Vol 79, No 7 (2018)

The subject of this paper is the analysis of sparse state feedback design procedures for linear discrete-time systems. By sparsity we mean the presence of zero rows in the gain matrix; this requirement is natural in the engineering practice when designing “economy” control systems which make use of a small amount of control inputs. Apart from the design of stabilizing sparse controllers, the linear-quadratic regulation problem is considered in the sparse formulation. Also, we consider a regularization scheme typical to the ℓ₁-optimization theory. The efficiency of the approach is illustrated via numerical examples.

The paper is devoted to multiple solutions of the classical problem on stationary configurations of an elastic rod on a plane; we describe boundary values for which there are more than two optimal configurations of a rod (optimal elasticae). We define sets of points where three or four optimal elasticae come together with the same value of elastic energy. We study all configurations that can be translated into each other by symmetries, i.e., reflections at the center of the elastica chord and reflections at the middle perpendicular to the elastica chord. For the first symmetry, the ends of the rod are directed in opposite directions, and the corresponding boundary values lie on a disk. For the second symmetry, the boundary values lie on a Möbius strip. As a result, we study both sets numerically and in some cases analytically; in each case, we find sets of points with several optimal configurations of the rod. These points form the currently known part of the reachability set where elasticae lose global optimality.

We consider the problem of stabilization of discrete-time bilinear control systems. Using the linear matrix inequality technique and quadratic Lyapunov functions, we formulate a method for the construction of the so-called stabilizability ellipsoid having the property that the trajectories of the closed-loop system emanating from the points in the ellipsoid asymptotically tend to the origin. The proposed approach allows for an efficient construction of nonconvex domains of stabilizability of discrete-time bilinear control systems. The results are extended to the robust statement of the problem where the system matrix is subjected to structured uncertainties.

The paper was devoted to developing numerical methods with the orders 1.5 and 2.0 of strong convergence for the multidimensional dynamic systems under random perturbations obeying stochastic differential Ito equations. Under the assumption of a special mean-square convergence criterion, attention was paid to the methods of numerical modeling of the iterated Ito and Stratonovich stochastic integrals of multiplicities 1 to 4 that are required to realize the aforementioned numerical methods.

We consider the problem of constructing multi-connected control of a robotic platform designed to protect technological objects and human operators from low-frequency influences on part of the moving base. The platform includes six drive mechanisms with stepper motors. The problem is solved by the methods of the modern theory of robust stabilization and optimal control based on H_∞-optimization in the state space. We construct a mathematical model of the multidimensional system, taking into account the characteristics of electromechanical drives and using signals of feedback sensors as state variables. We give an example of synthesizing a multidimensional optimal stabilizing controller in the form of state feedback for a system with disturbances bounded in L₂-norm. We define the feedback control structure and obtain the matrix of feedback coefficients. We also show the results of mathematical modeling.

We consider models of reliability for systems with protection; these models feature various factors for increasing accident-free operation and efficiency. We determine limit values for the accident-free index that can be provided only by increasing the reliability of the protection system and the protected technological object. We show that high requirements for accident-free operation can be guaranteed if there is a control of the operability of the protection system and its recovery after a failure is detected. Experiments based on the method of Markov processes with rewards confirm our theoretical conclusions and allow us to determine the range of rational values of maintenance parameters.

We study the sensitivity of a functional on the basis of the macroeconomic model. This analysis is a calculation of the derivative with respect to the parameters of the functional characterizing the optimal trajectory. To solve this problem, we apply an approach using conjugate functions and bring the results down to concrete computations. As the model we use a neoclassical model of optimal economic growth and estimate the sensitivity with the growth rate of civilian labor force of national economies in three European countries. Our results can be recommended for analysis and practical use by the relevant authorities. Since the ultimate goal of modeling is to consider feasible alternatives when making decisions, such analysis can be useful.

We show the results of a statistical study of the complexity of the asymmetric traveling salesman problem (ATSP) obtained by processing a specially generated pool of matrices. We show that the normal distribution can serve as an approximation to the distribution of the logarithm of complexity for a fixed problem dimension. We construct a family of probability distributions that represent satisfactory approximations of the complexity distribution with a dimension of the cost matrix from 20 to 49. Our main objective is to make probabilistic predictions of the complexity of individual problems for larger values of the dimension of the cost matrix. We propose a representation of the complexity distribution that makes it possible to predict the complexity. We formulate the unification hypothesis and show directions for further study, in particular proposals on the task of clustering “complex” and “simple” ATSP problems and proposals on the task of directly predicting the complexity of a specific problem instance based on the initial cost matrix.

A method for solving the analysis problem of a linear control system with input and output disturbances is suggested. Its higher efficiency in comparison with the conventional approach is shown using an example of a test problem from COMPleib.

This paper analyzes conditions of system compatibility in the game-theoretic models of resource allocation between social and private activities. We describe economic and administrative control mechanisms for system compatibility.

This paper is dedicated to the pursuit-evasion game in which both players (Lion and Man) move in a metric space, have equal maximum speeds and complete information about the location of each other. We assume that evasion is successful if, for some initial positions of players, there exists a positive number p and an evader’s non-anticipative strategy guaranteeing that the distance between the players is always greater than p. We consider connection between successful evasion and such properties of the phase space as geodesics behavior and the existence of non-expanding fixed point-free self-maps.