Adaptive ANC Reference Mixing for Transient Vehicle Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ANC systems struggle to effectively cancel noise sources that lack correlated reference signals and are unable to adapt quickly to transient or non-stationary noise sources, leading to degraded performance and audible artifacts.
Innovation Solution
A method for dynamically adjusting reference signals in ANC systems by estimating vehicle operating parameters and retrieving gain values from lookup tables, combining these signals using a mixer, and adjusting filter coefficients to accommodate a variety of noise sources, including transient ones, while minimizing computational overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If more reference inputs are added to accommodate every potential noise source, then noise cancellation performance is improved, but computational resources and memory limitations are exceeded
Solution Approach 1:
The patent segments the reference signal processing by creating multiple independent lookup tables, each dedicated to specific noise sources (road noise, wind noise, engine noise, HVAC noise). This segmentation allows the system to selectively process only relevant noise sources based on current operating conditions, reducing overall computational load while maintaining comprehensive noise cancellation capability.
Solution Approach 2:
The patent implements preliminary action by pre-computing and storing optimal filter coefficients and gain values in lookup tables during system calibration or offline processing. During real-time operation, the system simply retrieves pre-computed values based on current operating parameters rather than performing complex adaptive filtering calculations, dramatically reducing computational requirements while maintaining performance.
2Productivity
If traditional ANC systems use fixed reference signals, then computational overhead is minimized, but the system cannot adapt to transient or non-stationary noise sources
Solution Approach 1:
The patent implements dynamics by making the reference signal selection and gain adjustment dynamic rather than fixed. The system continuously monitors operating parameters (vehicle speed, engine RPM, HVAC status) and dynamically adjusts which lookup tables are active and what gain values are applied. This dynamic adaptation allows the system to respond to transient noise sources while maintaining computational efficiency through the use of pre-computed lookup tables.
Solution Approach 2:
The patent employs feedback mechanisms where the system continuously monitors operating parameters and noise levels, then uses this information to adjust the selection and weighting of reference signals from different lookup tables. This closed-loop feedback enables the system to adapt to changing noise conditions in real-time while maintaining computational efficiency through the structured lookup table architecture.
3Stability of the object's composition
If the adaptive filter takes several seconds to adapt when a noise source turns off, then computational stability is maintained, but audible artifacts are generated during the adaptation period
Solution Approach 1:
The patent applies preliminary action by proactively reducing the gain of reference signals corresponding to noise sources that are about to turn off or are no longer active. By anticipating the noise source shutdown and pre-adjusting the reference signal gains before the adaptive filter completes its natural adaptation period, the system prevents the generation of audible artifacts while maintaining filter stability.
Solution Approach 2:
The patent implements preliminary anti-action by applying countermeasures in advance to prevent the harmful effect of audible artifacts. When a noise source is detected to be turning off, the system preemptively reduces or mutes the corresponding reference signal gain, counteracting the potential artifact generation before it occurs. This preliminary anti-action resolves the contradiction by preventing the harmful effect while maintaining system stability.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Systems and methods are provided for enhancing the performance and adaptability of active noise cancellation (ANC) systems in vehicles by dynamically adjusting reference signal gains and combining reference signals based on vehicle operating conditions. A plurality of noise reference signals are acquired from sources like accelerometers, acoustic vehicle alerting system (AVAS) speakers, LiDAR sensors, seat motors, and HVAC blowers. Vehicle parameters such as speed, seat position, and blower speed are estimated to retrieve dynamic gain values from lookup tables. The dynamic gains are applied to the respective noise reference signals to generate gain-adjusted reference signals. The gain-adjusted signals are mixed using configurable mixing gains to produce a reduced set of combined reference signals provided to an adaptive filter. This approach enables the ANC system to effectively cancel a wider variety of noise sources, including transient sources, while preventing noise boosting artifacts when sources turn off.