Vol 57, No 2 (2018)

Based on the mathematical apparatus of cluster and variational-selective analysis, we develop a new intellectual-analytic method for constructing an estimate of irradiating the target position for the case of significant a priori indeterminacy with respect to the functioning conditions of a triangulation measuring system. This method is an alternative to the known methods of maximal verisimilitude, minimal squares, and minimum of various geometric and cinematic discrepancies, applied traditionally for solving the passive location problem within the normal functioning conditions of the system. We provide the results of comparative analysis and practical recommendations for applying the method.

This paper suggests frequency-domain stability criteria for homogeneous multiconnected automatic control systems that allow an easy stability analysis of high-order systems of a large dimension. The results are confirmed by mathematical modeling.

The problem of the active stabilization of the oscillations of an artificial satellite by thrusters is considered. The satellite moves in a circular orbit and oscillates around the center of mass in the plane of the orbit. Relay control is used to minimize fuel consumption. The state of the plant is not known with certainty, but it is refined by discrete inaccurate measurements. Therefore, the problem of the optimal on average control of a bundle of trajectories is investigated. The stability error is characterized by the average value of the energy integral. Taking into account the practical accuracy of executing the thruster firing and shutdown commands, the constrained minimization problem to be solved becomes discrete. The optimal control of one trajectory is used to control the bundle. This approach based on the principle of separation leads to the suboptimal control of the bundle, which, however, proves to be acceptable in practice.

In continuation of [1], the capabilities of the network flow modeling of resource supply processes are investigated in the case of a deterioration in their infrastructural properties. Within the multivariable model [1], energy supply options in spatially distributed systems after destructive impacts are analyzed. Mathematical formulations of the problems of optimization of energy flows in a damaged network are proposed. The strategies for controlling the flows based on a posteriori information on the change in the capacity of the arcs of the model network are determined. The control objective is the providing the users requirements as much as possible taking into account the regulatory constraints on the feasible levels of the accident/load on the network subsystems. This problem is considered as a multicriterion (MO) one. Different methods for the convolution of the criteria are analyzed depending on the emphasis attached to the content of the formulation.

A method for the multicriteria evaluation of alternatives based on preferences specified in fuzzy domains is proposed. The concept of fuzzy scales of the criteria and preference domains is formalized. An algorithm for the fuzzy ranking of alternatives is proposed. A free computer implementation of the fuzzy ranking algorithm is available on the portal ws-dss.com of web services for decision support systems. The capabilities of the ranking procedure based on the preferences specified in fuzzy domains are demonstrated using the important problem of selecting an electronic flight bag (EFB) for flight crews as an example.

The problem of the synthesis, analysis, and information support of a semiautomatic aircraft control system during a nap-of-the-earth (NOE) flight is solved. It is assumed that laser-ranging (LR), television (TV), and thermal imaging (TI) methods are used to remotely sense the underlying surface (US). The algorithm for integrated information processing and displaying images is proposed. The control system is synthesized, the parameters are optimized, and the real-time simulation is carried out using the full-scale registration of LR and TV images of industrial-urban scenes with forestpark zones. It is proved that the system can ensure safe piloting at an altitude of less than 10 m over a difficult terrain at flight velocities of 200 to 400 km/h.

This paper describes the algorithm for averaging the orbital parameters of the International Space Station (ISS), which was implemented for the International Cooperation for Animal Research Using Space (ICARUS) experiment aboard the ISS. Based on the ballistic and navigational information received from the control system, the algorithm aboard the station calculates the orbital motion parameters in the Two Line Elements format. The acquired data are averaged using the least-square method. To ensure the algorithm’s execution on the platform of the ISS onboard computer in a realtime system, the process of calculations is distributed over computational cycles. The efficiency of the proposed algorithm is demonstrated using the results of mathematical simulation.

The conventional problem of the time-optimal slew of a spacecraft considered as a solid body with a single symmetry axis subject to arbitrary boundary conditions for the attitude and angular velocity is considered in the quaternion statement. By making certain changes of variables, the original dynamic Euler equations are simplified, and the problem turns into the optimal slew problem for a solid body with a spherical distribution of mass containing one additional scalar differential equation. For this problem, a new analytical solution in the class of conical motions is found; in this solution, the initial and terminal attitudes of the space vehicle belong to the same cone realized under a bounded control. A modification of the optimal slew problem in the class of generalized conical motions is made that makes it possible to obtain its analytical solution under arbitrary boundary conditions for the attitude and angular velocity of the spacecraft. A numerical example of a spacecraft’s conical motion and examples demonstrating the proximity of the solutions of the conventional and modified optimal slew problems of an axially symmetric spacecraft are discussed.