On the control of chaotic systems in Lur'e form by using dither

Cataloged from PDF version of article.In this paper we propose the application of dither for controlling chaotic systems in the Lur’e form. Dither is a high-frequency periodic signal and has the effect of modifying the nonlinearity for some nonlinear systems. We use piecewise constant dither signals and propose three different methods for the selection of dither parameters. We also present some experimental results

Stabilization and Disturbance Rejection for the Beam Equation

Cataloged from PDF version of article.We consider a system described by the Euler–Bernoulli beam equation. For stabilization, we propose a dynamic boundary controller applied at the free end of the system. The transfer function of the controller is a marginally stable positive real function which may contain poles on the imaginary axis. We then give various asymptotical and exponential stability results. We also consider the disturbance rejection problem

A dynamic control law for the wave equation

Cataloged from PDF version of article.We consider a system described by the onedimensional linear wave equation in a bounded domain with appropriate boundary conditions. To stabilize the system, we propose a dynamic boundary controller applied at the free end of the system. The transfer function of the proposed controller is restricted to be a positive real function which could be strictly proper. We then show that, if the transfer function of the controller is strictly proper, then the resulting closed-loop system is asymptotically stable, and if proper but not strictly proper, then the resulting dosed-loop system is exponentially stable

On the Stabilization and Stability Robustness Against Small Delays of Some Damped wave equations

Cataloged from PDF version of article.In this note we consider a system which can be modeled by two different one-dimensional damped wave equations in a bounded domain, both parameterized by a nonnegative damping constant. We assume that the system is fixed at one end and is controlled by a boundary controller at the other end. We consider two problems, namely the stabilization and the stability robustness of the closed-loop system against arbitrary small time delays in the feedback loop. We propose a class of dynamic boundary controllers and show that these controllem solve the stabilization problem when the damping cuefMent is nonnegative and stability robustness problem when the damping coefficient is strictly positive

Further Stability Results for a Generalization of Delayed Feedback Control

Cataloged from PDF version of article.In this paper, we consider the stabilization of unstable periodic orbits for one-dimensional and discrete time chaotic systems. Various control schemes for this problem are available and we consider a recent generalization of delayed control scheme. We prove that if a certain condition, which depends only on the period number, is satisfied then the stabilization is always possible. We will also present some simulation results. © Springer Science+Business Media B.V. 2012

An unstable plant with no poles

Cataloged from PDF version of article.In the above paper, it was shown by way of an example that there exist bounded-input–bounded-output (BIBO) unstable linear systems whose transfer functions are analytic in the finite plane. We note that this result could easily be shown by using some examples already present in the literature

Control and Stabilization of Rotating flexible structure

Cataloged from PDF version of article.We consider a flexible beam clamped to a rigid base at one end and free at the other end. We assume that the rigid base rotates with a constant angular velocity and that the motion of the flexible beam takes place on a plane. To suppress the beam vibrations, we propose dynamic control laws for boundary control force and torque, both applied to the free end of the beam. We show that, under some conditions, one of which is the strict positive realness of the actuator transfer functions which generate the boundary control force and torque, the beam vibrations asymptotically decay to zero if the rigid base angular frequency is sufficiently small. Moreover, if the transfer functions are proper but not strictly proper, we show that the decay is exponential. We also give a bound on the constant angular velocity above which the system becomes unstable

An Exponential Stability Result for the Wave Equation

Cataloged from PDF version of article.We consider a system described by the one-dimensional linear wave equation in a bounded domain with appropriate boundary conditions. To stabilize this system, we propose a dynamic boundary controller applied at the free end of the system. The transfer function of the proposed controller is a proper rational function which consists of a strictly positive real function and some poles on the imaginary axis. We then show that under some conditions the closed-loop system is exponentially stable. ? 2002 Published by Elsevier Science Ltd

On the design of dynamic associative neural memories

Cataloged from PDF version of article.We consider the design problem for a class of discrete-time and continuous-time neural networks. We obtain a characterization of all connection weights that store a given set of vectors into the network; that is, each given vector becomes an equilibrium point of the network. We also give sufficient conditions that guarantee the asymptotic stability of these equilibrium points

Experimental Validation of a Feed-Forward Predictor for the Spring-Loaded Inverted Pendulum Template

Cataloged from PDF version of article.Widely accepted utility of simple spring-mass models for running behaviors as descriptive tools, as well as literal control targets, motivates accurate analytical approximations to their dynamics. Despite the availability of a number of such analytical predictors in the literature, their validation has mostly been done in simulation, and it is yet unclear how well they perform when applied to physical platforms. In this paper, we extend on one of the most recent approximations in the literature to ensure its accuracy and applicability to a physical monopedal platform. To this end, we present systematic experiments on a well-instrumented planar monopod robot, first to perform careful identification of system parameters and subsequently to assess predictor performance. Our results show that the approximate solutions to the spring-loaded inverted pendulum dynamics are capable of predicting physical robot position and velocity trajectories with average prediction errors of 2% and 7%, respectively. This predictive performance together with the simple analytic nature of the approximations shows their suitability as a basis for both state estimators and locomotion controllers. © 2004-2012 IEEE