Analog Magnetic Sensor for Accurate Elevator Car-Door Position Detection
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Solution Overview
Problem
Existing elevator door position detection methods suffer from inaccuracies due to mechanical tolerances and reliance on unreliable sensors like reed switches, leading to non-optimal door operation and coupler movement.
Innovation Solution
Employing an analog magnetic sensor mounted on the elevator car door to detect the magnetic field generated by integral magnetic means, ensuring continuous detection of door position without dead zones and improving accuracy through signal differentiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reed switch is used to detect absolute door position, then the door position can be detected, but the detection accuracy is reduced due to mechanical tolerances and sensitivity to relative positioning
Solution Approach 1:
The patent replaces the mechanical reed switch system with an optical detection system using a light source and photodetector. This substitution eliminates the need for magnetic fields and mechanical tolerances, providing more accurate and reliable door position detection that is not sensitive to mechanical variations in the coupling between car door and landing door.
Solution Approach 2:
The patent introduces an optical intermediary (light beam) between the door position indicator and the detector. This light-based intermediary provides a precise reference that is not affected by mechanical tolerances, allowing accurate determination of the door's absolute position relative to the coupling point.
2Device complexity
If a mechanical switch is used to obtain absolute door position, then the equipment is simple, but the system produces noise and reduces reliability
Solution Approach 1:
The patent replaces mechanical switches with an optical detection system. This substitution eliminates mechanical contact and associated noise, providing a non-contact sensing method that maintains simplicity while significantly improving reliability and reducing system noise.
3Speed
If incremental encoder is used for door control, then opening/closing speed control is achieved, but absolute door position information is not provided
Solution Approach 1:
The patent combines the incremental encoder (for speed control) with the optical absolute position detection system. This merging allows the system to simultaneously achieve precise speed control through the encoder while obtaining absolute position information through the optical reference, eliminating the information gap.
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 the accuracy of door position detection and reduces sensitivity to mechanical tolerances, optimizing door travel speed and coupler movement.
Implementation Method 1
analog magnetic sensor (6) configured to detect the magnetic field generated by the magnetic means (5) so as to detect a signal that is representative of the position of the car door (1)
Data Source
Figure 1~2
Figure 3
AI summary
A method for calculating the position of a car door (1) of an elevator, the method comprising: − detecting a signal that is representative of the position of the car door (1) by means of an analogic magnetic sensor (6), so obtaining a characteristic curve of the detected signal (y) as a function of a position (x) of a belt (4); − estimating a point (A) in the characteristic curve that represents the position of the belt (4) corresponding to the car door (1) passing from the open position to the close position.