Elevator Car Laser Ranging for Redundant Shaft Positioning
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Solution Overview
Problem
Existing elevator systems face challenges in accurately and reliably determining the position of an elevator car due to potential disturbances from smoke and the need for time-consuming learning runs, especially in tall systems, and laser-based methods are not sufficiently precise.
Innovation Solution
A laser distance measuring device mounted on the elevator car directs a laser beam both upward and downward to determine distances to the upper and lower boundaries of the travel path, using a mirror to switch configurations and optionally measure lateral distances, providing redundancy and reducing error risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic tape with position coding is used to measure the current height position of the elevator car, then position information can be obtained, but the installation effort and time required for learning runs increase considerably in tall elevator systems
Solution Approach 1:
The patent replaces the mechanical magnetic tape system with an optical laser-based distance measurement system. The laser distance measuring device mounted on the elevator car measures the distance to a reference point on the shaft wall, eliminating the need for magnetic tapes and lengthy learning runs while providing precise position measurement.
Solution Approach 2:
The patent introduces a laser beam as an intermediary between the elevator car and the reference point on the shaft wall. This laser intermediary enables direct distance measurement without requiring physical contact or pre-installed magnetic coding, thereby reducing installation effort and learning time.
2Ease of manufacture
If a laser distance measuring device is used to determine the position of the elevator car, then installation effort is reduced, but the measurement reliability and precision are insufficient
Solution Approach 1:
The patent combines multiple measurement approaches by integrating the laser distance measuring device with the existing drive machine encoder system. The laser provides coarse position measurement while the encoder provides fine measurement, merging their advantages to achieve both ease of installation and high precision.
Solution Approach 2:
The patent implements feedback by continuously comparing the position data from the laser distance measuring device with the position data from the drive machine encoder. This feedback mechanism allows for error detection and correction, thereby improving measurement reliability and precision while maintaining ease of installation.
3Reliability
If the laser beam is directed to measure distance to boundaries, then position determination reliability is improved, but the device complexity increases due to mirror mechanisms
Solution Approach 1:
The patent makes the laser distance measuring device multi-functional by enabling it to measure distances to multiple reference points (upper boundary, lower boundary, and intermediate reference points on the shaft wall) using a single device with mirror adjustment capability. This universality improves reliability through redundant measurements without requiring multiple separate devices.
Solution Approach 2:
The patent introduces dynamic mirror adjustment capability to the laser distance measuring device, allowing the laser beam direction to be changed dynamically between different reference points. This dynamic adjustment enables the single device to perform multiple measurement functions, improving reliability while avoiding the complexity of multiple fixed devices.
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
This approach allows for precise and reliable position determination with reduced error, enabling faster learning runs and independent height-based costs, while also providing additional information about local properties and door configurations.
Implementation Method 1
The laser distance measuring device is configured to emit a laser beam and to determine a distance to a position at which the laser beam impinges on an object
Implementation Method 2
laser distance measuring device is configured to emit a laser beam and to determine a distance to a position at which the laser beam impinges on an object
Data Source
AI summary
An elevator system includes an elevator car and a laser distance measuring device. The elevator car is moved along a travel path that is delimited at the top by an upper boundary and at the bottom by a lower boundary. The laser distance measuring device emits a laser beam and determines a distance to a position at which the laser beam impinges on an object. The laser distance measuring device is mounted on the elevator car such that the laser beam can be directed upward to the upper boundary in a first configuration and can be directed downward to the lower boundary in a second configuration. A current position of the elevator car can thereby be determined in a redundant manner. Furthermore, in a third configuration, lateral distances to boundary markers can be measured to read out information that is codified by the boundary markers.