Elevator Car Position Detection Self-Diagnosis via Magnetic Field Switching
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Solution Overview
Problem
Existing elevator systems face challenges in self-diagnosis without moving the car, as they lack the capability to perform failure diagnosis when no detection plates are present and incur increased costs due to scale-based magnet systems without self-diagnosis functions.
Innovation Solution
A car position detector system featuring identification plates with slit patterns, differential type detection coils, and a signal processor that enables self-diagnosis by switching between normal and self-diagnosis modes using a test coil and phase shifter, allowing for quadrature detection and fixing detection coil outputs to H or L levels regardless of the presence of the identification plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnet-based scale is used for car position detection, then detection precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical magnet-based scale system with an electromagnetic sensing system. The sensor uses coils to detect changes in magnetic flux caused by metal plates at different landing positions, eliminating the need for complex magnet scales while achieving accurate car position detection through electromagnetic induction principles
Solution Approach 2:
The patent creates a simplified electromagnetic field model that replicates the position detection function without requiring physical magnet scales. By using coils to generate and detect magnetic fields interacting with metal plates, the system copies the essential detection capability in a less complex manner
2Device complexity
If distance sensors or code reading apparatus are used without self-diagnosis capability, then device complexity is reduced, but reliability deteriorates due to inability to perform self-diagnosis without car movement
Solution Approach 1:
The patent implements a self-diagnosis function where the sensor can autonomously test its own operational status by detecting the metal plate structure without requiring car movement. The system automatically determines whether the sensor is functioning correctly by analyzing the presence or absence of expected metal plate signals at various positions
Solution Approach 2:
The patent performs preliminary diagnostic checks by detecting metal plate structures before actual car position detection operations. The system proactively identifies potential sensor failures by checking whether metal plates are detected when they should be present, enabling early detection of system issues
3Device complexity
If traditional detection systems are used without test coil, then device complexity is reduced, but reliability deteriorates due to inability to perform self-diagnosis
Solution Approach 1:
The patent makes the coil assembly multi-functional by using it for both normal car position detection and self-diagnosis operations. The same coils that detect metal plates during operation are also used in self-diagnosis mode to verify sensor functionality, eliminating the need for completely separate diagnostic hardware
Solution Approach 2:
The patent implements periodic self-diagnosis operations where the sensor alternates between normal detection mode and self-test mode. During self-diagnosis, the system periodically activates the test coil to generate magnetic fields and checks whether the detection coils respond appropriately, creating a rhythmic pattern of operational and diagnostic states
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 self-diagnosis of car position detection without car movement, reducing costs by eliminating the need for scale-based magnet systems and improving detection reliability through threshold processing and magnetic field manipulation.
Implementation Method 1
a plurality of coils formed of N coils each being configured to output a voltage value due to an AC magnetic response by being opposed to a part of the slit pattern
Implementation Method 2
a test coil configured to be supplied with an exciting current flowing through the exciting coil, to thereby apply a magnetic field corresponding to an amplitude of the exciting current to the differential type detection coil
Data Source
AI summary
Provided is an apparatus configured to detect a car position by performing threshold processing on a voltage caused by an AC magnetic response through use of an identification plate in which a slit pattern is formed and a plurality of coils, the apparatus including a circuit configuration capable of switching between a normal operation for detecting the car position based on an on/off detection operation using the plurality of coils and a self-diagnosis operation capable of verifying the on/off detection operation irrespective of the presence or absence of the identification plate with a car in a stopped state by forcedly applying a magnetic field to the coils.