scholarly journals Application of Adaptive Wave Cancellation Underwater to a Piezoelectric-Material-Based Multilayer Sensor

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 134
Author(s):  
Hyodong Lee ◽  
Hwijin Park ◽  
Kwan Kyu Park ◽  
Hak Yi
Keyword(s):  
Adaptive Control ◽  
Polyvinylidene Fluoride ◽  
Environmental Changes ◽  
Piezoelectric Materials ◽  
Active Noise Control ◽  
Low Frequency ◽  
Adaptive Controller ◽  
Frequency Noise ◽  
Control Approach ◽  
High Attenuation

This paper concerns the use of adaptive wave cancellation in a new multilayer smart skin sensor to attenuate the primary low-frequency noise underwater. The proposed multilayered system is designed with a piezoelectric actuator (Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 composite) and two layers of polyvinylidene fluoride to accelerate wave absorption. Furthermore, the use of a combination of an adaptive control scheme and a time-delay signal separation method has the potential to provide the proposed absorber system with a wave cancellation capability and thereby enable the absorber system to respond to environmental changes underwater. The use of smart piezoelectric materials and an adaptive control approach enables the absorber system to achieve the high attenuation level of the reflected waves, unlike typical absorber systems based on active noise control. Echo reduction experiments showed that the proposed piezoelectric-based multilayer sensor with an adaptive controller could attenuate reflected wave signals effectively.

scholarly journals Acoustic notch filtering earmuff utilizing Helmholtz resonator arrays

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258842
Author(s):  
Fumiya Mizukoshi ◽  
Hidetoshi Takahashi
Keyword(s):  
Resonant Frequency ◽  
Noise Control ◽  
Active Noise Control ◽  
Low Frequency ◽  
Helmholtz Resonator ◽  
Honeycomb Structure ◽  
Sound Insulation ◽  
Frequency Noise ◽  
Target Frequency ◽  
Notch Filtering

In recent years, noisy bustling environments have created situations in which earmuffs must soundproof only specific noise while transmitting significant sounds, such as voices, for work safety and efficiency. Two sound insulation technologies have been utilized: passive noise control (PNC) and active noise control (ANC). However, PNC is incapable of insulating selective frequencies of noise, and ANC is limited to low-frequency sounds. Thus, it has been difficult for traditional earmuffs to cancel out only high-frequency noise that people feel uncomfortable hearing. Here, we propose an acoustic notch filtering earmuff utilizing Helmholtz resonator (HR) arrays that provides a sound attenuation effect around the tuneable resonant frequency. A sheet-like sound insulating plate comprising HR arrays is realized in a honeycomb structure. Since the resonant frequency is determined by the geometry of the HR arrays, a highly audible sound region can be designed as the target frequency. In this research, the acoustic notch filtering performance of the proposed HR array plate is investigated in both simulations and experiments. Furthermore, the fabricated earmuffs using the novel HR array plates achieve a sound insulation performance exceeding 40 dB at the target frequency, which is sufficiently high compared to that of conventional earmuffs. The experimental results confirm that the proposed device is a useful approach for insulating frequency-selective sound.

Robust Adaptive Control Scheme for Discrete-Time System With Actuator Failures

2004 ◽  
Vol 127 (3) ◽  
pp. 520-526 ◽  
Author(s):  
Juntao Fei ◽  
Shuhao Chen ◽  
Gang Tao ◽  
Suresh M. Joshi
Keyword(s):  
Adaptive Control ◽  
Discrete Time ◽  
System Performance ◽  
Linear Time ◽  
Adaptive Controller ◽  
Robust Adaptive Control ◽  
Discrete Time System ◽  
Control Approach ◽  
Actuator Failures ◽  
Robust Adaptive

A robust adaptive control approach using output feedback for output tracking is developed for discrete-time linear time-invariant systems with uncertain failures of redundant actuators in the presence of the unmodeled dynamics and bounded output disturbance. Such actuator failures are characterized by some unknown inputs stuck at some unknown fixed values at unknown time instants. Technical issues such as plant-model output matching, adaptive controller structure, adaptive parameter update laws, stability and tracking analysis, and robustness of system performance are solved for the discrete-time adaptive actuator failure compensation problem. A case study is conducted for adaptive compensation of rudder servomechanism failures of a Boeing 747 dynamic model presented in discrete time, verifying the desired adaptive system performance in the presence of uncertain actuator failures.

scholarly journals Active Structural Acoustic Control of an Active Casing Placed in a Corner

2019 ◽  
Vol 9 (6) ◽  
pp. 1059 ◽  
Author(s):  
Anna Chraponska ◽  
Stanislaw Wrona ◽  
Jaroslaw Rzepecki ◽  
Krzysztof Mazur ◽  
Marek Pawelczyk
Keyword(s):  
Active Noise Control ◽  
Low Frequency ◽  
Frequency Noise ◽  
Noise Emission ◽  
Sound Sources ◽  
Low Frequencies ◽  
Emission Efficiency ◽  
Active Noise ◽  
Acoustic Control ◽  
Device Noise

Electric appliances used in workplaces and everyday life often generate a low-frequency noise, which affects human body systems. Passive methods employed to reduce noise are not effective at low frequencies. The classical approach to active noise control practically involves the generation of local zones of quiet, whereas at other areas the noise is reinforced. Moreover, it usually requires a large number of secondary sound sources. Hence, an active casing approach has been developed. The active casing panels’ vibrations are controlled to reduce the device noise emission. Efficiency of this method has been previously confirmed by the authors and the results have been reported in multiple journal publications. However, in the previous research experiments, the active casing was placed at a distance from the enclosure walls. In this research, the active casing is located in a corner and such placement is intentionally used to facilitate the active control system’s operation. The noise reduction performance is investigated at multiple configurations, including a range of distances from the corner and different error microphone arrangements. The analysis of both primary and secondary paths is given. Advantages and drawbacks of different active casing configurations are presented and discussed.

Efficiency of an ANC system in the tractor cabin under controlled engine workload

2020 ◽  
Vol 68 (5) ◽  
pp. 339-357
Author(s):  
Roberto Fanigliulo ◽  
Lindoro Del Duca ◽  
Laura Fornaciari ◽  
Renato Grilli ◽  
Roberto Tomasome ◽  
...  
Keyword(s):  
Sound Pressure ◽  
Noise Control ◽  
Active Noise Control ◽  
Low Frequency ◽  
Engine Performance ◽  
Noise Spectrum ◽  
Broadband Noise ◽  
Frequency Noise ◽  
Residual Noise ◽  
Agricultural Tractor

The noise at the driver seat of an agricultural tractor is produced mostly by the engine. Its characteristic broadband noise spectrum varies considerably with engine workload. The passive noise control techniques adopted in tractor cabins, based on the application of sound-absorbing and sound-proofing materials, are effective against medium-high frequencies noise components. The residual noise in sound-proof cabins is characterized by tonal emissions with low frequency components (< 500 Hz) but regarded as responsible for various disorders and diseases following long-term exposure. In addition to the "A" weighting filter adopted to evaluate occupational exposure to noise, other approaches are reported in the scientific literature considered more appropriate to evaluate low frequency noise (LFN), as well as studies testifying the effectiveness of active noise control (ANC) technologies in the low frequency range. In this article, the performance of an ANC system is evaluated in its ability to reduce noise levels inside the soundproof cabin of an agricultural tractor. To test this system, spectro-phonometric measurements of the equivalent linear sound pressure level were conducted under controlled and repeatable engine workloads, obtained by connecting the tractor to a dynamometric brake, while simultaneously acquiring the related engine performance curves. Altogether, three different couples of loudspeakers were tested. Frequency analysis in one-third octave band showed that the ANC system was mainly effective against LFN components (below 120 Hz) with peaks of reduction up to 20 dB. Then, on the basis of indications from previous studies, the data of linear sound pressure levels were processed applying the "A", "B", and "C" weighting filters, to show the different emphasis given to the effects of the system. Eventually, a point-by-point composition of the equivalent levels of sound pressure was drawn over the whole range of the engine, to highlight the conditions in which the ANC system was more effective.

Adaptive Active Control System of Vehicle Noise Design and Test

2014 ◽  
Vol 1028 ◽  
pp. 251-256 ◽  
Author(s):  
Ji Guang Jiang ◽  
Yue Zeng
Keyword(s):  
Active Noise Control ◽  
Low Frequency ◽  
Control Unit ◽  
Noise Signal ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Power Module ◽  
Vehicle Interior ◽  
Vehicle Noise ◽  
Active Noise

According to the vehicle interior low frequency noise existing, vehicle interior adaptive active noise control strategy is established based on the FXLMS algorithm, designed the core circuit module active noise controller, including the vehicle interior noise signal amplification module, a main control unit, audio power amplifier module and power module, completed development of the controller hardware, and programming the control software system; using this system, on vehicle driving conditions vice driver left ear position low frequency noise cancellation control in the steady state, the 8.5 dB (Lin) and 10.2dB (Lin) the amount of noise reduction.

Lyapunov Based Adaptive Control Method for Hydraulic Servo Drive

2016 ◽  
Author(s):  
Hamid Roozbahani ◽  
Konstantin Frumkin ◽  
Heikki Handroos
Keyword(s):  
Adaptive Control ◽  
Control Algorithm ◽  
Environmental Changes ◽  
Control Method ◽  
Servo System ◽  
Adaptive Controller ◽  
Servo Drive ◽  
Hydraulic Servo ◽  
Hydraulic Servo System ◽  
Adaptive Control Algorithm

Adaptive control systems are one of the most significant research directions of modern control theory. It is well known that every mechanical appliance’s behavior noticeably depends on environmental changes, functioning-mode parameter changes and changes in technical characteristics of internal functional devices. An adaptive controller involved in control process allows reducing an influence of such changes. In spite of this such type of control methods is applied seldom due to specifics of a controller designing. The work presented in this paper shows the design process of the adaptive controller built by Lyapunov’s function method for a hydraulic servo system. The modeling of the hydraulic servo system were conducting with MATLAB® software including Simulink® and Symbolic Math Toolbox™. In this study, the Jacobi matrix linearization of the object’s mathematical model and derivation of the suitable reference models based on Newton’s characteristic polynomial were applied. In addition, an intelligent adaptive control algorithm and system model including its nonlinearities was developed to solve Lyapunov’s equation. Developed algorithm works properly and considered plant is met requirement of functioning with. The results shows that the developed adaptive control algorithm increases system performance in use devices significantly and might be used for correction of system’s behavior and dynamics.

Inversion-Based Feedforward Approach to Broadband Acoustic Noise Reduction

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Tom C. Waite ◽  
Qingze Zou ◽  
Atul Kelkar
Keyword(s):  
Noise Control ◽  
Feedforward Control ◽  
Acoustic Noise ◽  
Active Noise Control ◽  
Low Frequency ◽  
Control Technique ◽  
Frequency Range ◽  
Nonminimum Phase ◽  
Control Approach ◽  
Active Noise

In this article, an inversion-based feedforward control approach to achieve broadband active-noise control is investigated. Broadband active-noise control is needed in many areas, from heating, ventilation and air conditioning (HVAC) ducts to aircraft cabins. Achieving broadband active-noise control, however, is very challenging due to issues such as the complexity of acoustic dynamics (which has no natural roll-off at high frequency, and is often nonminimum phase), the wide frequency spectrum of the acoustic noise, and the critical requirement to overcome the delay of the control input relative to the noise signal. These issues have limited the success of existing feedforward control techniques to the low-frequency range of [0,1]kHz. The modeling issues in capturing the complex acoustic dynamics coupled with its nonminimum-phase characteristic also prevent the use of high-gain feedback methods, making the design of an effective controller to combat broadband noises challenging. In this article, we explore, through experiments, the potential of inversion-based feedforward control approach for noise control over the 1kHz low-frequency range limit. Then we account for the effect of modeling errors on the feedforward input by a recently developed inversion-based iterative control technique. Experimental results presented show that noise reduction of over 10–15dB can be achieved in a broad frequency range of 5kHz by using the inversion-based feedforward control technique.

Experimental Study on an Active Noise Control System for Turboprop Driven Aircraft

2013 ◽  
Vol 333-335 ◽  
pp. 2142-2145
Author(s):  
Qing Fu Kong ◽  
Yu Liang Dai ◽  
Shi Jian Zhu ◽  
Jia Ming Wu
Keyword(s):  
Experimental Study ◽  
Control System ◽  
Sound Source ◽  
Noise Control ◽  
Active Noise Control ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Experimental Platform ◽  
Active Noise

In order to find a solution to the control of low frequency noise in the cabin of turboprop driven aircraft, an experimental active noise control (ANC) system is introduced in the paper, which consists of vibroacoustic field analogue subsystem, acoustic field measurement subsystem and acoustic barrier exciter subsystem. Effects of both different spaces between the primary sound source and secondary sound source of the ANC system and different frequency noises on noise-reduction result are investigated based on the experimental platform. Results of the experiment show a significant potential of the ANC method for the control of low frequency noise in the cabin of turboprop driven aircraft.

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