http://nova.newcastle.edu.au/vital/access/services/Feed ${session.getAttribute("locale")} 5 http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:1467 This paper designs and experimentally evaluates the performance of a feedback controller to suppress vibration of a flexible beam. The controller is designed to minimize the spatial ϰ₂ norm of the closed-loop system to ensure average reduction of vibration throughout the entire structure. Vibrations of the first six bending modes of the beam are controlled using a collocated piezoelectric actuator-sensor pair attached to the beam. Feedthrough terms are incorporated into the flexible-structure model to correct the locations of the in-bandwidth zeros. It is shown that the spatial ϰ₂ control has an advantage over the pointwise ϰ₂ control in minimizing the vibration of the entire structure. The spatial ϰ₂ controller minimizes the ϰ₂ norm of the entire structure more uniformly, while the pointwise ϰ₂ controller only has a local effect. The implemented spatial ϰ₂ controller is able to minimize the first six bending modes of the beam effectively. This spatial ϰ₂ control can also be applied to more general structural vibration suppression problems. 2012-10-08T00:10:06.677Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:1468 This paper is aimed to develop a feedback controller that suppresses vibration of flexible structures. The controller is designed to minimize the spatial ϰ∞ norm of the closed-loop system. This technique guarantees average reduction of vibration throughout the entire structure. A feedthrough term is incorporated into the truncated flexible-structure model to compensate for the neglected dynamics in the finite-dimensional model. Adding the feedthrough term reduces the uncertainty associated with the truncated model, which is instrumental in ensuring the robustness of the closed-loop system. The controller is applied to a simply-supported piezoelectric-laminate beam and is validated experimentally to show the effectiveness of the proposed controller in suppressing structural vibration. It is shown that the spatial ϰ∞. control has an advantage over the pointwise ϰ∞ control in minimizing the vibration of the entire structure. This spatial ϰ∞ control methodology can also be applied to more general structural vibration suppression problems. 2012-10-08T00:10:05.116Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:713 This thesis represents the work that has been done by the author in the area of vibration analysis and control of smart structures during his PhD candidature. The research was concentrated on flexible structures, using piezoelectric materials as actuators and sensors. The thesis consists of four major parts. The first part (Chapter 2) is the modelling of piezoelectric laminate structures using modal analysis and finite element methods. The second part (Chapter 4) involves the model correction of pointwise and spatial models of resonant systems. The model correction solution compensates for the errors associated with the truncation of high frequency modes. The third part (Chapter 5) is the optimal placement methodology for general actuators and sensors. In particular, optimal placement of piezoelectric actuators and sensors over a thin plate are considered and implemented in the laboratory. The last part (Chapters 6 to 8) deals with vibration control of smart structures. Several different approaches for vibration control are considered. Vibration control using resonant, spatial H-2 and H-infinity control is proposed and implemented on real systems experimentally. It is possible, for certain modes, to obtain the very satisfactory result of up to 30 dB vibration reduction. 2011-12-20T23:00:18.756Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:1303 Introduces a class of resonant controllers that can be used to minimize structural vibration using collocated piezoelectric actuator-sensor pairs. The proposed controller increases the damping of the structure so as to minimize a chosen number of resonant responses. The controller can be tuned to a chosen number of modes. This results in controllers of minimal dimension. The controller structure is chosen such that closed-loop stability is guaranteed. Moreover, the controller can be designed such that the spatial H2 norm of the system is minimized. This will guarantee average reduction of vibration throughout the entire structure. Experimental validation on a simply supported beam is presented showing the effectiveness of the proposed controller. 2010-04-27T06:56:31.176Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:1716 The purpose of this paper is to suggest a criterion for the optimal placement of collocated piezoelectric actuator–sensor pairs on a thin flexible plate using modal and spatial controllability measures. Consideration is given to the reduction of control spillover effect by adding an extra spatial controllability constraint in the optimization procedure. The spatial controllability is used to find the optimal placement of collocated actuator–sensor pairs for effective average vibration reduction over the entire structure, while maintaining modal controllability and observability of selected vibration modes. It is found that the methodology for optimal actuator placement can be used for a collocated system without damaging the observability performance of the collocated sensors. Experimental validation of our optimal placement is done on a simply supported thin plate with a collocated piezoelectric actuator–sensor pair. 2010-04-27T06:11:57.616Z ]]>