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smart structures and materials 2000 - mathematics and control in smart structures

作者： Gorinevsky, Dimitry Stein, Gunter Honeywell Technology Cent Cupertino CA United States

This paper considers control analysis approaches for systems incorporating large actuator and sensor arrays. Applications of such systems are increasingly common because of the development of micro-systems technology. Many imaging systems have large one-dimensional or two-dimensional arrays of actuators. This includes RF or optical reflectors, display, printing, and other systems. Signal processing for large sensor arrays has well-established theory and applications, especially in imaging. At the same time, approaches to control of large distributed actuator and sensor arrays are much less developed. This paper considers one of the fundamental issues and design and analysis of large actuator and sensor array systems. The key notion in modern feedback control theory is the notion of uncertainty and associated notion of control robustness to this uncertainty. In control of dynamical systems evolving in time, structured uncertainty models are commonly accepted for theoretical analysis (Structured Singular Value or μ-analysis) and practical control design. In control of spatially distributed processes, there is a need to establish appropriate models of the uncertainty of the system spatial and dynamical characteristics. This paper discusses an extension of structured uncertainty models towards controlled systems with spatially distributed arrays of actuators and sensors. Unlike a dynamical uncertainty, spatial uncertainty is not causal in the spatial coordinate. This leads to related but different uncertainty models in the two case. For spatial coordinates, boundary effects also contribute to the modeling error. By using the discussed uncertainty models, the existing methods of robust control design and analysis can be extended towards spatially distributed systems. As an illustrative example, this paper demonstrates an application of the developed approach to a one-dimensional model of a flexible reflector with a distributed actuator array for shape control.

关键词： Uncertain systems

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Strategies for smart control of large structures

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Proceedings of SPIE - The International Society for Optical Engineering 1999年 3667卷 604-613页

作者： Klein, Richard E. Univ of Illinois Urbana United States

Several decades ago, the principles of dynamic systems and controls were directed towards large engineering structures. In more recent years, the use of feedback control systems technology has been introduced to cause a structure to be `smart,' or to be semi-actively controlled. As structural control matures, and such things as `intelligent' structures and `smart' systems methodology become understood and accepted in the broader scientific and technical circles, the uttering of some thoughts in reflection becomes appropriate. The paper recounts the author's personal role and experiences, examines trends and underlying issues in structural control, and concludes with admonitions, recommendations and visions concerning future directions in structural control.

关键词： Intelligent structures

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control design which respects characteristic length scales in smart systems and smart structures

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Proceedings of SPIE - The International Society for Optical Engineering 1999年 3667卷 202-210页

作者： Baillieul, J. Boston Univ Boston United States

Although there is a mature and continually growing body of knowledge concerning the ways in which the dynamics of fluids and solids depend on characteristic length scales, current theories governing control design do not take explicit account of length scales. Recent research has demonstrated the need to take such considerations into account in designing control systems for smart materials and smart structures in which the goal is to employ small-scale actuators and sensors with characteristic length scales in the micron to millimeter range. For many applications, sensors and actuators will need to be separated by considerable distances (in terms of characteristic length scales). Closed loop feedback designs in this setting may involve communications delays, and both the communications channels and the sensors themselves will typically be relatively noisy. Hence traditional approaches to the design of feedback control laws need to be rethought and modified to work effectively in the noisy, nonlinear, bandlimited world of microelectromechanical systems (MEMS). This paper discusses one approach to a robust, length-scale respecting theory of control based on oscillatory actuation. It includes a brief outline of recent developments in the control of mechanical systems using oscillatory actuation, emphasizing the dependence on characteristic length scales. The principal applications with which we are working are micro-pendulum designs, micro-piston actuators for deformable mirrors as well as micro-valves for the control of fluid-structure boundary layer control.

关键词： Intelligent structures

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Strategies for smart control of large structures

Strategies for smart control of large structures

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smart structures and materials 1999 Conference

作者： Klein, RE Univ Illinois Dept Mech & Ind Engn Urbana IL 61801 USA

ISBN: (纸本)0819431419

Several decades ago, the principles of dynamic systems and controls were directed towards large engineering structures. In more recent years, the use of feedback control systems technology has:been introduced to cause a structure to be "smart," or to be semi-actively controlled. As structural control matures, and such things as "intelligent" structures and "smart" systems methodology become understood and accepted in the broader scientific and technical circles, the uttering of some thoughts in reflection becomes appropriate. The paper recounts the author's personal role and experiences, examines trends and underlying issues in structural control, and concludes with admonitions, recommendations and visions concerning future directions in structural control.

关键词： structures structural control vibration control systems wind loads smart systems dynamic response

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control design which respects characteristic length scales in smart systems and smart structures

Control design which respects characteristic length scales i...

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Proceedings of the 1999 smart structures and materials - mathematics and control in smart structures

作者： Baillieul, J. Boston Univ Boston MA United States

关键词： Intelligent structures

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Optimization of piezoelectric material distribution in smart structures

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Proceedings of SPIE - The International Society for Optical Engineering 1999年 3667卷 13-22页

作者： Gabbert, Ulrich Weber, Christian-Toralf Univ of Magdeburg Magdeburg Germany

The paper first presents a general purpose finite element based simulation tool for piezoelectric controlled smart structures. In addition to the standard finite elements, this tool contains a number of coupled electromechanical finite elements as well as numerical tools to simulate controlled structures in statics and dynamics. The effectiveness of a smart structure decisively depends on the amount and distribution of active materials across the passive structure and on the controller design. To solve this design problem automatically, a discrete optimization technique and ideas from topology optimization are presented. The control parameters are considered as continuous design variables. Mathematical solution algorithms for nonlinear, mixed continuous and discrete-valued optimization techniques are used to solve the optimization problem. As a test example the distribution of piezoelectric wafers over a beam structure is presented. Finally, this paper gives an outlook for new developments in this field.

关键词： Intelligent structures

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Computer-aided optimization of smart structures

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Proceedings of SPIE - The International Society for Optical Engineering 1999年 3667卷 2-12页

作者： Lerch, R. Kaltenbacher, M. Landes, H. Simkovics, R. Univ of Linz Linz Austria

In this paper, the finite-element/boundary-element program CAPA is presented, which has been developed by the authors during the last decade. With this software environment we are able to model quite different types of transducers which mostly ask for the numerical solution of a multifield problem, such as coupled electric-mechanical fields or magnetic-mechanical fields. Practical applications in the area of smart structures will demonstrate the applicability of the developed software.

关键词： Intelligent structures

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Optimization of actuator placement and structural parameters in smart structures

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Proceedings of SPIE - The International Society for Optical Engineering 1999年 3667卷 267-276页

作者： Baier, H. Locatelli, G. Technical Univ Munich Garching Germany

Adaptive structures optimal design problems and solution methods are presented and discussed for the cases of shape control and active damping. A general method to solve simultaneously optimal placement and control problems for active damping applications is outlined. This method is based on a finite element structural model and on the calculation of the closed-loop system poles. Numerical results are given to illustrate this method for the case of a beam with collocated PZT sensor/actuator pair and a direct velocity feedback controller.

关键词： Intelligent structures

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Modelling stresses in piezoelectric smart structures under combined thermal and mechanical excitations

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Proceedings of SPIE - The International Society for Optical Engineering 1999年 3667卷 474-485页

作者： Koko, Tamunoiyala S. Smith, Malcolm J. Orisamolu, Irewole R. Martec Ltd Halifax Canada

In this paper, the integrated finite element methodology developed in our earlier work for designing active vibration control strategies in smart structures, is extended to compute the stresses and strains in the structure, due to combined thermal, mechanical and electrical excitations. A layered composite brick elements with linear strain-displacement and linear thermopiezoelectric constitutive relations is used to model the structure. The method, which has been encoded into a software called smartCOM provides a design and analysis capability that simultaneously accounts for the coupled thermopiezoelectric and control capabilities of the smart structural systems. Numerical examples are provided for structures with surface bonded piezoelectric sensors and actuators, under various types of mechanical, thermal and electrical load. Comparisons are made to other available solutions to verify the accuracy of the smartCOM simulations. The method provides accurate results and is seen as a valuable tool for the design and analysis of these smart structures.

关键词： Intelligent structures

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Modeling of piezoelectric smart structures including absorbing materials for cabin noise problems

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Proceedings of SPIE - The International Society for Optical Engineering 1999年 3667卷 524-529页

作者： Kim, Jaehwan Lee, Joong-Kuen Im, Byoung-Soo Chung, Chae-Cheon Inha Univ Incheon Korea Republic of

Modeling of piezoelectric smart structures including absorbing material was studied for cabin noise problems. The finite element method which uses a combination of three dimensional piezoelectric, flat shell and transition finite elements is adopted to model the piezoelectric active structure. The acoustic pressure in the cubic shaped cavity, is represented in terms of modes of the cavity and the absorbing material is modeled using surface acoustic impedance. Finally, the effect of the cavity pressure is introduced in the finite element equations. The simulation result of sound pressure in the cavity is compared with an experiment and they show a good agreement. The cavity pressure is reduced in a wide frequency range except the resonance frequencies of the plate by applying absorbing material. It can be concluded that the piezoelectric smart structures with absorbing materials can be creative technology for cabin noise problems.

关键词： Intelligent structures

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