Elevator Door Controller Using Doppler Sensor for Passenger Detection

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Solution Overview

Problem

Existing elevator door control systems using sensors can fail to detect passengers due to limited detection range, slow approach speeds, and interference from dust, noise, or light, leading to potential door collisions and inefficient service times.

Innovation Solution

A door operation controller utilizing Doppler sensors arranged in the safety shoe near the door closing edge, capable of detecting moving direction and speed of individuals or objects within a 5-10 meter range, extending door opening time based on congestion assessment and preventing unwanted door closures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional sensors (infrared, ultrasonic) are used to detect passengers, then detection capability is provided, but detection range is limited and detection reliability deteriorates due to dust, noise, or light interference

Engineering Contradiction:

Improvedetection reliabilityVSAvoiddust, noise, light interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces conventional optical and ultrasonic sensors with a Doppler sensor that uses acoustic wave transmission and frequency shift detection. This substitution eliminates sensitivity to optical interference (dust, light) and provides more reliable detection of passenger movement toward the door, as the Doppler effect directly measures velocity changes of reflected acoustic waves from moving objects.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If door opening time is extended to accommodate slow-approaching passengers, then passenger safety is improved, but elevator service time increases

Engineering Contradiction:

Improvepassenger safetyVSAvoidelevator service time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The Doppler sensor performs preliminary detection of passenger approach velocity before the door closing sequence begins. By detecting slow approach speeds in advance, the system can proactively extend the door opening time to allow safe boarding, preventing last-minute door closures that would compromise safety. This preliminary detection enables timely door extension decisions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The door operation system dynamically adjusts the door opening time based on real-time Doppler sensor feedback regarding passenger approach velocity. When slow approach is detected, the door remains open longer; when no passengers or fast approach is detected, the door closes promptly. This dynamic adjustment optimizes both safety and service efficiency.

Inventive Principle:

Principle #15Dynamics

3Productivity

If door closes quickly to optimize service time, then productivity is improved, but risk of catching passengers increases

Engineering Contradiction:

Improveelevator service efficiencyVSAvoidpassenger safety

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The Doppler sensor provides continuous feedback during the door closing sequence about passenger presence and movement velocity. This feedback enables the control system to monitor the closing process in real-time and immediately reverse the door if a passenger is detected moving toward it, even during closure. This feedback mechanism maintains high service efficiency while preventing door-catching incidents.

Inventive Principle:

Principle #23Feedback

4Area of stationary object

If detection range is extended to cover larger area, then detection capability is improved, but false detection increases due to environmental factors

Engineering Contradiction:

Improvedetection rangeVSAvoiddetection accuracy

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The Doppler sensor detects passengers by measuring frequency shifts in reflected acoustic waves caused by motion, rather than relying on optical or ultrasonic parameters susceptible to environmental interference. This parameter change to velocity-based detection through the Doppler effect enables accurate distinction between actual passengers and environmental noise, maintaining high detection accuracy across extended ranges.

Inventive Principle:

Principle #35Parameter changes

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 passenger safety by reliably detecting approaching individuals, optimizing door operation to prevent collisions and reduce service time delays, while being less susceptible to environmental interferences.

Implementation Method 1

at least one sensor arranged in a doorway at a landing for detecting moving direction and/or moving speed of a person or an object

Methodology Applied

Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentUS11274020B2Door operation controller

Publication Date: 2022.03.15 OTIS ELEVATOR CO

AI summary

A door operation controller for an elevator includes at least one sensor arranged in a doorway at a landing for detecting moving direction and/or moving speed of a person or an object in or near the doorway during a time period from when the elevator door is opened until when the elevator door is closed at the landing. The controller is configured to control door operation in response to the detection of a person's or object's movement in or near the doorway at the landing.