In this paper active noise control strategies for noise barriers are presented which are based on the use of sensors near the noise barrier. Virtual error signals are derived from these near-field sensor signals such that reductions of the far-field sound pressure are obtained with the active system. The performance of the control algorithm is compared for far-field error signals, near-field error signals, and virtual far-field error signals, with and without additional reference sensors. The virtual error signals are obtained by using separate transfer functions for the primary sources and secondary sources. These separate transfer functions are determined in such a way that the necessity of the separation of the virtual sensors for the primary field and for the secondary field can be judged by direct comparison. The systems are evaluated for independent broadband and randomly positioned primary sources, changing source spectra, moving sources, and configurations involving a nonvanishing wind speed.

Control strategies for active noise barriers using near-field error sensing

Active noise control with linear control source and sensor arrays for a noise barrier

Theoretical and numerical analysis of regular one-side oscillations in a single pendulum system driven by a magnetic field

This paper deals with some recent developments in the design and performance of roadside barriers that are applied as a means of controlling road traffic noise. It is a review paper that is based on the outcomes of literature and information searches undertaken for and on behalf of the Roads and Traffic Authority of NSW. Some interesting, ongoing developments in the design and performance of traffic noise barriers have been identified. In particular, three types of innovative barrier designs were identified that appear to offer the potential for increased attenuation without the need for substantial increases in barrier height. Each of these developments is considered in some detail in the paper and recommendations are made of the possibility of pursuing them further.

Recent Developments in the Design and Performance of Road Traffic Noise Barriers

Active noise control (ANC), with counteracting sound in exact equal magnitude and opposite phase to the noise to be controlled, is often considered as a potential solution for solving complex noise...

A Review of Active Noise Control Applications on Noise Barrier in Three-Dimensional/Open Space: Myths and Challenges

Measurement of active control efficiency around noise barriers

The behaviour of a space-modulated, so-called “argumental” oscillator, is studied. The oscillator is submitted to an external harmonic force, which is amplitude-modulated by the oscillator's position in space. An analytic expression of a stability criterion is given. Using the averaging method, an integrating factor and a Van der Pol representation in the (amplitude, phase)-space, an exact implicit analytic solution is given when there is no damping, and an approximate implicit analytic solution is given when there is damping, allowing the plotting of the separatrix curve. An attractor is identified.

Non-linear argumental oscillators: Stability criterion and approximate implicit analytic solution

Attractor's capture probability in nonlinear argumental oscillators

When a Duffing oscillator with one degree of freedom is submitted to an external harmonic force whose frequency is much higher than that of the oscillator, it is possible, under certain conditions, that the motion of the oscillator, once launched, is maintained at a stable energy level. This may occur when the force exerts its action only when the oscillator is close to its center position.

https://hal.archives-ouvertes.fr/hal-00876552/document

Argumentary oscillation phenomenon.

Under certain conditions, an oscillator can enter a stable regime when submitted to an external harmonic force whose frequency is far from the natural frequency of the oscillator. This can happen when the external force acts on the oscillator depending on the oscillator's spatial position. This phenomenon has been named "argumentary oscillation".
Using the van der Pol representation, symbolic mathematical results are given. The capture probabilities can be expressed as simple symbolic formulas based on the system parameters and the initial state.

Daniel Cintra

Papers

Measurement of active control efficiency around noise barriers

Non-linear argumental oscillators: Stability criterion and approximate implicit analytic solution

Attractor's capture probability in nonlinear argumental oscillators

Argumentary oscillation phenomenon.

Argumentary Duffing oscillators - Stable-regime probability.