Vehicle Active Noise Control Using Youla Parameter Adaptation
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Solution Overview
Problem
Existing active noise control systems in vehicles, particularly those using 'feedback' structures, face challenges in effectively attenuating narrowband noise with varying frequencies due to sensitivity to changes in the passenger compartment's configuration and lack of robustness, especially when the noise frequency is unknown.
Innovation Solution
A real-time active noise control method using a feedback structure that incorporates a Youla parameter with an infinite impulse response filter, allowing for frequency-dependent coefficients stored in a table for precise noise attenuation, combined with a central corrector having fixed coefficients, to adapt to changing noise frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a feedback structure is used for active noise control, then the system can operate without a reference signal and allows classical control tools to be applied, but the system becomes sensitive to changes in the passenger compartment's transfer function and lacks robustness when noise frequency varies
Solution Approach 1:
The patent applies dynamics by making the Youla parameter adaptive to frequency variations. The parameter Q(z⁻¹) is designed to adjust its coefficients based on the current noise frequency, allowing the controller to dynamically adapt to changing acoustic conditions in the passenger compartment while maintaining stability through the fixed central corrector.
Solution Approach 2:
The patent changes parameters by separating the control law into fixed coefficients (central corrector) and frequency-dependent coefficients (Youla parameter). This parameter separation allows the system to maintain stability with fixed parameters while adapting to frequency variations through parameter changes in the Youla component, resolving the contradiction between ease of operation and reliability.
2Measurement precision
If frequency-dependent coefficients are implemented in the correction control law, then precise attenuation at specific frequencies is achieved, but the complexity of the control system increases
Solution Approach 1:
The patent segments the correction control law into two distinct parts: a central corrector with fixed coefficients and a Youla parameter with frequency-dependent coefficients. This segmentation allows precise frequency-specific attenuation through the Youla component while keeping the overall system manageable by separating complex adaptive functions from stable fixed functions.
Solution Approach 2:
The Youla parameter serves multiple functions simultaneously: it provides frequency-dependent adaptation, ensures stability through its specific mathematical structure, and enables precise attenuation at varying frequencies. This multi-functionality achieves high measurement precision without proportionally increasing device complexity.
3Stability of the object's composition
If the number of varying parameters in the control law is reduced, then system stability is improved, but the adaptability to different noise frequencies may be compromised
Solution Approach 1:
The patent applies local quality by concentrating frequency-dependent adaptation in a specific local component (the Youla parameter) while keeping the rest of the system (central corrector) with fixed stable coefficients. This localized adaptability ensures that only the necessary part of the system varies, maintaining overall stability while providing frequency-specific adaptability.
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 enhances the robustness and adaptability of the noise control system, ensuring effective noise attenuation across varying frequencies and configurations, minimizing the number of varying parameters and maintaining stability.
Implementation Method 1
by emission of a sound by at least a transducer, typically a loudspeaker
Implementation Method 2
controlled with a signal u(t) or U(t) generated by a programmable computer, as a function of an acoustic measurement signal y(t) or Y(t) carried out by at least one acoustic sensor, typically a microphone
Data Source
Figure 1~2
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Figure 6~7
AI summary
The invention relates to a method and a device for suppressing noise in the passenger compartment of a vehicle, which includes at least one transducer, a programmable computer, at least one acoustic sensor, the computer being configured such as to apply an electro-acoustic model of the passenger compartment to a correcting system model comprising a central corrector with fixed coefficients joined to a block of variable coefficients, comprising a Youla parameter in the form of a Youla block Q. The first phase comprises determining and calculating the electro-acoustic model and the correction control law for at least one predetermined noise frequency. In a second phase, in real time, the computer applies the correction control law to the electro-acoustic model in accordance with the common frequency of the noise to be suppressed.