Adaptive Feedforward Control System Low Speed Adaptation Disable
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Solution Overview
Problem
Adaptive noise-cancellation systems in vehicle cabins face challenges in accurately distinguishing between actual road noise and electronic sensor noise at low vehicle speeds, leading to misinterpretation and excessive noise cancellation adjustments.
Innovation Solution
Implementing a low speed turn-off mechanism that disables adaptation and adjusts noise-cancellation signal transmission based on vehicle speed thresholds, preventing unnecessary filter updates and reducing residual noise, using a controller with adaptive processing and filter W ADAPT to manage filter coefficients and variable gain for optimal noise cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adaptive processing continuously updates filter coefficients to cancel noise, then noise cancellation effectiveness is improved, but at low vehicle speeds electronic sensor noise is misinterpreted as road noise causing excessive and inaccurate filter updates
Solution Approach 1:
The system changes the operational parameter of the adaptive filter by disabling adaptation (setting update rate to zero) when vehicle speed falls below a threshold. This prevents the filter coefficients from being updated based on erroneous low-speed sensor noise, thereby maintaining measurement precision while preserving noise cancellation effectiveness at higher speeds.
2Adaptability or versatility
If adaptation is continuously enabled to respond to changing noise conditions, then adaptability is improved, but residual noise increases due to excessive filter updates at low speeds causing audible distortions
Solution Approach 1:
The system dynamically adjusts the adaptation state of the noise cancellation filter based on vehicle speed conditions. At higher speeds, adaptation is enabled to respond to changing noise conditions, while at low speeds adaptation is disabled to prevent residual noise generation. This dynamic switching resolves the contradiction by enabling adaptability only when it produces beneficial effects.
3Speed
If filter coefficients are continuously updated based on sensor input, then responsiveness to noise changes is improved, but system complexity increases due to the need for speed threshold monitoring and adaptation control
Solution Approach 1:
The system introduces a speed threshold monitor as an intermediary component that mediates between the adaptive filter and the vehicle speed sensor. This intermediary enables the filter to respond quickly to noise changes at higher speeds while automatically preventing erroneous updates at low speeds, thereby improving response effectiveness without significantly increasing overall system complexity.
Data Source
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AI summary
A system and method for disabling adaptation in an adaptive feedforward control system at low speeds. The method includes generating a noise signal representative of undesired noise detected by a noise sensor of a vehicle and generating a noise-cancellation signal via a controller within the vehicle. Residual noise resulting from the combination of the acoustic energy of the noise-cancellation signal and the undesired noise is detected by a reference sensor, which generates an error signal based on the residual noise. The error signal and a speed signal from a speed sensor on the vehicle are transmitted to an adaptive processing module for the generation of a filter update signal. The adaptive processing module selectively permits or prevents the filter update signal to adapt filter coefficients of a filter when the speed signal is within a set of conditions.