Automatyka/Automatics publishes original papers in an automatic control engineering field and related disciplines including: control theory and optimisation, dynamical system analysis and synthesis, control engineering applications, electrical engineering, computer science, information technology, electronics, and biomedical engineering. Discussion and review papers presenting current state of the art as well as new and emerging areas are also welkomed. The journal publishes letters to the editorial board, reviews, bibliographies and biographies of distinguished researchers in pertinent fields, historical materials, etc.
AGH University of Science and Technology Press
Online environment for data acquisition from car sensors
Modern cars are equipped with a lot of electronic devices called Electronic Control Units (ECU). They collect diagnostic data from different car components to control their work, assess the quality of their work and and detect defects. Regardless of the development of on-board computers in cars, only a small amount of information is passed on to the driver. The paper describes how to build a data collecting environment for acquisition real data from a car. The system whose components include an Android based smartphone and Torque PRO application is able to send data via the Internet in real-time to the chosen server. The collected data can be further analysed both on-line and off-line.
Copyright (c) 2019 Automatyka/Automatics
A novel method to simplify Boolean functions
Most methods for the determination of prime implicants of a Boolean function depend on minterms of the function. Deviating from this philosophy, this paper presents a method which depends on maxterms ( minterms of the complement of the function) for this purpose. Normally maxterms are used to get prime implicates and not prime implicants. It is shown that all prime implicants of a Boolean function can be obtained by expanding and simplifying any product of sums form of the function appropriately. No special form of product of sums is required. More generally prime implicants can be generated from any form of the function by converting it into a POS using well known techniques. The prime implicants of a product of Boolean functions can be obtained from the prime implicants of individual Boolean functions. This allows us to handle big functions by breaking them into product of smaller functions. A simple method is presented to obtain one minimal set of prime implicants from all prime implicants without using minterms. Similar statements hold for prime implicates also . In particular all prime implicates can be obtained from any sum of products form. Twelve variable examples are solved to illustrate the methods.
A sufficient condition for existence of constantly nondominated trajectories in linear time-invariant systems
The paper considers multicriteria optimal control problem in linear time-invariant systems with a single bounded input. It is proven that under certain assumptions a state trajectory is nondominated throughout the whole control process if and only if it is yielded by a control signal which belongs to a particular class of bang-bang functions. Furthermore, an explicit formula relating hyperplanes tangent to attainable set and control switching times is presented.
Supervising control system for oriented PV using weather forecast
This paper is devoted to the problem of control of oriented PV using weather forecast. Described solution presents usage of fuzzy logic fundamentals in order to increase efficiency of PV system. Differs from most of related papers, it's using fuzzy logic in order to process weather condition numeric values as an input. All of necessary steps to reproduce proposed solution has been included. Artykuł ten jest poświęcony tematyce opracowania sterowania nadrzędnego ogniw słonecznych, za pomocą prognoz pogody. Przedstawione w nim rozwiązanie korzysta z podstaw logiki rozmytej, aby zwiększyć wydajność energetyczną ogniw solarnych. W odróżnieniu od większośći prac o podobnej tematyce, wnioskowanie rozmyte zostało użyte w celu przetworzenia danych numerycznych uzyskanych z prognozy pogody. Wszystkie komponenty potrzebne do odtworzenia rozwiązania zostały opisane w artykule.
Copyright (c) 2018 Automatyka/Automatics
On D-Decomposition of Periodically Sampled Hybrid Systems
The problem of the stability of nonunifomly sampled systems is considerate. To this aim, the D decomposition method for determining stability region in parameter space is introduced. Basing on obtained simulation results some comparisons of systems with dierent sampling patterns are considerate.
Asymmetric cryptography and trapdoor one-way functions
The asymmetric-key (public-key) encryption scheme is considered to be the most important discovery in the history of cryptography. It is based on the use of two complementary keys generated according to a chosen trapdoor one-way function (TOWF). Since its first implementation, asymmetric encryption has revolutionized our way of communicating as well as the safety of information transfer, and it is now widely used around the world for various purposes, especially in the field of online transaction security. The safety of the asymmetric-key scheme relies on the assumption that any known cryptographic attack using an efficient problem-solving algorithm will not be able to succeed in applying the inverse (decryption) function onto the cryptogram in a polynomial time without additional knowledge (secret information). The most-challenging aspect of creating a new asymmetric cryptographic algorithm is selecting a one-way function for encryption purposes and finding a trapdoor in its inverse. In this paper, the concept of public-key cryptography will be explained using the RSA algorithm as an example. In addition, the review of the most-important functions that are considered to be trapdoor one-way functions will be conducted.
Copyright (c) 2017 Automatyka/Automatics
Modelling of Unmanned Aerial Vehicle – Tricopter
This paper presents detailed models of small aerial unmanned vehicle’s subsystems like propeller, BLDC motor or Li–poly battery. Furthermore, more accurate dynamic model of Tricopter is described. This, multi–system model can be used to synthesize precise controller which may have the advantage in hazardous situations. W niniejszym artykule zaprezentowano modele poszczególnych podsystemów wchodzących w skład bezzałogowych statków latających. Opisano między innymi zespół napędowy składający się z silnika bezszczotkowego (BLDC) i śmigła oraz akumulator litowo-polimerowy. Dodatkowo zaproponowano dokładniejszy model dynamiki lotu tricoptera. Przytoczone modele można wykorzystać do syntezy bardziej optymalnego regulatora, który może mieć przewagę w krytycznych sytuacjach.
Wspomnienie o doktorze inżynierze Piotrze Tabakowskim
Design, construction and control of a spherical rolling robot with internal two-wheel cart
This elaboration presents a spherical rolling robot with a 2-wheel cart. The custom design of the hardware and control software is presented to demonstrate the solution. The robot was started to realize an autonomous task. The embedded robot control system is based on a 32-bit microcontroller and uses a Bluetooth module for wireless communication. The simplified model has been proposed and its parameters identified. The results obtained at the simulation and experimental stages are shown and compared. Finally, the robot’s motion was recorded and analyzed with the support of image signal processing techniques. W artykule przedstawiony został opis sferycznego robota mobilnego z napędem w postaci dwukołowego wózka. Praca prezentuje dedykowany układ mechaniczny, elektroniczny oraz oprogramowanie sterujące. System wbudowany robota jest oparty na 32-bitowym mikrokontrolerze oraz wykorzystuje bezprzewodową komunikację Bluetooth. Parametry uproszczonego modelu matematycznego robota sferycznego zostały zidentyfikowane, a wyniki symulacji porównano do rezultatów rzeczywistych eksperymentów. Analiza obrazu zarejestrowanego za pomocą zewnętrznej kamery pozwoliła na obserwacje trajektorii ruchu robota.
The use of EMG signal in human-machine interface
In this paper, the analysis and processing algorithms of EMG signals have been presented. The main purpose of the research was to verify the usefulness of EMG signals in controlling a bionic prosthesis or exoskeleton. The physiological nature of the EMG signal has been introduced. An original measurement system has been presented. Analysis of the time and frequency domains of the signal has been conducted to extract vital information that the signal carries. Methods of using the EMG signal as a control signal for devices that operate in a human-machine interface have been proposed. The result shows that a processed EMG signal can be used as a basis for a simple control system. W artykule przedstawiono analizę oraz propozycję algorytmów przetwarzania sygnału EMG. Głównym celem badań było sprawdzenie przydatności tego sygnału dla sterowania bioniczną protezą lub egzoszkieletem. W pracy został przedstawiony fizjologiczny charakter sygnału EMG. Przedstawiono autorski system pomiarowy. Przeprowadzono analizę sygnału w dziedzinie czasu i częstotliwości, aby wyodrębnić informacje, które niesie sygnał EMG. Zaproponowano sposoby wykorzystania sygnału EMG jako sygnał sterujący dla urządzeń, które działają w interfejsie człowiek-maszyna. Wyniki pokazują, że przetworzony sygnał EMG mogą być wykorzystywane jako podstawa dla prostego układu sterowania.
New approach in modelling of the patients behavior in Primary Health Care (PHC)
The purpose of this paper is to show the concept of simulation of Primary Health Care (PHC) patients behavior. There are two reasons for interest in this area. The first of them is the need for support in decision making regarding financing and management of PHC facilities on levels from national (Natonal Health Fund) to local (PHC provider). The second one is the lack of effective methods for such population modeling. In this paper author describe an idea of probability distribution modeling and present preliminary results of patient visits simulation over a period of a year. Celem artykułu jest pokazanie koncepcji symulacji zachowań pacjentów Podstawowej Opieki Zdrowotnej (POZ). Temat ten jest ważny z dwóch powodów. Po pierwsze model taki mógłby posłużyć w podejmowaniu decyzji w rozdzielaniu funduszy pomiędzy jednostkami POZ przez Narodowy Fundusz Zdrowia. Drugim z powodów jest obecnie brak efektywnych metod modelowania populacji POZ. W niniejszej pracy autor opisuje ideę modelowania populacji przy użyciu rozkładu prawdopodobieństwa i przedstawia wstępne wyniki symulacji dla wizyt pacjentów w ciągu roku.
Copyright (c) 2015 Automatyka/Automatics
The approximate location of imperfection in a unit circle using the spectrum of Laplace operator as a research tool
In the following article we will try to find the dependence between the location of imperfections in a closed domain and the spectrum of the Laplace operator for this region. In the theoretical part we will define the spectral problem which is solved by eigenvalues. These eigenvalues are dependent on location and size of the imperfection. However, we are interested in the inverse task which consists in localizing the imperfection of the domain on a basis of the spectrum of the operator. W artykule przeanalizowano zastosowanie widma operatora Laplace'a jako narzędzia do przybliżonej lokalizacji uszkodzeń w kole jednostkowym. W części teoretycznej zdefiniowano zagadnienie spektralne rozwiązywane za pomocą wartości własnych. Znalezione wartości zależą od położenia i rozmiaru uszkodzeń. W artykule został zdefiniowany problem odwrotny, który polega na znalezieniu miejsca uszkodzenia na podstawie znanego widma.
Copyright (c) 2014 Automatyka/Automatics
A Comparison between Integer Order and Non-integer Order Controllers Applied to a Water Levelling System
The purpose of this paper is to compare responses of two systems with two types of controllers: integer order PI controller and non-integer order PIλ controller (FOPI). Comparison is made on the grounds of time domain responses of waters level in tank. In order to design both of the controllers, numerical model is established and described. Synthesis method with use of simulated annealing optimisation method is developed for each controller. In order to do a correct comparison, the two control systems have the same designing parameters. Matlab/Simulink environment and numerical model are used to do the computing. Numerically designed controllers are verified experimentally with tank system. The obtained results show that using non-integer order PIλ controller instead of a ”traditional” PI controller in simple integrating systems is useless.
Analytic Method Grafpol TM of Synthesing Sequential Control Systems
This paper presents the Grafpol TM method and principles of synthesising sequential control algorithms by this method, as well as examples of applying this method for modelling processes and programming PLC controllers.
The article presents the problem of the use of flywheels as an energy storage. More specifically focused on the issue of the optimal shape for isotropic materials and shapes, for which you can analytically determine the internal stress. The optimality criterion takes into account parameters such as moment of inertia (stored energy) and energy density. Efforts were made to choose a compromise between these two conflicting values, and therefore have been used multi-criteria optimization methods.
A Thermal Model of the Building for the Design of Temperature Control Algorithms
This paper presents an efficient and effective method for modeling the temperature dynamics in buildings. The method relies on the simultaneous application of heat transfer and engineering thermodynamics principles. The model takes into consideration dissipated thermal power from the room (heat loses by conduction and ventilation) and applied thermal power to the room (radiator, solar, and internal heat gains). The model parameters can be determined uniquely from the geometry of the building and thermal properties of construction materials. The model can be used to research and validate the algorithms for thermal control in the building. An exemplary building structure is used to verify the theoretical analysis and mathematical formulation. The example includes creating the model, calculating the parameters, designing the temperature control algorithm, and making the simulations.
Time Stability of Computer Generated Control in Real-time
This paper is devoted to analyze time stability of robot arm controller. Controller is implemented on PC platform with Windows XP and Matlab/Simulink environment with additional toolbox RT-CON. Described robot is 3 DOF Stanford Arm. It is powered with high torque, gearless electrical engines. The analyze of jitter effect influence on robot period moves was made. Experiment was made with PD and PD extended by neural network controllers. During experiment the test of influence of stressed system on control generation was made.
Application of Fuzzy Cognitive Maps to Analysis of Development Scenarios for Academic Units
For many classes of problems it is difficult to make decisions, assessments or develop plans based on precise quantitative models. Fuzzy Cognitive Maps (FCM) are a well-known tool for qualitative analysis of systems that uses a simple representation of knowledge in the form of a graph of concepts linked by causal relationships. Advantages of FCMs are the ease of gathering and representing knowledge and the simplicity of reasoning techniques, very close to neural networks. The paper gives results of experiments aiming at application of FCMs to analysis of development scenarios for research and teaching units. The analyzes were conducted for four representative classes of academic units: strong, medium, weak with a development potential and weak; their results are discussed and several observations related to reasoning with FCMs are made.
FPGA Based Hardware Accelerator for Parallel Robot Kinematic Calculations
The paper presents an application of FPGA to support the calculation of the inverse kinematics problem of a parallel robot. The presented robot is designed for milling by moving the spindle along a desired trajectory generated in Cartesian space. This means that for each point of the trajectory solution of the inverse kinematics problem is needed. The resulting sequence of data creates the joint space trajectory. The trajectory in joint space must be calculated in real time. Required high frequency and complex equations makes the problem of the calculation time crucial. The paper shows how to increase the computing power for inverse kinematics problem solving, preserving required calculation accuracy, by augmenting the arithmetic coprocessor with custom instructions. The paper shows hardware implementation of the accelerator and presents results of calculations per-formed on Altera FPGA chip.
Application of Android OS as Real-time Control Platform
This paper presents an application of an Android device to control a laboratory Antilock Breaking System (ABS). The controllers to avoid the locking of the wheel are considered. The architecture of Android OS is given. The discussion is focused on the features of the Android helpful to build real-time control systems. The mobile phone acts as a controller performing the control algorithm of avoiding the locks of the wheel. The controller application is implemented in Java which is the basic Android development language. The controller use only standard system functions without the use of real-time extensions. The results of experiments show punctuality of control task running on Android. Also the braking experiments are given. The conclusions include comments on the applicability of Android devices as a platform for real-time control.
Rapid Design and Development of Control Applications for Electrical Engineering
This paper presents a control application programming concept based on attributive logic and context-based reasoning. General features and benefits. comparing with other contemporary approaches, are given. The proposed solution is targeted at electric machine tests and diagnostics. An illustrative example of programming an induction motor no-load test which compares the proposed solution with a Matlab-based application is also given.
An Approach to Guidelines Implementation in an E-health System Supporting Chronic Care
Guidelines developed in line with Evidence-Based Medicine paradigm usually take form of narrative recommendations formulated on the basis of available evidence resulting from clinical trials and other types of studies. For past ten years there were developed several Formal Guidelines Representation languages that attempted to express them in form of algorithms or processes. Analysis of specific requirements related to e-health and in particular telemonitoring systems indicated, that a process oriented formalization of guidelines is in this case inappropriate, as such systems should be reactive, event driven and enable adaptation to cope with the quality of entered data. In this paper we describe an approach to guidelines implementation in the e-health system. Contrary to various FGR languages developed earlier the decision support will be based on the set of fuzzy rules that on the technical level will be implemented as XQuery transformations of XML data. We discuss this approach on an example related to the management of bronchial asthma, as customization of the system to this disease was selected as one of the proof-of-concept exemplifications of the system.