Robust control of an articulating flexible structure using MIMO QFT

Kerr, Murray Lawrence (2004). Robust control of an articulating flexible structure using MIMO QFT PhD Thesis, School of Engineering, The University of Queensland.

       
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Author Kerr, Murray Lawrence
Thesis Title Robust control of an articulating flexible structure using MIMO QFT
School, Centre or Institute School of Engineering
Institution The University of Queensland
Publication date 2004
Thesis type PhD Thesis
Supervisor Dr Samuel Asokanthan
Daniel, Bill
Total pages 251
Collection year 2004
Subjects L
230119 Systems Theory and Control
671401 Scientific instrumentation
Abstract/Summary Quantitative Feedback Theory (QFT) is a control system design methodology founded on the premise that feedback is necessary only because of system uncertainty. Articulating flexible structures, such as flexible manipulators, present a difficult closed-loop control problem. In such servo systems, the coupling of the rigid and flexible modes and the non-minimum phase dynamics severely limit system stability and performance. The difficulties in controlling these structures is exacerbated by the denumerably infinite number of flexible modes and associated difficulties in developing accurate dynamic models for controller design. As such, the control of articulating flexible structures presents a non-trivial testbed for the design of QFT based robust control systems. This dissertation examines the multi-input multi-output (MIMO) QFT based control of an articulating flexible structure and presents an enhancement of the theoretical basis for the MIMO QFT design methodologies. The control problem under consideration is the active vibration control of an articulating single-link flexible manipulator. This is facilitated by an actuation scheme comprised of a combination of spatially discrete actuation, in the form of a DC motor to perform articulation, and spatially distributed actuation, in the form of a piezoelectric transducer for active vibration control. In the process of developing and experimentally validating the QFT based control system, shortcomings in the theoretical basis for the MIMO QFT design methodologies are addressed. Robust stability theorems are developed for the two main MIMO QFT design methodologies, namely the sequential and non-sequential MIMO QFT design methodologies. The theorems complement and extend the existing theoretical basis for the MIMO QFT design methodologies. The dissertation results expose salient features of the MIMO QFT design methodologies and provide connections to other multivariable design methodologies.
Keyword QFT
Control
Multivariable Control
Robust Control
Flexible Manipulator
Piezoelectric

 
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Created: Fri, 21 Nov 2008, 17:03:35 EST