Active Noise Control Headrest Loudspeaker Subsystem
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Solution Overview
Problem
Existing automatic noise control (ANC) systems in the automotive industry face robustness issues due to variations in secondary paths between loudspeakers and error microphones, leading to instability, especially when passengers occupy seats or trunk conditions change, necessitating improved stability measures.
Innovation Solution
The implementation of an active noise control system with a combination of system loudspeakers and active headrest loudspeakers, where the headrest loudspeakers form a robust sub-system that minimizes distance variations and operates independently, while system loudspeakers handle lower frequencies, reducing instability and extending the ANC system's spectral range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional ANC systems use fixed secondary path parameters measured in normal operational state, then system complexity is reduced, but stability deteriorates when conditions change (passenger occupancy, trunk conditions)
Solution Approach 1:
The patent implements dynamic adaptation of secondary path parameters through continuous monitoring of system stability. The controller detects instability conditions (oscillations) and adapts the secondary path parameters in real-time to match current operational conditions, transforming the fixed-parameter system into a dynamic one that maintains stability across varying conditions.
Solution Approach 2:
The system incorporates feedback mechanisms where the controller continuously monitors the ANC system's performance and detects instability. Based on this feedback, the controller adjusts the secondary path parameters to restore stability, creating a closed-loop control system that adapts to changing conditions.
2Adaptability or versatility
If ANC systems operate in changing conditions (passenger positions, trunk conditions), then adaptability is improved, but stability deteriorates due to secondary path variations
Solution Approach 1:
The system dynamically adapts secondary path parameters based on real-time stability monitoring. When conditions change (passenger occupancy, trunk conditions), the controller detects the resulting instability and adjusts parameters accordingly, enabling the system to maintain stability across diverse operational conditions.
Solution Approach 2:
The patent changes the parameters of the secondary path model dynamically based on operational conditions. By adjusting these parameters in response to detected instability, the system maintains accurate noise cancellation performance despite variations in passenger positions, occupancy, and trunk conditions.
3Reliability
If headrest loudspeakers are added to form a robust sub-system, then stability is improved, but device complexity increases
Solution Approach 1:
The patent segments the ANC system into two independent subsystems: headrest loudspeakers forming a robust sub-system and system loudspeakers handling lower frequencies. This segmentation allows each subsystem to be optimized independently, with the headrest sub-system providing inherent stability through its close proximity to the error microphone, reducing the need for complex robustness measures in the overall system.
Solution Approach 2:
The system merges the headrest loudspeaker sub-system with the system loudspeaker sub-system to create a comprehensive ANC solution. The headrest loudspeakers handle higher frequencies with inherent stability, while system loudspeakers cover lower frequencies, together providing broadband noise control with improved overall stability.
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 enhances the robustness and spectral range of ANC systems, allowing for stable operation even with changing passenger positions and trunk conditions, reducing the need for additional robustness measures and enabling a broadband ANC solution.
Implementation Method 1
generate via the loudspeaker anti-noise that is configured to reduce or cancel noise occurring at the seat
Data Source
AI summary
Active noise control system and methods are disclosed that include generating anti-noise that is configured to reduce or cancel noise occurring at a listening position in the ambiance of a seat with a backrest enclosing a hollow volume. Radiating the anti-noise from within the hollow volume of the backrest of the seat.