Piezoelectric Speaker Array for Active Noise Control
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Solution Overview
Problem
Existing active noise control systems face limitations in generating a large region where sound can be effectively reduced, particularly due to challenges in diffraction noise reduction at the ends of structures and varying noise phases across different heights.
Innovation Solution
The active noise control system employs a plurality of piezoelectric speakers with radiation surfaces oriented along specific dimensions and intervals, allowing for effective sound reduction across a broader area by controlling diffracted sound and phase differences, with the speakers' arrangement and dimensions optimized to accommodate varying heights and frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If piezoelectric speakers are arranged in a conventional configuration, then the structure is simple, but the sound reduction region is limited in size
Solution Approach 1:
The patent divides the sound reduction region into multiple sub-regions by arranging multiple piezoelectric speakers (first and second piezoelectric speakers) at different positions. Each speaker generates sound waves that contribute to noise cancellation in specific spatial zones, allowing the overall system to achieve extensive sound reduction coverage through segmented control of acoustic fields.
Solution Approach 2:
The patent transitions from conventional single-plane speaker arrangement to a three-dimensional configuration where speakers are positioned at different heights and locations. The first piezoelectric speaker is arranged at a first position and the second piezoelectric speaker at a second position, creating vertical and spatial separation that expands the sound reduction region into multiple dimensions.
2Reliability
If speakers are positioned to control diffracted sound at structure ends, then noise reduction effectiveness improves, but the system becomes more complex
Solution Approach 1:
The patent applies different positioning strategies for different regions of the structure. The first piezoelectric speaker is specifically positioned to address diffracted sound at one end of the structure, while the second piezoelectric speaker is positioned to address diffracted sound at another end or at different heights. This localized optimization of speaker positions for specific noise control objectives improves effectiveness without requiring a complete system redesign.
Solution Approach 2:
The patent employs microphones to detect noise levels and uses this feedback information to adjust the operation of piezoelectric speakers. The controller receives signals from microphones monitoring noise at different positions and heights, and dynamically adjusts speaker activation to maintain effective noise reduction, thereby improving reliability through adaptive control.
3Reliability
If the radiation surface dimensions are optimized for specific frequencies, then frequency-specific noise reduction improves, but adaptability to different frequencies decreases
Solution Approach 1:
The patent employs dynamic control of piezoelectric speakers where the controller adjusts the operating parameters of individual speakers based on detected noise characteristics. The system can dynamically activate different speakers or adjust their output levels depending on the frequency content of the noise, allowing the fixed physical structure to adapt to varying frequency requirements through dynamic signal processing.
Solution Approach 2:
The patent designs the speaker arrangement and control system to serve multiple frequency ranges simultaneously. By strategically positioning multiple piezoelectric speakers and using feedback control, the system achieves effective noise reduction across both low and high frequencies, making the system universally applicable to diverse noise types without requiring frequency-specific dedicated systems.
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 configuration significantly enhances sound reduction capabilities, maintaining effectiveness across different heights and frequencies, even when individuals change posture or position, by strategically arranging piezoelectric speakers to manage diffracted sound and phase variations.
Implementation Method 1
a plurality of piezoelectric speakers disposed on a surface of the structure
Implementation Method 2
the piezoelectric speakers each have a radiation surface extending along a first direction and a second direction orthogonal to the first direction
Implementation Method 3
challenges in diffraction noise reduction at the ends of structures
Data Source
AI summary
An active noise control system (500) includes a structure (80) and a plurality of piezoelectric speakers (10). The piezoelectric speakers (10) are disposed on a surface (80s) of the structure (80). The piezoelectric speakers (10) each have a radiation surface extending along a first direction (D1) and a second direction (D2). The first direction (D1) is a direction along which centers of the radiation surfaces of the piezoelectric speakers (10) are arranged so that the piezoelectric speakers (10) are adjacent to each other. The second direction (D2) is a direction orthogonal to the first direction (D1). The radiation surface of each of the piezoelectric speakers (10) is shorter in a dimension (L1) in the first direction (D1) than in a dimension (L2) in the second direction (D2).