Robot Joint Speed Reducer Resin Gradient for Impact and Accuracy

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Solution Overview

Problem

Articulated robots face challenges in mitigating impact when contacting humans or objects due to high stiffness, which can compromise accuracy if made too flexible.

Innovation Solution

The robot incorporates speed reducers with varying resin proportions along its joints, with higher resin proportions at the tip end for impact mitigation and lower proportions at the base end to maintain accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the robot is made with high stiffness to maintain positioning accuracy, then positioning accuracy is improved, but impact mitigation capability deteriorates

Engineering Contradiction:

Improvepositioning accuracyVSAvoidimpact

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by making different parts of the robot arm have different material properties. Specifically, the tip end side of the robot arm uses a material with lower stiffness (higher resin proportion) to mitigate impact during contact, while the base end side maintains higher stiffness for positioning accuracy. This creates a gradient structure where stiffness varies along the length of the robot arm.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The robot arm is segmented into different regions with distinct material compositions. The arm is divided into a tip end side portion and a base end side portion, each with different resin proportions in the speed reducer constituents. This segmentation allows each section to independently optimize for its specific function.

Inventive Principle:

Principle #1Segmentation

2Object-affected harmful factors

If resin proportion in speed reducer constituents is increased to reduce impact, then impact mitigation is improved, but positioning accuracy deteriorates

Engineering Contradiction:

ImproveimpactVSAvoidpositioning accuracy

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent implements local quality by varying the resin proportion in speed reducer constituents based on location. The tip end side speed reducer has a higher resin proportion (greater than 50%) to provide impact mitigation, while the base end side speed reducer has a lower resin proportion to maintain stiffness and positioning accuracy.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the material composition parameter (resin proportion) of the speed reducer constituents to achieve different mechanical properties in different locations. By adjusting the resin proportion from less than 50% at the base end to greater than 50% at the tip end, the patent optimizes both impact mitigation and positioning accuracy.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11548143B2Robot

Publication Date: 2023.01.10 SUMITOMO HEAVY IND LTD

AI summary

A robot includes a first joint and a second joint positioned on a base end side from the first joint. A first speed reducer is incorporated in the first joint. A second speed reducer is incorporated in the second joint. A volume proportion of a resin occupying a constituent member of the first speed reducer is larger than a volume proportion of a resin occupying a constituent member of the second speed reducer.