Painting Robot Redundant Upper Arm Axis

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Solution Overview

Problem

When painting an inner panel of a vehicle, interference between the painting robot and the workpiece is a significant issue, and to prevent this, the paint booth often needs to be enlarged, compromising efficiency and space utilization.

Innovation Solution

A painting robot with a unique multi-axis configuration, including a swivel base, lower arm, upper arm, and wrist unit, allows for improved accessibility by extending the effective range of motion without interfering with the workpiece, featuring a second upper arm with a redundant axis that can be bent and extended to approach the workpiece closely while avoiding interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the robot is positioned closer to the workpiece to improve accessibility, then painting efficiency is improved, but interference between the robot and workpiece occurs

Engineering Contradiction:
Improvepainting efficiencyVSAvoidinterference between robot and workpiece
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a redundant fourth axis (A4) parallel to the third axis (A3) in the upper arm mechanism. This additional degree of freedom allows the robot to access workpiece areas that would otherwise be unreachable without interference, enabling the robot to operate in previously inaccessible dimensions while maintaining safe distances from the workpiece.

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

Solution Approach 2:

The patent specifies that the second upper arm has an arm length longer than the first upper arm but shorter than twice the arm length of the first upper arm. This parameter optimization allows the robot to extend its reach closer to the workpiece for improved accessibility while maintaining sufficient clearance to avoid interference, effectively tuning the geometric parameters to resolve the contradiction.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If distance is ensured between the robot and workpiece to prevent interference, then safety is improved, but accessibility to the workpiece deteriorates

Engineering Contradiction:
ImprovesafetyVSAvoidaccessibility to workpiece
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The redundant fourth axis provides an additional dimensional capability that allows the robot to reach around and access confined areas of the workpiece without needing to position the entire robot arm assembly close to the workpiece. This enables safe distancing while maintaining operational accessibility.

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

Solution Approach 2:

The robot's multi-axis configuration with the redundant fourth axis provides dynamic adaptability, allowing the arm to pivot and reposition itself to access different workpiece areas. This dynamic capability enables the robot to maintain safe baseline distances while still achieving close proximity access when necessary through coordinated axis movements.

Inventive Principle:
Principle #15Dynamics

3Area of stationary object

If a standard-sized paint booth is used to maintain compactness, then space utilization is improved, but the robot cannot access all workpiece areas without interference

Engineering Contradiction:
Improvepaint booth sizeVSAvoidworkpiece accessibility
Core Design Contradiction:
Area of stationary objectVSEase of operation

Solution Approach 1:

The redundant fourth axis enables the robot to access confined spaces and complex geometries within a standard-sized paint booth by utilizing an additional degree of freedom. This allows complete workpiece coverage without requiring the expanded space of a larger booth.

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

4Ease of operation

If the second upper arm length is increased to extend reach, then accessibility is improved, but device complexity and interference risk increase

Engineering Contradiction:
Improveworkpiece accessibilityVSAvoidarm configuration complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent specifies that the second upper arm length is longer than the first upper arm but shorter than twice the arm length of the first upper arm. This constrained parameter range optimizes the balance between extended reach for improved accessibility and controlled complexity to minimize interference risks and maintain manageable device complexity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4173774A1Painting robot and painting system
Publication Date: 2023.05.03 YASKAWA DENKI KK
  • EP4173774A1 patent drawingFigure 1
  • EP4173774A1 patent drawingFigure 2A~2B
  • EP4173774A1 patent drawingFigure 3A~3B

AI summary

[Problem] To provide a painting robot (10) for improving accessibility to a workpiece (500). [Solving method] A painting robot (10) includes a base (10b), a swivel base (11), a lower arm (12), an upper arm (UA), and a wrist unit (WU). The base (10b) is fixed to an installation surface (IS). The swivel base (11) is supported, on a base end side, on an upper surface side of the base (10b) and swivels about a first axis (A1) along a vertical direction. The lower arm (12) is supported, on a base end side, by the swivel base (11) and pivots about a second axis (A2) perpendicular to the first axis (A1). The upper arm (UA) is supported, on a base end side, by a tip end side of the lower arm (12) and pivots about a third axis (A3) parallel to the second axis (A4). The wrist unit (WU) has a three-axis configuration in which a base end side is supported by a tip end side of the upper arm (UA) and a tip end side is configured to receive attachment of an end effector (EE). The upper arm (UA) includes a first upper arm (13) on a base end side and a second upper arm (14) on a tip end side. The second upper arm (14) pivots about a fourth axis (A4) parallel to the third axis (A3), and an arm length is longer than an arm length of the first upper arm (13), and is shorter than twice the arm length of the first upper arm (13).