### INSTRUMENTS AND SYSTEMS OF AUTOMATIC CONTROL

APPLICATION OF THE METHOD OF VIRTUAL MEASUREMENTS OF STARS ZENITH DISTANCES
IN SOLVING THE ORIENTATION PROBLEM
Kuznetsov Vladislav I., Калашников С. Д.

245

Application of the method of virtual measurements of stars zenith distances of in spacecraft orientation system are considered, results of modeling the orientation system operation with various algorithms for solving navigation problems are presented. The problem of orientation is solved based on determining the orbit of the spacecraft using two charge-coupled optical-electronic devices (OEDs) installed in gimbal suspensions to be pointed at specially selected bright stars in the sky. The spacecraft orbit determined according to the information from the OEDs is used by the algorithm for solving the orientation problem. Information from the third (possibly the fourth) OED rigidly connected to the spacecraft body is applied to determine parameters of the spacecraft body orientation in space using special mechanisms and algorithms of the least squares method for data averaged over a measuring interval.

FAULT IDENTIFICATION BASED ON SLIDING MODE OBSERVERS
WITH RELAXED EXISTENCE CONDITIONS
Alexey N. Zhirabok, Alexander V. Zuev, Vladimir V. Filaretov, Alexey E. Shumsky

255

The problem of fault identification in technical systems described by linear differential equations under disturbances is considered. To solve the problem, sliding mode observers are used. The proposed approach is based on a reduced-order model of the original system selectively sensitive to faults and disturbances. Instead of the original system, the sliding mode observer is constructed based on the reduced-order model. The main purpose of introducing such a model is to weaken the conditions for the existence of sliding observers in comparison with the known works; another purpose is to decrease in the dimension of the constructed sliding observers. The conditions relaxation is achieved since the reduced-order model may not have the properties of the original system, which prevent the possibility of constructing a sliding observer for it. The stated theoretical considerations are illustrated by an example.

### ELECTRONIC AND ELECTROMAGNETIC DEVICES

DETERMINING THE OPTIMAL NUMBER OF CONTACT PAIRS FOR A SLIP RING DESIGN
Petr Simonov, Abramchuk Mikhail V., Islam A. Bzhikhatlov

264

Several features of constructing concentric conductive rings using rolling elements, which are planned to be used as structures like rolling bearings, are described. Such a design is reported to have advantages over sliding elements, including a large service life, high rotation speed, and low drag moment. The reasons for the occurrence of electrical noise in working slip rings are considered in detail using the example of electrical circuits containing resistors connected in parallel. Using the example of the investigated electrical circuit, to which a pair of contacts is added, the dependence of the resistance value in the slip rings on the number of contacts connected to them is determined.

IMPROVING THE EFFICIENCY OF THE FUNCTIONING
OF ELECTRIC MOTORS OF MECHATRONIC SYSTEMS IN A WIDE RANGE
OF ROTATIONAL FREQUENCIES
Silaev Alexey A., Marusina Maria Ya., Evgeniya Yu. Zakemovskaya

270

Brushless direct current motors (BDCM) used in various robotic and mechatronic systems are considered. A method for analysis and optimization of the motors synthesis is proposed. Results of magnetic field modeling in the electric motor in question performed with the use of the FEMM finite element analysis program are presented. Maintaining a high efficiency of the electric motor in an extended range of rotation speeds is ensured by turning the rotor magnets and introducing an angle of advance for the current supply to the stator windings.

### OPTICAL AND OPTO-ELECTRONIC INSTRUMENTS AND SYSTEMS

DYNAMIC MODEL OF AN OPTOELECTRONIC SYSTEM
FOR MEASURING THE PARAMETERS OF A VIBRATION SUPPORT IN A LASER GYROSCOPE
Alexey A. Aviev , Vitaliy N. Enin

276

An optoelectronic system that measures relative vibration parameters of a laser gyro sensing element in the dither mode is studied. The system enables to compensate the component of the gyro output signal caused by the oscillations. The measuring system under consideration consists of a flat miniature pattern plate mounted on the sensing element monoblock, an optoelectronic module mounted on the laser gyro body and an electronic unit for processing electrical signals. The system operation is based on registration of laser radiation reflected from areas of the pattern plate with micromarks. A dynamic model of the measuring system is constructed with the use of equations of analytical mechanics. The developed model enables to study translational and rotational motions of the system elements. Results of numerical modeling of the motion of the gyroscope sensing element rigidly connected to the pattern plate, are presented. It is anticipated that the motion parameters obtained with the model will make it possible to estimate the instrumental errors of the measuring system.

INVARIANCE OF THE ISOPHOTOMETRY PRINCIPLES
IN COMPUTER SIMULATION OF INTERFEROGRAM
Kirillovsky Vladimir K., Tatiana V. Tochilina

288

The problem of increasing the accuracy of interferometric measurements is solved on the base of isophotometric processing of the interferogram. Invariance of the isophotometry principles in computer modeling of the interferogram is revealed. The invariance is provided by the apparatus of transformation functions, in particular by the receiver-image analyzer, which changes the image with the transformation of the comb type. This solution can be used when processing any interferograms to improve the accuracy of measuring the interference fringes coordinates.

SPECTROPHOTOMETRY OF BASIC DISINFECTANTS IN THE ULTRAVIOLET WAVELENGTH RANGE
Aleksander V. Arefiev, Ramiz B. Guliyev, Majorov Evgeniy E., Vladimir B. Kotskovich, Vera P. Pushkina, Khokhlova Marina V.

294

The relevance of studying the optical properties of disinfectants by means of spectrophotometry is demonstrated. A block diagram of a spectrophotometer operating in the ultraviolet wavelength range is presented. The technical and operational characteristics of the spectrophotometer are given. Spectral dependences of the transmittance, T(λ), of aldehydes (formaldehyde, glutaraldehyde), alcohols (ethyl, isopropyl), peracetic acid, and hydrogen peroxide 30% are obtained. Spectral maxima of transparency in the short-wave region of the ultraviolet range, which occurred at λ = 230, 250, 285, 300, 330, 340 nm ("shoulders" in the T(λ) spectrum) are revealed. At the long-wave boundary of the operating spectral range (λ ≥ 400 nm), all the spectra are shown to converge monotonically with the account for the transmittance measurement error.

### TECHNOLOGY OF INSTRUMENT MANUFACTURING

IMPROVEMENT OF A LASER HEAD BY CHANGING THE TOPOLOGY OF ITS BODY PARTS
AND THE COLLIMATOR MOUNTING METHOD
Aleksey D. Nikolaev, Kirill P. Pompeev

300

A method is proposed for expanding the technological capabilities of numerically controlled machine by integrating a fiber laser system into the tool composition. To lighten the parts of the laser head body while maintaining their rigidity parameters, the body is modified, some structural elements are combined, and all the body walls are made lighter and more functional. Due to the proposed design, the laser head is easy to use while maintaining the construction rigidity. The new body of the laser head expands the list of works for numerically controlled machines, which makes it possible to reduce the production time not only of a single part, but also for the final product. This approach reduces the cost of maintaining and servicing equipment by integrating it into numerically controlled machines. Marking and manufacturing of parts on one machine allows not only to automate the processes of further assembly of the final product using QR codes, but also to increase the accuracy of marking and engraving on the product due to a one-stage process.

MODELING THE PROCESS OF FINISHING THE SPHERICAL ROTOR OF A BALL GYROSCOPE
Sergey N. Fedorovich

307

One of the key issues in the process of shaping the spherical rotor of a ball gyroscope, namely, the process of removing material from the surface of the rotor during abrasive finishing, is discussed. A model describing the process of removing material from the surface of the rotor in the process of finishing is proposed. The model is based on energy-based wear theory by Fleischer, as well as elements of the theory of the introduction of a system of punches into an elastic half-space by I. G. Goryacheva. The hypotheses used in the mathematical model of material removal are confirmed experimentally, as evidenced by the discrepancy between the results of modeling and experiment at the level of measurement error. Results of simulation using the model can be used in the construction of control algorithms for precision spherical finishing machines. Practical recommendations on method of lappers preparing are formulated.

### SCIENTIFIC AND PRACTICAL DEVELOPMENTS

A COMPREHENSIVE METHOD FOR ASSESSING THE RELIABILITY
OF RADIO-TECHNICAL DEVICES OF SPACECRAFT EQUIPMENT
Pavel S. Korolev

316

A method is presented for evaluating reliability indicators of electronic devices of spacecraft equipment at the design stage. The method accounts for the following factors: the effectiveness of the quality management system of the implementing organization; compliance of the design results with the requirements of the terms of reference; the quality of additional tests of electrical and radio products; the quality of implementation of the necessary measures contained in the regulatory and technical documentation. The method of refining the numerical value of the "production quality factor", which is included in the mathematical model of the failure rate, is improved. The advantage of the method is the continuous monitoring of the necessary measures contained in the regulatory and technical documentation, when designing radio engineering devices. The effectiveness of the new method in assessing the target level of reliability indicators of radio engineering devices of space equipment is shown.

MULTI-CHAMBER APPARATUS WITH A CONVEYOR MAGNETIC DRIVE
FOR DETERMINING THE KINETICS OF DISSOLUTION OF PHARMACEUTICAL FORMS
Ludmila Yu. Vodneva, Andrey A. Vodnev, Sergey N. Lopaev, Oleg B. Korotkov, Valery A. Skorykh, Svetlana Yu. Perepelkina

329

It is obvious for both drug developers and manufacturers, that the solubility of various pharmaceutical forms is very important for the delivery of active substances; in addition, this characteristic is used in the standard method of quality control in production. Methods for testing the solubility of various pharmaceuticals require expensive, mostly imported, equipment with a small number of simultaneously used solution containers. The presented device for testing solubility uses the principle of magnetically activated mixing and contains twelve tanks (reservoirs) mounted in a thermostat. A moving magnetic field, generated either by the windings of electromagnets or by permanent magnets moving on a conveyor or on a disk along the tanks, affects the standard agitators with the dissolution medium located in each tank. In order to confirm the satisfactory coincidence of the physical and chemical processes occurring in all containers, the model of the device was created and tested for the simultaneous digestion of such samples as coated tablets and gelatin-based capsules. To check the obtained results, three types of buffer solutions and distilled water were used as a solvent liquid, and the method of comparing the luminescence intensity and measuring the acidity of the samples was used in the analysis of the dissolution kinetics. Good reproducibility of the measurement results showed similar parameters of digestion process provided by the device.