N.U. Ahmed

Dynamic Systems and Control with Applications

Basic Mathematical Background Linear Systems Nonlinear Systems Basic Stability Theory Observability and Identification Controllability and Stabilizability Basic Calculus of Variations Optimal Control: Necessary Conditions and Existence Linear Quadratic Regulator Theory Time Optimal Control Stochastic Systems with Applications.

Existence of Optimal Controls for a General Class of Impulsive Systems on Banach Spaces

This paper presents some results on the question of existence of optimal controls for a large class of semilinear impulsive systems in infinite dimensional spaces with admissible controls from the space of vector measures. This also includes, as a special case, the class of purely impulsive controls. Two physical examples are presented for illustration.

Feedback control of chaotic systems

A suboptimal feedback controller implemented by a multilayer feed-forward neural network is presented to control the unpredictable behavior of chaotic systems. The controller has been tested on the Lorenz and the Rössler systems using numerical simulation. Results show that chaotic systems, subject to feedback control, can be tamed to behave like a system having point attractors with associated basins of attraction.

Nonlinear impulsive systems on infinite dimensional spaces

Abstract In this paper we consider two different classes of nonlinear impulsive systems one driven purely by Dirac measures at a fixed set of points and the second driven by signed measures. The later class is easily extended to systems driven by general vector measures. The principal nonlinear operator is monotone hemicontinuous and coercive with respect to certain triple of Banach spaces called Gelfand triple. The other nonlinear operators are more regular, non-monotone continuous operators with respect to suitable Banach spaces. We present here a new result on compact embedding of the space of vector-valued functions of bounded variation and then use this result to prove two new results on existence and regularity properties of solutions for impulsive systems described above. The new embedding result covers the well-known embedding result due to Aubin.

Nonlinear stochastic differential inclusions on balance space

In this paper we present some new results on the existence and regularity of mild solutions of a class of nonlinear stochastic differential inclusions on Hilbert space. The drift is multivalued and the diffusion is single valued but both nonlinear admitting differential operators unlike in [3]. The drift term contains a generator of a C 0 analytic semigroup in addition to the multivalued drift

Nonlinear Optimal Feedback Regulation of Satellite Angular Monenta

Some important regulation properties of satellite angular momentum dynamics are investigated using a combination of reaction jets and flywheels. The optimal feedback controller is designed in such a way that system regulation, under large perturbations, to a proper bounded subset in Rn, is achieved by using reaction jets. Thereafter, flywheels are activated to bring the system to the rest (desired) state. The domain and the size over which reaction jets are active, as well as the corresponding fuel cost, are discussed. Further, the effect of linear as well as nonlinear optimal feedback regulators on system behavior is indicated. Finally, the range (in the state space Rn) over which the flywheels are capable of regulating the system is also studied.

Linear and Nonlinear Filtering for Scientists and Engineers

Introduction to stochastic processes stochastic differential equations Kalman filtering for linear systems driven by Weiner process I Kalman filtering for linear systems driven by Weiner process II discrete Kalman filtering linear filtering with correlated noise I linear filtering with correlated noise II linear filtering with correlated noise III linear filtering of jump processes linear filtering with constraints filtering for linear systems driven by second order random processes extended Kalman filtering I,II, and III nonlinear filtering numerical techniques for nonlinear filtering partially observed control system identification.

Systems governed by impulsive differential inclusions on Hilbert spaces

A double lift dobby for dobby looms, jacquard looms and the like comprising a first and second double arm crank, each of which is rotatably journaled about independent axes spaced from and parallel to each other. One arm of each of the cranks is provided with latch means for selectively engaging a corresponding one of a driven pair of lifting knives. The cranks are thereby rotatable about their axes by and conjointly with the lifting knife after such engagement. The other arms of each of the cranks is interconnected with the means for raising and lowering the heald frame which comprises a lever connected at one end to the first of the cranks and at the other end to the means for lowering the heald frame and a tie rod connected at one end of the second of the cranks and at its other end between the ends of the lever.

Stochastic Control on Hilbert Space for Linear Evolution Equations with Random Operator-Valued Coefficients

We consider a problem of optimal control of the stochastic evolution equation

Modified extended Kalman filtering

d\xi = (A(t)\xi + B(t)u)dt + \sigma (t)dw