Variable Step-Size Active Noise Control for Impulsive Noise
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Solution Overview
Problem
The fixed step size in active control methods with post filters and filtered reference affine projection sign algorithms limits the convergence performance of noise control systems in impulsive noise environments.
Innovation Solution
An active control method with a variable step size strategy and convex combination structure is introduced, allowing for adaptive adjustment of step size coefficients in control filters to improve convergence performance and stabilize the algorithm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a fixed step size is used in the filtered reference affine projection sign algorithm, then the algorithm stability is maintained, but the convergence performance is limited and cannot be further improved
Solution Approach 1:
The patent applies the dynamics principle by transforming the fixed step size into a variable step size that changes over time. The step size is dynamically adjusted based on the iteration count and error signal characteristics, allowing the algorithm to achieve fast initial convergence while maintaining stability in the steady state. This resolves the contradiction by making the step size adaptive rather than static.
Solution Approach 2:
The patent implements parameter changes by modifying the step size parameter from a constant value to a time-varying parameter. The step size is changed according to the iteration number and error magnitude, enabling the algorithm to adapt its convergence behavior. This parameter transformation allows simultaneous achievement of fast convergence and stability by adjusting the step size throughout the adaptation process.
2Productivity
If the step size is increased to improve convergence speed, then the convergence performance improves, but the steady-state error increases and stability deteriorates
Solution Approach 1:
The patent applies periodic action through the multi-stage step size adjustment strategy. Different step size values are used at different stages of the adaptation process: a larger step size in early iterations for fast convergence, and a smaller step size in later iterations for precise steady-state performance. This periodic variation in step size parameters resolves the contradiction between convergence speed and steady-state accuracy.
Solution Approach 2:
The dynamic step size adjustment allows the algorithm to automatically adapt the step size based on the current error magnitude and iteration stage. When the error is large, a larger step size is used for rapid convergence; when the error becomes small, the step size is reduced to minimize steady-state error. This dynamic adaptation resolves the contradiction between productivity and manufacturing precision.
Data Source
AI summary
An active control method for filtered reference affine projection sign algorithm based on variable step size includes: S1, acquiring impulse noise signals and transmitting the signals to control filters; S2, transmitting the impulse noise signals by the control filters to post filters; S3, generating cancellation signals of the impulse noise signals by the post filters according to the impulse noise signals and internal active control algorithms, and transmitting the cancellation signals to a speaker; S4, sending out the cancellation signal by the speaker to superimpose with the impulse noise signals to cancel the impulse noise signal. A convex combination structure and a variable step size strategy are adopted, and by adjusting step size coefficients in the control filter structure, convergence speed of algorithm is controlled, contradiction between convergence speed and steady-state error is coordinated, convergence performance of control algorithm to impulse noises is improved, and impulse noises are effectively controlled.