Papers by Author: Mariusz Dąbkowski

Abstract: One of the important factors that affect the reliable operation of the power system and the rapid restitution after disaster is a quick and effective combining synchronous electric power facilities to operate in parallel [. Hence, diagnostics of automatic synchronizers at every stage of their life, from building a prototype, through the whole life, until removing such devices from the operation, is an extremely important and responsible activity. In ordinary practice, this action is performed by dedicated test of mechatronics systems, called simulators [2, , in close to real - or even more restricted - conditions. One of the major limitations in the relevant field undoubtedly concerns the selection of an appropriate structure and implementation of models of the angular velocity control systems involved in the process of connection. These models must be simple enough to allow computation with a frequency of kHz, and, at the same time, developed enough to be able to form diverse and close to real working conditions. For these reasons, classical approach is not possible, allowing the use of well-known Parks model [ of the synchronous generator and the complex - and often nonlinear [. Hence, considered above-mentioned requirements and indicated constraints, to test the automatic synchronizer the designers of mechatronics systems use a number of simplifications during modeling of the angular speed control systems [. However, models are not detailed enough to study the impact of changes in the shape of relevant characteristics under the influence of changes the angle of phase discrepancy in the process of connecting. Hence, this paper presents the results of the research of the currently used method of modeling the most commonly used control systems of angular velocity, in the respective systems.

Abstract: In many automatics and mechatronics systems accurate modeling of several physical processes is needed. In power system, one of these is the process of control of angular velocity of power blocks during their connection to parallel operation. This process is extremely dynamic and the response of control system results from continuous changes in many physical parameters (temperature, pressure and flow of the working medium, etc.). An accuracy of modeling this process influences int. al. on: quality of the automatic synchronizer diagnostic tests in the laboratory, as well as the possibility of evaluation of prospects for connection process in the power system, without the automatic synchronizer [. Automatics systems used for research and diagnosis of automatic synchronizers are known in the literature as and simulators [2, . To impose similar to real working conditions, it is required to implement an appropriate models of control systems. One of such models, representative for the larger population of objects, is model of control systems of angular velocity. Currently used models, e.g. [3, 4, 5, , allow to approximate the response of real object, or to impose higher restricted conditions of work, for example: related to the angular acceleration dω/dt, the size of overshoots and decay time of transitional characteristics, while accurate modeling the real working conditions using them is not possible. Furthermore, their use requires knowledge of the (often difficult to access) object parameters and time-consuming selection of manual procedure of certain substitute settings, occurring in these models. To eliminate inconveniences mentioned above, in the paper the proposal and mathematical modeling procedure is presented, which allow to obtain much more accurate transitional characteristics of real objects.

Abstract: River Formation Dynamics is a heuristic optimization algorithm based on the manner, in which drops of water form the river bed. The idea is to imitate the movement of drops on the edges between given nodes thus performing a search based on their height, which is modified through the mechanism of soil erosion and sediment deposition. In this way decreasing gradients are constructed, and these are followed by subsequent drops to compose new gradients and reinforce the best ones. This paper presents implementation of the method in wheeled mobile robot path searching task in an environment with obstacles. At first, a concise introduction to the RFD algorithm is presented, along with the problems requirements. In the main part a simulation test has been performed using the algorithm to find the shortest route from the starting point to the goal. The tests were made with different landscape layouts, measuring the computation time. The last section presents a real life implementation of the algorithm using a Pioneer P3-DX mobile robot. The validity of this solution is discussed, as well as any modifications, along with a brief comparison with a similar, popular search path algorithm.

Abstract: In the paper the behavior based control system of an autonomous mobile robot SCORPION is presented to execute the one of the most difficult navigation task, which is the complete coverage task of unknown area with static obstacles in the environment. The main principle assumed to design control system was that the robot should cover all area only once, if it possible, to optimize the length of path and energy consumption. All commercial robots like Roomba, Trilobite or IVO move using structured templates combined with random movement. Therefore the path of coverage is not optimal directions of movement are often chosen randomly, so robot covers the same area many times wasting time and energy. In paper the five main developed templates of movement were described to fulfill main task in ordered manner using primarily the way of the ox template of coverage [1, 2, 5, 1. The behavioral control system is implemented in a computer application written in Python [5]. In the paper the test methodology of the developed system on real mobile robot ERSP SCORPION equipped with IR sensors is presented. Graphical and quantitative results of tests of accomplishment of complete coverage task are given for 6 different configurations of obstacles in the robots environment. Conclusions are presented and discussed [5]. Ways to improve the quality indicators [1, of the task of complete coverage of a unknown area are also showed.

Abstract: In this paper the identification method of the parameter representing the inertia of masses flowing water throw the pipes in water power plants has been presented. The value of this parameter is used in adaptable method of synchronizing power generators. The identification based on the simplified mathematical model of the hydro-turbine and initial phase of the response to synchronizing power object. Application mathematical model compose synchronous generator during idle work, hydro-turbine with long pipes and large head and controller of governor. Identification Tw parameter process consists of two steps. The first step is connected with analyzing initial phase of transient characteristic. And the next point is connected with determinate coefficients of linear flattening and characteristic point. This point is realized by sending control signals of angular velocity from automatic synchronizer to controller. This cause changing frequency of voltage which is the next (point by point) registered in selected moments in matrix. A shown synchronization method is

Abstract: The main goal of this article is to compare the accuracy of the extrapolations time phase coincidence for the selected methods. In the comparing analysis selected the method using calculable function, polynomial function and linear function. The general idea of synchronization proceed in electrical power system is presented. The most important work conditions during realization of this proceed are mentioned. The most important is the realization of phase condition. Incorrect realization of the phase condition may causes numerous consequences, from power impact and current compensatory impact till loose of synchronous work. For this reason known methods of extrapolation of the time phase coincidence are recalled and their pros and cons are described. Next a new non-linear method of extrapolation of the time phase coinci¬dence realized by calculable function is presented. Then the comparison analysis of the selected methods is made. As the comparative criterion the time phase error is taken. The methods were tested for different parameters concerning frequency difference of voltages synchronizing power objects. One of the testing data set obtained from the mathematical model of the control speed angle unit for water plant with long pipes and large difference water levels. This gives the rigorous testing conditions because of the dynamic changing frequency difference. The values of the numerous tests done on the testing device showed that the new method results in better performance parameters. The paper includes the most important results of the comparative tests. Conclusions and final summary are made.

Abstract: In this paper the authors present the localization system which uses triangulation and trilateration to position mobile robot in the two-dimensional space. Distance was measured with the strength of radio signal emitted by devices of existing communication network, which were constructed by the authors. To get the actual distance in the function of radio signal strength the calibration curve, which was set empirically, made from the spline of linear functions was used. Research in this paper can be divided into two parts: the quality tests of communication and the localization using radio waves. Quantity measure of the correctly transmitted frames showed that the communication network works with the credibility of 80%, which is good result for the radio waves. Outcome of the localization quality showed that the position error did not surpass 1.7 m, which is a good result compared to the error of a typical GPS receiver is 15 m. Summing up, the localization system proposed by the authors is working well. Furthermore the test showed that triangulation and trilateration are universal methods of positioning and they can be used in other systems. Additionally the test indicated that the accuracy can by increased by using devices with a better signal strength measure.

Abstract: In paper the methodology of complete coverage of unknown area by autonomous mobile robot is described. The main principles of complete coverage task using sensory data only are given. The shape of coverage area is defined. The modified "the way of the ox" algorithm is proposed to realize this task and its following stages are described. Definitions of two quality indicators of realization of complete coverage task are given. The behaviour based control methodology imitated reactions of animals, realized the robot's movement, is presented. The general structure of reactive and proactive behaviours is showed. The example structures of defined reactive and proactive beheaviours, which allow to achive given task, are described. The example structure of complex behaviour implemented in Matlab-Simulink environment is presented. Graphical results of simulations of complete coverage task are presented. Values of quality indicators D and E are given and discussed.

Abstract: Robotics is actually one of the most important technologies; which in the last year has been developing very fast. It’s interdisciplinary since combine mechanics, automatic, electric, and computer since. This paper presents generally the problems in navigation which should be solved by all who wants to build such educational and mobile robots [1, 3, 5, and 7]. For this reason the mechanical structure, module of communication, digital sonar and main board of autonomous and mobile robot for laboratory tasks has been described [2, 4]. After that the operation principle was given and some of the realized tests have been shown. A next possibility of development of the robot has been presented. Moreover the way, which satisfies the need of the large computational power on usually small platforms of mobile robots and the most advantageous sorts of the power supply from the point of view of the robot which realizes specify functions has been described. At the end of paper the conclusions has been extracted. Wide laboratory tests of the robot presented in this paper fully confirm all guideliness. In spite of fact that the device is very simple and very cheep, succesfully meet tasks in teaching, and enables students to meet fascinating subject of the mobile robots. Possibility of extension this subject can be continued during realization of other programs.