Dual-Arm Work Unit Layout for Fast Precise End-Effector Control

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Solution Overview

Problem

Existing multi-articulated robot work devices face challenges in performing delicate tasks at high speed due to complex motor coordination requirements, large movement ranges, and the need for extensive barriers to prevent collisions, making them difficult to operate without experience and costly to implement, especially in dual-arm configurations.

Innovation Solution

A work device with six degrees of freedom, comprising a linear motion unit with three degrees of freedom and a rotation unit with three degrees of freedom, allowing precise position and posture control of the end effector using separate linear motion actuators and rotation mechanisms, enabling compact design and easy operation without extensive knowledge or experience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If six rotation mechanisms are combined to achieve six degrees of freedom, then the work device can perform various movements, but the coordination of multiple motors becomes complex and delicate works cannot be performed at high speed

Engineering Contradiction:
Improvemovement capabilityVSAvoidmotor coordination complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the six degrees of freedom into two independent units: a linear motion unit with three linear motion actuators and a rotation unit with three rotation mechanisms. This segmentation separates position control from posture control, reducing the coordination complexity while maintaining full six-degree-of-freedom capability.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the posture of the end effector is slightly changed, then the movement amounts of the wrist joint and arm become large, but this increases the likelihood of contact with nearby objects and requires larger barriers

Engineering Contradiction:
Improveposture adjustment capabilityVSAvoidoccupation area
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

By separating the linear motion unit (position) from the rotation unit (posture), the patent allows independent adjustment of end effector posture without requiring large movements of the entire arm. The rotation unit can achieve posture changes locally at the wrist, reducing the need for large barriers.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the range of possible movement is made wide to prevent contact with humans or objects, then safety is improved, but the occupation area increases and cost increases

Engineering Contradiction:
ImprovesafetyVSAvoidoccupation area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent employs a Cartesian coordinate system-based control method that dynamically calculates movement paths to avoid obstacles and humans. This allows the device to maintain a compact physical structure while achieving safe operation through intelligent motion planning that adapts to the environment.

Inventive Principle:
Principle #15Dynamics

4Reliability

If barriers are enhanced to prevent contact, then safety is improved, but workers remain anxious and coexistence with humans becomes difficult

Engineering Contradiction:
ImprovesafetyVSAvoidhuman coexistence
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent uses dynamic motion control based on Cartesian coordinates to enable smooth, predictable movements that can be programmed to avoid humans and objects. This reduces the need for physical barriers and creates a more comfortable environment for human workers while maintaining safety.

Inventive Principle:
Principle #15Dynamics

5Reliability

If work is performed at reduced motion speed or limited motion range to prevent contact, then safety is improved, but the capability of the device cannot be sufficiently exhibited

Engineering Contradiction:
ImprovesafetyVSAvoidwork capability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements dynamic motion planning that allows the device to operate at high speeds when the environment is clear, while automatically reducing speed or adjusting paths when humans or objects are detected. This maintains both safety and full productivity capability.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3446836B1Work device and dual-arm work device
Publication Date: 2023.04.05 NTN CORP
  • EP3446836B1 patent drawingFigure 1
  • EP3446836B1 patent drawingFigure 2A~2B
  • EP3446836B1 patent drawingFigure 3A~3B

AI summary

A work device (1) is configured to perform a work with use of an end effector (5) and have six degrees of freedom. The work device (1) including: a linear motion unit (3) obtained by combining three linear motion actuators (11, 12, 13), to have three degrees of freedom; and a rotation unit (4) obtained by combining a plurality of rotation mechanisms (21, 22, 23) each having one or more degrees of rotational freedom, to have three degrees of freedom. A base portion of the linear motion unit (3) is fixed to a mount (2). A base portion of the rotation unit (4) is fixed to an output portion (13a) of the linear motion unit (3). The end effector (5) is mounted to an output portion (23a) of the rotation unit (4).