Dobrila Škatarić

Optimal SIR-based power updates in wireless CDMA communication systems

In this paper we present two new control algorithms that potentially can be used as efficient techniques for power updates in wireless CDMA communication networks. The algorithms are obtained by optimizing the signal-to-interference error. The control laws are distributed, respectively linear and bilinear, and require either estimation of the channel interference (or a quantity inversely proportional to the signal interference) or the development of efficient numerical algorithms for solving the set of algebraic equations obtained. In addition, ideas of how to accelerate the convergence of a Nash game power control algorithm are presented.

Suboptimal design of hydroturbine governors

A state space method for the design of turbine governors in hydro power plants with Kaplan turbines is presented. The design is based on the suboptimal regulator problem solved by the use of projective controls. A design procedure that permits the design of multivariable static and low order dynamic hydroturbine governors is proposed. It provides an organized way of choosing the governor structure and the tuning of its parameters. A case study is presented to illustrate the proposed design method and to demonstrate the extensive applicability of the suboptimal solution and its merits as compared to conventional governors. >

Linear control of nearly singularly perturbed hydropower plants

Abstract In this paper we consider a special class of linear control systems represented by the standard singularly perturbed system matrix and with the control input matrix having three different nonstandard forms. Many real systems (such as hydropower plants, systems with only few actuators) possess the control structure studied in this paper. The obtained results are quite simplified (comparing to the standard singularly perturbed control systems), and in one case the optimal solution of the algebraic Riccati equation is completely determined in terms of the reduced-order algebraic Lyapunov equations. The proposed method is successfully applied to the reduced-order design of optimal controllers for the real hydropower plant of the Serbian power system.

Recursive approach to Nash games of quasi-singularly perturbed linear systems

We derive an algorithm for solving the linear-quadratic differential Nash game problem of singularly perturbed systems. It is known that the general steady state solution to the above problem is given in terms of the ill-conditioned coupled algebraic Riccati equations. We show that for a special class, so-called quasi-singularly perturbed systems, the positive definite stabilizing solutions of the coupled Nash algebraic Riccati equations can be obtained in terms of reduced-order well-conditioned algebraic equations corresponding to slow and fast variables.

Optimal linear and bilinear algorithms for power control in 3G wireless CDMA networks

In this paper we present two power control algorithms that potentially can be used as efficient techniques for power updates in 3G wireless CDMA communication networks. The algorithms are obtained by optimising the signal-to-interference-ratio (SIR) error. The control laws are distributed, respectively linear and bilinear, and either requires estimation of the channel interference (or the quantity inversely proportional to the signal interference, known as the channel variation) or the development of efficient numerical algorithms for solving a set of obtained algebraic equations. Simulation results show superiority of the proposed algorithm over the distributed constrained power control (DCPC) algorithm. Copyright

Subsystem Level Optimal Control and Filtering of Non-Classically Damped Matrix Second-Order Linear Mechanical Stochastic Systems

Matrix second-order damped linear dynamic systems are frequently encountered in mechanical, structural, civil, aerospace engineering, and related fields. In this paper, we show how to optimally control matrix second-order systems using locally optimal Kalman filters corresponding to scalar second-order subsystems and how to find the corresponding filter and linear-quadratic (LQ) controller optimal gains at the subsystem level. The globally optimal linear-quadratic controller and the globally optimal Kalman filter and obtained in terms of locally optimal LQ controllers and locally optimal scalar second-order parallel Kalman filters. Conditions are established under which the presented procedure is applicable. Examples are included to demonstrate the efficiency of the proposed technique.Copyright