SYSTEM ANALYSIS, CONTROL AND INFORMATION PROCESSING
The paper deals with the method for the design of linear controllers with sparse state feedback matrices for control the plants under conditions of unknown and bounded disturbances. The importance of the sparsity property in feedback can be explained by two factors. First, by minimizing the columnar norm of the feedback matrix in the control it becomes pos- sible to use a minimum number of measuring devices. Secondly, by minimizing the row norm of the feedback matrix, the required number of executive (control) devices is minimized. Both properties, if they are achievable in the synthesis of the controller, reduce the cost of the system and improve the fault tolerance and quality of regulation by reducing the structural complexity. The search algorithm for sparse matrices is based on the method of invariant ellipsoids and is formulated as a solution to a system of linear matrix inequalities with additional constraints. A special set of optimization conditions is
proposed which for a disturbed system minimizes overshoot and overshoots in transient processes of the disturbed closed- loop system simultaneously with minimizing errors in the steady state. The proposed method also assumes the possibility of minimizing both the row norm of the feedback matrix and the column one, while preserving the robustness properties, which makes it possible to solve the sparse control problem (a sparse control is understood as a linear controller with a sparse feedback matrix). The efficiency of the proposed control scheme is confirmed by the results of computer modeling and comparison with some existing ones.
AUTOMATION AND CONTROL TECHNOLOGICAL PROCESSES
The control system of a shearer is considered, which is designed for destroying rock and loading it onto a scraper conveyor. When working out a coal seam by a shearer, external disturbances — the coal resistance to cutting, solid inclu- sions of rock, changes in the width of the screw, which vary indefinitely, lead to a deterioration in the quality of transients. The paper focuses on the shearer control system, the key elements of which are: a movement drive, a cutting drive, a coal face and a standard regulator that provides the system with the desired control quality indicators. A typical cutting current controller in the form of a PI controller with parameters configured for a specific mode of operation of the shearer cannot ensure the optimal functioning of the control system in all modes due to the non-linearity of the control object and the random of changes in the coal resistance to cutting. To improve the control quality indicators, it is necessary to choose the parameters of the PI controller so as to minimize the amplitudes of the current steps of the cutting motor, and therefore reduce the amplitudes of the moment in the transmission of the cutting drive and minimize the system quieting time. In this paper, we propose a tuning algorithm based on obtaining the values of the controller parameters for each of the possible modes of operation of the shearer, identifying the type of disturbing effect by the response curves of the system available to observation. At the same time, the use of an artificial feed forward neural network, acting as an operational means of recognizing a multidimensional response curve in the control loop, is proposed. A neural network of two architectures was used: with a scalar and a vector output function. The curve recognition algorithm satisfies the limitations on the speed of solving the problem of controlling an electromechanical system, since the recognition of a disturbance occurs in a time that does not exceed the output of the process to the maximum of the current step. The correctness of the obtained results was confirmed by the results of computer modeling.
ROBOT, MECHATRONICS AND ROBOTIC SYSTEMS
The solution of task of maintaining the dynamic accuracy of control of working tools of multilink manipulators (MM) when they move along arbitrary spatial trajectories is presented in this paper. In this case, constructive restrictions in all degrees of freedom (DoF) of manipulators and special cases of location of their links are taken into account. These special (singular) positions are characterized by ambiguity in solving inverse kinematics problem of these MM. Maintaining of control accuracy is proposed to be ensured by excluding the enter of all DoFs of manipulators to the restrictions, as well as excluding the enter of their working tools to the boundaries of the working area. This is accomplished by using a redundant DoF when approaching these undesirable positions. In the first part of the article, the features of the new solution of the inverse kinematics problem are considered and singular positions for 6-DoF manipulators with PUMA kinematic schemes are described. The presented solution of the inverse kinematics problem takes into account various combinations of genera- lized coordinates of the MM, which ensure the movement of their working tools to the specified positions with the required spatial orientation. This solution has low computational complexity compared to other known methods. This allows the use of low-power microprocessor computers to control the MM. The results of the performed mathematical simulation confirmed the high efficiency of using the proposed approach to the contour control of the MM.
One of the main and most difficult tasks in the development of automotive systems is the classification of the workspace of a mobile robot. Based on the classification results, a local map of the area is built, with the help of which, then, the robot trajectory is planned. The article describes a method of classification the working area of an autonomous mobile robot moving in rough terrain. The developed classification method is based on the analysis of a three-dimensional point cloud obtained by a laser scan- ning 3D rangefinder. Using a scanning laser rangefinder allows you to classify the robots motion zone at any time of the day or year. A set of classification features is proposed, the calculation of which is carried out using the least square method and elements of probability theory and mathematical statistics. The classification of the robot workspace is carried out by four classes: "Flat surface", "Small roughness", "Large roughness" and "Obstacle". Each class characterizes the degree of passability of the robot movement surface. Classification results are saved as a local map of passability. In each cell of such a map a number is written that characterizes the passability of the region of the working area bounded by this cell. The developed classifier is integrated into the on-board control system of the wheeled mobile robot. The results of experimental studies confirming the efficiency and effectiveness of the proposed classification method are presented. The accuracy of class recognition of the mobile robot workspace has been determined. The developed classifier successfully operates in various conditions, including in winter and at dusk, but at the same time it has limitations when working in conditions of natural noise, such as rain, snow. The average classification accuracy with the minimal influence of natural noise is 92.3 %, and the execution time of each iteration does not exceed 0.085 s, which allows using developed classifier as a part of on-board control systems of autonomous mobile robots.
DYNAMICS, BALLISTICS AND CONTROL OF AIRCRAFT
The use of low-orbit constellation of small or super-small satellites for solving problems of remote sensing of the Earth is a promising direction for the development of space activities. In order to ensure the communication of these satellites with ground-based points in advanced space systems, it is planned to use groupings of low-orbit communication satellites. At that, a certain formation of this grouping is considered. It is assumed that the satellites are evenly distributed in several orbital planes, and each of them has a connection with two neighboring satellites in its plane and two satellites in neighboring planes. The object of research in the article is the problem of routing, namely, the search for routes for relaying data streams from remote sensing satellites to ground-based information reception points. The proposed approach to solving the routing problem uses the following network specifics. The nodes of the network are remote sensing satellites, communication satellites and objects of ground infrastructure. In this case, you can highlight two fragments of the network. Communication satellites form the first fragment of the network, and the second one — the communication channels of these satellites with ground infrastructure objects and remote sensing satellites. The topology of the first network fragment is static, and the topology of the second fragment is dynamically changing. However, the dynamics of changes in the topology of this network fragment is predictable. It can be calculated based on satellite flight simulations and described as a contact plan that defines the time parameters of satellite communication sessions with ground stations. The solution of the problem is based on an agent-based approach. Satellite agents form the overlay layer of the network and, based on information interaction, provide route search, traffic balancing, and data transmission without delays at network nodes. The article offers information interaction schemes that provide both centralized and distributed route search options.
The article proposes the principles of the main structural components formation for the implementation of the task of managing the on-board equipment complexs (OEC) redundant resources: configurations tables, readiness indices and functional efficiency indicators of the software and hardware equipment components, allowing to formalize the processes of their development and use in the task of managing the excess on-board equipment complex resources. The separation of redundant components into groups of resources is proposed: computing modules, operating system core components, onboard software components, peripheral switching system components, hardware peripheral components. The general organization of redundant resources monitoring is formulated, which allows using the schemes and capabilities of both traditional built-in controls (the lower level of monitoring) and more advanced algorithmic solutions based on the logical processing of control results (the middle and upper levels of moni- toring). The formation mechanisms, as well as the forms of configuration tables for hardware components and on-board applications, as well as the rules for filling them, focused on the use of configuration supervisors, are proposed. The principles of readiness indices and functional efficiency indicators forming have been developed and detailed, allowing to implement in the software environment the accounting of various factors that determine the capabilities and effectiveness of various computing tools and OEC configurations. A method for correcting the configurations functional efficiency indicator due to the mode generator, which adapts the complex reconfiguration to the conditions of its use, the tasks to be solved, and the operators commands, is proposed. An example of considering the variety of tasks and modes of the OEC of an aircraft: flight stages, emergency situations, services and support, life support modes, the operation of the flight and navigation complex, as well as the crew control commands, is given. The proposed solutions can be used in computer-aided design systems for equipment complexes, flight safety systems, control of general aircraft equipment, software-controlled radio communication equipment systems, multispectral onboard reco naissance systems, target designation and control of aviation weapons and special target loads of promising aviation complexes.
ISSN 2619-1253 (Online)