Том 57, № 2 (2018)
- Жылы: 2018
- Мақалалар: 12
- URL: https://journals.rcsi.science/1064-2307/issue/view/13636
Data Processing and Identification
Cluster Variational-Selective Method of Passive Location for Triangulation Measuring Systems
Аннотация
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.
Systems Theory and General Control Theory
Stability Analysis of Dynamic Systems in the Polynomial Vector-Matrix Representation
Аннотация
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.
Optimal Control
Suboptimal on Average Satellite Attitude Control in the Presence of Discrete Inaccurate Measurements
Аннотация
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.
Systems Analysis and Operations Research
Fuel and Energy System Control at Large-Scale Damages. II. Optimization Problems
Аннотация
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.
Scheduling in Multiprocessor Systems with Additional Restrictions
Аннотация
An admissible multiprocessor preemptive scheduling problem is solved for the given execution intervals. In addition, a number of generalizations are considered—interprocessor communications are arbitrary and may vary in time; costs for processing interruptions and switches from one processor to another are taken into account; and besides the processors, additional resources are used. Algorithms based on reducing the original problem to finding paths of a specific length in a graph, a flow problem, and an integer system of linear restrictions are developed.
Artificial Intelligence
Fuzzy Preference Domains and Their Use for Selecting an Electronic Flight Bag for Flight Crews
Аннотация
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.
Control Systems of Moving Objects
Active-Passive System of Safe Nap-of-the-Earth Piloting
Аннотация
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.
Estimating the Domain of Admissible Parameters of a Control System of a Vibratory Robot
Аннотация
We consider the rectilinear motion of a vibratory robot on a plane; the robot is presented by a rigid body and a pendulum inside it. The motion is carried out in the gravity field; the force of dry friction acts between the body and the plane. The robot is controlled by choosing the angular acceleration of the pendulum. Two modes of the robot’s control that correspond to various constraints on the choice of the control are investigated. Each of the studied control laws ensures a periodic displacement of the robot; here, the robot moves only in one direction (the motion is irreversible). We discuss the problem of finding the boundaries of the dry friction parameter and the control parameter; we find the boundaries with which the proposed control modes are feasible.
The Onboard Algorithm for Averaging the Orbital Motion Parameters of the International Space Station in the ICARUS Experiment
Аннотация
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.
Analytic Controlling Reorientation of a Spacecraft Using a Combined Criterion of Optimality
Аннотация
We consider the problem of optimally controlling the reorientation of a spacecraft (SC) from an arbitrary initial angular state into a given final angular position. We study the case when the minimized functional joins, in the given proportion, the time spent and the integral of the squared modulus of the angular momentum on the reorientation of a SC. The problem is solved in a kinematic setting. We consider two versions of the problem of the optimal rotation of a SC, with bounded and unbounded control. Using the necessary optimality conditions in the form of the Pontryagin maximum principle and the quaternion method for solving control problems on the motion of spacecrafts, we obtain an analytical solution of the posed problem. The solution of the problem is based on the quaternionic differential equation relating the angular momentum vector of a SC with the orientation quaternion of the related coordinate system. We present formalized equations and give computational expressions for constructing the optimal control program. We state the control law as an explicit dependence of the control variables on the phase coordinates. Using the transversality condition as a necessary optimality condition, we determine the maximal value of the modulus of the angular momentum for the optimal motion. For a dynamically symmetric SC, the problem of reorientation in space is solved completely: we obtain the dependences for the optimal law of the change of the angular momentum vector as explicit time functions. We give the results of the mathematical modeling of the motion for optimal control which demonstrate the practical realizability of designed algorithm for controlling the spatial orientation of a SC.
Robotics
Analytical Solution of the Minimum Time Slew Maneuver Problem for an Axially Symmetric Spacecraft in the Class of Conical Motions
Аннотация
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.
Modeling the Dynamics of an Exoskeleton with Control Torques in the Joints and a Variable Length of the Links Using the Recurrent Method for Constructing Differential Equations of Motion
Аннотация
The process of modeling the dynamics of an exoskeleton is considered (from a description of the model and the formulation of differential equations of motion to numerical calculations with the given control torques). For the first time, a new recurrent method for constructing the differential equations of motion of an exoskeleton that makes it possible to reduce labor and time costs is proposed and described. A comparison with well-known methods is carried out. The novelty of the approach is to take into account the variation in the lengths of the links of the exoskeleton. The problem of determining the control torques is solved experimentally. The urgency of the research lies in the possibility of restoring the motor functions of a person using an exoskeleton based on an empirical solution of the inverse problem of dynamics. The problem of determining the angles of rotation, angular velocities, angular accelerations of the links, and coordinates of the center of mass of the exoskeleton with a given control is solved. Only the plane motion is considered.