Aktivno smanjenje buke u kabini lakog zrakoplova višekanalnom koherentnom metodom

doctoral thesis

• Author: Dubravko Miljković
• Mentor: Mladen Maletić (mentor)
• Committee member: Branko Somek (član povjerenstva)
• Committee member: Mladen Maletić (član povjerenstva)
• Committee member: Zdravko Toš (član povjerenstva)
• Committee member: Hrvoje Domitrović (član povjerenstva)
• Committee member: Siniša Fajt (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; (Department of Electroacoustics); Zagreb
• Defense date and country: 2006-12-21, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering
• Universal decimal classification (UDC): 621.3 - Electrical engineering

Abstract

U disertaciji je razvijen višekanalni sustav za aktivno smanjenje buke u lakom zrakoplovu. Osnovni sustav se temelji na koherentnom usrednjavanju rezidualnog signala greške kojim se protufazno pogoni sekundarni izvor. Naprednije verzije ovog sustava koriste a-priori informaciju o valnom obliku buke te postupak adaptacije već započinje od pretpostavljenog valnog oblika (sinusoidalnog valnog oblika prikladne amplitude, faze i frekvencije ili čak samog niskim propustom filtriranog signala buke). Nakon ispitivanja svojstava jednokanalnog sustava, sustav je proširen na višekanalni sustav tipa SIMO (Single Input Multiple Output), pri čemu se koristi isti taho/referentni signal koji se uz adekvatna kašnjenja (zbog akustičke propagacije signala buke u kabini) raspoređuje na osam jednokanalnih sustava povezanih višestrukim kombinacijama elemenata pojačanje-kašnjenje za smanjenje međusobnih preslušavanja kanala. Time se ostvaruje osmerokanalni sustav koji u kabini lakog zrakoplova četverosjeda proizvodi osam zona tišine na pozicijama ušiju pilota i putnika. Cjelokupni sustav je ispitan u raznim režimima leta uz pomoć signala sa simulatora leta (PC-ATD). Ostvareno smanjenje buke potom je provjereno dodatnom simulacijom koja je uzimala u obzir i izmjerene akustičke karakteristike stvarne kabine zrakoplova (impulsni odzivi).

Abstract (english)

This thesis deals with development of multichannel active noise control system for cabin of light aircraft. Basic system uses coherent averaging method on residual error signal to produce signal that drives secondary source. Advanced versions of this system use a-priori information about noise waveform and adaptation process begins with assumed waveform (sinus signal of adequate amplitude, phase and frequency or even low pass filtered referent noise signal). After testing single-channel system, system is extended to multichannel version of type SIMO (Single Input Multiple Output) where same tacho/referent signal after adequate delay (because of acoustic propagation of noise signal through the cabin) is driving eight single-channel systems connected with multiple gain-delay combinations to diminish crosstalk between individual channels. In this way we get eight-channel system for four seat light aircraft that produces eight silent zones around ear positions of pilot and passengers. Whole system is tested in various flight regimes using signal from flight simulator (PC-ATD). Achieved noise suppression is verified with additional simulation that took into account measured acoustic characteristics of real aircraft cabin (impulse responses).

• Keywords: aktivno smanjenje buke; koherento usrednjavanje; višekanalni sustav
• Keywords (english): active noise control; coherent averaging; multichannel system
• Language: croatian
• URN:NBN: urn:nbn:hr:168:397537
• Study programme: Title: Doctoral study programme "Electrical Engineering and Computing"; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, po-dručje tehničkih znanosti (doktor/doktorica znanosti, po-dručje tehničkih znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2020-03-18 10:21:43