Double-Arm Working Head with Split Linear-Rotary Motion Control

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Solution Overview

Problem

Existing articulated robot working devices with six degrees of freedom face challenges in performing fine, high-speed work due to the need for cooperative motor driving, increased movement ranges, and potential collisions, leading to wide operational spaces and reduced efficiency, making them difficult to operate without specialized knowledge and increasing costs.

Innovation Solution

A working device configuration with a linear motion unit having three degrees of freedom and a rotary unit with three degrees of freedom, where the linear motion unit determines end effector positions and the rotary unit determines posture, allowing for independent operation of end effectors suited for different tasks, reducing the operation amount, and enabling high-speed, accurate movements with a compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If six rotational mechanisms are combined to achieve six degrees of freedom, then the working device can perform various movements, but the operation amount increases and fine high-speed work cannot be performed

Engineering Contradiction:
Improverange of movementVSAvoidoperation speed
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent divides the six degrees of freedom into two independent units: a linear motion unit with three degrees of freedom and a rotary unit with three degrees of freedom. This segmentation allows each unit to be optimized for its specific function, enabling high-speed linear positioning while maintaining versatile rotational capabilities, thus resolving the contradiction between range of movement and operation speed.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If the range of movement is increased to avoid contact with objects, then the working device can operate more freely, but the occupation area becomes wider

Engineering Contradiction:
Improverange of movementVSAvoidoccupation area
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent introduces linear motion degrees of freedom in addition to rotational degrees of freedom, effectively adding a new dimension of movement capability. This allows the end effector to reach various positions and postures within a compact base footprint, increasing range of movement without proportionally increasing the occupation area.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Manufacturing precision

If multiple motors are driven cooperatively to change end effector posture, then the working device can achieve precise positioning, but fine work cannot be performed at high speed

Engineering Contradiction:
Improvepositioning accuracyVSAvoidoperation speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent segments the control system into two independent units: the linear motion unit for high-speed positioning and the rotary unit for precise posture control. This segmentation allows the linear motion actuators to operate at high speed for positioning while the rotary mechanisms provide precise angular control, enabling both high speed and precision simultaneously.

Inventive Principle:
Principle #1Segmentation

4Reliability

If contact prevention functions are enhanced to ensure safety, then the working device can coexist with persons, but the device becomes expensive

Engineering Contradiction:
ImprovesafetyVSAvoiddevice cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent designs the working device with inherent safety features through its compact structure and controlled motion ranges. The linear motion unit with defined travel limits and the rotary unit with controlled rotation ranges provide inherent boundary constraints that prevent unintended contact, reducing the need for additional expensive safety systems while maintaining reliability.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3539727B1Working device and double-arm type working device
Publication Date: 2025.01.08 NTN CORP
  • EP3539727B1 patent drawingFigure 1
  • EP3539727B1 patent drawingFigure 2A~2B
  • EP3539727B1 patent drawingFigure 3A~3B

AI summary

A working device (1) includes: a linear motion unit (3) having three degrees of freedom and obtained by combining three linear motion actuators (11, 12, 13); and a rotary unit (4) having three degrees of freedom and obtained by combining a plurality of rotating mechanisms (21, 22, 23) each having one or more rotational degrees of freedom. The linear motion unit (3) is mounted on a mount (2) such that a base portion of the linear motion unit (3) is fixed to the mount (2). A base portion of the rotary unit (4) is fixedly mounted on an output portion (13a) of the linear motion unit (3). End effectors (5A, 5B) are mounted on both the output portion (13a) of the linear motion unit (3) and an output portion (23a) of the rotary unit (4).