Conveying Robot Coordinate Switching for Offset Wafer Transfer
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Solution Overview
Problem
Conventional conveying systems experience reduced throughput due to large changes in the posture of conveying robots when accessing multiple transfer positions, as the rotation axis of the robot is often not aligned with the transfer trajectory, leading to inefficient motion paths.
Innovation Solution
The system employs a controller that selects a standby posture with minimal arm unit posture change and switches between cylindrical and rectangular coordinate systems to optimize the trajectory of the conveying robot, ensuring the rotation axis is aligned with the transfer trajectory, thereby reducing motion time and increasing throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If all transfer positions are provided at offset positions, then the rotation axis of the conveying robot is not located on an extension of the trajectory of the hand, but a change in the posture of the arm becomes large, resulting in reduction in throughput
Solution Approach 1:
The patent applies dynamics by switching between two coordinate systems (cylindrical and rectangular) depending on the transfer position. When the transfer position is at an offset, cylindrical coordinate control is used; when it is on the extension line, rectangular coordinate control is used. This dynamic switching optimizes the arm posture changes and maintains high throughput.
Solution Approach 2:
The patent changes the control parameter (coordinate system type) based on the transfer position characteristics. By detecting whether the transfer position lies on the extension line of the hand trajectory or at an offset, the system switches between rectangular and cylindrical coordinate controls, thereby optimizing motion efficiency and throughput.
2Adaptability or versatility
If cylindrical coordinate control is used for offset positions, then the robot can access offset transfer positions, but the arm posture change becomes large when accessing multiple different positions
Solution Approach 1:
The system dynamically selects the coordinate control type based on the target transfer position. For positions on the extension line, rectangular coordinate control minimizes posture changes. For offset positions, cylindrical coordinate control enables access. This dynamic selection reduces unnecessary motion time.
Solution Approach 2:
The patent creates two different control models (rectangular and cylindrical coordinate systems) to handle different transfer position scenarios. By copying the control approach to match the specific geometric relationship, the system optimizes motion efficiency for each case.
3Productivity
If rectangular coordinate control is used, then the trajectory of the hand can be optimized for non-offset positions, but it cannot effectively handle offset positions
Solution Approach 1:
The system dynamically switches between rectangular and cylindrical coordinate controls based on whether the transfer position is on the extension line or at an offset. This ensures optimal performance for each position type while maintaining overall system versatility.
Solution Approach 2:
The patent makes the control system universal by incorporating both rectangular and cylindrical coordinate controls. The switching unit enables the system to handle both offset and non-offset transfer positions effectively, providing multi-functionality and broad adaptability.
Data Source
AI summary
A conveying system according to an embodiment includes a robot and a controller. The controller includes a switching unit. The robot includes an arm unit formed of a hand and a plurality of arms connected rotatably with respect to one another, and a base unit. An arm on a rear end side is connected to the base unit rotatably about a rotation axis, and the hand is rotatably connected to an arm on a front end side. The switching unit switches cylindrical coordinate control for controlling the arm unit such that a trajectory of the hand overlaps with any one of lines radiating from the rotation axis and rectangular coordinate control for controlling the arm unit such that the trajectory of the hand overlaps with none of the lines at a predetermined timing.