Print Email Facebook Twitter Flat acoustic sources with frequency response correction based on feedback and feed-forward distributed control Title Flat acoustic sources with frequency response correction based on feedback and feed-forward distributed control Author Ho, J.H. Berkhoff, A.P. Publication year 2015 Abstract This paper presents an acoustic source with a small thickness and high bending stiffness. The high bending stiffness is obtained with a sandwich structure in which the face of the sandwich structure internal to the source is perforated to increase the acoustic compliance, thereby leading to increased electroacoustic conversion efficiency. Multiple actuators are used to drive the moving component of the acoustic source. Control of the acoustic resonances and structural resonances is required to obtain an even frequency response. The use of collocated decentralized feedback control based on velocity sensing was found to be ineffective for controlling these resonances due to the destabilizing asymmetric modes caused by the coupling of the internal acoustic cavity and the rigid body vibration of the moving component. Resonances can be controlled by a set of independent combinations of symmetric driving patterns with corresponding velocity feedback controllers such that the fundamental mass-air resonance is effectively controlled, as is the lowest bending mode of the moving component. Finally, a compensation scheme for low frequencies is used which enables a flat frequency response in the range of 30 Hz to 1 kHz with deviations smaller than 3 dB. Subject Observation, Weapon & Protection SystemsAS - Acoustics & SonarTS - Technical SciencesHigh Tech Systems & MaterialsAcoustics and AudiologyIndustrial InnovationAcoustic fieldsAcoustic noise measurementFeedback controlFrequency responseSandwich structuresStiffnessAcoustic resonanceCompensation schemeDecentralized feedbackDistributed controlFlat frequency responseMoving componentsResponse correctionsStructural resonanceResonance To reference this document use: http://resolver.tudelft.nl/uuid:5d9a6f8f-9109-4d1a-a39c-a4cc4210f027 TNO identifier 525588 Publisher Acoustical Society of America ISSN 0001-4966 Source Journal of the Acoustical Society of America, 137 (4), 2080-2088 Document type article Files To receive the publication files, please send an e-mail request to TNO Library.