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P. E. Crouch

Bio: P. E. Crouch is an academic researcher from Arizona State University. The author has contributed to research in topics: Rotor (electric) & Helicopter rotor. The author has an hindex of 2, co-authored 2 publications receiving 22 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, a linear quadratic regulator-based least square output feedback control (LQ-OPC) procedure is proposed for rotor systems. But the LQ regulator is not suitable for the case of linear asymmetric rotor systems, and it cannot be applied to the complex mode model.
Abstract: The complex mode and balanced realization methods are used separately to obtain reduced-order models for general linear asymmetric rotor systems. The methods are outlined and then applied to a typical rotor system represented by a 52 degree-offreedom finite element model. The accuracy of the two methods is compared for this model and the complex model method is found to be more accurate than the balanced realization method for the desired frequency bandwidth and for models of the same reduced order. However, with some limitations, it is also shown that the balanced realization method can be applied to the reduced-order complex mode model to obtain further order reduction without loss of model accuracy. A “Linear-Quadratic-Regulator-based least-squares output feedback control” procedure is developed for the vibration control of rotor systems. This output feedback procedure eliminates the requirement of an observer for the use of an LQ regulator, and provides the advantage that the rotor vibration can be effectively controlled by monitoring only one single location along the rotor shaft while maintaining an acceptable performance. The procedures presented are quite general and may be applied to a large class of vibration problems including rotordynamics.

18 citations

Proceedings ArticleDOI
01 Jun 1992
TL;DR: In this article, a linear quadratic-regulator-based least square output feedback control (LQ-OPC) procedure is proposed for rotor control. But the LQ regulator is not used in this paper.
Abstract: The complex mode and balanced realization methods are used separately to obtain reduced-order models for general linear asymmetric rotor systems. The methods are outlined and then applied to a typical rotor system which is represented by a 52 degree-of-freedom finite element model. The accuracy of the two methods is compared for this model and the complex mode method is found to be more accurate than the balanced realization method for the desired frequency bandwidth and for models of the same reduced order. However, with some limitations, it is also shown that the balanced realization method can be applied to the reduced-order complex mode model to obtain further order reduction without loss of model accuracy. An “Linear-Quadratic-Regulator-based least-squares output feedback control” procedure is developed for the vibration control of rotor systems. This output feedback procedure eliminates the requirement of an observer for the use of an LQ regulator, and provides the advantage that the rotor vibration can be effectively controlled by monitoring only one single location along the rotor shaft while maintaining an acceptable performance. The procedures presented are quite general and may be applied to a large class of vibration problems including rotor-dynamics.Copyright © 1992 by ASME

4 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the effects of damping on rotational vibratory solutions of a multiple pulley-flat viscoelastomeric belt system with rotary arm tensioner are developed.
Abstract: The effects of damping on rotational vibratory solutions of a multiple pulley-flat viscoelastomeric belt system with rotary arm tensioner is developed. A complex model procedure is developed to solve both underdamped and overdamped cases. This complex modal procedure allows for future extension to include nonsymmetric rotational models, such as transverse belt vibration coupling. The modal solution enables rapid analysis over a spectrum of frequencies. Seven pulley system experimental results reported in the literature support the analytical development. Belt damping has significant vibration and belt tension amplitude effects. Tensioner spring rate and coulomb damping has minor effects.

63 citations

Journal ArticleDOI
TL;DR: This survey discusses the previous literature reviews on model reduction, reduction methods applied to rotor systems, the current state of these reduction methods in rotor dynamics, and the ability of the literature to reduce the complexities of large order rotor dynamic systems but allow accurate solutions.
Abstract: The focus of this literature survey and review is model reduction methods and their application to rotor dynamic systems. Rotor dynamic systems require careful consideration in their dynamic models as they include unsymmetric stiffness, localized nonproportional damping, and frequency-dependent gyroscopic effects. The literature reviewed originates from both controls and mechanical systems analysis and has been previously applied to rotor systems. This survey discusses the previous literature reviews on model reduction, reduction methods applied to rotor systems, the current state of these reduction methods in rotor dynamics, and the ability of the literature to reduce the complexities of large order rotor dynamic systems but allow accurate solutions.

56 citations

Journal ArticleDOI
TL;DR: In this paper, a bibliographical review of the finite element methods (FEMs) applied to the analysis and simulation of smart materials and structures is presented, including smart materials, smart components/structures, smart sensors and actuators, controlled structures technology, and other topics.
Abstract: This paper gives a bibliographical review of the finite-element methods (FEMs) applied to the analysis and simulation of smart materials and structures. The bibliography at the end of the paper contains references to papers, conference proceedings and theses/dissertations on the subject that were published between 1986-1997. The following topics are included: smart materials; smart components/structures; smart sensors and actuators; controlled structures technology; and other topics.

33 citations

Journal ArticleDOI
TL;DR: In this article, the problem of designing accurate state observers for flexible link mechanisms is tackled, and a general approach is developed and experimental results are given for the case of a four bar linkage with flexible links.
Abstract: The design of an observer estimating the state variables of a plant is an essential step towards the synthesis of high-performance model-based control schemes. In this paper, the problem of designing accurate state observers for flexible link mechanisms is tackled. The complexity of such a problem is considerable due to the nonlinear characteristics of flexible link mechanism dynamic models. Since nonlinear state observers have limited practical utility, in this work an investigation is made on the possibility of employing the Kalman filter theory together with suitable piecewise-linear truncated dynamic models. A general approach is developed and experimental results are given for the case of a four bar linkage with flexible links. Not only do these results confirm the theoretical and numerical results, but they also prove the practical effectiveness and efficiency of the proposed approach.

28 citations

Journal ArticleDOI
TL;DR: In this article, a modified System Equivalent Reduction Expansion Process (SEREP) is proposed to reduce large linear system-equations of motion, which also include gyroscopic effect, internal and external damping.

20 citations