Occupancy-Based Virtual Microphone Active Noise Cancellation
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Solution Overview
Problem
Existing active noise cancellation (ANC) systems in vehicles face challenges in optimizing noise cancellation performance based on varying vehicle occupancy configurations, leading to suboptimal noise reduction at passenger locations.
Innovation Solution
The implementation of a virtual microphone ANC system that modifies the transfer function between physical and virtual microphones based on occupancy signals, allowing for adaptive filtering and optimized anti-noise signal generation to improve noise cancellation at passenger locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed transfer function is used between physical and virtual microphones in ANC systems, then the system structure remains simple, but noise cancellation performance becomes suboptimal when vehicle occupancy configurations change
Solution Approach 1:
The transfer function between physical and virtual microphones is made dynamic by modifying it based on occupancy signals. The system adapts the transfer function parameters according to detected occupancy configurations, enabling the ANC system to maintain optimal noise cancellation performance across different vehicle occupancy scenarios without requiring a completely different system architecture
Solution Approach 2:
The system changes parameters of the transfer function based on occupancy signals. By adjusting transfer function parameters according to detected occupancy configurations, the system optimizes noise cancellation performance for different passenger arrangements while maintaining the same physical hardware setup
2Adaptability or versatility
If the ANC system is designed to accommodate all possible occupancy configurations, then it can serve all passengers, but the system complexity and computational load increase significantly
Solution Approach 1:
The system dynamically adapts to different occupancy configurations by modifying the transfer function based on occupancy signals. This allows the ANC system to serve different passenger arrangements effectively without requiring separate fixed configurations for each scenario, reducing overall system complexity while maintaining versatility
Solution Approach 2:
The approach segments the occupancy space by using occupancy signals to identify specific configuration patterns. By segmenting the problem into recognizable occupancy patterns and applying appropriate transfer function modifications for each, the system achieves adaptability without the complexity of handling all possible configurations simultaneously
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 noise cancellation performance by tailoring the ANC system's parameters to the current vehicle occupancy configuration, resulting in improved noise reduction at the locations of vehicle passengers.
Implementation Method 1
ANC systems generally cancel or reduce unwanted noise by generating cancellation sound waves to destructively interfere with the unwanted audible noise. Destructive interference results when noise and 'anti-noise,' which is largely identical in magnitude but opposite in phase to the noise, reduce the sound pressure level (SPL) at a location.
Implementation Method 2
An adaptive filter controller is programmed to filter the error signal using the transfer function to obtain an estimated virtual microphone error signal
Data Source
AI summary
An active noise cancellation (ANC) system is provided with at least one loudspeaker to project anti-noise sound within a passenger cabin of a vehicle in response to receiving an anti-noise signal. At least one microphone provides an error signal indicative of noise and the anti-noise sound within the passenger cabin. An occupancy controller is programmed to modify a transfer function between the at least one microphone and at least one virtual microphone based on an occupancy signal indicative of occupant presence within the passenger cabin. An adaptive filter controller is programmed to filter the error signal using the transfer function to obtain an estimated virtual microphone error signal. A controllable filter generates the anti-noise signal based on the estimated virtual microphone error signal.