Seat Noise Control Calibration Under External Cabin Noise
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Solution Overview
Problem
Existing noise reduction technologies face challenges in accurately and quickly measuring the acoustic transfer function of multiple noise reduction devices installed in each seat of an aircraft, especially when external noise is present.
Innovation Solution
A noise reduction device and system that allow each seat to be driven into its actual usage state for accurate identification of the acoustic transfer function, while ensuring safety during maintenance and minimizing interference from external noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If noise reduction devices are installed in each seat to provide personalized noise control, then noise reduction effectiveness is improved, but the time and complexity required to measure acoustic transfer functions increases significantly
Solution Approach 1:
The patent divides the aircraft cabin into multiple independent control zones, each corresponding to a seat equipped with its own noise reduction device. Each device independently measures and processes acoustic transfer functions for its specific zone, allowing parallel processing and eliminating the need for sequential measurement of all seats. This segmentation enables simultaneous noise control across multiple seats without proportionally increasing total measurement time.
Solution Approach 2:
The patent implements preliminary measurement of acoustic transfer functions during aircraft maintenance or setup phases, storing these measurements for later use during actual flights. This preliminary action allows the system to be pre-configured with acoustic characteristics of each seat, so that during operational flights, noise reduction can be activated immediately without requiring real-time measurement, thus resolving the time contradiction.
2Productivity
If acoustic transfer function measurement is performed with external noise present, then measurement speed is improved, but measurement precision deteriorates due to noise interference
Solution Approach 1:
The patent employs periodic measurement cycles where the system alternates between measurement phases and noise control phases. During designated measurement windows, the system briefly suspends or minimizes active noise control signals to create quiet measurement intervals, even when external noise is present. This periodic approach allows accurate transfer function measurement without requiring complete isolation from external noise, maintaining both speed and precision.
Solution Approach 2:
The patent implements feedback mechanisms where the noise reduction device continuously monitors acoustic environment and adjusts measurements accordingly. When external noise levels exceed thresholds during measurement attempts, the system automatically compensates or re-schedules measurements, using feedback from noise level sensors to ensure measurement accuracy is maintained despite external noise conditions.
3Measurement precision
If seats are driven into actual usage state for accurate measurement, then measurement accuracy is improved, but safety risks increase during maintenance operations
Solution Approach 1:
The patent implements a dynamic measurement system that can adaptively adjust the seat configuration based on measurement requirements and safety conditions. The system can measure acoustic transfer functions in multiple seat configurations (upright, reclined, bed mode) and selectively use the most appropriate measurements for different flight conditions. During maintenance, the system dynamically switches to safe measurement modes that don't require actuating seat mechanisms, while during operations, it utilizes pre-measured data from actual usage states.
Solution Approach 2:
The patent introduces an intermediary control system that mediates between measurement requirements and safety constraints. This intermediary layer includes safety sensors and control logic that prevent seat actuation when occupancy or maintenance conditions are detected, while still enabling accurate measurements to be taken during safe windows. The intermediary system ensures that measurement accuracy goals are met without compromising maintenance safety.
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
Enables rapid and accurate calculation of the acoustic transfer function for each noise reduction device, ensuring effective noise reduction and safe operation during maintenance, while reducing the impact of external noise.
Implementation Method 1
an error microphone 350 which detects sound
Implementation Method 2
a control speaker 340 which outputs sound
Implementation Method 3
a noise controller for reversing the phase of noise detected by the microphone based on information outputted from the microphone
Data Source
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AI summary
A system management device (501) notifies to drive a seat. A seat detector (582) detects that a seat position is in its actual usage state, a control speaker (340) outputs white noise generated by a white noise generator (337), and an acoustic transfer function including the path from the control speaker (340) to an error microphone (350) is identified by detecting this white noise with the error microphone (350). The system management device (501) also notifies an identification controller (538) of the initial values of the acoustic transfer function and a filter coefficient.