Elevator Speed Verification via Dual-Channel Sensor Fusion
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Solution Overview
Problem
Current elevator systems have inadequate overspeed monitoring, with low Safety Integrity Level (SIL) and limited two-channel monitoring, particularly in the electrical rescue drive function, which compromises safety.
Innovation Solution
A method and system for verifying elevator car speed data using two-channel monitoring, where continuous speed data from accelerometers or encoders and zone speed data from Hall sensors and magnets are compared to generate control signals for safety devices, ensuring accurate overspeed detection and meeting predetermined SIL levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motor encoder or absolute position sensor is used for speed monitoring, then speed data can be obtained, but the SIL level of overspeed monitoring remains too low (2 or less) and two-channel monitoring is not achieved
Solution Approach 1:
The speed monitoring function is segmented into two independent channels, each with its own sensor and processing path. This segmentation allows the system to achieve both continuous speed data and zone speed data through separate measurement paths, thereby achieving SIL3 level reliability while maintaining measurement precision
Solution Approach 2:
A safety control unit is introduced as an intermediary component that receives data from multiple sensors (motor encoder/absolute position sensor for continuous speed, Hall sensors for zone speed) and performs verification. This intermediary coordinates the multiple channels and ensures the SIL3 level through systematic comparison and validation
2Reliability
If two-channel monitoring is implemented using door zones, then SIL level improves, but overspeed monitoring is provided only within a part of the elevator shaft
Solution Approach 1:
The system merges two types of speed monitoring into a unified two-channel system: continuous speed monitoring (available throughout the shaft) and zone speed monitoring (at specific locations). By combining these complementary approaches, the system achieves both comprehensive coverage and high SIL level reliability
Solution Approach 2:
The safety control unit performs multiple functions: it processes continuous speed data from encoders, processes zone speed data from Hall sensors, performs verification between channels, and generates control signals. This multi-functional approach enables the system to achieve SIL3 level while maintaining monitoring coverage throughout the entire elevator shaft
3Reliability
If continuous speed data and zone speed data are compared for verification, then speed data validity is improved, but system complexity increases
Solution Approach 1:
The system performs preliminary verification by comparing continuous speed data with zone speed data before final overspeed determination. This preliminary action filters out invalid data early in the process, simplifying subsequent decision-making while maintaining high reliability
Solution Approach 2:
The verification process creates a feedback loop where zone speed measurements are used to validate continuous speed measurements, and discrepancies trigger re-evaluation. This feedback mechanism systematically improves data validity while managing complexity through structured validation logic
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
Enhances elevator safety by achieving two-channel SIL3 level overspeed monitoring during service and electrical rescue drive functions, improving the reliability of speed control and reducing the risk of overspeed incidents.
Implementation Method 1
obtaining a zone speed data of the elevator car within at least one zone of an elevator shaft at two channels
Data Source
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AI summary
The invention relates to a method for verifying speed data of an elevator car (102) for overspeed monitoring of the elevator car (102). The method comprising obtaining at least one continuous speed data of the elevator car (202) at two channels; obtaining a zone speed data of the elevator car (204) within at least one zone of an elevator shaft at two channels, generating a two- channel verified speed information (206) by comparing the said at least one continuous speed data to the zone speed data at least at one channel; generating a control signal (208), if the comparison indicates a mismatch at least at one channel; and if the comparison indicates a match at each of the at least one channel in which the comparison is provided; the method further comprising comparing (210) the verified speed information at each channel between each other; and generating the control signal (208), if the reciprocal comparison indicates a mismatch. The invention also relates to a safety control unit and an elevator system performing at least partly the method.