Multicriteria Minimax Problems: Localization of the Pareto Set and Suboptimal Control Design

Automation and Remote Control - We consider multicriteria minimax optimization problems with criteria in the form of the maxima of functionals given by the induced norms of linear operators taking...     

Boronitriding of Die Steels in Fluidized Bed

Processes of progressive and simultaneous boronitriding of die steels in fluidized bed are considered in comparison with conventional diffusion boronizing. A comparative analysis of the microhardness and wear resistance of die steels after boronitriding and boronizing is performed.     

Synthesis of quasi-invariant controllers using pattern recognition methods

The study presents a new approach to the synthesis of multidimensional quasi-invariant control systems based on the formulation and solution of the synthesis problem as an pattern recognition problem. The capabilities and specific features of the new approach are illustrated by two mathematical models of control systems.     

A motion control for a spherical robot with pendulum drive

Problems of controlling a spherical robot with pendulum drive are considered. A mathematical model of the dynamics of this robot is constructed and control laws in the form of state feedback that provide robot motion along a given trajectory are synthesized. Results of computer simulation that demonstrate efficiency of the proposed control laws are presented.     

Design of generalized discrete-time H ∞-optimal control over finite and infinite intervals

For the discrete linear nonstationary plants, the state or output feedbacks were designed for which the generalized H _∞-norm of a closed-loop system characterizing the joint effect of initial state and external perturbation on the controlled output and terminal state takes on the minimal value.     

ZnO growth on Si with low-temperature CdO and ZnO buffer layers by molecular-beam epitaxy

Low-temperature (LT) buffer-layer techniques were employed to improve the crystalline quality of ZnO films grown by molecular-beam epitaxy (MBE). Photoluminescence (PL) spectra show that CdO, as a hetero-buffer layer with a rock-salt structure, does not improve the quality of ZnO film grown on top. However, by using ZnO as a homo-buffer layer, the crystalline quality can be greatly enhanced, as indicated by PL, atomic force microscopy (AFM), x-ray diffraction (XRD), and Raman scattering. Moreover, the buffer layer grown at 450°C is found to be the best template to further improve the quality of top ZnO film. The mechanisms behind this result are the strong interactions between point defects and threading dislocations in the ZnO buffer layer.     

Synthesis of Optimal Robust H ∞-Control by Convex Optimization Methods

It is shown that the synthesis of robust H -control with respect to the output for systems with unknown limited parameters reduces to the solution of an optimization problem under constraints prescribed by a system of linear matrix inequalities. For this kind of problems, an optimization algorithm implemented with the use of standard procedures of the MATLAB package is suggested.The algorithm effectiveness is illustrated by the example of an optimal dampening of vibrations of a parametrically perturbed pendulum.