Vol 57, No 4 (2018)

A time-frequency method for identifying linear dynamic systems of a general form with constant parameters and delays in their observable variables is considered. The identification problem is found to be decomposable into the problem of estimating unknown parameters and the problem of estimating the initial conditions. Applying the time-frequency method to identify the differential equation of the Van der Pol oscillator, which is nonlinear by both its state and parameters, is considered. Examples are used to show that the time-frequency method solves the identification problem both for stable and unstable dynamic systems.

This paper considers continuous-time state estimation for a dynamic system with Gaussian and Poisson white noise. We design a finite-dimensional filter with a lower computational cost than the extended Kalman–Bucy filter: its order is the dimension of the estimated part of the system state vector. The nonlinear structure of the filter is selected using the mean squared optimal unbiased estimation for each infinitesimal period of time. We develop an algorithm to find the structural functions of the filter that is based on the Kolmogorov–Feller equation for the density function. A numerical method to calculate them a priori by sequential Monte Carlo trials is presented, which requires the histograms of the desired functions. Due to its cumbersome form, some numerical and analytical approximations of the suggested filter are also given. They structurally coincide with the corresponding nonlinear extensions of the Kalman–Bucy filter but have a considerably smaller order and calculable parameters.

In this paper, the problem of synthesizing an optimal system controlled with switches is considered. The term switching is understood more broadly than in hybrid systems; i.e., there is a controlled change of the mathematical model of the controlled system at a switching moment: the equations of motion, the state space, and controls are changed. The quality of the control process is estimated by the functional that takes into account both the losses in the continuous motion of the system between switching moments and the cost of each switch. The number of switches and the switching moments themselves are not preassigned and are found during the process of optimization. The sufficient conditions for optimal control are obtained and their application is demonstrated by academic examples of group performance.

A network flow model analyzes the functional capabilities of large spatially distributed fuel and energy systems. The maximum achievable volumes of energy supplies are calculated for these systems. The obtained values are used to generate a vector of the maximum feasible functional characteristics of the original system and normalize the multicriterion model. The concepts of stationary and emergency control modes are introduced. The possibilities of compliance with standard operating conditions of subsystems for the transportation and extraction of energy resources are analyzed. Possible deviations for different standard values of the functional characteristics are estimated. A method for estimating the increase in the network load in the case of a uniform increase in the amounts of all types of energy flows transmitted is proposed.

A hierarchically ordered group of jet fighters escorts attack aircraft. This group is headed by the group commander, who is also in charge of the subgroup commanders. Enemy jet fighters ready to attack the strike aircraft appear. The group commander allocates a subgroup (the selected group) to repulse the attack. We consider the intellectual support of solving this task by the commander of the selected group and his coordination with the commander of the group of escort jet fighters.

A system of methods for improving the quality of face recognition from infrared images is described. For testing the recognition algorithm in a multidomain environment, a database of ordinary and infrared face images is collected. An algorithm based on cyclic generative neural networks is developed. This algorithm makes it possible to transform images from the color domain into the infrared domain, which significantly increases the size of the training sample. It is shown that fine-tuning the recognition algorithm using the generated infrared images improves the recognition result on the test sample.

We provide the synthesis procedure for a mathematical model of the 20ChN26.5/31 diesel engine treated as a part of 20EDG500 diesel-electric set (power 6.3 MW). The model is designed for synthesis of engine speed control and simulation of closed-loop control systems in generator sets. The model structure is based on the fundamental laws of physics, while its parameters and static functions are obtained using least squares approach and the data taken during experimental testing of the set. The results of model verification are presented, and the model outputs are compared with the experimental data. Simulation of the control system closed by proportional-integral-differential law is presented as an example of the model application.

The possibilities of using of single-gimbal control momentum gyros (gyrodynes) in the control system of an advanced remote sensing satellite of the Earth are studied. The main difficulty arising in the phase of designing a composition of the motion control system for this satellite is that the gyrodynes currently produced in the Russian Federation have an angular momentum magnitude, considerably exceeding the value required for this satellite. The second circumstance is the limited range of the selected angular rate sensor, which hampers performing attitude maneuvers at high rates. Ways of solving these problems are considered and the possibility to ensure the required accuracies of stabilization in surveying the Earth’s surface is shown. The capability of this satellite to conduct areal and corridor surveys is demonstrated by the results of mathematical simulation.

In an emergency situation, the normal reaction of a control system is to switch off the power supply of the actuators. In the resulting uncontrolled motion, the gripper significantly deviates from the programmed trajectory. It is proposed to form the braking trajectory by switching off the power supply of the degrees of freedom in a certain sequence. Estimates show that this can reduce the deviation almost by an order of magnitude.