Substrate Transfer Robot Inclined Hand Detection
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Solution Overview
Problem
Conventional substrate transfer robots face challenges in accurately detecting the arrangement state of substrates in storage cassettes due to the limitations of their hand center line being perpendicular to the cassette's front surface, which can lead to incomplete detection, especially when the arm length is short, making it difficult to match the hand center line with the substrate storage center line.
Innovation Solution
The substrate transfer robot incorporates a hand with detectors that can be inclined relative to the substrate storage center line, allowing the hand center line to be positioned at a predetermined angle, enabling detection of substrate arrangement states without physical contact and accommodating shorter arm lengths by controlling the detectors to ensure accurate positioning and detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the hand center line is positioned perpendicular to the substrate storage front surface, then the detection structure is simple, but the detection accuracy deteriorates when arm length is short
Solution Approach 1:
The hand is designed with rotational capability around the substrate holding center, allowing the hand center line to be dynamically adjusted to an inclined position relative to the substrate storage center line. This dynamic positioning enables the detection optical axis to pass through the substrate storage center line even with short arm length, resolving the contradiction between simple structure and accurate detection.
2Volume of moving object
If the arm length is shortened to improve robot compactness, then the robot size is reduced, but the ability to align hand center line with substrate storage center line deteriorates
Solution Approach 1:
The hand can rotate around the substrate holding center to adjust its orientation. This rotational degree of freedom compensates for the short arm length by dynamically positioning the hand center line at an inclination angle that ensures the detection optical axis passes through the substrate storage center line, maintaining alignment precision despite reduced robot size.
Solution Approach 2:
The inclination angle of the hand center line relative to the substrate storage center line is changed from 0 degrees (perpendicular position) to a predetermined non-zero angle. This parameter change allows the detection optical axis to pass through the substrate storage center line even with short arm length, resolving the alignment issue while maintaining compact robot dimensions.
3Productivity
If the hand is positioned close to the substrate storage for efficient transfer, then transfer efficiency is improved, but detection accuracy deteriorates due to insufficient detection distance
Solution Approach 1:
The detection optical axis is oriented along the hand center line which is inclined relative to the substrate storage center line. This dimensional change in the detection path allows the optical axis to pass through the substrate storage center line even when the hand is positioned close to the substrate storage, maintaining detection accuracy while enabling efficient substrate transfer.
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 solution allows for reliable detection of substrate arrangement states, even with short arm lengths, by maintaining the hand out of contact with the cassette and ensuring accurate alignment, thus enhancing the robot's ability to transfer substrates efficiently.
Implementation Method 1
The transmission optical sensor includes a light emitting device and a light receiving device. The light emitting device emits a beam, while the light receiving device receives the beam.
Data Source
AI summary
A substrate transfer robot includes a hand and a controller. The hand includes at least one detector configured to detect an arrangement state of a substrate in a substrate storage. The controller is configured to control the at least one detector to detect the arrangement state of the substrate in the substrate storage with the hand inclined in plan view toward a rotation center of the substrate transfer robot relative to a substrate storage center line. The substrate storage center line is in a direction perpendicular to a front surface of the substrate storage.