Vibration characteristics of an elastic plate in the shape of an infinite strip are changed by applying a lateral concentrated force to the plate. The homogeneous, isotropic, elastic plate is infinite in the x-directi...
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Vibration characteristics of an elastic plate in the shape of an infinite strip are changed by applying a lateral concentrated force to the plate. The homogeneous, isotropic, elastic plate is infinite in the x-direction and the sides are simply supported. The size of the force is changed in proportion to the displacement measured at a certain point of the plate. The proportionality constant serves as the control parameter. The mathematical formulation of this distributed control problem and its analytical solution in terms of the vibration frequencies of the plate are given. The vibration frequencies are plotted as a function of the control parameter.
A time-varying sensor delay is inevitable in a mining cable elevator operating at a maximum distance which is more than 2000-m underground, when the sensor signals are transmitted from a cage at the bottom of the cabl...
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A time-varying sensor delay is inevitable in a mining cable elevator operating at a maximum distance which is more than 2000-m underground, when the sensor signals are transmitted from a cage at the bottom of the cable to a control center on the ground through a set of wireless devices, including emitters and receivers. This sensor delay may degrade the estimation precision of the state observer or even destroy the stability of the closed-loop system. In this brief, we design an observer which can compensate the sensor delay with a time-varying and arbitrary length to estimate the vibration states of the mining cable elevator, including the time-varying-length mining cable and the cage. The vibration dynamics of the mining cable elevator is described by a wave partial differential equation (PDE)-ordinary differential equation (ODE) coupled system on a time-varying domain, and the sensor delay dynamics is represented by a transport PDE on a time-varying domain. A full-order infinite dimensional observer is constructed to estimate the states of such a wave PDE-ODE-transport PDE coupled system where PDEs are on time-varying domains, only using available boundary values without measurements at the connection points of the PDEs and ODE. The exponential stability of the observer error system is proved via Lyapunov analysis. The effectiveness of the proposed observer is verified via numerical simulation.
A fourier space basis function based 3D fuzzy modeling method for distributed parameter systems is proposed in this paper. Unlike the traditional modeling method with model reduction, 3D fuzzy modeling integrates the ...
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A fourier space basis function based 3D fuzzy modeling method for distributed parameter systems is proposed in this paper. Unlike the traditional modeling method with model reduction, 3D fuzzy modeling integrates the time-space seperation and the time-space sysnsis into a 3D fuzzy model framework naturally. In this study, the construction of the 3D fuzzy model is of data-driven style. The antecedent parts of the 3D fuzzy rules is learned by Affinity Propagation Clustering *** space basis function is considered as the concequent set of the 3D fuzzy rule, and its parameters are learned by the gradient descent algorithm. The proposed modeling method is successful applied to a simulated parabolic rod reactor system. In comparison with other modeling methods, the simulation results validate the superiority of the proposed modeling method.
The detailed rigorous solution to the optimal rocket problem proposed by Lawden (1963) is examined. It is noted that the most important special case admitting a closed-form solution occurs when the gravity field can b...
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The detailed rigorous solution to the optimal rocket problem proposed by Lawden (1963) is examined. It is noted that the most important special case admitting a closed-form solution occurs when the gravity field can be treated as uniform. An expression for the angular velocity of the primer vector is obtained for this special case. The concept of parametric guidance is then considered, and an analysis is presented to show that, under some conditions, a 'straightening out' of the pitch profile occurs. The analysis also suggests a more rigorous approach to parametric guidance. (AIAA)
The vibration control of flexible structures with variable disturbances in different frequencies becomes more and more important because of the demand for higher positional accuracy and more stable manipulation. This ...
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The vibration control of flexible structures with variable disturbances in different frequencies becomes more and more important because of the demand for higher positional accuracy and more stable manipulation. This paper reports on a proof-of-concept experimental investigation focused on evaluating the elastodynamic characteristics of hollow cantilever beams filed with a hydrous-based ER fluid consisting of cornstarch and silicone oil. The beams are considered to be uniform viscoelastic materials and modeled as a viscously damped harmonic oscillator. Electric field dependent natural frequencies, loss factors, and complex moduli are evaluated and compared among three different beams: two types of different volume fraction of the ER fluid and one type of different particle concentration of the ER fluid by weight.
The present stability analysis of a magnetoplasmadynamic system is based on the Liapunov theorem's extension to the coverage of distributed-parametersystems. The results of the stability analysis are supported by...
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The present stability analysis of a magnetoplasmadynamic system is based on the Liapunov theorem's extension to the coverage of distributed-parametersystems. The results of the stability analysis are supported by those derived from a spectral-analytic perspective. It is demonstrated that, although the spectral technique was applied to the stability analysis of a special class of systems, the present method is applicable to any form of distributed parameter system. (O.C.)
While the standard mode acceleration formulation in structural dynamics has often been interpreted to suggest that the reason for improved convergence obtainable is that the dynamic correction factor is divided by the...
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While the standard mode acceleration formulation in structural dynamics has often been interpreted to suggest that the reason for improved convergence obtainable is that the dynamic correction factor is divided by the modal frequencies-squared, an alternative formulation is presented which clearly indicates that the only difference between mode acceleration and mode displacement data recovery is the addition of a static correction term. Attention is given to the advantages in numerical implementation associated with this alternative, as well as to an illustrative example. (O.C.)
Three types of boundary controls are considered: proportional control, feed-forward control and integrated-by-past-values control. They stabilise the diffusion process exponentially at the desired reference on the con...
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Three types of boundary controls are considered: proportional control, feed-forward control and integrated-by-past-values control. They stabilise the diffusion process exponentially at the desired reference on the controlled boundary. The process is actuated through the Neumann boundary while on other boundaries it is given with the Dirichlet data and, in higher dimensions, also with the homogeneous Neumann boundary condition. Two systems, deterministic and stochastic, are compared as an ideal and real description of a physical system. Disturbance in the stochastic system is induced by a white noise on the controlled boundary. Physically, this noise represents different types of uncertainties like a side-reaction mass flux and other uncertainties that are not part of a deterministic model. At first the proportional control is analysed on the deterministic system and then it is represented in the feedback-integrated past controls form, and finally the developed controls are applied on the stochastic system, which boundary is disturbed with an unmeasured white noise. The regulation error that emerges in stochastic control is analysed and proved to be a zero-mean, bounded-variance Gaussian variable that is correlated temporarily. As an example of such a system, any electrochemical reduction or oxidation process where diffusion mass transfer is important can be considered.
This paper is concerned with the dynamics and control of systems with time-varying configuration, such as maneuvering articulated flexible spacecraft. The mathematical model consists of a rigid platform and a given nu...
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This paper is concerned with the dynamics and control of systems with time-varying configuration, such as maneuvering articulated flexible spacecraft. The mathematical model consists of a rigid platform and a given number of retargeting flexible antennas. The mission consists of maneuvering the antennas so as to coincide with preselected lines of sight while stabilizing the platform in an inertial space and suppressing the elastic vibration of the antennas. A perturbation technique permits the derivation of a new control law for systems with time-varying configuration, in which the time-varying terms are relatively small. According to the proposed perturbation method, the control gains consist of zero-order time-invariant gains obtained from the solution of a matrix algebraic Riccati equation, which are valid both during and after the maneuver, and higher-order time-varying gains obtained from the solution of matrix differential Lyapunov equations, which are valid only during the maneuver. The approach is illustrated by means of a numerical example.
This paper addresses the problem of exponential stability and stabilization for a class of delayed distributed parameter systems, which is modeled by partial integro-differential equations (PIDEs). By employing the ve...
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This paper addresses the problem of exponential stability and stabilization for a class of delayed distributed parameter systems, which is modeled by partial integro-differential equations (PIDEs). By employing the vector-valued Wirtinger's inequality, the sufficient condition of exponential stability of the PIDE system with a given decay rate is investigated. The condition is presented by linear matrix inequality (LMIs). After that, we develop a spatial proportional-integral-derivative state-feedback controller that ensures the exponential stabilization of the PIDE system in terms of LMIs. Finally, numerical examples are presented to verify the effectiveness of the proposed theoretical results.
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