### INFORMATION TECHNOLOGIES AND SYSTEMS

FAST ESTIMATION OF CHAOTIC SIGNAL GENERATOR PARAMETERS
Bobtsov Alexey Alexeevich, Borisov Oleg I., Gromov Vladislav S., Pyrkin Anton Alexandrovich

487

The problem of parameter estimation for Duffing-like chaotic signal is addressed. A new method with performance enhancement is proposed. Fast estimation of parameters is achieved with introduction of additional filtered linear regression models for each parameter of the signal. Results of simulation are presented, comparison with the gradient method is carried out. Various applications of the proposed method, such as double well and pendulum system, electrical circuits with specific parameters, and chaotic types transmitting systems are considered. The short time of parameters estimation allows for using the proposed method for estimating switching parameters in chaotic Duffing-like systems.

ROBUST SUBOPTIMAL CONTROL OVER MULTICHANNEL OBJECTS UNDER SATURATION CONDITIONS
Sergey A. Vrazhevsky, Chugina Julia V., Furtat Igor Borisivich

495

A robust suboptimal stabilization algorithm for multiple-input-multiple-output (MIMO) systems with input signal restrictions of amplitude saturation type is considered. The proposed approach uses auxiliary loop method for disturbances compensation together with the optimal control provided by a linear quadratic regulator. The object under control is described by a linear interval model in which the effect of unmeasured bounded external disturbances is taken into account. Interval linearization allows to use the proposed approach in practical testing with Twin Rotor MIMO System laboratory setup. Comparison of obtained results with performance at conventional control approaches demonstrate the lack of overshoot and increase the accuracy of stabilization in the steady state with the proposed algorithm.

RECONSTRUCTION OF FINITE-LENGTH PERIODIC DISCRETE-TIME SIGNALS WITH THE USE OF TRIGONOMETRIC INTERPOLATION
Porshnev Sergey V., Kusaykin Dmitry V.

504

Results of a research on the accuracy of finite-length discrete-time signal (DS) reconstruction by means of trigonometric interpolation are presented. The case when a non-integer number of discrete counts is placed in one period of the signal is considered. Formal increase in the number of counts of discrete signal is found not to provide always a reduction in interpolation error. The relations between the frequency of the periodic signal, the sampling frequency and the number of counts of DS, providing the least error recovery of the signal, are derived. It is demonstrated that the increase in the number of DS counts used for reconstruction the original signal, may decrease reconstruction accuracy of the continuous signal; the effect is explained by the Gibbs phenomenon when the repair interval of the periodic signal fits a non-integer number of its periods.

### COMPUTER TECHNIQUE

FPGA LOGIC ELEMENT FOR IMPLEMENTATION OF DISJUNCTIVE NORMAL FORM
Grekov Artem V., Tyurin Sergey F.

513

Logical element of programmable logic integrated circuits of FPGA (field-programmable gate array) type is called in foreign sources LUT (Look Up Table), i.e. it is essentially a truth table of a logic function. This implementation is based on the perfect disjunctive normal forms (PDNF) representation of the logic functions that require significant hardware costs, as opposed to the implementation in the disjunctive normal form (DNF), used with the 70-ies of XX century in the programmable logic array (PLA). At the same time, much of the logic functions implemented by a number k of conjunctions is much smaller than
the total number of sets of n binary variables. However, for programming the PLA requires special programmers, whereas the configuration LUT is loaded into random access memory (RAM or SRAM). A DNF-LUT is proposed to implement a system of logical functions in DNF which significantly reduces the hardware cost of implementing the logic of programmable logic integrated circuits with no deterioration of the performance. Complexity of the proposed technical solutions and the results of functional simulation are analyzed.

519

A model of complex-periodic lattice function, which is convenient to analyze the process of formation of two-level fluctuations at the output of a system of passive digital frequency synthesis is considered. The mechanism of noise generation in the spectrum of the output oscillations and the ways of their reduction with the help of devices for pulse signal delay control are analyzed. Several variants of implementation of such devices on the basis of intermediate transformations of the current delay code into time interval are proposed.

### GYROSCOPIC AND NAVIGATION SYSTEMS

THE USE OF MOBILE LONG-BASE RADIO INTERFEROMETERS TO IMPROVE STABILITY OF NAVIGATION AND TIME MEASUREMENTS
Andrey P. Aleoshkin , Makarov Andrey A., Ivanov Dmitry V., Ipatov Alexander V.

529

A perspective approach to the problem of improvement of coordinate-time and navigation support by direct measurement of coordinates and departure of the clock for an arbitrary consumer throughout the territory of Russia and abroad is considered. Application of coordinate-time reference systems using mobile VLBI stations with known precise coordinates is proposed.

### HEAT REGIMES AND RELIABILITY OF INSTRUMENTS AND SYSTEMS

RETRIEVAL OF NON-STATIONARY HEAT FLOW BASED ON SOLUTION OF INVERSE PROBLEMS OF HEAT CONDUCTION
Pilipenko Nikolay V.

538

The problem of non-stationary heat flux retrieval in shock and pulse aero- and hydrodynamic tubes is addressed. Peculiarities of the method of parameter identification for difference-differential models of heat transfer in a system containing heat flux inverter and the object of study is considered. Results obtained with the use of the described method are reported to agree well with results of other authors. Recommendations on improvement of the inverter parameters and decrease in the flux measurement uncertainty are formulated. Matrix of feedback, control and measurement obtained using the method allow to determine the dynamic characteristics of the inverter such as transient, pulsed, amplitude- and phasefrequency characteristics, and transfer function.

TEMPERATURE FLUCTUATIONS OF ISOTHERMAL CYLINDRICAL OBJECTS WITH STABILIZED AXIS IN CIRCULAR SOLAR-SYNCHRONIZED ORBIT
Dzitoev Azamat M., Lapovok Yevgeniy V., Pen’kov Maxim M., Hankov Sergei I.

545

A technique is proposed for calculations of non-stationary temperature of an isothermal space object of a cylindrical form with the axis stabilized in world system of coordinates, moving on a circular solarsynchronized orbit in the terminator plane. The class of objects under consideration includes a tubulardesign telescope body with axis fixed in the direction to a remote object, e. g. a star. Temperature fluctuations for objects of the class are subject to periodic changes of effective irradiance coefficient reproduced in each cycle of the object revolution around the Earth. For a great value of fixed thermal inertia realized in the case of thick enough wall of the cylinder, the fluctuations may occur with a temporary delay relative to external thermal impacts determined by fluctuations of irradiance coefficient. Average values of the effective irradiation coefficient decrease significantly as the orbit height increases: from a few tenths for an orbit height of 600 km to hundredths at the orbit height of 10000 km, and to several thousandths for a geostationary orbit. At the same time, the fluctuations of the effective irradiance coefficients are diminished, and contribution caused by the power of absorbed solar radiation to the energy balance of the space object increases. When the height changes from 600 to 40 000 km, the temperature level of the object with a completely black surface is lowered by 35 K, while the oscillation amplitude decreases from 5.6 to 0.4 K.

### SCIENTIFIC AND PRACTICAL DEVELOPMENTS

SYNTHESIS OF A SYSTEM FOR AUTOMATIC CORRECTION OF AXIAL DISPLACEMENT OF MECHATRONIC MODULE SPINNING ROTOR
Dymov Ilya S., Kotin Denis A., Anosov Vladimir N., Kucher Ekaterina S.

552

The problem of centering spatial position of a rotor in mechatronic module used in high-precision processing equipment. The known methods of eliminating the unbalance of the rotating parts of electromechanical and mechatronic devices are analyzed. The main disadvantage of the methods is found to be the principle impossibility of achieving high accuracy in eliminating radial displacement of the rotor. A new approach to the problem of stabilization of a rotating part of the mechatronic module is proposed; the method is based on an active current correction of spatial position of the rotor. Design of the electromechanical part of the device is improved by introducing into it correcting electromagnetic coils and a magnetic system to control over the spatial correction of the rotor. A functional diagram of the proposed method and results of simulations are presented. Methods of synthesis of control loops for variables of the active correction system are discussed. The conclusion is made about technical prospects of the proposed method and on the general direction of the further research.

THE USE OF ADAPTIVE PLATFORM FOR TECHNOLOGICAL EQUIPMENT IN MACHINE-TO-MACHINE INTERACTION CONDITIONS
Gribovsky Andrey A., Ivashkova Ksenia P., Demkovich Nataliia A.

560

The main provisions of the concept of adaptive platform for technological equipment ADAPTEQ are cited. The list of problems that need to be addressed to implement ADAPTEQ, are formulated. The logic is described and the main aspects of web-oriented system management platform are presented. Peculiarities of application of the hardware interface to enable machine-to-machine interaction are discussed. The logic of joint work of various production units in the frames of Smart-M3 approach is demonstrated.

HARDWARE-SOFTWARE COMPLEX FOR RODS CONTROL BY MIRROR-SHADOW METHOD USING MULTIPLE REFLECTIONS
Strizhak Viktor A., Pryakhin Andrey V., Khasanov Robert R., Efremov Andrey B.

565

A hardware-software complex for rods control is developed. The complex performance is investigated in various hardware configurations that implements the mirror-shadow method of non-destructive control with the use of multiple reflections on the passing electromagnetic-acoustic transducer. The scanning speed is measured at various parameters of the object under control. The influence of component characteristics on the performance of the complex is estimated. The possibility of a compromise between the maximum possible scanning speed of the rod, the length of the acoustic path, and the size of the recorded echograms is demonstrated based on the balance between the computer performance and registration system capacity. The developed system may be used for solving several problems of structural analysis, thickness gauging, and flaw detection by EMA method.

DEVICE FOR STUDIES ON ACOUSTIC-ELASTIC CHARACTERISTICS OF THIN WIRES
Muraviev Vitaly V., Zlobin Denis V., Platunov Andrey V.

572

Results of development of an instrument and non-contact electromagnetic acoustic transducers providing high-accurate measurement of speed and amplitudes of core waves in thin wires are presented. The advantages of the model is reported to be the possibility of quick adjustment of gain, center frequency, amplitude-frequency characteristic, and the quality factor in a wide range that is necessary in the study of signals using pilot converters.

FAST-ACTING ANTI-SURGE SYSTEM OF GAS TURBINE ENGINE
Kudashov Dmitry D., Tоkarev Vladimir P.

578

The factors affecting the occurrence of unstable modes of operation of a gas turbine engine (GTE) associated with the rate of change of the flow surge are examined. The problem of surge diagnostic system performance is considered. Several options are proposed to improve the performance of systems, diagnosing the GTE surge. Modeling of anti-surge system operation is performed with the use of simulation of majoritarian diagnostics of pre-damping state and surge. Results of the simulation study demonstrate that the use of the first derivative of operating parameters reduces the time of diagnosis for 40-120 ms, depending on operation mode and is beneficial to the whole system performance.

### BRIEF NOTES

EXPERT SYSTEM FOR MODELLING DEGRADATION AND FAILURE OF COMPLEX TECHNICAL OBJECTS
Konyakhin Igor A., Ziniakov Vladimir

582

Results of experimental testing of an expert system for modelling of degradation and failure of complex scientific and industrial systems are presented. The expert system under testing is based on a model, which uses logical linguistic approach. The effectiveness of the expert system, which issues recommendations for vitality control of the exploited complex system, is demonstrated.