Open Fluid-Duct Active Noise Cancellation with MIMO Sensor Arrays
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Solution Overview
Problem
Existing noise cancellation technologies, such as earbuds and passive sound isolation, are limited in their ability to reduce noise across the full audio frequency range, especially at higher frequencies, and are sensitive to placement variations and changes in fluid properties, leading to inefficiencies and increased costs.
Innovation Solution
A multi-input-multi-output (MIMO) active sound-cancellation system for open fluid-ducts, utilizing an axial array of sensors and actuators, with a sound-cancellation controller that adapts to fluid conditions, providing robust noise reduction across a wide frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional noise cancellation technologies (earbuds, passive sound isolation) are used, then noise reduction is achieved at lower frequencies, but noise reduction effectiveness deteriorates at middle and higher frequencies
Solution Approach 1:
The duct is divided into multiple sections with sensors and actuators distributed along its length. Each sensor-actuator pair operates independently to cancel noise at specific locations and frequencies, enabling comprehensive coverage across the full frequency spectrum rather than relying on a single passive barrier
Solution Approach 2:
The system dynamically adjusts the operational parameters of actuators based on real-time noise measurements from sensors. By changing parameters such as actuator activation, frequency response, and cancellation intensity, the system adapts to different frequency ranges and noise conditions, achieving effective noise reduction across all frequencies
2Reliability
If sensors and actuators are placed in open fluid ducts, then noise cancellation is achieved, but the system becomes sensitive to placement variations and changes in fluid properties
Solution Approach 1:
Sensors continuously monitor noise levels and fluid conditions in the duct, providing real-time feedback to the control system. The system adjusts actuator operations based on this feedback, compensating for placement variations and changes in fluid properties such as temperature, pressure, and flow rate, thereby maintaining consistent noise cancellation performance
Solution Approach 2:
The system transitions from static placement to dynamic adaptation. Sensors and actuators are configured to respond dynamically to changing environmental conditions, with the control system continuously optimizing their operation based on real-time measurements of fluid properties and noise characteristics
3Adaptability or versatility
If multiple sensors and actuators are deployed in a MIMO configuration, then noise reduction across wide frequency range is achieved, but system complexity increases
Solution Approach 1:
Each sensor-actuator unit in the distributed array is designed as a universal module capable of handling multiple functions and frequency ranges. This modular approach allows the system to achieve wide frequency coverage through multiple identical units rather than requiring complex specialized components for each frequency band, thereby managing system complexity
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 MIMO system achieves significant noise reduction of up to 40 dB, is less sensitive to placement variations, and reduces system size and cost, while maintaining efficiency and adaptability to environmental changes.
Implementation Method 1
Each source generates two waves travelling in opposite directions; those travelling in the same direction as the unwanted wave sum to give a resultant which interferes destructively with the unwanted wave
Implementation Method 2
at least one axial array of ns×ms audio sensors and na×ma audio actuators
Data Source
AI summary
The present invention is in the field of an active sound-cancellation system, an open fluid-duct comprising such an active sound-cancellation system, such as an air duct, and an active sound-cancellation computer program comprising instructions for operating such an active sound-cancellation system. The active sound-cancellation system reduces noise significantly.