Active Acoustic Control via Filtered Pressure Estimation
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Solution Overview
Problem
Existing active acoustic control systems face challenges in accurately separating scattered acoustic pressure from total acoustic pressure, leading to ineffective control of acoustic waves and requiring complex setups or significant computational power, especially when conditions change.
Innovation Solution
An active acoustic control system comprising a first sensor arrangement to sense total acoustic pressure and a processor that applies filters to estimate the scattered acoustic pressure component, using a regularisation parameter to improve control accuracy and adaptability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If known systems are used to determine scattered acoustic pressure, then the system can operate, but measurement precision is insufficient to accurately separate scattered acoustic pressure from total acoustic pressure
Solution Approach 1:
The patent introduces a filter as an intermediary element that processes the total acoustic pressure signal to extract the scattered acoustic pressure component. The filter acts as a mediator between the sensor output and the control system, enabling accurate separation of the scattered pressure from the total pressure without requiring direct measurement of the scattered component alone.
Solution Approach 2:
The patent segments the total acoustic pressure signal into distinct components (incident pressure and scattered pressure) through filtering operations. By applying filters to separate these components in the frequency or time domain, the system achieves precise measurement of the scattered acoustic pressure that would otherwise be buried within the total signal.
2Measurement precision
If complex componentry or experimental setups are used to determine scattered acoustic pressure, then measurement precision may improve, but device complexity increases significantly
Solution Approach 1:
The patent employs a single sensor arrangement that serves multiple functions: measuring total acoustic pressure, providing input to the filter, and enabling scattered pressure determination. This multi-functional approach eliminates the need for separate measurement systems or complex experimental setups, achieving accurate scattered pressure determination with minimal hardware.
Solution Approach 2:
The patent replaces complex mechanical or experimental measurement setups with a computational filtering approach. Instead of using multiple sensors or complex physical arrangements to isolate scattered pressure, the system uses signal processing filters to extract the scattered component from the total pressure signal, reducing hardware complexity while maintaining measurement precision.
3Adaptability or versatility
If known systems control acoustic scattering under first conditions, then control is effective, but adaptability is insufficient when conditions change
Solution Approach 1:
The patent implements a dynamic filtering approach where the filter characteristics can be adjusted based on changing acoustic conditions. This allows the system to maintain accurate scattered pressure determination across varying frequencies, amplitudes, or environmental conditions, rather than being optimized for a single fixed condition.
Solution Approach 2:
The system uses feedback from the filtered signal to continuously adjust the control of scattered acoustic pressure. By monitoring the extracted scattered pressure component and adjusting control parameters accordingly, the system maintains measurement precision and control accuracy even when operating conditions change.
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 estimates and controls scattered acoustic pressure, enabling acoustic cloaking of objects by reducing the presence of scattered waves in the soundfield, even under changing conditions, with improved accuracy and reduced complexity.
Implementation Method 1
a first sensor arrangement arranged to sense an acoustic signal in the region of an object, the acoustic signal having a scattered acoustic pressure component and a total acoustic pressure
Implementation Method 2
a processor configured to: apply a first filter to filter the total acoustic pressure and provide a filtered output signal; and estimate the scattered acoustic pressure component based on the filtered output signal
Implementation Method 3
In effective control of the primary disturbance signal to reduce said signal, the primary acoustic disturbance signal 32 and control signal 36 exhibit destructive interference
Data Source
Figure 1~2(c)
Figure 3~4
Figure 5
AI summary
The present disclosure relates to an active acoustic control system comprising: a first sensor arrangement arranged to sense an acoustic signal in the region of an object, the acoustic signal having a scattered acoustic pressure component and a total acoustic pressure, the first sensor arrangement being arranged to sense the total acoustic pressure of the acoustic signal; a processor configured to: apply a filter to filter the total acoustic pressure and provide a filtered output signal; and estimate the scattered acoustic pressure component based on the filtered output signal from the filter; and a control source arrangement operable to control the scattered acoustic pressure component based on the estimation and a regularisation parameter determined based on a relationship between: level of control of the scattered acoustic pressure component of the acoustic signal when controlled using the control source arrangement of the system using a set of test regularisation parameters.