Active Noise Hybrid Time-Varying Control for Motorcycle Helmets
TL;DR: In this paper, an LTI controller is designed for a motorcycle helmet active noise control (ANC) in order to improve the resulting attenuation, which is achieved by adding an extra pair of microphones which measure the external noise that is then used as the feedforward input signal.
Abstract: Recent noise at work regulations in the EU (2003) have been established to prevent noise induced hearing loss (NIHL). This imposes better performance results to traditional feedback active noise control (ANC) in motorcycle helmets, which suffer from well known limitations. Here two new ideas are applied to this problem. First, an hybrid (feedforward/feedback) linear time invariant (LTI) controller is designed for a motorcycle helmet ANC, which improves the resulting attenuation. This is achieved by adding an extra pair of microphones which measure the external noise that is then used as the feedforward input signal. In addition and to increase even more the resulting performance, the air velocity is measured in real-time and used as the parameter which schedules a linear parameter varying (LPV) feedback (FB) controller. This is combined with the previous feedforward (FF) controller, resulting in a time-varying hybrid controller. Both hybrid, LTI and LPV controllers are designed using linear matrix inequality (LMI)-based optimization. Two experiments have been carried out to measure the relation between external noise spectra and velocity: a wind tunnel test and a freeway ride experience. The resulting controllers are tested in a simulation which uses actual data obtained from the freeway experiment. The resulting attenuations in this motivating study seem promising for future controller tests to be performed in real-time, with the adequate hardware.
Citations
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01 Dec 2012
TL;DR: Active noise control (ANC) was developed in the early 20th century to help reduce noise as discussed by the authors, but it is still not widely used owing to the effectiveness of control algorithms, and to the physical and economical constraints of practical applications.
Abstract: The problem of acoustic noise is becoming increasingly serious with the growing use of industrial and medical equipment, appliances, and consumer electronics. Active noise control (ANC), based on the principle of superposition, was developed in the early 20th century to help reduce noise. However, ANC is still not widely used owing to the effectiveness of control algorithms, and to the physical and economical constraints of practical applications. In this paper, we briefly introduce some fundamental ANC algorithms and theoretical analyses, and focus on recent advances on signal processing algorithms, implementation techniques, challenges for innovative applications, and open issues for further research and development of ANC systems.
270 citations
TL;DR: A new adaptive strategy based on fractional signal processing is proposed using multi-directional step size fractional least mean square algorithm for online secondary path modeling, which outperforms other state-of-the-art methods in terms of model accuracy and convergence rate.
95 citations
TL;DR: An improved hybrid ANC system that can simultaneously control both the correlated and uncorrelated noise signals is proposed and improved performance is achieved at only a small increase in computational complexity.
Abstract: In filtered-x LMS (FxLMS) single-channel feedforward active noise control (ANC) systems, a reference signal is available that is correlated with the primary disturbance at the error microphone. In some practical situations, there may also be a disturbance uncorrelated with the primary disturbance at the error microphone, for which a correlated reference signal is not available. This disturbance, being uncorrelated with the primary noise, cannot be controlled by the standard FxLMS algorithm, and increases the residual noise. In this paper we propose an improved hybrid ANC system that can simultaneously control both the correlated and uncorrelated noise signals. The proposed method comprises three adaptive filters: 1) the FxLMS-based ANC filter to cancel the primary noise; 2) a separate FxLMS-based ANC filter to cancel the uncorrelated disturbance; and 3) an LMS-based supporting adaptive filter to generate appropriate signals for the two ANC filters. Computer simulations demonstrate that the proposed method can effectively mitigate the correlated and uncorrelated primary disturbances. This improved performance is achieved at only a small increase in computational complexity.
57 citations
Cites background from "Active Noise Hybrid Time-Varying Co..."
...Another interesting example is noise reduction for motorcycle helmets, and some interesting results using hybrid ANC have been reported in [22]....
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TL;DR: In this article, audio-Integrated ANC algorithms were briefly explained and several potential audio-integrated ANC products were discussed and realtime experiments were conducted to verify the performance of noise reduction.
Abstract: Have you ever faced a situation where you really wanted to enjoy your favorite music in a very noisy environment? To overcome this problem, you can either block the noise or increase the music level to mask the annoying sounds. This begets the question, "Is there a better solution?" In recent years, the technology industry has grown enormously, especially in the areas of smart, mobile, and wearable electronic products. Many companies are trying to gain consumers' attention by developing high-quality products equipped with advanced noise reduction. Among them, several companies have successfully used active noise control (ANC) techniques to cope with noise problems.
41 citations
Additional excerpts
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TL;DR: In this article, two decoupling methods are proposed to optimize the feedforward and feedback structures separately, which provide more flexibility in the design and optimization of the adaptive filters in practical active noise control (ANC) applications.
37 citations
References
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Book•
08 Feb 1996
TL;DR: For practicing engineers, researchers, and advanced students in signal processing, Active Noise Control Systems: Algorithms and DSP Implementations will serve as a comprehensive, state-of-the-art text/reference on this important and rapidly changing area of signal processing.
Abstract: From the Publisher:
Active noise control (ANC) is rapidly becoming the most effective way to reduce noises that can otherwise be very difficult and expensive to control ANC is achieved by introducing a canceling "anti-noise" wave through an appropriate array of secondary sources When applied accurately, ANC can provide effective solutions to noise-related problems in a broad range of areas, including manufacturing and industrial operations as well as consumer products Consequently, ANC research and development has become an important focus of both industrial applications and engineering research Active Noise Control Systems: Algorithms and DSP Implementations introduces the basic concepts of ANC with an emphasis on digital signal processing (DSP) hardware and adaptive signal processing algorithms, both of which have come into prominence within the last decade The authors emphasize the practical aspects of ANC systems by combining the principles of adaptive signal processing with both experimental results and practical implementation Applications are cited in many fields and encompass all types of noise media, including air-acoustic, hydroacoustic, vibrations, and others The specific implementation stressed is based on the TMS320 family of signal processors from Texas Instruments, which are the most widely used worldwide Coverage of theory includes concise derivations and analyses of commonly used adaptive structures and algorithms for active noise control applications, which are enhanced by the inclusion of a floppy disk featuring C and assembly programs for implementing many ANC systems Mathematical representations are employed and the source code included on the disk is in a form that is easily accessible to anyone using the book For practicing engineers, researchers, and advanced students in signal processing, Active Noise Control Systems: Algorithms and DSP Implementations will serve as a comprehensive, state-of-the-art text/reference on this important and rapidly de
1,561 citations
"Active Noise Hybrid Time-Varying Co..." refers background in this paper
...ANC is a well documented area of research [ 10 ], [11] that presents many particularities, depending on the application....
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...In [ 10 ], [13], and [26], a comparison between three basic control structures [FF, FB and hybrid (FB/FF)] for controllers in ANC applications is performed....
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TL;DR: This book brings together results from research in the two disciplines of acoustics and signal processing and presents the fundamentals of noise control in a unified manner and focuses on algorithmic principles which form the foundation of practical systems.
Abstract: Recent technological advances in the development of fast digital signal processors have made the active control of sound a practical proposition. This book brings together results from research in the two disciplinesof acoustics and signal processing and presents the fundamentals of noise control in a unified manner. Practical applications are presented wherever possible although the emphasis is on the algorithmic principles which form the foundation of practical systems. The volume is written in textbook style and aimed at both undergraduate and postgraduate students of acoustics and signal processing, professional acoustical and electrical engineers, and researchers in the field of active control.
1,440 citations
"Active Noise Hybrid Time-Varying Co..." refers background in this paper
...ANC is a well documented area of research [10], [ 11 ] that presents many particularities, depending on the application....
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TL;DR: The methodology presented in this paper is applied to the gain scheduling of a missile autopilot and is to bypass most difficulties associated with more classical schemes such as gain-interpolation or gain-scheduling techniques.
1,439 citations
"Active Noise Hybrid Time-Varying Co..." refers background in this paper
...However for a more general time varying model it can be solved with a post-filter in the control inputs and a prefilter in the measured outputs (see [ 28 ])....
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...Both robust controllers will guarantee robust stability and performance of the closed loop [22]–[24], [27], [ 28 ]....
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TL;DR: Extensions of H/sub /spl infin// synthesis techniques to allow for controller dependence on time-varying but measured parameters are discussed and simple heuristics are proposed to compute robust time-invariant controllers.
Abstract: An important class of linear time-varying systems consists of plants where the state-space matrices are fixed functions of some time-varying physical parameters /spl theta/. Small gain techniques can be applied to such systems to derive robust time-invariant controllers. Yet, this approach is often overly conservative when the parameters /spl theta/ undergo large variations during system operation. In general, higher performance can be achieved by control laws that incorporate available measurements of /spl theta/ and therefore "adjust" to the current plant dynamics. This paper discusses extensions of H/sub /spl infin// synthesis techniques to allow for controller dependence on time-varying but measured parameters. When this dependence is linear fractional, the existence of such gain-scheduled H/sub /spl infin// controllers is fully characterized in terms of linear matrix inequalities. The underlying synthesis problem is therefore a convex program for which efficient optimization techniques are available. The formalism and derivation techniques developed here apply to both the continuous- and discrete-time problems. Existence conditions for robust time-invariant controllers are recovered as a special case, and extensions to gain-scheduling in the face of parametric uncertainty are discussed. In particular, simple heuristics are proposed to compute such controllers. >
1,229 citations
"Active Noise Hybrid Time-Varying Co..." refers background or methods in this paper
...The control structure for the design of the linear parameter varying FB controller can be seen in Fig. 3, which can be transformed into Fig. 12. In the first figure, the performance weight and the controller are both LPV models, the latter designed according to [ 27 ]....
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...Both robust controllers will guarantee robust stability and performance of the closed loop [22]–[24], [ 27 ], [28]....
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