Modelowanie układów sterowania z użyciem pochodnych ułamkowych

In the paper is presented review of some approaches corelated with subject of using fractional derivatives in control system theory. Popular algorithms used in the industry are presented, along with relating designing methodology. Using of fractional derivatives calculations is relatively new concept, but constantly getting increasing interest. Deliberation in recent years indicate that many scientific problems like thermodynamic or biology problems can be well considered and modeled by fractional order derivatives. On the market there is available tools that support a processes of identification and regulators designing, based on experimental data. One of such tools are toolbox CRONE for MATLAB, which contains three modules: mathematical, identifying, system control designing. That toolbox allows implementation of CRONE regulators with different level of complexity. Other tool is FOMCON, which also is a toolbox for MATLAB and it is based on already existed toolbox FOTF. FOMCON allows to identifying of control system and PIλDµ regulator designing. This article is aiming to present current state of art, discussion about existing tools and concepts correlated with fractional order derivatives and their usage in control system theory, like: gamma function, definition of fractional derivative, Laplace transform and basics of control system theory.

Analiza wpływu współ- czynników odbicia światła od powierzchni na obliczenia fotometryczne

The article presents the results of simulation tests carried out in the DIALux program concerning the influence of light reflection coefficients on photometric calculations. The analysis was made for two exemplary rooms for various purposes and for different capacities. For each of the rooms, the parameters of the calculation plane have been defined. The lighting fixtures were good depending on the work being done in each of the rooms and the height of the ceiling. The standard reflection coefficients for each room have been pre-assigned. The number of fittings and placement is planned in accordance with the lighting standard. Photometric calculations were made for different values of co-factors, while maintaining the initial values of the other two coefficients. The results obtained were compiled and compared in terms of the impact of variability of coefficients on average illumination and its uniformity. For extreme cases that do not meet the lighting standards, the optimized arrangement of the luminaires was proposed and the results obtained were presented. The research has shown that in the case of the rooms in question, the biggest influence on the results of photometric calculations has the reflectivity of light from the walls. Discrepancies between the intensity obtained in the case of smaller rooms indicate how important factor in the lighting design process is information about the planned interior design.

Kalibracja małej anteny pętlowej

The article presents examples of calibration of a small loop antenna, witch can be used to measure the magnetic component of the electromagnetic field. The source of such a field may be, for example, lightning. There are many methods of calibration a loop antenna. Two of them are presented below – using test antenna with is calibrated and with known parameters, and using a homogenous magnetic field generated inside Helmholtz coil. Measurements using the first method were carried out in the anechoic chamber of the EMC laboratory.

Performance analysis of write operations in identity and UUID ordered tables

Design of the database includes the decision about the physical storage. This is often overlooked as 1) this cannot be expressed in standard SQL and in result each Database Systems have their own way to specify the physical storage and 2) the decision is often made implicitly. This is dangerous situation as many of the databases use B+ trees as table implementation which stores the data physically sorted by some ordering attribute. The choice of the ordering attribute largely affects read and write operations. Commonly, IDENTITY/AUTO_INCREMENT constraint are being chosen as ordering attributes, due to their easy usage and monotonic nature. In some cases ordering tables by the attributes whose values are drawn from uniform distribution leads to better performance in terms of Transactions-Per-Second. Such cases includes situation when data does fit entirely in-memory or when we can limit the set of physical pages being accessed. In the end, however, We cannot entirely say that either monotonic or random attributes are superior. Both have their pros and cons. In this article We present (1) short description of the data structures in contemporary Database Systems, (2) the advantages and the disadvantages of the two common types which are used as the clustering attributes: GUID and IDENTITY, (3) performance analysis of write operation which compare both data types using B+ tree as primary storage and (4) evaluate the efficiency of these bulk load operation using heap files and B+ trees.

Wielopoziomowe przekształtniki energoelektroniczne – topologie, zasada działania, metody modulacji

In this paper selected issues concerning topological structure, operation and control as well as modulation methods used in multilevel converters are presented. There is reviewed general topologies of multilevel converters, which include Diode-Clamped Converters, Capacitor-Clamped Converters, Cascade Converters and Hybrid Converters. The general structure of a multilevel converter consisting of several stages depending on its application and topology is described. In the structure of operation, the stages of Outer Control Loop, Inner Control Loop, DC voltage stabilization and modulation are specified. Next, the division of modulation methods used in multilevel converters is presented and a detailed description of selected modulation methods is made. In the further part of the article the modulation methods were described in detail, i.e. the Level-Shifted Carrier Modulation Technique and Phase-Shifted Carrier Modulation Technique were used to present the analysis of power losses in multilevel converters.

Sterowanie i konstrukcje bezszczotkowych silników prądu stałego

The article presents the working principles and construction of a brushless DC motor. The BLDC motor control methods were discussed, including the division into methods using sensors for determining the rotor position and sensorless methods with an example of implementing BLDC motor control using microcontrollers. High efficiency and high durability as well as falling prices of electronic components and controllers cooperating with BLDC motors in recent years have caused a growing interest in this type of motors. The design of BLDC motors does not require the use of brushes, which in traditional brush motors supply voltage through the commutator to the rotor windings. Brushless motors are characterized by high efficiency, durability and reliability. The use of sensors in BLDC motor control systems increases the number of motor and commutator connections, thereby reducing the reliability of the drive system. For this reason, direct position and speed measurements are often abandoned for the use of sensorless control methods. DC brushless motors have various application areas, and due to their reliability and the ability to control speed, they are used, among others, in electric vehicles, medicine and industry.

Pomiary wysokości i prędkości lotu małego samolotu bezzałogowego z wykorzystaniem rurek Prandtla

Reliable measurements of the air velocity flowing around the wings of the aircraft and the altitude at which the aircraft is located are necessary for controlling the unmanned aircraft. Due to the need to use automatic flight stabilization processes, unmanned aircraft require a minimal delay in the measuring path. For correct measurement of these quantities, a system based on two measuring lines using backflow tubes was built. This article describes the effects of a research project carried out by the Student Scientific Group of Electronics at the Rzeszów University of Technology, who were seeking a reliable and quick solution with increased accuracy.

Wielokryterialna optymalizacja zużycia energii w domu jednorodzinnym z modyfikacją preferencji entropią

The article discusses examples of solutions that reduce energy consumption in a single-family home. 7 variants were selected to optimize energy consumption and 6 criteria, which describe the designated solutions. The validity value of the adopted criteria was chosen and four preference variants were subjectively determined for them. The data was then collected in a table and normalized to be able to use the weighted sum method to determine the best solution. In the next step, the entropy method was used and the subjective preferences adopted earlier, were used to determine the way to optimize electricity in a single-family home.