Home – Home – Jornals – Avtometriya 2012 number 5

The piecewise continuous (relay) nature of lumped control actions in problems of timeand energy-optimal control of a wide range of distributed-parameter nonlinear objects of engineering thermophysics is established. On this basis, the required programmed controls in a number of practical situations can be found by the proposed algorithmically precise (alternance) method. As an example, which is of independent interest, the problem of optimal control of nonlinear models of induction heating of metal semi-products before subsequent pressure treatment is considered.

The synthesis of automatic extremum seeking systems for a one-channel object whose model can be represented as a series connection of a nonlinear dynamic component and a static quality function with a distinct minimum or maximum is considered. The possibility of extremum seeking by the localization method involving the use of the highest derivative of the output variable of the dynamic part of the object in the feedback is discussed. Depending on the version of implementation of such feedbacks, two main types of extremal systems are distinguished: one-loop systems, in which data on the static characteristic gradient is sent to the controller, and two-loop systems. In the latter systems, it is suggested to use controllers based on the localization method for preliminary stabilization of processes in the internal loop containing the dynamic part. In the external loop, an integral control law is used and motion to the extremum with specified dynamic quality is implemented taking into account the data on the gradient. Modeling shows the features of the extremal systems under consideration.

A method for calculating the parameters of controllers for nonlinear nonstationary dynamic systems is proposed. The structure of the controller is a generalization of the structure of proportional-integral and proportional-integral-differential controllers. The method is applicable to unstable nonlinear systems with incomplete information on the plant model. The method is based on the deliberate formation of different-rate processes in a control system in which the stability of fast processes is provided by choosing the controller parameters, and the slow processes formed correspond to the reference model of the desired behavior of a nonlinear system. An example of the results of numerical simulation is given

The problem of control of an autonomous unmanned aerial vehicle with vertical takeoff and landing, which moves over a trajectory specified in the coordinate space, is considered. A method of constructing a system of automatic control of quadrotor vehicle takeoff and flight is proposed. Analytical relations for control actions on four engines that ensure vehicle motion over a prescribed trajectory with desired values of altitude and velocity are derived.

It is shown that the problem of synthesis of control systems (with a reference model) for a multivariable dynamic object can be solved exactly using the embedding technique. The synthesis algorithm presented provides stability and physical implementation of the solution obtained.

This paper presents synthesis procedures of discrete single-channel control systems with specified performance parameters of transient processes for an uncertain plant model. An integral law of adjusting the controller parameters with respect to the mismatch between the current and desired values of the output variable on the highest step is considered. Results of an analysis of a closed-loop system performed using a discrete analog of the Lyapunov second method are given.

Control adjustment of the air-gas path of a thermal power boiler using the localization principle is considered. A mathematical model of the object, its constituent equations, conditions of their derivation, and the transition to state equations are described. The synthesis problem is formulated and controllers are calculated for each channel of the system. A block diagram of the automatic control system is designed and is used to model the transient processes to make conclusions on the system. A program for automatic calculation of the coefficients of differential equations is presented.

Discrete multichannel systems whose separate channels are characterized by discrete intervals of varying duration satisfying the multiplicity condition are considered for possible degeneration. The main result is based on the concept of reducibility of these channels to a model representation in the form of a discrete description with discrete intervals equal to half the minimum. A possibility of degeneration of discrete multichannel systems in the event of incorrect correspondence of the intensities of input fluxes to the original discrete intervals is studied. The problem is solved quantitatively by using degeneration functionals designed on the spectrum of singular values of criterial matrices

A method is proposed for optimal tuning of the adjustable parameters of the correction device of a measuring system with partially known characteristics of the useful signal and noise described by spectral densities and using the measured state coordinate vector.

A new approach is proposed to construct a multichannel filter for detecting small-size targets in images recorded by a matrix photodetector. For estimating the pulse response of each channel of the filter, the set of experimentally obtained images of targets having different locations with respect to photodetector cells is divided into several subsets, which are used as reference elements in calculating the pulse response of the filter. Experimental data are presented, which demonstrate appreciable reduction of the probability of missing the targets in images subjected to processing with a filter constructed by the proposed method.

A closed analytical relation required to describe the reliability of readout of a random discrete-point field by integrators with two threshold levels is rigorously proved. The corresponding probabilistic problem is solved with the use of two nonstandard tricks: first, codes are developed for performing analytical computations on a computer; second, a new notion of "three-dimensional generalized Catalan numbers" is introduced and successfully applied.

A comparative study of the informativeness of statistical and structural features in anthropogenic zone detection in high-resolution satellite images by using decision rules formed on the basis of the Bayes and Neumann-Pearson criteria is performed. It is found that the greatest efficiency of man-made object detection on the natural background is reached by anomaly detection in the local structure of images with the use of the Harris response function.

Abstract-The problem of object classification in seismic guard systems on the basis of statistical analysis of spectral moments used as features for classification is considered. An adaptive algorithm is developed, and its efficiency is experimentally determined.

An approach is proposed to increase the efficiency of nonparametric two-sample tests of scale by using a preliminarily grouping of initial observations by the level. The groups are formed using order statistics.