Elevator Position Recovery via Dummy Landing Patterns
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Solution Overview
Problem
Existing elevator systems face challenges in determining the current position of the elevator car after a power loss, as shaft encoders lose data on rotations and absolute positions, requiring lengthy correction runs to reset the position, which affects performance and efficiency.
Innovation Solution
The implementation of a position determining system with landing and dummy position indicators forming unique patterns along the hoistway, a sensor on the elevator car to detect these patterns, and a processor to calculate the absolute position, allowing for shorter correction runs by estimating the minimum travel distance to determine the car's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the elevator car performs a terminal position recovery run to reset the position device, then the position accuracy is improved, but the time required for correction increases
Solution Approach 1:
The hoistway is segmented into multiple zones with dummy landing indicators placed at specific intervals rather than relying on a single terminal indicator. This segmentation allows the system to perform shorter correction runs by resetting position at intermediate points, thereby reducing correction time while maintaining position accuracy.
Solution Approach 2:
Dummy landing indicators are pre-installed at predetermined positions throughout the hoistway to serve as advance position reference points. These indicators are prepared in advance to enable quick position recovery without requiring the elevator to travel to the actual terminal ends, thus reducing correction run time.
2Reliability
If initialization switches are placed at distal ends of the hoistway, then the position recovery is reliable, but the correction run distance increases
Solution Approach 1:
Dummy landing indicators serve as intermediary position reference points between the elevator car and the actual terminal switches. These intermediate indicators provide reliable position recovery references that are closer to the car's current position, reducing the correction run distance while maintaining recovery reliability.
Solution Approach 2:
Position indicators are strategically placed at local positions throughout the hoistway rather than only at the distal ends. This local placement creates multiple reliable reference points that are accessible to the elevator car, enabling shorter and more efficient correction runs while maintaining position recovery reliability.
3Measurement precision
If the elevator controller causes the elevator car to perform a correction run to the other end of the hoistway, then the position device can be reset, but the elevator performance deteriorates
Solution Approach 1:
The hoistway is divided into segments with dummy landing indicators at intermediate positions. This segmentation enables the elevator to perform shorter correction runs within individual segments rather than traveling the entire hoistway length, thereby maintaining position reset capability while improving elevator performance and productivity.
Solution Approach 2:
Dummy landing indicators are pre-positioned throughout the hoistway to enable quick position recovery at intermediate points. This preliminary placement allows the elevator to reset position without performing lengthy correction runs to the far ends, thus maintaining productivity while achieving position reset capability.
Data Source
AI summary
An elevator system (10) includes an elevator hoistway (12) having a plurality of landings (14), an elevator car (16) configured to move within the elevator hoistway (12), and a position determining system (40) having a plurality of landing position indicators (48) and a plurality of dummy position indicators (50). At least one of the landing position indicators (48) is mounted proximate to each of the plurality of landings (14). Each dummy position indicator (50) is mounted within the elevator hoistway (12) at a predetermined vertical position between various of the plurality of landing position indicators (48). The position determining system (40) additionally includes a sensor (42) configured to determine when the elevator car is adjacent one of the plurality of landing position indicators (48) or one of the plurality of dummy position indicators (50). The plurality of landing position indicators (48) and the plurality of dummy position indicators (50) are positioned to form a sequence of unique patterns. The position determining system is more cost effective and timesaving than the absolute position reference systems.