Elevator Load Measurement via Power and Direction Correlation

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Solution Overview

Problem

Existing elevator systems face challenges in accurately measuring load without requiring permanent sensors, which limits flexibility and increases maintenance complexity, especially when counterweights are present, making it difficult to determine whether the elevator car is full or empty based on mechanical power alone.

Innovation Solution

A system comprising a first sensor system for measuring performance parameters and a second sensor system for determining movement direction parameters, along with a logic unit that calculates the load of the elevator car without being integrated into the control or drive electronics, allowing for flexible retrofitting and increased redundancy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If permanently installed sensors are used to measure load, then measurement precision is improved, but device complexity and ease of manufacture deteriorate due to requiring design planning during system construction

Engineering Contradiction:
Improveload measurement accuracyVSAvoidsystem installation flexibility
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent extracts the load measurement function from the traditional permanent sensor installation approach. Instead of installing dedicated sensors during construction, the system uses existing sensors (already present in the elevator for other functions) to gather data that can be processed to determine load, thereby eliminating the need for additional permanent sensor installations while maintaining measurement capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary processing system that collects data from existing sensors and calculates load indirectly. Rather than directly measuring load with dedicated sensors, the system uses power consumption data and movement direction data as intermediaries to derive load information, enabling retrofitting without permanent sensor installation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If permanently installed sensors are used to measure load, then measurement precision is improved, but device complexity worsens due to integration requirements with control electronics

Engineering Contradiction:
Improveload measurement accuracyVSAvoidintegration with control electronics
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the load measurement function into a separate, independent evaluation unit that operates autonomously from the elevator control electronics. This evaluation unit collects data from existing sensors and performs load calculations independently, avoiding complex integrations with the control system while maintaining measurement precision

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The evaluation unit is designed to be self-contained and self-sufficient, using data from existing sensors without requiring continuous interaction or integration with the elevator control electronics. This self-service approach reduces device complexity by isolating the load measurement function from the main control system

Inventive Principle:
Principle #25Self-service

3Device complexity

If mechanical power alone is used to determine load, then device complexity is reduced, but measurement precision deteriorates when counterweights are present

Engineering Contradiction:
Improvemeasurement system simplicityVSAvoidload determination accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent adds another dimension to the load measurement approach by incorporating movement direction data alongside power consumption data. This additional dimension (direction of movement) provides the extra information needed to accurately determine load when counterweights are present, resolving the precision issue without significantly increasing system complexity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the parameters used for load determination from solely mechanical power to a combination of power consumption and movement direction. This parameter change enables accurate load measurement in the presence of counterweights by providing contextual information about the elevator's operational state

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If retrofits are performed on existing elevator systems, then adaptability is improved, but device complexity increases due to unknown functionality of relevant parts

Engineering Contradiction:
Improveretrofit capabilityVSAvoidsystem modification effort
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the load measurement functionality from the elevator's core control system, using existing sensors that are already part of the elevator infrastructure. This extraction approach enables retrofits on existing systems without requiring deep understanding or modification of the elevator's control electronics, thereby improving adaptability while limiting the increase in device complexity

Inventive Principle:
Principle #2Taking out (Extraction)

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 load determination of the elevator car by correlating power consumption with movement direction, enhancing the informative value of operating data and allowing for flexible integration into existing systems without altering existing control or drive electronics, thus improving flexibility and reliability.

Implementation Method 1

a first sensor system (130, 131) for measuring a power parameter. The power parameter is indicative of the power of the drive motor (120)

Methodology Applied
Scientific EffectElectrical resistance measurement: Electrical Resistance

Implementation Method 2

a second sensor system (140-143) for measuring a motion direction parameter of the elevator car (110)

Methodology Applied
Scientific EffectAccelerometer detection: Accelerometer

Data Source

PatentEP3848314B1System for measuring load in an elevator system and method for determining the load of an elevator car
Publication Date: 2023.10.04 INVENTIO AG
  • EP3848314B1 patent drawingFigure 1
  • EP3848314B1 patent drawingFigure 2a~2b
  • EP3848314B1 patent drawing

AI summary

System for measuring the load in an elevator system comprising an elevator car, a power supply system, and a drive machine, wherein the drive machine is configured to move the elevator car along a shaft, the power supply system is connected to a mains connection via electrical conductors, and wherein the drive machine is connected to the power supply system via electrical conductors, wherein the system comprises a first sensor system for measuring a power parameter, the power parameter being indicative of the power of the drive machine, the system comprises a second sensor system for measuring a direction of movement parameter of the elevator car, the direction of movement parameter being indicative of the direction of movement of the elevator car, and the system comprises a logic unit, wherein the logic unit is configured to calculate a load of the elevator car from the measured power and direction of movement parameters.