ANC Headrest Flange Position Sensor Noise Control
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Solution Overview
Problem
Existing active noise control (ANC) systems in vehicles face challenges in effectively canceling noise due to varying noise patterns and environments, such as turboprop and jet aircraft, where noise coherence and frequency changes pose difficulties in achieving consistent noise reduction across different vehicle types.
Innovation Solution
An ANC headrest system with a movable flange and position sensor, coupled with processing circuitry, produces antinoise that destructively interferes with ambient sound, using feedback and position data to adjust attenuation levels and employ feedforward or feedback control, and a tuning microphone to optimize noise reduction based on ambient conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed ANC system is used in vehicles, then the structure is simple, but the noise reduction effectiveness deteriorates due to varying noise patterns and environments
Solution Approach 1:
The patent implements a movable flange with position sensor that detects flange position and dynamically adjusts the ANC system's attenuation levels and control parameters based on the detected position. This allows the system to adapt to varying noise patterns and environments (such as different vehicle types like turboprop and jet aircraft) while maintaining reliable noise reduction effectiveness across diverse conditions.
2Adaptability or versatility
If the flange is made movable to adjust noise control, then the adaptability improves, but the device complexity increases
Solution Approach 1:
The patent introduces a movable flange mechanism with position sensor detection and processing circuitry that adjusts attenuation levels based on detected position. This dynamic configuration enables the system to adapt to different noise environments (turboprop, jet aircraft, and other vehicle types) while the processing circuitry automatically manages the complexity through position-based control algorithms.
3Object-affected harmful factors
If high attenuation levels are used for noise reduction, then the noise cancellation improves, but the harmful factors increase due to over-suppression of certain frequencies
Solution Approach 1:
The patent employs processing circuitry that dynamically adjusts attenuation levels based on detected flange position and ambient noise characteristics. The system modifies control parameters in real-time to achieve effective noise cancellation while preventing over-suppression of certain frequencies, thereby reducing harmful effects such as unnatural sound fields and excessive attenuation artifacts.
4Reliability
If feedforward control is enabled for better noise prediction, then the noise reduction performance improves, but the device complexity increases
Solution Approach 1:
The patent implements feedforward control that uses position sensor data to predict upcoming noise conditions and pre-adjust attenuation levels before the noise reaches the listener. The processing circuitry integrates feedforward and feedback control mechanisms, using detected flange position to anticipate noise patterns and proactively optimize noise reduction performance while managing system complexity through unified control architecture.
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 achieves enhanced noise reduction by dynamically adjusting antinoise production based on position and ambient feedback, improving overall a-weighted Root Mean Square (RMS) sound pressure reduction and peak amplitude at higher frequencies, suitable for diverse vehicle noise environments.
Implementation Method 1
The speaker is configured to produce antinoise that destructively interferes with frequencies of ambient sound
Data Source
AI summary
An active noise control (ANC) headrest comprises a speaker configured to produce antinoise that destructively interferes with frequencies of ambient sound, and a microphone configured to receive feedback comprising a combination of the antinoise and the ambient sound. The headrest further comprises a position sensor configured to detect a position of a flange to which the speaker is mounted relative to a center section of the headrest. The headrest further comprises processing circuitry configured to control the speaker to produce the antinoise based on the feedback and the position detected by the position sensor.