is both the rotating component for the output rotating body and the reference component for both angle detection mechanisms. This multi-functional design allows a single component to fulfill multiple detection functions, reducing the need for additional separate components that would increase axial thickness.

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

2Measurement precision

If multiple angle detection mechanisms are provided, then control accuracy is improved, but device size increases

Engineering Contradiction:
Improvecontrol accuracyVSAvoidjoint unit size
Core Design Contradiction:
Measurement precisionVSVolume of stationary object

Solution Approach 1:

By nesting the second angle detection mechanism within the first mechanism's axial space and having them share the associated rotating body, the patent reduces the overall volume required for housing multiple detection mechanisms, thereby maintaining compact joint unit size while providing multiple detection capabilities for improved control accuracy.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent merges the functional components of multiple angle detection mechanisms by having them share the associated rotating body and overlap their axial positions. This combining approach reduces redundant components and minimizes the total volume occupied by the detection system.

Inventive Principle:
Principle #5Merging (Combining)

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

Enables a compact joint unit with multiple angle detection mechanisms, enhancing size reduction and maintaining accurate detection capabilities.

Implementation Method 1

an output rotating body (44) that is coupled to the deceleration output shaft, and includes a strain generating portion (441) that generates strain due to rotation transmitted by the deceleration output shaft

Methodology Applied
Scientific EffectStrain generation: Elasticity

Data Source

PatentEP3778155B1Articulation unit, robot arm, and robot
Publication Date: 2022.05.25 TOKYO ROBOTICS INC
  • EP3778155B1 patent drawingFigure 1(a)~1(b)
  • EP3778155B1 patent drawingFigure 2
  • EP3778155B1 patent drawingFigure 3

AI summary

There is provided a joint unit that is reduced in size while being provided with a plurality of angle detection mechanisms. There is provided a joint unit including an input-side support member that supports a rotationally driven input shaft, a decelerator that decelerates the input shaft to provide a deceleration output shaft, an output rotating body that is coupled to the deceleration output shaft, and includes a strain generating portion that generates strain due to rotation transmitted by the deceleration output shaft, and an associated rotating body that is coupled to a output-side portion of the strain generating portion of the output rotating body to rotate together with the output rotating body, and is disposed in a space between the input-side support member and an input-side portion of the strain generating portion of the output rotating body. In the joint unit, a first angle detection mechanism for detecting an angle formed between the associated rotating body and the input-side support member is provided for the associated rotating body and the input-side support member, and a second angle detection mechanism for detecting an angle formed between the associated rotating body and the input-side portion of the strain generating portion of the output rotating body is provided for the associated rotating body and the input-side portion.