Robot Hand Tilter for Inertial Misalignment Control
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Solution Overview
Problem
Conventional robots transferring workpieces, such as semiconductor wafers and printed circuit boards, experience misalignment due to inertia when the arm starts moving, leading to inaccurate transfer between cassettes and processing apparatuses.
Innovation Solution
A robot configuration that includes an arm, a hand, and a tilter with a hand orientation controller, which tilts the hand's orientation to absorb inertial forces during transfer, ensuring the back or front side of the hand is higher than the other relative to the horizontal acceleration component, thereby preventing misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the arm starts moving the end effector with the substrate placed on it, then the transfer speed is improved, but the substrate becomes misaligned with the end effector due to inertia
Solution Approach 1:
The hand orientation is tilted in advance before the arm starts moving, so that when acceleration occurs, the inertial force acting on the substrate is already compensated by the pre-adjusted hand orientation. This preliminary action prevents misalignment rather than correcting it after the fact.
Solution Approach 2:
The hand orientation parameter is dynamically changed based on the acceleration state. When acceleration is detected or anticipated, the hand tilt angle is adjusted to match the inertial force magnitude, allowing high-speed transfer without sacrificing alignment precision.
2Productivity
If the arm moves the end effector at high speed, then productivity is improved, but the substrate is likely to be misaligned with the hand
Solution Approach 1:
The hand orientation parameter is dynamically adjusted according to the acceleration magnitude during high-speed transfer. By changing the tilt angle in response to acceleration, the system maintains substrate alignment while achieving high transfer speeds, thus improving productivity without sacrificing precision.
Solution Approach 2:
The system monitors the acceleration state of the arm and hand, and uses this feedback to adjust the hand orientation via the tilter. This closed-loop control ensures that the hand remains properly oriented relative to the substrate even during high-speed movements, maintaining both productivity and precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively prevents misalignment during high-speed transfers, ensuring a smooth and accurate transfer of workpieces by adjusting the tilt of the hand to match the magnitude of inertial forces, maintaining stability throughout the transfer process.
Implementation Method 1
the substrate held by the end effector and placed on the end effector may be affected by inertia and misaligned with the end effector when the arm starts moving
Data Source
AI summary
A robot that transfers a workpiece includes an arm, a hand, a tilter, and a hand orientation controller. The hand is installed to the arm and holds the workpiece W on a top side of the hand and transfers it. The tilter tilts an orientation of the hand. The hand orientation controller tilts the orientation of the hand by the tilter when an acceleration is produced in the hand during a process of holing and transferring the workpiece by the hand so that a back side of the hand with respect to a direction of a horizontal component of the acceleration becomes higher than another.