Elevator Position Detection Using Magnetic ID Sequences
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Solution Overview
Problem
Conventional elevator position detection systems face inaccuracies when the car speed varies and incur cost increases due to the need for multiple conductor types to enhance position detection.
Innovation Solution
An elevator position detection apparatus featuring a detection subject body with an ID sequence of segments having different magnetic properties, an eddy current detection unit, an identification unit, a digital data conversion unit, and a position specification unit to accurately detect the position of the elevating body within the hoistway while minimizing cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a slit pattern is used for position detection, then the position of the car can be detected, but when the speed of the car varies, it becomes impossible to detect the widths of the slits accurately, resulting in position detection errors
Solution Approach 1:
The patent replaces the optical slit pattern detection system with a magnetic field-based eddy current detection system. Instead of using optical slits whose width detection fails at varying speeds, the invention uses magnetic conductors with different magnetic properties that generate eddy currents when exposed to a magnetic field from the detector. This substitution of detection mechanism eliminates speed-dependent detection errors.
Solution Approach 2:
The invention changes the detection parameter from optical width measurement to magnetic property detection. By using conductors with different magnetic properties (magnetic conductivity, eddy current characteristics) instead of varying slit widths, the system can accurately distinguish different positions regardless of detection speed. The magnetic properties remain constant while the car moves, enabling reliable position detection at any speed.
2Measurement precision
If the number of types of conductors is increased to increase the number of car detection positions, then more position detection points are available, but a cost increase occurs
Solution Approach 1:
The patent applies local quality by varying the magnetic properties of conductor segments at different positions along the identification plate. Instead of using different types of conductors for different positions, each conductor segment has a specific magnetic property (different magnetic conductivity or eddy current characteristics) that encodes its position information. This allows multiple detection positions to be achieved using the same conductor material with locally varied properties.
Solution Approach 2:
The invention changes the approach from increasing conductor type diversity to varying magnetic property parameters within the same conductor material. By adjusting magnetic conductivity, thickness, or eddy current characteristics of different conductor segments, the system achieves multiple detectable positions without needing multiple conductor types, thereby reducing manufacturing complexity and cost.
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
The system provides accurate position detection of the elevating body within the hoistway, preventing errors from varying car speeds and reducing costs by increasing information without increasing the number of conductor types.
Implementation Method 1
an eddy current type detection unit provided in the elevating body in order to generate signals corresponding to the magnetic properties of the respective segments by applying a magnetic field to the ID sequence while passing through a position of the detection subject body
Data Source
AI summary
A detection subject body provided in a hoistway includes an ID sequence formed by arranging three or more types of segments having different magnetic properties in a movement direction of an elevating body. An eddy current type detection unit is provided on the elevating body to generate signals corresponding to the magnetic properties of the respective segments. An identification unit identifies the respective types of the segments on the basis of the signals from the detection unit, and outputs a time series signal in a different output condition depending on the type of each segment. A digital data conversion unit converts the time series signal into digital data on the basis of variations in the output condition of the time series signal from the identification unit. A position specification unit specifies the position of the elevating body on the basis of the digital data.