Adaptive Filter Transfer Function Phase Tuning for Stability

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Active noise control systems face challenges in dynamically adapting to changes in their environment, leading to instability and reduced noise cancellation efficiency, particularly in dynamic settings like vehicles where acoustic changes occur frequently.

Innovation Solution

The system dynamically updates the phase of the adaptive filter's transfer function based on identified phase errors, using a model that represents the path between the anti-noise source and error sensor, allowing the filter coefficients to adjust and maintain stability while improving noise cancellation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the adaptive filter uses fixed transfer function parameters, then the system is simpler to implement, but it cannot adapt to dynamic environmental changes, leading to reduced noise cancellation efficiency

Engineering Contradiction:
Improveadaptability to environmental changesVSAvoidcomplexity of transfer function tuning
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system automatically identifies phase errors from coefficient trajectories and adjusts transfer function phases without manual intervention. The adaptive filter self-tunes by detecting phase errors in its own coefficient behavior and correcting them through automated phase adjustment, eliminating the need for external manual tuning while maintaining adaptability to environmental changes

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system monitors the trajectory of adaptive filter coefficients over time and uses this feedback to identify phase errors. By continuously analyzing coefficient behavior and adjusting transfer function phases based on detected errors, the system creates a closed-loop feedback mechanism that maintains optimal performance in dynamic environments

Inventive Principle:
Principle #23Feedback

2Reliability

If the adaptive filter coefficients are continuously updated to improve noise cancellation, then noise cancellation efficiency improves, but system stability may be compromised

Engineering Contradiction:
Improvenoise cancellation efficiencyVSAvoidsystem stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The system analyzes the trajectory of adaptive filter coefficients to identify phase errors that indicate instability trends. By detecting these phase errors early in the coefficient evolution process, the system can adjust transfer function phases to correct destabilizing trends before they cause system failure, maintaining both stability and noise cancellation efficiency

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system proactively identifies phase errors by monitoring coefficient trajectories before they lead to system instability. By detecting and correcting phase errors in advance, the system prevents instability from developing while maintaining continuous noise cancellation improvement through adaptive coefficient updates

Inventive Principle:
Principle #10Preliminary action

3Reliability

If manual tuning of the adaptive filter is performed to optimize performance, then noise cancellation efficiency improves, but time and operational complexity increase

Engineering Contradiction:
Improvenoise cancellation efficiencyVSAvoidtuning time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system automatically performs what would traditionally require manual tuning by identifying phase errors from coefficient trajectories and adjusting transfer function phases autonomously. This self-tuning capability eliminates the time and expertise required for manual optimization while maintaining high noise cancellation efficiency through continuous adaptive adjustment

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS9633647B2Self-tuning transfer function for adaptive filtering
Publication Date: 2017.04.25 BOSE CORP
  • US9633647B2 patent drawing
  • US9633647B2 patent drawing
  • US9633647B2 patent drawing

AI summary

The technology described in this document can be embodied in a computer-implemented method that includes receiving, at one or more processing devices, a plurality of values representing a set of coefficients of an adaptive filter over a period of time, and identifying, by the one or more processing devices based on the plurality of values, a phase error associated with a transfer function of the adaptive filter. The method also includes adjusting, based on the identified phase error, a phase associated with the transfer function of the adaptive filter such that coefficients calculated using the adjusted transfer function reduce the phase error. The method further includes determining a set of coefficients for the adaptive filter based on the adjusted transfer function, and programming the adaptive filter with the determined set of coefficients to enable operation of the adaptive filter.