Vol 56, No 4 (2017)

The problem of maximizing the horizontal coordinate of a point moving in the vertical plane driven by gravity, viscous friction, which is proportional to the nth degree of the velocity, and an accelerating force is considered, along with the related brachistochrone problem. The optimal control problem is reduced to a boundary value problem for a system of two nonlinear differential equations. The qualitative analysis of the trajectories of this system is performed, and their characteristic features that allow us to elaborate the results obtained in other studies are revealed. The optimality of the found extremals is discussed.

The previously developed methods for analyzing the controllability of linear multidimensional plants with distributed parameters on a given set of open-loop trajectories of their transfer into the desired finite state are extended to interconnected physically heterogeneous distributed dynamic systems. An example (which is of independent interest) of estimating the open-loop controllability of nonstationary heat conduction processes under the conditions of the perfect contact of the interacting environments is presented.

We develop the mathematical apparatus of permutation-masking transformations (PMTs) of different types, enabling us to assign the full set of possible images to the initial generating function. We study the algebraic, spectral, and autocorrelation properties of these transformations. We substantiate the possibility of constructing complex broadband (in the frequency sense) images based on a simple generating function. We study the action of these transformations on stationary random processes, in particular, noncorrelated ones (of the white noise type). The developed apparatus can be applied in many areas, in particular related with the synthesis of the optimal ensembles of signals for communication and management systems; sounding signals for problems of radio-location and navigation; and coding, masking, and enciphering information; and also optimal signal processing in noisy conditions. We consider a demonstrational model example showing the possibility of raising the resolution and estimating quality of the signal parameters on the base of a modified correlator.

We have compared the efficiency of 14 modifications of the differential evolution method for optimizing the parameters of fuzzy classifiers, the rule bases of which are initialized by the algorithm of the structure generation on the basis of extreme parameter values. The comparison was conducted on 12 well-known datasets of the KEEL repository. Based on the results of the operation of classifiers optimized by these algorithms, we ranked the methods and compared their analogs. The comparison criteria are represented by the percentage of correct classification and the number of rules in a classifier.

The optimal control problem for a switched system whose state vector includes both continuous and discrete components is considered. The continuous part of the system is governed by differential equations, while its discrete part, which models the operation of a switching device with memory, is governed by recurrence inclusions. The discrete part switches the operation modes of the continuous part of the system, and is itself affected by the continuous part. The switching times and their number are not specified in advance. They are found as a result of optimizing a performance index. This problem is a generalization of a classical optimal control problem for continuous–discrete systems. It is shown that the cost function is constructed from certain auxiliary functions—the so-called conditional cost functions. Equations for the conditional cost functions are derived and sufficient optimality conditions are proved. The application of these conditions is demonstrated by the example of designing a time optimal switched system that is similar to A.A. Fel’dbaum’s classical example of the time optimal continuous system.

We propose a design structure and conception for a logical-dynamical controller for separate subsystems of a multiply connected automatic control system for a complex technical object. Basing on the discrete analysis of the movement of the multiply connected control object towards its equilibrium state, we synthesize a double logical algorithm forming a logically corrected signal taking into account the influence of natural cross interfaces inside the object. Using the simulation modeling of the proposed logical-dynamical multiply connected automatic control system for an aviation gas-turbine engine, we confirm the efficiency of the double logical control algorithm authority for a complex technical object functioning under conditions of parametric and functional indefiniteness.

In this paper, we propose an ant colony optimization (ACO)-based method for the design of the fuzzy proportional integral derivative (FPID) controllers for both single input single output (SISO) systems and multiple input and multiple output (MIMO) systems. Specifically, the method is used such as to minimize or maximize a cost function which quantifies the overall system performance in response to desired inputs. Without loss of generality the sum of squared error is used. The proposed method has the faculty of introducing the available knowledge about the system at hand. In order to show its efficiency, we have applied the method with tree dynamical systems; an inverted pendulum, a mini helicopter and a quadrotor.The simulation results demonstrate the efficiency of the method.

A new concept of a multitask distributed heterogeneous computing system is proposed. The basic principles of such system are that it uses only idle supercomputer resources and does it as a common user; thus, it does not conflict with the administration policy in any way. The efficiency of the proposed concept is demonstrated by the example of the real grid system that currently uses supercomputer resources to boost the performance of the SAT@home and OPTIMA@home volunteer distributed computing projects.

This paper presents an algorithm for the terminal synthesis of the orbital orientation for a spacecraft. The algorithm is based on solving the following problems: the analytical determination of the program values for the angular velocity vector components in an orbital coordinate system and the stabilization of the program values for the turn rate vector components and the desired terminal angular position of a spacecraft. The program values of the angular velocity vector components are determined analytically using the method previously proposed by the authors for solving a boundary value problem based on the parameter identification of a discrete model with the use of modal control. The simulation results demonstrating the effectiveness of the proposed algorithm, as well as the high accuracy level of the steady-state control, are presented.

This paper addresses the path planning problem for autonomous mobile robots operating in an unknown environment with obstacles. Paths are formed based on third-order Bezier splines and, then, are corrected on the move as a robot detects obstacles with its onboard sensors. During this correction, the initial path between two reference points is divided into two segments (described by Bezier splines) in such a way as to allow the robot to move at a safe distance from a detected obstacle along a smooth resultant trajectory. In this case, the use of smooth paths ensures a high levels of accuracy and velocity of mobile robots during their operation.