Outdoor AC Noise Control Layout for Moving Listener Positions

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Solution Overview

Problem

Existing noise control systems for creating a noise cancellation field in open spaces face challenges when the user moves, as the secondary noise source can be obstructed by the user's head, preventing effective noise cancellation.

Innovation Solution

A noise control system comprising reference sensors, error sensors, and control speakers arranged to create a noise cancellation field at a desired position, using adaptive signal processing to generate noise cancellation signals that can be effectively applied regardless of the user's head position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a noise control system is mounted on a pillow near the user's head, then noise cancellation can be provided, but the user's head may cover the secondary noise source when moving, preventing effective noise cancellation

Engineering Contradiction:
Improvenoise cancellation effectivenessVSAvoidrobustness to user movement
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent relocates the noise control system from a two-dimensional surface mounting on the pillow to a three-dimensional spatial deployment in the room. By placing speakers at multiple locations (including ceiling-mounted and floor-standing speakers) rather than confining them to the pillow surface, the system creates a distributed acoustic field that remains effective regardless of the user's head position and movement.

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

2Adaptability or versatility

If the noise control system is placed in open space rather than on the pillow, then the secondary noise source is not obstructed by the user's head, but the system complexity increases

Engineering Contradiction:
Improverobustness to user movementVSAvoidsystem configuration complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs the noise control system with multi-functional speakers that serve dual purposes: floor-standing speakers function both as aesthetic room decorations and as noise cancellation actuators. This integration reduces the need for dedicated specialized components and simplifies the overall system configuration while maintaining effectiveness in open space.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 effectively reduces noise levels at a desired position, providing a comfortable environment by ensuring continuous noise cancellation even when the user moves, and can be applied to various settings such as air-conditioning apparatus and fan structures.

Implementation Method 1

one or more control speakers 13 for radiating a noise cancellation signal... to create a noise cancellation field 60 where noise is reduced

Methodology Applied
Scientific EffectAcoustic interference: Interference

Implementation Method 2

one or more reference sensors 10 for detecting a noise sound wave from a noise source 2

Methodology Applied
Scientific EffectSound detection: Sound

Implementation Method 3

two or more error sensors 11 for detecting an acoustic signal component of the noise cancellation field 60

Methodology Applied
Scientific EffectSound detection: Sound

Data Source

PatentEP3511930B1Outdoor unit of an air-conditioning-apparatus equipped with noise control system
Publication Date: 2023.07.19 MITSUBISHI ELECTRIC CORP
  • EP3511930B1 patent drawingFigure 1~2
  • EP3511930B1 patent drawingFigure 3~4
  • EP3511930B1 patent drawingFigure 5

AI summary

To provide a noise control system capable of generating a noise cancellation field where noise is reduced at a desired position in a space. An error scanning filter 12 generates a noise cancellation signal using an adaptive control algorithm based on error scanning, the signal having a phase opposite to that of an acoustic signal component detected by a reference sensor. A control speaker 13 radiates the noise cancellation signal to create a noise cancellation field 60 near the head of a person 26 receiving sound.