Horizontal Articulated Robot Curved Arm Design

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Solution Overview

Problem

Conventional SCARA robots face limitations in miniaturization and extending their movable range while maintaining high responsiveness and positioning precision, as the larger second arm increases mass and inertia, compromising these performance metrics.

Innovation Solution

The design incorporates a first arm with a recessed portion that allows for a curved shape, enabling the main shaft to enter smoothly into the curved portion, minimizing the distance between the main shaft and the first rotation axis, and includes a wiring duct positioned to extend the movable range to the rear side of the base, allowing for a more compact and flexible configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the second arm is made longer than the first arm to extend the movable range, then the movable range is increased, but the mass and inertia of the second arm increase, deteriorating responsiveness and positioning precision

Engineering Contradiction:
Improvemovable rangeVSAvoidmass and inertia of second arm
Core Design Contradiction:
Area of stationary objectVSWeight of moving object

Solution Approach 1:

The first arm is designed with a curved configuration instead of a straight line, allowing the arm to achieve a more compact arrangement. This curvature enables the robot to extend its movable range without increasing the length of the second arm, thereby avoiding the increase in mass and inertia that would compromise responsiveness and positioning precision.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Volume of moving object

If the arm frame is miniaturized to reduce the minimum radius, then the robot size is reduced, but the strength and rigidity required to support the second arm cannot be maintained

Engineering Contradiction:
Improverobot sizeVSAvoidstrength and rigidity of arm frame
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The curved configuration of the first arm allows for a more efficient use of space, enabling the arm frame to be compact without compromising structural integrity. The curvature distributes stresses more effectively, maintaining strength and rigidity while reducing the overall minimum radius and robot size.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Adaptability or versatility

If the first arm is designed with a recessed portion to allow reversal and connection to both rotation axes, then configuration flexibility is improved, but the structural complexity increases

Engineering Contradiction:
Improveconfiguration flexibilityVSAvoidstructural complexity of first arm
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The recessed portion is integrated into the curved configuration of the first arm, allowing the arm to be reversed and connected to both the first and second rotation axes. This design achieves configuration flexibility while the curvature itself provides structural efficiency, minimizing the increase in overall complexity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP2159012B1Horizontal articulated robot
Publication Date: 2011.10.26 SEIKO EPSON CORP
  • EP2159012B1 patent drawingFigure 1
  • EP2159012B1 patent drawingFigure 2
  • EP2159012B1 patent drawingFigure 3A~3C

AI summary

A horizontal articulated robot includes a base (11), a first arm (13) provided rotatably around a first rotation axis on the base, a second arm (15) provided rotatably around a second rotation axis on the first arm, the second rotation axis being parallel to the first rotation axis, and a main shaft (16) provided in the second arm to be extended in a direction parallel to the second rotation axis. A distance between the second rotation axis and the main shaft is shorter than a length of a straight line connecting the first and the second rotation axes. Additionally, the first arm has a recessed portion (13d) formed so as to include a position on a rotation path where a rotation radius around the second rotation axis is equivalent to the distance between the second rotation axis and the main shaft.