Active Noise Control for Tracking Peak Frequency Changes
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Solution Overview
Problem
Conventional active noise reduction systems fail to effectively reduce noise at varying peak frequencies due to changes in input conditions, such as vehicle speed and road conditions, leading to residual noise at the peak frequency.
Innovation Solution
An active noise reduction system that includes a canceling sound generator, error detector, and controller to dynamically adjust the control target frequency based on detected noise components, using adaptive algorithms to generate a control signal that cancels noise at the peak frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed control target frequency is used in the active noise reduction system, then the system structure is simple and easy to implement, but the system cannot follow the change in peak frequency of the noise when input conditions change
Solution Approach 1:
The patent applies dynamics by making the control target frequency variable instead of fixed. The system dynamically adjusts the control target frequency based on detected noise characteristics, allowing it to follow peak frequency changes when input conditions change, while maintaining a relatively simple overall system structure.
Solution Approach 2:
The patent changes the parameter of control target frequency from a fixed value to a variable that adapts to noise conditions. By detecting the peak frequency of the noise and adjusting the control target frequency accordingly, the system achieves adaptability without requiring complete structural redesign.
2Reliability
If the control target frequency is dynamically adjusted to follow noise peak frequency, then the noise reduction effectiveness is improved, but the system complexity increases
Solution Approach 1:
The patent implements feedback by detecting the noise signal, identifying its peak frequency, and using this information to adjust the control target frequency. This feedback mechanism ensures the system maintains effective noise reduction by continuously adapting to changing noise characteristics, while the feedback loop is designed to be as simple as possible.
Solution Approach 2:
The system performs self-adjustment by automatically detecting the noise peak frequency and setting the control target frequency accordingly, without requiring external intervention or complex manual tuning. This self-service capability improves reliability while keeping the control mechanism relatively simple.
3Adaptability or versatility
If a single frequency control is used, then the system is simple to operate, but it cannot effectively reduce noise when the peak frequency varies due to changing input conditions
Solution Approach 1:
The system automatically detects and tracks the noise peak frequency, adjusting the control target frequency without user intervention. This self-service operation maintains ease of use while achieving adaptability to varying input conditions, as the system handles the frequency adjustment autonomously.
Solution Approach 2:
The system uses feedback from noise detection to automatically adjust the control frequency, eliminating the need for manual operation while maintaining simplicity. The feedback loop continuously monitors noise characteristics and adjusts the control target frequency accordingly, providing adaptability without complicating user interaction.
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 at the peak frequency by following changes in the input conditions, providing enhanced noise cancellation by dynamically adjusting the control target frequency.
Implementation Method 1
an active noise reduction system that reduces a noise by causing a canceling sound in an opposite phase to the noise to interfere with the noise
Data Source
AI summary
An active noise reduction system includes a canceling sound generator configured to generate a canceling sound for canceling a noise, an error detector configured to detect an error between the noise and the canceling sound and generate an error signal corresponding to the error, and a controller configured to control the canceling sound generator based on the error signal, wherein the controller is configured to extract noise components at a plurality of frequencies based on the error signal, determine a control target frequency among the plurality of frequencies based on the noise components at the plurality of frequencies, select a value of a prescribed control parameter based on the control target frequency, and generate a control signal to control the canceling sound generator based on the selected value of the control parameter.