The results of simulation in MATLAB/Simulink and on the real-time testbed of a digital control system for a plasma unstable vertical position are presented on the example of the tokamak T-15MD model. Feedback is implemented on two computers of the testbed: "Plant model-Controller". Real-time computers have communication devices with the plant: DAC and ADC together with their drivers. On one side of these devices there are digital signals (inside computers) and on the other side (outside computers) there are analog signals that characterize the operation of a closed-loop control system. The unstable plasma model in the tokamak control system is similar to the plasma models used to develop and tune the vertical plasma position control systems in the Globus-M/M2 tokamak (Ioffe Physical and Technical Institute, St. Petersburg) and the T-11M tokamak (JSC «SSC RF TRINITI», Troitsk). A voltage inverter relay model is used as an actuator, which puts the control system into a stable auto-oscillatory operating mode in the presence of negative feedback. The winding of the horizontal control field (WHCF) in the T-15MD is located between the chamber and the winding of the toroidal field (WTF). The digital controller is characterized by robust properties and can be additionally configured during the operation of the control system. The system was tested by two types of external actions: additive disturbance with imitation of a minor disruption of 400 A and a control set point of 0.1 m. The sampling time is set to 100 µs. © 2022 National Research Center Kurchatov Institute. All rights reserved.

In the paper, stability of a fourth-order switched affine system with state-dependent switching law is studied. Such a system arises when stabilizing the chain of four integrators with the help of a special control that makes the system track a desired trajectory when approaching the equilibrium state. The target trajectory is defined implicitly as that of the second-order integrator stabilized by means of a feedback in the form of nested saturators. One of the three linear systems composing the switched system under study is stable at the origin, while the two others have no stationary equilibria at all. The set of values of the feedback coefficients is determined for which the zero solution of the switched system is globally stable. Studying global stability of the system is shown to reduce to a simpler task of establishing stability of a second-order switched linear system with state-dependent switching law. It is proved that the latter system is stable for arbitrary switchings.

Fifth-generation (5G) networks are characterized by three use cases - massive machine-type communication (mMTC), ultra-reliable low-latency communication (URLLC), and enhanced mobile broadband (eMBB). Quality of service requirements as well as service parameters within these use cases vary significantly, e. g., URLLC is characterized by an ultralow latency of up to 1 ms, while eMBB has an ultrahigh data transfer rate. The task is to organize the joint provision of such services. The paper proposes a scheme for joint URLLC and eMBB traffic transmission. It is based on the fact that URLLC data has a small volume and can occupy less than one physical resource block. The authors analyze the scheme using the developed retrial queuing system with two orbits - one for temporary storage of interrupted eMBB users and the other for eMBB users waiting for service to start. The authors propose the matrix geometric algorithm for calculating the probability distribution as well as formulas for probabilistic characteristics.

Предложена модель элемента стрейнтроники квадратной формы. Показано совпадение экспериментальных и теоретических результатов.