Feedback control of sound
Feedback control of sound
This thesis is concerned with the development and application of feedback control techniques for active sound control. Both fixed and adaptive controllers are considered. The controller design problem for active sound control is formulated as a constrained optimisation problem with an H2 performance objective, of minimising the variance of the control error, and H2 and H∞ design constraints involving control power output, disturbance enhancement, and robust stability. An Internal Model Controller with an FIR control filter is assumed.
Conventional H2 design models for feedback controllers are studied first. Although such controllers can satisfy the design constraints by employing effort terms in the quadratic cost function, they do not achieve the best possible performance, and when adapted using LMS-based algorithms, they suffer from instabilities if the plant response varies significantly. Improved H2/H∞ design methods for fixed and adaptive controllers are then developed, which achieve the best H2 performance under the design constraints, offer an improved stability when made adaptive, and in general outperform the conventional H2 controllers. The H2/H∞ design problems employ convex programming to ensure a unique solution. The Sequential Quadratic Programming method is used for the off-line design of fixed controllers, and penalty and barrier function methods, together with frequency domain LMS-based algorithms are employed in the H2/H∞ adaptive controllers.
The controllers studied and developed here were applied to three active sound control systems: a noise-reducing headset, an active headrest, and a sound radiating panel. The emphasis was put on developing control strategies that improve system performance. First, a high performance controller for the noise-reducing headset was implemented in real-time, which combines analogue and adaptive digital controllers, and can thus reject disturbances which has both broad-band and periodic components. Then, robust H2/H∞ controllers were designed for an active headrest system using a virtual microphone arrangement to reject the sound at the listener's ears.
University of Southampton
Rafaely, Boaz
0839a7e8-bdbc-4f46-b57b-a9e5c625e968
1997
Rafaely, Boaz
0839a7e8-bdbc-4f46-b57b-a9e5c625e968
Rafaely, Boaz
(1997)
Feedback control of sound.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
This thesis is concerned with the development and application of feedback control techniques for active sound control. Both fixed and adaptive controllers are considered. The controller design problem for active sound control is formulated as a constrained optimisation problem with an H2 performance objective, of minimising the variance of the control error, and H2 and H∞ design constraints involving control power output, disturbance enhancement, and robust stability. An Internal Model Controller with an FIR control filter is assumed.
Conventional H2 design models for feedback controllers are studied first. Although such controllers can satisfy the design constraints by employing effort terms in the quadratic cost function, they do not achieve the best possible performance, and when adapted using LMS-based algorithms, they suffer from instabilities if the plant response varies significantly. Improved H2/H∞ design methods for fixed and adaptive controllers are then developed, which achieve the best H2 performance under the design constraints, offer an improved stability when made adaptive, and in general outperform the conventional H2 controllers. The H2/H∞ design problems employ convex programming to ensure a unique solution. The Sequential Quadratic Programming method is used for the off-line design of fixed controllers, and penalty and barrier function methods, together with frequency domain LMS-based algorithms are employed in the H2/H∞ adaptive controllers.
The controllers studied and developed here were applied to three active sound control systems: a noise-reducing headset, an active headrest, and a sound radiating panel. The emphasis was put on developing control strategies that improve system performance. First, a high performance controller for the noise-reducing headset was implemented in real-time, which combines analogue and adaptive digital controllers, and can thus reject disturbances which has both broad-band and periodic components. Then, robust H2/H∞ controllers were designed for an active headrest system using a virtual microphone arrangement to reject the sound at the listener's ears.
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Published date: 1997
Identifiers
Local EPrints ID: 463061
URI: http://eprints.soton.ac.uk/id/eprint/463061
PURE UUID: 15fc5e31-e154-42b4-90a3-888fdc8f4b23
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Date deposited: 04 Jul 2022 20:43
Last modified: 04 Jul 2022 20:43
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Author:
Boaz Rafaely
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