Robot Payload Edge Sensing for End-Effector Misalignment Correction
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Solution Overview
Problem
In semiconductor, LCD, and LED manufacturing, automated cluster tools face challenges in accurately determining the position of polygonal payloads on robot end-effectors due to the absence of active grippers, leading to misalignment and contamination risks, which necessitate a solution for precise position determination and correction.
Innovation Solution
A system and method involving sensors to detect edges of the payload as it moves along a carefully planned motion path, capturing positions to estimate the payload's location on the end-effector, and using optimization algorithms to correct for misalignment, allowing precise delivery to a specified location without additional mechanical complexity or impacting tool throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If no active gripper is used to avoid contamination, then the material is protected from contamination, but the material cannot be mechanically aligned on the end-effector
Solution Approach 1:
The patent replaces the mechanical gripping and alignment system with an optical sensing system. Sensors detect the material's position and orientation on the end-effector, and a controller calculates correction values to compensate for misalignment, substituting mechanical alignment with optical detection and computational correction.
Solution Approach 2:
The patent introduces sensors as an intermediary between the material and the control system. These sensors detect edge positions of the material on the end-effector, providing information that enables the controller to calculate and apply position corrections without requiring mechanical contact or active gripping.
2Measurement precision
If sensors are added to detect payload position, then position detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the essential detection function needed for position determination. Instead of using complex active grippers with integrated sensors, it employs simple optical sensors that detect edge positions of the material on the end-effector, extracting minimal necessary information for correction calculations.
Solution Approach 2:
The patent uses optical sensors to create a digital copy or representation of the material's physical position and orientation on the end-effector. This virtual model is then used by the controller to calculate correction values, replacing the need for complex mechanical alignment systems.
3Measurement precision
If edge detection with multiple points is implemented, then position determination accuracy is improved, but detection time increases
Solution Approach 1:
The patent detects more edge points than the absolute minimum required (at least three points on at least two edges). By detecting additional edge points, the system obtains redundant information that improves the accuracy of position and orientation determination through optimization algorithms, accepting the trade-off of increased detection time for enhanced precision.
Solution Approach 2:
The patent performs edge detection and position calculation during the robot's motion path traversal. The detection process is integrated into the existing motion sequence, and the controller calculates correction values in advance before the delivery operation, minimizing additional time loss.
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
Enables accurate determination and correction of payload misalignment on the end-effector, ensuring precise delivery to the specified location, minimizing contamination risks and maintaining high tool throughput.
Implementation Method 1
Detecting edges of the payload such that at least three points on at least two edges are detected
Data Source
AI summary
Disclosed herein is a method. The method includes moving a payload through a motion path proximate at least one sensor. Detecting edges of the payload such that at least three points on at least two edges are detected. Capturing a position when the at least one sensor detects at least one edge of the payload.