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Journal ArticleDOI

Positive position feedback control for large space structures

01 Apr 1990-AIAA Journal (American Institute of Aeronautics and Astronautics)-Vol. 28, Iss: 4, pp 717-724
TL;DR: In this paper, a new technique for vibration suppression in large space structures is investigated in laboratory experiments on a thin cantilever beam, which makes use of generalized displacement measurements to accomplish vibration suppression.
Abstract: A new technique for vibration suppression in large space structures is investigated in laboratory experiments on a thin cantilever beam. This technique, called Positive Position Feedback, makes use of generalized displacement measurements to accomplish vibration suppression. Several features of Positive Position Feedback make it attractive for the large space structure control environment: The realization of the controller is simple and straightforward. Global stability conditions can be derived which are independent of the dynamical characteristics of the structure being controlled, i.e., all spillover is stabilizing. The method cannot be destabilized by finite actuator dynamics, and the technique is amenable to a strain-based sensing approach. The experiments control the first six bending modes of a cantilever beam, and make use of piezoelectric materials for actuators and sensors, simulating a piezoelectric active-member. The modal damping ratios are increased by factors ranging from 2 to 130.
Citations
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Journal ArticleDOI
TL;DR: This paper presents an overview of nanopositioning technologies and devices emphasizing the key role of advanced control techniques in improving precision, accuracy, and speed of operation of these systems.
Abstract: Nanotechnology is the science of understanding matter and the control of matter at dimensions of 100 nm or less. Encompassing nanoscale science, engineering, and technology, nanotechnology involves imaging, measuring, modeling, and manipulation of matter at this level of precision. An important aspect of research in nanotechnology involves precision control and manipulation of devices and materials at a nanoscale, i.e., nanopositioning. Nanopositioners are precision mechatronic systems designed to move objects over a small range with a resolution down to a fraction of an atomic diameter. The desired attributes of a nanopositioner are extremely high resolution, accuracy, stability, and fast response. The key to successful nanopositioning is accurate position sensing and feedback control of the motion. This paper presents an overview of nanopositioning technologies and devices emphasizing the key role of advanced control techniques in improving precision, accuracy, and speed of operation of these systems.

1,027 citations

Journal ArticleDOI
TL;DR: In this paper, a technique has been developed which allows a single piece of piezoelec tric material to concurrently sense and actuate in a closed-loop system.
Abstract: A technique has been developed which allows a single piece of piezoelec tric material to concurrently sense and actuate in a closed loop system. The motivation behind the technique is that such a s...

824 citations


Cites background from "Positive position feedback control ..."

  • ...Equations (3) and (4) are physically equivalent to Equations (1) and (2) but note that in Equation (4) the permittivity is measured at constant strain and in Equation (2) the permittivity is measured at constant stress....

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  • ...Using the compact notation Equations (1-4) reduce to’:...

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Book
31 Jan 1997

811 citations

Journal ArticleDOI
TL;DR: In this paper, the classical preisach hysteresis modeling and tracking control of a curved pre-stressed piezoceramic patch actuator system with severe hystresis is presented.
Abstract: This paper presents the classical Preisach hysteresis modeling and tracking control of a curved pre-stressed piezoceramic patch actuator system with severe hysteresis The actuator is also flexible with very small inherent damping It has potential applications in active antennas A series of tests are conducted to study the hysteresis properties of the piezoceramic actuator system The numerical expressions of the classical Preisach model for different input variations are presented The classical Preisach model is applied to simulate the static hysteresis behavior of the system Higher order hysteresis reversal curves predicted by the classical Preisach model are verified experimentally The good agreement found between the measured and predicted curves showed that the classical Preisach model is an effective mean for modeling the hysteresis of the piezoceramic actuator system Subsequently, the inverse classical Preisach model is established and applied to cancel the hysteresis the piezoceramic actuator system for the real-time microposition tracking control In order to improve the control accuracy and to increase damping of the actuator system, a cascaded PD/lead-lag feedback controller is designed with consideration of the dynamics of the actuator In the experiments, two cases are considered, control with major loop hysteresis compensation, and control with minor loop hysteresis compensation Experimental results show that RMS tracking errors are reduced by 50% to 70% if the hysteresis compensation is added in the feedforward path in both cases Therefore, hysteresis compensation with the feedback controller greatly improves the tracking control accuracy of the piezoceramic actuator

465 citations

Journal ArticleDOI
TL;DR: In this article, a finite element formulation for vibration control of a laminated plate with piezoelectric sensors/actuators is presented, and the static responses of a bimorph beam are calculated.
Abstract: A finite element formulation for vibration control of a laminated plate with piezoelectric sensors/actuators is presented. Classical laminate theory with the induced strain actuation and Hamilton's principle are used to formulate the equations of motion. The total charge developed on the sensor layer is calculated from the direct piezoelectric equation. The equations of motion and the total charge are discretized with four-node, 12-degreeof-freedom quadrilateral plate bending elements with one electrical degree of freedom. The piezoelectric sensor is distributed, but is also integrated since the output voltage is dependent on the integrated strain rates over the sensor area. Also, the piezoelectric actuator induces the control moments at the ends of the actuator. Therefore, the number, size, and locations of the sensors/actuators are very important in the control system design. By selective assembling of the element matrices for each electrode, responses with various sensor/actuator geometries can be investigated. The static responses of a piezoelectric bimorph beam are calculated. For a laminated plate under the negative velocity feedback control, the direct time responses are calculated by the Newmark-/? method, and the damped frequencies and modal damping ratios are derived by modal state space analysis.

464 citations

References
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Journal ArticleDOI
TL;DR: In this paper, the authors consider the class of flexible systems that can be described by a generalized wave equation, which relates the displacementu(x,t) of a body Θ in 3D space to the applied force distribution.
Abstract: Since mechanically flexible systems are distributed-parameter systems, they are infinite-dimensional in theory and, in practice, must be modelled by large-dimensional systems. The fundamental problem of actively controlling very flexible systems is to control a large-dimensional system with a much smaller dimensional controller. For example, a large number of elastic modes may be needed to describe the behavior of a flexible satellite; however, active control of all these modes would be out of the question due to onboard computer limitations and modelling error. Consequently, active control must be restricted to a few critical modes. The effect of the residual (uncontrolled) modes on the closed-loop system is often ignored. In this paper, we consider the class of flexible systems that can be described by a generalized wave equation,u tt+Au=F, which relates the displacementu(x,t) of a body Θ inn-dimensional space to the applied force distributionF(x,t). The operatorA is a time-invariant symmetric differential operator with a discrete, semibounded spectrum. This class of distributed parameter systems includes vibrating strings, membranes, thin beams, and thin plates. The control force distribution $$F(x,t) = \sum\limits_{i = 1}^M { \delta (x - x_i )f_i (t)} $$ is provided byM point force actuators located at pointsx i on the body. The displacements (or their velocities) are measured byP point sensorsy i(t)=u(z j,t), oru t(z j,t),j=1, 2, ...,P, located at various pointsz j along the body. We obtain feedback control ofN modes of the flexible system and display the controllability and observability conditions required for successful operation. We examine the control and observation spillover due to the residual modes and show that the combined effect of spillover can lead to instabilities in the closed-loop system. We suggest some remedies for spillover, including a straightforward phase-locked loop prefilter, to remove the instability mechanism. To illustrate the concepts of this paper, we present the results of some numerical studies on the active control of a simply supported beam. The beam dynamics are modelled by the Euler-Bernoulli partial differential equation, and the feedback controller is obtained by the above procedures. One actuator and one sensor (at different locations) are used to control three modes of the beam quite effectively. A fourth residual mode is simulated, and the destabilizing effect of control and observation spillover together on this mode is clearly illustrated. Once observation spillover is eliminated (e.g., by prefiltering the sensor outputs), the effect of control spillover alone on this system is negligible.

753 citations

Journal ArticleDOI
TL;DR: In this paper, the nature of these stability problems is investigated, and a technique using position feedback is considered to solve the problem of low-frequency modes not destabilizing intermediate and higher-order modes.
Abstract: As large space structures are basically distributed systems, serious consideration must be given to the very high order, and consequently very high bandwidth, of these systems. In particular, as practical active control devices such as sensors and actuators have finite bandwidth, great care must be exercised so that control of low-frequency modes does not destabilize the intermediate and higher-order modes. In this paper, the nature of these stability problems is investigated and a technique using position feedback is considered.

394 citations

Journal ArticleDOI
TL;DR: In this article, the root perturbation technique is used to predict the behavior of the total system, assuming that the controller is allowed to modify only moderately the natural modes and frequencies of the structure.
Abstract: The novel idea presented is based on the observation that if a structure is controlled by distributed systems of sensors and actuators with limited authority, i.e., if the controller is allowed to modify only moderately the natural modes and frequencies of the structure, then it should be possible to apply root perturbation techniques to predict analytically the behavior of the total system. Attention is given to the root perturbation formula first derived by Jacobi for infinitesimal perturbations which neglect the induced eigenvector perturbation, a more general form of Jacobi's formula, first-order structural equations and modal state vectors, state-space equations for damper-augmented structures, and modal damping prediction formulas.

170 citations

Book ChapterDOI
01 Jan 1971

55 citations