Overhead Transport Gripping Unit Control for Swing Recovery
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Solution Overview
Problem
Overhead transport vehicles experience swing-related abnormalities in the gripping unit, leading to operational stops and potential rail jams, necessitating manual intervention to restore operations.
Innovation Solution
An overhead transport vehicle equipped with a detection unit to sense swing, a controller to manage the drive unit for the suspension system, and a method to control the raising/lowering of the gripping unit by maintaining it at a standby position until swing is within a predetermined width, then restarting the operation when the swing subsides, combined with slower reel-up speeds at convergence positions to ensure safe storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the gripping unit is raised/lowered while being suspended by the suspension unit, then the gripping unit can descend to grip an article and rise to transport it, but swing of the gripping unit occurs causing operational stops and potential rail jams
Solution Approach 1:
The detection unit continuously monitors swing of the gripping unit during raising/lowering operations. When swing exceeds a predetermined threshold, the control unit automatically stops the reel-up operation to prevent abnormality. This feedback mechanism enables automatic restoration of operations without manual intervention, maintaining productivity while preventing swing-related reliability issues.
Solution Approach 2:
The system performs self-diagnosis and self-restoration through the detection unit and control unit. When swing is detected, the system automatically stops operation and waits for swing to subside, then automatically resumes operation. This self-service capability eliminates the need for manual intervention to restore operations after swing occurs, ensuring continuous productivity.
2Reliability
If the controller stops reeling up the suspension unit when swing exceeds predetermined width and maintains the gripping unit at a standby position, then swing-related abnormality is prevented, but operation time is extended
Solution Approach 1:
The control unit implements periodic monitoring of grip force during the reel-up operation. When swing is detected, instead of completely stopping the operation, the system periodically adjusts the reel-up speed or pauses briefly to allow swing to subside, then resumes operation. This periodic action maintains reliability by controlling swing while minimizing operation time loss compared to complete stops.
Data Source
AI summary
An overhead transport vehicle includes a gripping unit to grip an article, an suspension unit by which the gripping unit is suspended, a drive unit that reels up the suspension unit to thereby raise the gripping unit, a detection unit to detect swing of the gripping unit, and a controller that controls the drive unit to reel up the suspension unit and store the gripping unit into the transport vehicle body. In reel-up control to reel up the suspension unit, when swing of the gripping unit exceeds a predetermined width, the controller stops reeling up the suspension unit, maintains the gripping unit at a standby position lower than a storage position, and then, reels up the suspension unit when the swing of the gripping unit becomes equal to or less than the predetermined width.