scholarly journals First investigation on the applicability of an active noise control system on a tracked tractor without cab

2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
Daniele Pochi ◽  
Roberto Fanigliulo ◽  
Lindoro Del Duca ◽  
Pietro Nataletti ◽  
Gennaro Vassalini ◽  
...  
Keyword(s):  
Sound Pressure Level ◽  
Digital Signal Processor ◽  
Sound Pressure ◽  
Engine Speed ◽  
Noise Control ◽  
Active Noise Control ◽  
Control Unit ◽  
Pressure Level ◽  
Maximum Speed ◽  
Active Noise

In last years, several research teams pointed their attention on the application of active noise control systems (ANC) inside the cabs of agricultural tractor, with the purpose of reducing the driver exposition to noise, that is only partially controlled by the frame of the cab. This paper reports the results of a first experience that aimed at verifying the applicability of an ANC on a medium-high power, tracked tractor without cab. The tested tractor was a Fiat Allis 150 A, equipped with rear power take off, used in the execution of deep primary tillage in compact soils. It is a tracked tractor without cab, with maximum power of 108.8 kW at 1840 min–1 of the engine. The ANC consists of a control unit box based on a digital signal processor (DPS), two microphones, two speakers and a power amplifier. The instrumentation used in noise data collecting and processing consisted of a multichannel signal analyzer (Sinus - Soundbook), a ½” microphone capsule and an acoustic calibrator, both Bruel & Kjaer. The study aimed at evaluating the behaviour of the ANC by means of tests carried out under repeatable conditions, characterized by pre-defined engine speed values. Three replications have been made for each engine speed. The sampling time was 30 s. Two series of tests were performed in order to compare the results observed with the ANC on and off. The engine speed adopted in the study ranged from 600 min– 1, up to 2000 min–1 (maximum speed) with steps of 100 min–1. The ANC proved to be effective in the interval of speed between 1400 and 1700 min–1, where the samplings have been intensified, adopting steps of 50 min–1. In such an interval, the attenuation observed with the ANC system on appeared evident both as weighed A sound pressure level (from 1.29 up to 2.46 dB(A)) and linear (from 4.54 up to 8.53 dB). The best performance has been observed at the engine speed of 1550 min–1, with attenuations, respectively of 2.46 dB(A) and 7.67 dB. Outside of the engine speed interval 1400 - 1700 min–1, the attenuations always resulted lower than 1 dB(A) for the weighed A sound pressure level and between 0.66 and 7.72 dB.

Active noise control system in a fire helmet – a proposal of the solution

2018 ◽  
Vol 558 (3) ◽  
pp. 11-15
Author(s):  
Leszek Morzyński ◽  
Grzegorz Szczepański
Keyword(s):  
Control System ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Noise Control ◽  
Active Noise Control ◽  
Warning Signal ◽  
Verbal Communication ◽  
Pressure Level ◽  
Emergency Vehicle ◽  
Active Noise

An auditory warning signal emitted by a moving emergency vehicle is intended to inform other road users about an approaching emergency vehicle and the need to give way to it. Emission of a warning signal with the highest possible sound pressure level is the main method of ensuring the audibility and recognition of the warning signal by traffic participants at unknown and varying traffic noise, acoustic insulation of vehicles and noise in the interior of the vehicle. The A-weighted sound pressure level of the auditory warning signal reaching the interior of an emergency vehicle may exceed 90 dB, which can be harmful to the hearing, can adversely affect psychophysical fitness of the crew members and can significantly hinder verbal communication in the vehicle. This article presents the concept and results of numerical simulations of an active noise control system in fire helmets, which will reduce the exposure of the crew to the warning signal and improve the quality of verbal communication in an emergency vehicle. This system is integrated with the signal generation system. The Notch algorithm and the NLMS adaptation algorithm were used in the system's control algorithm. The construction of the controller was based on a microcontroller from the STM32F4 family.

Optimization of the Location of Secondary Sources for the Active Engine Vibration Acoustic Noise Control in the Generator Room

2015 ◽  
Vol 766-767 ◽  
pp. 968-973
Author(s):  
T. Ramachandran ◽  
M.C. Lenin Babu
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Noise Control ◽  
Acoustic Noise ◽  
Active Noise Control ◽  
Pressure Level ◽  
Secondary Source ◽  
Secondary Sources ◽  
Quadratic Minimization ◽  
Room Model

The noise acoustic control in the interior of a diesel engine generator room model is studied and optimized. The finite element modelling and discretization of the engine room is carried out and the noise control is achieved using global active control of sound. The Genetic algorithm (GA) is used to find the optimized location of secondary sources to minimize the sound pressure level at receiver’s location. The secondary sources strengths for the active noise control system are computed using quadratic minimization acoustic potential energy. It is found that the sound pressure level at receiver’s location has been significantly reduced with changing the secondary source positions from arbitrarily to optimal location.

Multi-Agent Based Active Noise Intelligent Control

2014 ◽  
Vol 496-500 ◽  
pp. 1685-1689
Author(s):  
Huai Feng Cui ◽  
Nan Chen
Keyword(s):  
Control Problem ◽  
Local Control ◽  
Noise Control ◽  
Active Noise Control ◽  
Control Unit ◽  
Good Control ◽  
Agent Based ◽  
Active Noise ◽  
Flexible Plates ◽  
Multi Agent

Multi-agent based active noise control (ANC) is investigated in this paper. An enclosure consisting of two flexible plates is discussed. The noise control problem is decomposed into several local control problems on the basis of the dominant structural modal. Each local control problem is solved by an intelligent structure, i.e. agent control unit (ACU). The ACU includes sensor, actuator and controller. The relationship among the ACUs is negotiated by a coordination object. The architecture of multi-agent based active control is established using the coordination object. The control system can work smoothly in dynamic environments. It has the flexibility and robustness. The simulation results indicate that the good control performances are attained.

121 Improvement in Noise Attenuation of Active Noise Control Unit

2011 ◽  
Vol 2011.21 (0) ◽  
pp. 75-78
Author(s):  
Xun WANG ◽  
Shinya KIJIMOTO ◽  
Koichi MATSUDA ◽  
Yosuke KOBA
Keyword(s):  
Noise Control ◽  
Active Noise Control ◽  
Control Unit ◽  
Noise Attenuation ◽  
Active Noise

Characterization and Design of a Non Ported Conventional Speaker for Acoustic Control

2005 ◽  
Author(s):  
Taehyun Shim
Keyword(s):  
Sound Pressure ◽  
Active Noise Control ◽  
Nonlinear Effects ◽  
Measured Data ◽  
Pressure Level ◽  
Design Procedures ◽  
Active Noise ◽  
Acoustic Control ◽  
Parameter Variations ◽  
Loud Speaker

A loud speaker has been widely used as a major actuator in the field of active noise control (ANC). In this paper, the design procedures for a non-ported conventional speaker that must meet restrictive size constraint as well as required sound pressure level at a targeted frequency for an acoustic control was presented. Dynamic model of a speaker that includes linear and nonlinear effects such as radiation resistance on speaker damping, voice coil electrical resistance has been developed and its responses were compared to measured data. The effects of speaker design parameter variations on a sound pressure and power consumption were also assessed experimentally and through simulation. It was found that the simulation results are well collated with experimental data and the desired objective has been met.

A Study on the Far-Filed Sound Pressure Level of Rectangular Plate Based on Fourier Transform

2013 ◽  
Vol 753-755 ◽  
pp. 1779-1784
Author(s):  
Ren Wen Dai ◽  
De Shi Wang ◽  
Yong Yong Zhu
Keyword(s):  
Fourier Transform ◽  
Rectangular Plate ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Active Noise Control ◽  
Pressure Level ◽  
External Excitation ◽  
Approximation Solution ◽  
Transform Method ◽  
Line Force

The far-filed approximation solution was derived in a closed formula by using Fourier transform method. Two kind of possible concentrated forces, a line force, a point force, were included in the analysis. Moreover, a parametric study was carried out to clarify the effect of the incentive loading position and the various physical characteristics parameters of the rectangular plate. Conclusion is drawn that, the far-filed pressure level decreased with external excitation approached to the edge. Through analysis on far-filed sound pressure level, that can give foundation of designing acoustical elements and active noise control.

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