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smart structures and materials 1994 Conference - smart structures and Intelligent Systems

作者： OLSON, SE DRAKE, ML FRANK, GJ WHITE, EV UNIV DAYTON RES INSTDAYTONOH 45469

ISBN: (纸本)0819414859

The University of Dayton Research Institute (UDRI) is teamed with McDonnell Douglas Aerospace (MDA) to develop and fly a NASA IN- STEP experiment entitled Jitter Suppression Experiment (JSX). The JSX will demonstrate a combined active/passive vibration control system on an actual full scale space structure. This paper will present the impact of the JSX system requirements on the passive and active vibration control system and verification that these requirements were met. The basic JSX system requirements are broken down into two categories, shuttle requirements and experiment requirements.

关键词： control systems Telecommunications Actuators Sensors Electronics Temperature metrology Ceramics Safety Aerospace engineering Vibration control

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A PIEZOTHERMOELASTIC THIN SHELL THEORY APPLIED TO ACTIVE structures

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JOURNAL OF VIBRATION AND ACOUSTICS-TRANSACTIONS OF THE ASME 1994年第3期116卷 295-302页

作者： TZOU, HS HOWARD, RV Department of Mechanical Engineering University of Kentucky Lexington KY 40506-0046

''smart '' structures with integrated sensors, actuators, and control electronics are of importance to the next-generation high-performance structural systems. Piezoelectric materials possess unique electromechanical properties, the direct and converse effects, which, respectively, can be used in sensor and actuator applications. In this study, piezothermoelastic characteristics of piezoelectric shell continua are studied and applications of the theory to active structures in sensing and control are discussed. A generic piezothermoelastic shell theory for thin piezoelectric shells is derived, using the linear piezoelectric theory and Kirchhoff-Love assumptions. It shows that the piezothermoelastic equations, in three principal directions, include thermal induced loads, as well as conventional electric and mechanical loads. The electric membrane forces and moments induced by the con verse effect can be used to control the thermal and mechanical loads. A simplification procedure, based on the Lame parameters and radii of curvatures, is proposed and applications of the theory to (1) a piezoelectric cylindrical shell, (2) a piezoelectric ring, and (3) a piezoelectric beam are demonstrated.

关键词： Pipes Actuators Thin shells Shells Stress Piezoelectric materials Adaptive structures Electronics Membranes Sensors

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POWER CONVERTERS AND POWER-SYSTEMS FOR PIEZOELECTRIC ACTUATORS

POWER CONVERTERS AND POWER-SYSTEMS FOR PIEZOELECTRIC ACTUATO...

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smart structures and materials 1994 Conference - smart structures and Intelligent Systems

作者： LINDNER, DK KIRBY, G SABLE, D VIRGINIA TECH BRADLEY DEPT ELECT ENGNBLACKSBURGVA 24061

ISBN: (纸本)0819414859

The next generation of materials will contain many embedded or attached actuators and/or sensors. They will also contain support electronics including power electronics and a computer processor with a communication network along with the `smarts' to respond to their environment. Current research is also directed toward miniaturization of the components, particularly the sensor and actuators with the idea of incorporating large numbers of actuators and sensors into the material. In keeping with this trend, the electronics should also be miniaturized along with the sensors and actuators. In this paper we discuss miniaturized power converters and power systems with potential applications to materials with miniaturized sensors and actuators.

关键词： Actuators Amplifiers Sensors Electronics Transformers smart structures Switching Magnetism Switches Distributed computing

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BOUNDARY TRANSITION OF A PIEZO-LAMINATED BEAM WITH LARGE FEEDBACK VOLTAGES

BOUNDARY TRANSITION OF A PIEZO-LAMINATED BEAM WITH LARGE FEE...

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smart structures and materials 1994 Conference - smart structures and Intelligent Systems

作者： TZOU, HS JOHNSON, D LIU, KJ UNIV KENTUCKY DEPT MECH ENGNLEXINGTONKY 40506

ISBN: (纸本)0819414859

Distributed control of a cantilever beam using a fully distributed piezoelectric layer has been a classical problem for years. In general, the equivalent actuation is introduced at the free end of the cantilever beam, and the control action is equivalent to an (electric) counteracting moment. The control effect is proportional to the feedback voltage, if the system is considered linear. If the feedback voltage is continuously increased, what would happen to the cantilever beam was not investigated. In this study, nonlinear control effects and boundary transition of the cantilever beam with large feedback voltages are studied. Analytical solutions are compared with finite element simulations.

关键词： Sensors Actuators Feedback control control systems Chemical elements Nonlinear control Radon Distance measurement Feedback signals Ferroelectric polymers

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DYNAMIC ANALYSIS ON smart materials 2

DYNAMIC ANALYSIS ON SMART MATERIALS

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2nd European Conference on smart structures and materials

作者： WU, WB CHANG GUNG COLL MED & TECHNOL DEPT MECH ENGNTAYUANTAIWAN

Active vibration control of smart structural materials has been achieved by using distributed piezoelectric actuators. Numerical simulation and experimental testing have been conducted to investigate vibration suppres... 详细信息

ISBN: (纸本)0819417009

关键词： control systems smart materials Numerical simulations Actuators Computer simulations Feedback control Active vibration control Sensors Aluminum Optical simulations

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MODE SHAPE DISTORTIONS DUE TO PIEZOCERAMIC ACTUATORS AND IMPLICATIONS FOR control

MODE SHAPE DISTORTIONS DUE TO PIEZOCERAMIC ACTUATORS AND IMP...

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smart structures and materials 1994 Conference - smart structures and Intelligent Systems

作者： KIRBY, GC LINDNER, DK MATIC, P MIRMAK, M USN RES LABMECH MAT BRANCHWASHINGTONDC 20375

ISBN: (纸本)0819414859

While the phenomenon of shifts in the poles of flexible structures caused by local stiffening due to bonded piezoceramic actuators is well documentated, shifts in the zeros associated with the distorted mode shapes due to localized stiffening has yet to be investigated. The finite element method in conjunction with state space models was used to derive transfer functions for both collocated and noncollocated sensor/actuator pairs. Models that considered the mode shape distortions compared favorably with experimental measurements. With the numerical models validated by experiments, state variable feedback control gains were determined using linear quadratic regulator design for noncollocated and collocated sensor/actuator pairs for the cases of classical mode shapes and distorted mode shapes. It is demonstrated that lack of consideration of distorted mode shapes can lead to a loss of performance of the control systems.

关键词： Actuators Sensors control systems control systems design Finite element methods Bridges Wheatstone bridges Resistance Feedback control Systems modeling

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INVESTIGATION OF MODAL BASED AND WAVE-TYPE VIBRATION ENERGY TRANSMISSION FOR ACTIVE control OF structures

INVESTIGATION OF MODAL BASED AND WAVE-TYPE VIBRATION ENERGY ...

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smart structures and materials 1994 Conference - smart structures and Intelligent Systems

作者： PRAKAHASANTE, KO CRAIG, KC RENSSELAER POLYTECH INST DEPT MECH ENGNTROYNY 12180

ISBN: (纸本)0819414859

In order to develop effective controllers for active vibration control of complex flexible structural systems, it is imperative to be thorough with vibratory transmission analysis in such systems. This paper addresses the interpretation of vibration behavior in active structures in the form of modal synthesis and waveform propagation, from which control architectures for vibration reduction are developed and specialized. Multi-input multi-output robust control methods for actively controlling vibration transmission of narrow-band disturbances, based on modal vibration characteristics in a typical beam structure bonded with piezoelectric sensors and actuators are presented. The development of compensators based on wave-propagation techniques for active control of stationary and propagating wave-forms in an active beam structure is also discussed. Vibration transmission in the structure in the form of intensity and energy density is investigated for effective vibration minimization. A LMS based adaptive feedforward algorithm, and nonlinear feedback gain scheduling of wave parameters targeting transient and steady state vibration isolation is presented. Numerical and experimental results obtained from the implementation of the active control techniques from analysis of the modal based, and wave-type vibration transmission characteristics for an aluminum and a composite active structure is presented. © 1994 SPIE. All rights reserved.

关键词： Vibration analysis

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THERMOMECHANICAL MODELING OF LAMINATED PLATES WITH PIEZOELECTRIC SENSORS AND ACTUATORS

THERMOMECHANICAL MODELING OF LAMINATED PLATES WITH PIEZOELEC...

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smart structures and materials 1994 Conference - smart structures and Intelligent Systems

作者： CHANDRASHEKHARA, K TENNETI, R UNIV MISSOURI DEPT GEN & COMPARAT BIOCHEMROLLAMO 65401

ISBN: (纸本)0819414859

A finite element model is developed for the active control of thermally induced vibration of laminated composite plates with piezoelectric sensors and actuators. The present model takes into account the mass, stiffness and thermal expansion of the piezoelectric patches. A C degree(s) continuous nine-noded shear flexible element is implemented to model the plate. The piezoelectric sensing layer monitors the structural oscillation due to the direct piezoelectric effect and the actuator suppresses the oscillation via the converse piezoelectric effect. These two effects are then coupled with a constant gain negative velocity/positive position feedback control algorithm to actively control the dynamic response of the plate in a closed loop. Numerical results indicate that thermally induced deformation of a laminated plate can be suppressed through the application of electrical potential to the piezoelectric patches.

关键词： Actuators Sensors Piezoelectric effects Composites Mathematical modeling Chemical elements Thermal modeling Feedback control Finite element methods Temperature metrology

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Vibration suppression of a flexible manipulating system by using transfer matrix method

Vibration suppression of a flexible manipulating system by u...

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smart structures and materials 1994: mathematics and control in smart structures

作者： Shen, Ji Yao Sharpe, Lonnie He, Zhong Q. Keckler, Claude R. Dept. of Mechanical Engineering School of Engineering North Carolina A and T State University GreensboroNC27411 United States Control and Guidance Division NASA Langley Research Center HamptonVA23681 United States

The modeling and control of manipulating systems with rigid-body links have been successfully developed within the robotics literature. The investigation of manipulating system with joint compliance and link flexibility has been also studied by some researchers. In general, the methods applied the 4 by 4 homogeneous transformation matrices of Devanit and Hartenberg. The generalized coordinates associated with the link degree of freedom and flexible modal coordinates were selected to describe the kinematics and dynamic behavior of the manipulating system. The Lagrange's equation was then used to obtain a large set of nonlinear partial differential equations. The expansion and solution of the equations are tedious. The method presented thus far in the literature were all very complicated. To simplify the analytical process, this paper models a two-arm flexible manipulating system by a set of generic partial differential equations, from which the transfer matrices for the flexible arms and revolute joints have been constructed. Based upon the compatibility conditions at the connecting points, the global system dynamic equation has been derived. Joint moments are used as the control actions. A typical control problem for end-effector vibration suppression has been investigated. control law computation proceeds in the frequency domain based on the pole-placement method. The effectiveness of the vibration suppression by using distributed parameter modeling technique along with the application of transfer matrix method is indicated by means of the decay of the end-effector response time history computed based upon the modal expansion method. © 1994 SPIE.

关键词： End effectors

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PHASE-control OF A MICROPATCH ANTENNA ELEMENT

PHASE-CONTROL OF A MICROPATCH ANTENNA ELEMENT

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smart structures and materials 1994 Conference - smart structures and Intelligent Systems

作者： THURSBY, MH HSU, R FLORIDA INST TECHNOL DEPT ELECT & COMP ENGNMELBOURNEFL 32901

ISBN: (纸本)0819414859

We will describe an effort that to date has produced a working prototype of a micropatch antenna incorporating a single-dollar- per-bit phase shifter. In this paper we will describe a method of controlling a micropatch antenna to provide phase only variation of the antenna characteristics using a similar device to that used for the frequency control experiments. We have successfully varied the phase of the antenna element without significantly changing the operating frequency. This work has led us to pursue further the design and fabrication of an array of such phase adjustable element to test the hypothesis that such phase- controlled micropatch elements can be used to fabricate a low- cost phased-array antenna.

关键词： Antennas Manufacturing control systems Neural networks Neurons Phase shifts Phased arrays Capacitance Satellites Tolerancing

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