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1
Content available Binary valves in analog control
Mielewczyk A.
Journal of KONES
|
2017
|
Vol. 24, No. 2
141--146
EN
Continuous control systems are built with standard transducer measured signal, the controller and actuator. The actuator is responsible for the direct setting of the size of the control object. The actuator is connected to the control valve and the actuator position change signal into the flow rate of the working medium. Since the operating element is required the linear characteristics in the standard signal range to work. The other hand, the control valve provides flow characteristics linear or equal percentage. This flow control principle is used in various control systems. The actuator of the control valve is always equipped with a positioner, which corrects errors in the position of the valve relative to the input signal. The presented design of the control valve is an analogue system. Using the technique of converting multiple digital signal causes, the system is susceptible to damage. Remove the intermediate elements can improve the quality control and safety system. Such benefits give a design of the operating element based on direct digital processing unit and control program. The examples of control present article.
2
Zawór regulacyjny o sterowaniu cyfrowym
Mielewczyk A.
Zeszyty Naukowe. Mechanika / Politechnika Opolska
|
2015
|
z. 106
70
PL
Układy automatyki ciągłej standardowo są zbudowane z przetwornika wielkości mierzonej, regulatora i siłownika. Siłownik odpowiada za bezpośrednią nastawę wielkości sterującej obiektu. Siłownik jest połączony z zaworem regulacyjnym i zmiana pozycji siłownika przekłada się na zmianę natężenia przepływu medium roboczego. Od elementu roboczego wymaga się liniowej charakterystyki pracy w zakresie sygnału standardowego. Natomiast zawór regulacyjny oferuje charakterystykę przepływu liniową lub stałoprocentową. Taka zasada regulacji przepływu czynnika jest stosowana w różnych układach sterowania. Siłownik z zaworem regulacyjnym zawsze wyposażony jest w ustawnik pozycyjny, który koryguje błędy w pozycji zaworu względem sygnału regulowanego. Przedstawiona konstrukcja zaworu z siłownikiem jest układem analogowym. Stosując technikę cyfrową, wielokrotne przekształcanie sygnału powoduje układ złożony i podatny na zakłócenia i uszkodzenia. Wyeliminowanie elementów pośrednich może poprawić jakość sterowania i bezpieczeństwo systemu. Takie zalety ma mieć konstrukcja zespołu wykonawczego oparta o bezpośredni zespół przetwarzania cyfrowego. Celem pracy jest przedstawienie konstrukcji zaworu wykonawczego, który całkowicie rezygnuje z przetwornika cyfrowo-analogowego. Nowa konstrukcja powinna podnieść poziom bezpieczeństwa systemu i jakość sterowania.
3
Content available Modern actuator
Mielewczyk A.
Journal of KONES
|
2014
|
Vol. 21, No. 2
221--226
EN
The main engine of the ship is a complex technical object, which provides propulsion of the screw and ensures the safety of a ship at sea. It consists of a number of control systems such as lube oil temperature control, temperature control of the cooling water, fuel viscosity control or adjustable speed control of the main engine. Each of the main propulsion control system affects the safety of the ship. Continuous automation systems are built with standard transducer of measured quantity, the controller and actuator. The actuator is responsible for the direct setting of the size of the control object. The actuator is connected to the control valve and the actuator position change translates into a change in the flow rate of the working medium. Thus, the operating element is required to operate in the linear characteristics of the standard signal range. From the other hand, the control valve provides flow characteristics linear or of equal percentage. This control principle of medium flow is used in various control systems. The actuator of the control valve is always equipped with a positioner, which corrects errors in the position of the valve relative to the input signal. The presented design of the motorized valve is an analog system. Using the technique of converting multiple digital signal causes the system complexity and predisposition to damage. Eliminating the intermediate elements can improve the quality control and system safety. Then it is beneficial to have a design of the operating element based on the direct digital processing unit. The aim of paper has been to present design of the valve actuator, which completely abandons the digital-to-analogue convertor. The new design should increase the level of security of the system and quality control. The design layout is presented in the article. The new actuator is on-off valves, which control, directly from the digital bits, the form of the output signal. The control signal may use the control algorithms to be used or developed individually to the actuator design.
4
Content available Linearization of the ship equations of motion
Mielewczyk A.
Journal of KONES
|
2013
|
Vol. 20, No. 2
269--275
EN
In real systems are non-linear mathematical description. The exact solution can not be determined, and then look for approximate methods. Important is the type of nonlinearity, solutions and error method approximation. Linearization is an essential part of creating a model of the selected process. Ship resistance is a function of power with exponent two and higher. Model motion of the ship must have a solution in terms of maneuverability speed and speed of the sea. The solution must be well reproduce the actual path of the transition and the transition time of the ship. Nonlinear solution method determines the accuracy of the answers. Has presented the revised approach to solve the nonlinear differential equation of parabolic function. Linearization has been made in the selected range, and not where you want it to work and solve the error estimate. Range of solutions selected by external priorities adopted. Before the solution is estimated response error. The error value determines whether the selected interval will apply. If the problem solution is unacceptable, it will increase the accuracy of the result of the narrow scope of the work. The new scope of work should also be reassessed a solution error. This type of approach correlates with fuzzy logic, where we use the value of the Boolean variable with the function of belonging. The combination of classical methods of solving differential equations of the theory of fuzzy sets can bring new benefits. Such a solution must have the function of the accuracy of the answers. The linearization method meets this requirement.
5
Content available remote Fuzzy–neuron Model of the Ship Propulsion Risk
Brandowski A., Mielewczyk A., Nguyen H., Frackowiak W.
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
|
2011
|
Vol. 5, no. 3
337--343
EN
A prediction model is presented of the ship propulsion risk, i.e. a risk of the consequences of loss of the ship propulsion capability. This is an expert model based on opinions elicited by the ship power plant operators. The risk level depends, among other things, on the reliability state of the ship propulsion sys-tem components. This state is defined by operators in a linguistic form. The formal risk model parameters are determined by means of a neural network. The model may be useful in the ship operation decision processes.
6
Content available remote Model wymiany ciepła w chłodnicy płytowej
Mielewczyk A.
Zeszyty Naukowe Akademii Morskiej w Gdyni
|
2010
|
nr 64
59-68
PL
Rozwijanie metod regulacji oraz symulacji cyfrowej wymaga dokładnych modeli urządzeń technicznych. W artykule przedstawiono model wymiany ciepła w chłodnicy płytowej. Został on wyznaczony na podstawie równań różniczkowych, co zapewniło wysoką dokładność. Poprawność modelu sprawdzono na danych chłodnicy M10 - MFM firmy Alfa-Laval.
EN
This paper presents exchange heat model in the plate cooler. It is calculated on base of partial differ-ential equation and Z-transform. This model is verified for cooler type M10 - MFM of Alfa-Laval company.
7
Content available remote Structure and electric properties of double magnesium zirconium orthophosphate
Mielewczyk A., Molin S., Gdula K., Jasiński G., Kusz B., Jasiński P., Gazda M.
Materiały Ceramiczne
|
2010
|
T. 62, nr 4
477-480
EN
Double magnesium zirconium orthophosphate (MZP) is a magnesium ion conducting material. In this work, an MZP structure and properties were studied, especially in relation to its possible application as an active material in gas sensors. Double magnesium zirconium orthophosphate was produced both by sol-gel and solid state methods. The phase composition of the material was studied by X-ray diffraction method. Influence of the synthesis method on the quality of obtained material was significant. The single phase material was obtained by the sol-gel method. The precursors (ZrOCl2•6H2O, NH4H2PO4 and Mg(NO3)2•8H2O) were dissolved in water, the solutions mixed and then dehydrated for 12 h using a hot plate at 75°C. Dried powder was ball milled for 12 h and then uniaxially pressed into pellets that were sintered at various temperatures in the range of 700–1200°C. The influence of a synthesis method on electric conductivity of the samples was investigated by impedance spectroscopy (IS). Cyclic voltammetry (CV) was used to examine the possibility of application of MZP as a sensor in the presence of various gases.
PL
Podwójny ortofosforan magnezowo-cyrkonowy (MZP) jest materiałem przewodzącym jony magnezowe. W prezentowanej pracy badano budowę i właściwości MZP, szczególnie w odniesieniu do jego potencjalnego zastosowania w czujnikach gazowych. Podwójny ortofosforan magnezowo-cyrkonowy wytworzono zarówno metodą zol-żel, jak i metodą reakcji w fazie stałej. Skład fazowy otrzymanych materiałów zbadano za pomocą dyfrakcji promieniowania rentgenowskiego. Wpływ metody syntezy na jakość otrzymanego materiału był znaczący. Metodą zol-żel otrzymano materiał jednofazowy. Prekursory (ZrOCl2•6H2O, NH4H2PO4 and Mg(NO3)2•8H2O) rozpuszczano w wodzie, roztwory mieszano i odwadniona na płycie grzejnej o temperaturze 75°C przez 12 h. Wysuszony proszek mielono w młynie kulowym i prasowano jednoosiowo aby uformować tabletki, które spiekano w różnych temperaturach z przedziału 700–1200°C. Wpływ metody syntezy na przewodność elektryczną próbek badano za pomocą spektroskopii impedancyjnej (IS). Woltamperometrię cykliczną (CV) w obecności różnych gazów wykorzystano do zbadania możliwości zastosowania MPZ jako czujnika gazowego.
8
Content available Propulsion risk of a seagoing ship prediction based on expert opinions
Brandowski A., Mielewczyk A., Nguyen H., Nguyen H., Frąckowiak W.
Journal of Polish CIMAC
|
2010
|
Vol. 5, no 2
29-40
EN
A prediction model of the ship propulsion risk is presented, i.e. a risk of the consequences of loss of the ship propulsion capability. This is an expert model based on opinions elicited by the ship power plant operators. The risk level depends, among other things, on the reliability state of the ship propulsion system components. This state is defined by operators in a linguistic form. The formal risk model parameters are determined by means of a neural network. The model may be useful in the ship operation decision processes.
9
Content available remote A fuzzy - neuron model of the ship propulsion risk prediction
Brandowski A., Mielewczyk A., Nguyen H., Frąckowiak W.
Journal of KONBiN
|
2010
|
No. 1 (13)
117-128
EN
A prediction model is presented of the ship propulsion risk, i.e. a risk of the consequences of loss of the ship propulsion capability. This is an expert model based on opinions elicited by the ship power plant operators. The risk level depends, among other things, on the reliability state of the ship propulsion system components. This state is defined by operators in a linguistic form. The formal risk model parameters are determined by means of a neural network.
PL
Przedstawiony został model predykcji ryzyka napędowego statku, czyli ryzyka konsekwencji utraty zdolności do realizacji przezeń funkcji napędu. Jest to model ekspertowy, oparty na opiniach uzyskanych od operatorów siłowni okrętowych. Poziom ryzyka zależy między innymi od stanów niezawodnościowych urządzeń systemu napędowego statku. Stany te wyznaczają operatorzy w formie lingwistycznej. Parametry formalnego modelu ryzyka wyznacza się siecią neuronową.
10
Content available A discrete model of the plate heat exchanger
Mielewczyk A.
Polish Maritime Research
|
2008
|
nr 2
71-76
EN
Developing numerical control methods requires precise models of technical machines. The article presents a discrete model of a plate heat exchanger. The model was worked out based on differential equations to secure high accuracy. Correctness of the model was verified using the data for the M10 – MFM cooler produced by Alfa-Laval.
11
Content available Numerical simulation of heat flow processes
Mielewczyk A.
Polish Maritime Research
|
2005
|
nr 4
22-25
EN
Numerical simulation methodis basedon mathematical models of physical processes, which describe run of a given process with a various accuracy. This paper presents a method for elaborating the computer simulation models based on differential equations. This makes it possible to obtain a high accuracy of representing dynamic features of a real process. The derived results are given in the form of numerical series. An example of modelling the dynamics of heat transfer through aflat wall is presented in the second part of the paper. Basing on the model one can simulate the process of operation of ship engine as well as such auxiliary devices as a cooler, evaporator, condenser, tank heating system etc.
12
Content available remote A simulation model of flow of working media within auxiliary systems of ship main engine
Mielewczyk A.
Polish Maritime Research
|
2002
|
Vol. 9, nr 2
21-25
EN
In the paper a non-linear model of hudraulic flow network as well as a way of its numerical solving is presented. The proposed flow network model can be applied to real-time simulation. In order to verify the model the simulation of main engine auxiliary systems was performed.
13
Content available remote A simulation model of plate cooler
Mielewczyk A.
Polish Maritime Research
|
2001
|
Vol. 8, nr 3
16-21
EN
Models of controled objects sre necessary for digital simulation of the industrial automatic control systems. The paper deals with three computational models of the plate heat exchanger, applicable to digital simulation at different accuracy levels, i.e. analytical, simplified and difference model. Calculation results of the analytical model ware compared with the producer's data of Alfa-Laval plate coolers.
14
Content available remote Computer simulation of control processes of ship power plant auxiliary systems
Mielewczyk A.
Polish Maritime Research
|
2000
|
Vol. 7, nr 3
24-28
EN
In the peper a way of forming numerical models of some ship power plant systems is presented, which makes it possible to monitor work of the entire system, control it, simulate failures and analyse phenomena occuring within the entire system. Particular elements of a simulated system are modeled by using theoretical description of physical phenomena occurring in it. Final results of such simulation obtained from a synthesis of basic elements is presented, as an example, for B672 ship systems.
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