### INFORMATION TECHNOLOGIES AND SYSTEMS, COMPUTER TECHNIQUE

ISOMORPHIC SYSTEM MODULES FOR CONSTRUCTION OF SCALABLE EMBEDDED COMPUTERS
Vladimir P. Dashevsky, Viktor Yu. Budkov

871

System modules are considered as the main parts of specialized computing systems. An approach to development of scalable embedded computers based on self-similar system modules stacked on top of each other without extra cables, is presented. The existing system module specifications are optimized for using a single module per one embedded computer that makes it difficult to increase system performance by using multiple modules without significant reconstruction of the carrier board. The proposed alternative approach uses isomorphic (self-similar) modules that can be mated using planar board-to-board hermaphrodite connectors. If assembled in a stack, these modules form a compact computing cluster. New approach also introduces a dynamic system connector pin allocation based on routing system signals through a FPGA. The dynamic allocation improves the efficiency of system connector pins utilization, and allows to get a wider range of hardware interfaces implemented using fewer pins of system connector while maintaining the modules compatibility with various application systems. This is achieved by flexible software controllable FPGA configuration depending on the module neighbors. Special system microcontrollers inspect overall system compatibility by using data stored in electronic passport of each module, so that the computing system can be automatically inspected for conflicts and correctly configured before powering up the main processors.

### INSTRUMENTS AND SYSTEMS OF AUTOMATIC CONTROL

ESTIMATING MULTICHANNEL SYSTEM RELIABILITY ON THE EXAMPLE
OF A SMALL SPACECRAFT ONBOARD CONTROL COMPLEX
Aleksey V. Averianov, Vadim V. Kuznetsov, Aleksey V. Kaliujnii

880

The reliability of the multi-channel information and control system functioning is evaluated. As an example of such a system implementation, an onboard control system of a small spacecraft is chosen. The probability of failure-free operation, the failure rate, and the average time to failure are used as quantitative reliability indicators. Various redundancy schemes for separate blocks and modules of the onboard control system are analyzed. The inexpediency of excessive hardware redundancy of multichannel systems used on board the small spacecraft is substantiated. Suggestions and recommendations are formulated that can be used at the design stage of a complex multichannel information and control system when choosing a rational structure for hardware, determining reasonable limits for redundancy of hardware and software.

DIGITAL TRACKING SYSTEM WITH A FINITE TIME OF FREE PROCESS COMPLETE DECAY
AND A GIVEN ORDER OF ASTATISM
Artyom М. Konovalov, Anatoly I. Korshunov

888

A method is proposed for choosing a sequential discrete correcting device of a digital tracking system, which provides both the finite time of free process complete decay and the astatism order 2 or 3. The desired transfer function of the digital tracking system is selected taking into account the requirements of the system roughness and of the order of astatism. At the same time, to simplify the discrete correcting device and exclude "hidden" oscillations at the output of the continuous part of the system between quantization moments, the polynomial numerator of the desired transfer function should be multiplied by the polynomial numerator of the discrete transfer function of the continuous part, even if it does not have zeros greater than or equal to 1 in absolute value. It is proposed to choose the coefficients of the numerator of the desired transfer function of the CSR according to the minimum of the sum of their squares while simultaneously fulfilling the conditions determined by the given astatism order.

STUDY OF CURRENT REGULATION PROCESSES
IN ELECTRIC DRIVES WITH SHUNT SENSORS
AND DELTA-SIGMA SIGNAL MODULATION
Alecksey S. Anuchin , Galina L. Demidova, Evgeny O. Stolyarov, Alexander A. Zharkov, Dimid K. Surnin, Fernando Briz

897

A method is proposed for measuring electric current using shunt and delta-sigma modulation. The research is conducted with a mathematical model of the motor: the open-loop control system was used to determine the measurement accuracy, while the closed-loop system was employed to investigate the effect of measurement error on the system stability and the motor torque pulsation. It is shown that oversampling coefficients of digital filters equal to 8 and lower lead to large disturbances in the current loop due to a high measurement error, even when using the Sinc3 filter. Acceptable results are achieved using the oversampling factor of 16 or higher with the Sinc3 filter type.

### GYROSCOPIC AND NAVIGATION SYSTEMS

ESTIMATION OF PERTURBING ACCELERATIONS AFFECTING
THE SPACE GRAVITATIONAL WAVE ANTENNA SOIGA-2
Ekaterina A. Karaush, Davlatov Ruslan A., Sergey S. Donchenko, Yury V. Gostev, Denis A. Sokolov, Evgeny A. Lavrov, Pavel G. Kharlamov

907

Russian gravitational wave antenna SOIGA-2 is a cluster including four spacecrafts in each of GLONASS orbits located at the vertices of a square. An analysis of disturbing forces applied to the spacecraft SOIGA-2 is performed. An estimate of values of the gravitational and non-gravitational disturbing accelerations is presented. The allowable level of disturbing accelerations for detection of gravitational waves are listed. A method for compensation of non-gravitational forces using a drag-free satellite system is proposed as well as preliminary calculation of the forces of gravitational nature and their subsequent subtraction.

INFLUENCE OF EXTERNAL FACTORS ON TRANSIENT PROCESSES
OF MAGNETIC COMPASS AT HIGH LATITUDES
Gryazin Dmitry G., Igor V. Sergachev

921

A mathematical model describing operation of the card of a ship's magnetic compass, is developed. The influence of external factors on the model coefficients is demonstrated. Results of experimental studies of the influence of low temperatures and small value of the horizontal component of Earth's magnetic field on transient characteristics and a dead zone of the card carried out with three samples of the magnetic compass are presented. Based on the analysis of obtained results, it is concluded that a decrease in the horizontal component of the Earth's magnetic field vector significantly affects the transition characteristics of the magnetic compass, while a decrease in temperature leads to an increase in the transition process duration.

### OPTICAL AND OPTO-ELECTRONIC INSTRUMENTS AND SYSTEMS

USING AN OPTICAL FIBER MACRO BEND AS THE BASIS FOR CREATING A MASS SENSOR
Herman V. Vasileuski, Andrej O. Zenevich, Siarhei V. Zhdanovich, Tatiana M. Lukashik, Nastassia A. Lahutsik

930

A fiber-optic sensor is developed which, in contrast to widely used detectors, allows to detect not only the fact of crossing the protected area border intrusion into, but also a characteristic of the intruder, namely its mass. The optical fiber selected for the presented sensor, G 655, demonstrate the highest susceptibility to macro bending. It shown that an increase in the length of the macro bending arc at a constant radius, R, leads to an increase in the attenuation of optical radiation passing through the fiber. This dependence is close to linear in the range of macro bend arc lengths from zero to πR.

AIRBORNE COLLIMATOR DISPLAY WITH LIQUID CRYSTAL IMAGING DEVICE
AND LASER BACKLIGHT SYSTEM
Anton A. Kishalov, Vladimir M. Zhurba, Yury D. Pimenov, Dmitry A. Tretyakov, Lev Yu. Harberger

938

Optical design of a new airborne head-up display with liquid crystal imager and laser backlight is presented. The laser backlight system for LCD matrix is based on green laser diodes and micro-lens arrays. A head-up display with 26×17° field of view and aberration correction is developed. A prototype of the head-up display with image brightness of up to 1.6‧104 cd/m2 is manufactured. The prototype description is presented, its optical properties are listed.

### TECHNOLOGY OF INSTRUMENT MANUFACTURING

MAIN WAYS FOR INCREASING THE FLEXIBILITY
OF AUTOMATIC AND ROBOTIC ASSEMBLY LINES
Medunetskiy Viktor M. , Nikolaev Vyacheslav V.

946

Several issues of increasing the flexibility of technological automated and robotic assembly lines of small-sized products are considered. The features of robotic assembly lines are considered, methods of their organization and modification of mechanical components of technological equipment are proposed.

### SCIENTIFIC AND PRACTICAL DEVELOPMENTS

AN INSTRUMENT FOR FRICTION PARAMETERS REGISTRATION
Alexey O. Pozdnyakov, Maksim I. Chernyshov, Semencha Alexander V. , Nikolaev Vladimir I, Ilya A. Kobykhno, Yury A. Fadin

950

The paper presents the model of friction machine and its approbation in the friction geometry of thrust cylinder rotating on its axis against the flat counterbody. The paper also presents the principles of the registration of the friction torque by using strain gauge and calculation of friction coefficient in the fric-tion geometry used in the machine. The operability and accuracy of friction coefficient measurements by using the instrument is illustrated by the friction experiments with the symmetric and asymmetric friction pairs of organic and inorganic materials (polymers, crystals, metals).