Elevator Load Detection via Cable Elongation for Car Dispatch
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Solution Overview
Problem
Existing elevator systems rely on costly and difficult-to-maintain load-weighing devices within the hoistway to determine car occupancy, which can malfunction during emergencies, leading to inefficient dispatching and increased wait times.
Innovation Solution
A system that determines elevator car loads using positional counts measured by devices outside the hoistway, calculating load based on changes in cable length due to occupant weight, allowing for efficient dispatching without requiring load-weighing devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If load-weighing devices are installed within the hoistway of each elevator car, then load measurement accuracy is improved, but device cost and maintenance complexity increase
Solution Approach 1:
The patent extracts the load measurement function from the traditional hoistway-mounted weighing devices and relocates it to the cable system. By measuring cable elongation caused by load changes, the system eliminates the need for complex mechanical weighing devices inside the hoistway while maintaining measurement capability.
Solution Approach 2:
The patent replaces mechanical load-weighing devices with an optical measurement system. Instead of using mechanical sensors and encoders in the hoistway, the system uses optical elements (such as optical fibers or sensors) to measure cable elongation, thereby reducing mechanical complexity and maintenance requirements.
2Reliability
If traditional load-weighing devices are used, then load determination is achieved, but reliability decreases during emergency situations
Solution Approach 1:
The patent introduces the cable as an intermediary element between the load and the measurement system. Instead of directly measuring load with complex devices, the system measures cable elongation, which is a more reliable parameter that can be sensed even during emergency conditions when direct load measurement may fail.
Solution Approach 2:
The patent replaces mechanical load-weighing devices with an optical measurement system. Optical sensors and fibers are more reliable than mechanical devices during emergencies (such as fire or power failures) because they can detect changes in cable elongation without requiring complex mechanical components that may fail under extreme conditions.
3Loss of information
If hoistway-mounted sensors are installed, then load data is obtained, but ease of operation and maintenance deteriorates
Solution Approach 1:
The patent extracts the sensing function from the hoistway environment and relocates it to the cable system. By measuring cable elongation rather than directly sensing load in the hoistway, the system eliminates the need for difficult-to-access sensors while maintaining continuous load data availability.
Solution Approach 2:
The cable itself serves as both the load-bearing element and the sensing element. The cable's own elongation under load provides the measurement signal, eliminating the need for separate sensors that require maintenance and calibration. The system is self-diagnostic and requires minimal human intervention.
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 accurate and reliable elevator dispatching based on real-time load data, reducing wait times and improving traffic flow by optimizing the assignment of cars to passenger demands.
Implementation Method 1
a relative movement of the car as a result of a change in the load is determined using the absolute value encoder, and the load in the car is determined from the determined position of the car, the determined relative movement, and the spring constant of the elevator system
Data Source
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AI summary
A method for dispatching an elevator car that includes determining the elevator car is located at a first location of a plurality of locations, and a predefined positional count corresponds to each of the plurality of locations. The method includes determining a positional count of the elevator car at the first location, and determining a load of the elevator car at the first location based on a difference between the positional count and the predefined positional count corresponding to the first location. The method includes controlling an operation of the elevator car based on the load of the elevator car at the first location.