Four-Bar Linkage Maintains Radial Orientation in Vacuum Robot Arm

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Solution Overview

Problem

Conventional vacuum environment robotic manipulators have limited configurations and performance due to passive arm mechanisms, which restrict the number of independently driven links and motion axes, affecting reach and throughput.

Innovation Solution

A substrate transport arm with a four-bar linkage system maintains radial orientation of the end effector by connecting a first link to a second link through a shaft and a wrist, using a 2:1 gear ratio and preloaded bearing connections to ensure consistent orientation regardless of the rotational angle of the links.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If passive arm mechanisms are used in vacuum environment robotic manipulators, then the structure is simple, but the number of independently driven links and motion axes is limited

Engineering Contradiction:

ImprovestructureVSAvoidnumber of independently driven links and motion axes

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The robotic arm is divided into multiple independently controllable segments or links. Each link can be independently driven, allowing the system to achieve complex motion patterns and access multiple degrees of freedom without requiring a completely active arm mechanism throughout.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Passive linkage mechanisms serve as intermediaries between actively driven links. These passive linkages transmit and transform motion from fewer active drivers to achieve the equivalent of more independent motion axes, resolving the contradiction between structural simplicity and motion versatility.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If passive arm mechanisms are used, then the device complexity is reduced, but the reach and throughput of the robotic manipulator are restricted

Engineering Contradiction:

Improvearm mechanismVSAvoidreach and throughput

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The system dynamically adjusts the configuration and activation of different links based on the required task. Passive linkages can transition between constrained and unconstrained states, allowing the arm to achieve extended reach when needed while maintaining structural simplicity during routine operations.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Multiple functional capabilities are nested within the passive linkage structure. The same passive links that provide structural simplicity also enable extended reach through clever geometric arrangement and coordination with actively driven segments, allowing throughput enhancement without adding complex active mechanisms.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Device complexity

If conventional robotic manipulator configurations are used, then the design is straightforward, but the performance in vacuum environments is limited

Engineering Contradiction:

ImproveconfigurationVSAvoidperformance in vacuum environments

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent replaces complex active mechanical driving mechanisms with passive mechanical linkages that rely on geometric constraints and force transmission. This substitution reduces the number of moving parts requiring vacuum seals and maintenance, thereby improving reliability in vacuum environments while maintaining straightforward configuration.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS9452527B2Robot having high stiffness coupling

Publication Date: 2016.09.27 PERSIMMON TECHNOLOGIES CORP

AI summary

A substrate transport arm including a plurality of links rotatably connected to each other in series; and a system for maintaining radial orientation of a third one of the links regardless of a rotational angle of first and second ones of the links relative to each other. The system for maintaining radial orientation includes a four-bar linkage.