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A mathematical model was developed, during which the voltage equations of the three-phase winding of a brushless DC motor with permanent magnets, the electromagnetic torque of a brushless DC motor, electromagnetic power, the induced emf of each winding, and the differential torque equation of the servo system were obtained. Based on the constructed mathematical model of the BLDC for a specific motor with given parameters, simulation modeling was carried out and the dependences of electromechanical quantities were obtained: angular velocity of the rotor, electromagnetic torque, stator phase current and rotor rotation angle on time. The simulation results confirmed the theoretical justification of the mathematical model. The resulting mathematical description of the BLDC can be used to build the architecture of a control unit based on a neural network controller.

Mathematical models for controlling centrally oriented and non-centrally oriented rotary wheels of a mobile robot are considered. Based on the analysis of the kinematics of the mobile robot, the dependences of the rotation angle of the rear and front free wheel on the angular velocities of the right and left differentially driven drive wheel were obtained. For a specific mobile robot with certain kinematic parameters, graphs of the dependences of the angle of rotation of the free wheels on the radius of rotation of each wheel and graphs of the dependences of the angle of rotation of the free wheels on the angular velocities of the driving wheels were constructed. The results obtained made it possible to establish a pattern between the angle of rotation of the castor wheels and the design characteristics of the robot. A certain range of angular velocities of the driving wheels in accordance with the limiting values of the caster wheel rotation angles makes it possible to take into account the obtained mathematical models to increase the stability of the movement of the mobile robot.

The paper developed a mathematical model of the control system for a mobile tracked robot, which takes into account the kinematic parameters (angular speeds of rotation of the rollers and the center of mass of the robot, the linear speed of the robot and its angle of rotation relative to the normal to the axis) and dynamic parameters (moments of inertia, resistance forces and electromechanical parameters used electric motors), which made it possible to give the most complete mathematical representation of the description of the movement of a caterpillar mobile robot. A control system for mobile robots along a predetermined trajectory is obtained, taking into account position feedback.

The article presents an analysis of the state of development of solar energy in Europe and the Republic of Belarus for 2020. An algorithm for increasing the efficiency factor of solar power plants by localizing the solar trajectory depending on the latitude and longitude of the area has been proposed. In particular, taking into account the angle of the Sun position above the horizon and the azimuth angle of the Sun, the increase in the efficiency factor of solar power plants for the Republic of Belarus is calculated. Based on this algorithm, a program has been written that makes it possible to draw a diagram of the solar trajectory. An analysis has been made of the degree of localization of solar energy for solstice days in 6 oblast (regional) centers of the Republic of Belarus; it is found that the highest intensity of solar radiation is observed in Brest and Gomel, the average in Grodno, Minsk and Mogilev, while the lowest one – in the city of Vitebsk. A comparative analysis of the solar trajectory of the city of Berlin (Germany) with the city of Gomel and the city of Brest is carried out. Recommendations have been developed for the effective operation of solar power plants in the oblast (regional) cities of the Republic of Belarus during the year in an autonomous and combined mode of operation. The obtained numerical calculations of the solar trajectory make it possible to optimize the orientation of solar panels for permanently installed panels and for automated solar tracking systems, as well as to select the optimal configuration of the power plant equipment for any geographic area.

The article considers the question of assessment of professional risk of workers. The analysis of conditions and safety of work in production of construction materials is carried out. The method of assessment of professional risk on the basis of integrated indicators of conditions and safety of work is offered. Interpretation of characteristics of working conditions on indicators of qualitative and quantitative standard of professional risk is given. Calculation of professional risk for the former of reinforced concrete structures is presented.

The article presents the development of an intelligent control system for LED lighting, applicable to autonomous electric lighting installations, outdoor lighting fixtures on posts to illuminate highways, roads, streets and surrounding areas. The system combines all local lighting systems in which the motion sensor and the LED luminaire are integrated into one network. Turning on the LED luminaire at reduced power is carried out automatically when the level of external natural light is less than a certain threshold value. In the case of appearance of an object moving along the motion sensors of neighboring local lighting systems, the speed and direction of movement of the object are determined. In accordance to the speed and direction of the object movement the number of local lighting systems is determined whose LED lamps should be switched on at a higher power and the appearance of the object at the next design point is predicted. The increase in the power of LED lamps is carried out smoothly when the object is approaching the corresponding local lighting system. Due to the dynamic control of the power of the LED luminaires, as moving objects appear in the coverage area of the intelligent lighting system, significant energy savings are achieved. Traffic safety conditions are increased, as the number of LED lamps operating with increased power is determined by the speed of the object, and its possible braking distance will be significantly less than the illuminated section of the roadway. Smooth changes in the power of LED lamps reduce the pressure on the driver of the vehicle. The choice of the motion sensor based on the autodyne radio blocking, which detects moving objects in a given sector of the controlled space, regardless of the time of day and weather conditions, is grounded.

The new method of minority charge carriers basic parameters determination and the ratio of minority charge carriers conductivity to majority ones in solid matter based on magnetoresistance curve analyses within the framework of the phenomenological two-band model has been proposed. The criterion of the applying of the method has been found. As the examples of using this method the conductor, semiconductor and superconductor have been given. From the obtained temperature dependences of the aforementioned values in superconductor the conclusion about the deciding role of minority charge carriers in the emergence of superconductivity state has been made. [ABSTRACT FROM AUTHOR]

Therapy for Ph-positive chronic myeloid leukemia (CML) with the tyrosine kinase inhibitor imatinib results in achievement of high hematological and cytogenetic response rates. However, most patients with a complete cytogenetic response were found to have a minimal residual disease. Therefore the role of molecular monitoring during CML therapy has recently increased. Regular molecular monitoring allows to early diagnosis of relapse and improvement of treatment outcome as a result of therapeutic intervention. For the imatinib-treated patients therapy resistance or increased BCR-ABL gene expression is an indication for kinase domain mutations testing. Detection of the mutations causing imatinib resistance is required for therapy choice. Real-time polymerase chain reaction and DNA sequencing should become customary for CML monitoring.

Magnetoresistance as a tool of basic parameters determination of minority charge carriers and the ratio of minority charge carriers conductivity to majority ones in solid matter has been considered within the framework of the phenomenological two-band model. The criterion of the application of this model has been found. As examples of these equations usage the conductor, semiconductor and superconductor have been introduced. From the obtained temperature dependences of the aforementioned values in superconductor, a supposition of a deciding role of minority charge carriers in the emergence of superconductivity state has been made.