Elevator Car Position Sensing With Pseudorandom Code Tape
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Solution Overview
Problem
Existing position-determining systems for elevator cars require a large number of Hall sensors, leading to increased material costs and space requirements, especially when redundancy is needed for safety.
Innovation Solution
A position-determining system that uses a code tape with a code-mark pattern and a detection apparatus with a shorter detection length than the position-mark length, allowing for detection of only part of a position mark at a time, thus reducing the number of sensors needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large number of Hall sensors is used to achieve reliable and redundant car position determination, then the reliability of position determination is improved, but the material costs and space requirements increase
Solution Approach 1:
The code-mark pattern is segmented into multiple code marks that form position marks in a pseudorandom sequence. The detection apparatus detects individual code marks sequentially rather than requiring all sensors to detect complete position marks simultaneously, enabling reliable position determination with fewer sensors through time-sequential detection of segmented position information
Solution Approach 2:
The code-mark pattern is pre-configured with position marks arranged in an unambiguous pseudorandom sequence, where each position mark consists of a specific number of code marks. This preliminary arrangement allows the evaluation unit to determine car position reliably by detecting code marks in sequence and identifying complete position marks based on the predetermined pattern, reducing the need for redundant simultaneous detection
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 allows for a cost-effective and space-efficient determination of the elevator car position, while maintaining reliable detection capabilities, particularly suitable for applications where immediate restart determination is not critical.
Implementation Method 1
The detection apparatus has a number of Hall sensors which contactlessly scan the code-mark pattern and thus detect the position mark
Data Source
AI summary
A position-determining system and a method for ascertaining a car position of an elevator car use a code tape mounted next to the elevator car in parallel with a movement direction and that includes a code-mark pattern of individual code marks, a detection apparatus mounted on the elevator car that detects the code marks, and an evaluation unit that determines the car position on the basis of the detected code marks. Here, n successive code marks of the code-mark pattern form a position mark, the position marks are unambiguously arranged in an n-digit pseudorandom sequence of various position marks, the position marks form a single-track code-mark pattern, and a discrete car position is assigned to each position mark. A detection region of the detection apparatus has a detection length in the movement direction that is shorter than a position-mark length of a position mark in the movement direction.