Adaptive Noise Reduction Apparatus with Multi-Source Directivity Control
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Solution Overview
Problem
Existing noise reduction systems are ineffective in addressing noise from rotating systems with unknown directivity characteristics, as they assume noise sources are non-directional point sources, leading to reduced noise reduction effectiveness.
Innovation Solution
A noise reduction apparatus comprising multiple control sound sources and detection units that adjust sound phases and amplitudes to maximize total current amplitude, allowing for adaptive directivity matching of noise reduction control sounds to the noise source's directivity, even if unknown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a non-directional point sound source approximation is used for noise reduction control, then the system complexity is reduced and ease of operation is improved, but the noise reduction effectiveness deteriorates when the actual noise source has unknown directivity characteristics
Solution Approach 1:
The patent applies dynamics by making the control sound source directivity adjustable and adaptive. The system dynamically changes the directivity characteristics of control sound sources based on detected noise directivity, allowing the noise reduction system to adapt to different noise source configurations rather than relying on fixed non-directional assumptions.
Solution Approach 2:
The patent changes the directivity parameter of control sound sources to match the noise source directivity. By adjusting the directivity parameter based on detection results, the system optimizes noise reduction effectiveness for different noise source types without requiring complete reconstruction of the noise source model.
2Reliability
If multiple control sound sources with adaptive directivity matching are used, then noise reduction effectiveness is improved, but the device complexity increases
Solution Approach 1:
The patent implements feedback by detecting the directivity characteristics of the noise source and using this information to adjust the directivity of control sound sources. This closed-loop approach ensures that the control sound sources are optimally configured for the actual noise conditions, improving effectiveness while avoiding the need for overly complex predetermined models.
Solution Approach 2:
The system performs self-service by automatically detecting noise directivity and adjusting control sound source directivity without requiring manual configuration or complex external control. The noise reduction system adapts itself to the noise source characteristics, reducing the need for complex external calibration procedures.
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 minimizes acoustic power propagation by generating control sounds with directivity matching the noise source, enhancing noise reduction effectiveness compared to single loudspeaker systems.
Implementation Method 1
generates a first control sound for reducing noise from the noise source... generates a second control sound for reducing the noise from the noise source
Data Source
AI summary
According to one embodiment, a noise reduction apparatus includes a first control sound source, a first current detection unit, a second control sound source, a second current detection unit, and an adjustment unit. The first control sound source generates a first control sound for reducing noise from a noise source. The first current detection unit detects a first current flowing from the first control sound source upon receiving the noise from the noise source. The second control sound source is provided at a position different from a position of the first control sound source and generates a second control sound for reducing the noise from the noise source. The second current detection unit detects a second current flowing from the second control sound source upon receiving the noise from the noise source. The adjustment unit adjusts the first control sound and the second control sound so as to make the first current and the second current satisfy a predetermined condition.