Robot Drive Module With Integrated Encoder for Precise Rotary Joints

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Solution Overview

Problem

Existing robot drive modules lack high precision and compactness for rotary joints, particularly in collaborative and humanoid robots, due to mechanical inaccuracies and encoder limitations, which hinder their performance in demanding applications like metrology and precision assembly.

Innovation Solution

A robot drive module design featuring a motor circuit board, stator, and rotor with a gearbox and integrated rotary encoder, where the encoder is positioned on the input side to provide high precision feedback, and a connecting part ensures rotation is transferred rigidly from the gearbox output to the input, allowing for compact and accurate position control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the encoder is mounted on the gearbox output axis as an independent module, then measurement precision is improved, but device complexity and space requirements increase

Engineering Contradiction:
Improveencoder measurement precisionVSAvoidencoder mounting complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The encoder is integrated into the motor structure, merging the encoder mounting interface with the motor output flange. This eliminates the need for separate encoder mounting brackets and alignment procedures, reducing device complexity while maintaining measurement precision through the rigid direct connection to the rotor.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The motor output flange is designed to serve dual functions: as the mechanical output interface for the motor and as the mounting interface for the encoder. This multi-functional design reduces the number of separate components and simplifies the overall structure while ensuring precise encoder positioning.

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

2Measurement precision

If the encoder is mounted on the gearbox output axis, then measurement precision is improved, but the space required and cabling requirements increase

Engineering Contradiction:
Improveencoder measurement precisionVSAvoidspace required for encoder
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The encoder is positioned within the motor housing structure, merging the encoder space with the existing motor volume. This eliminates the need for additional external mounting space and reduces the overall footprint of the drive module while maintaining encoder functionality.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If a rigid connection is used to transfer rotation from gearbox output to input, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improverotation transfer accuracyVSAvoidconnection structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The motor shaft serves multiple functions: as the rotor rotation axis, as the gearbox input shaft, and as the encoder measurement axis. This multi-functional design eliminates the need for separate rigid connection elements while ensuring accurate rotation transfer through the inherent rigidity of the motor shaft structure.

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

Data Source

PatentEP4382262A1Robot drive module
Publication Date: 2024.06.12 HEXAGON ROBOTICS GMBH
  • EP4382262A1 patent drawingFigure 1~2
  • EP4382262A1 patent drawingFigure 3a~3b
  • EP4382262A1 patent drawingFigure 4

AI summary

The invention relates to robot drive module (1, 1') for driving a rotary joint movement of a robot with at least a rotary drive and at least a rotary encoder (6, 6o, 6i) arrangement and a method for a robot having such a robot drive module (1, 1').