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1
Content available The usage of a thermoclimatic chamber for technoclimatic tests of special vehicles and mobile machines
Kucybała P., Gawlik A., Pobędza J., Walczak P.
Journal of KONES
|
2018
|
Vol. 25, No. 2
199--206
EN
Constantly increasing technical and operational demands are set for modern manned and unmanned special vehicles, all − terrain vehicles, and mobile machines. Their producers must comply with very restrictive standards, strict legal regulations, and high customer requirements. They concern not only functionality and efficiency of described objects, but also resistance to the impact of environmental and climatic exposure. Vehicles and mobile machines must be adapted to work in different climatic conditions such as low and high temperature, variable humidity, wind, dustiness, rainfall, variable atmospheric pressure, solar radiation. Verification of the correctness of operation of all these systems installed in machines, vehicles and engineering units requires experimental research in specified and stable climatic conditions. These special conditions can only be implemented in a thermoclimatic chamber. Thanks to these researches, it is possible to confirm the effectiveness of solutions that allow machines to work in extreme climatic conditions, as well as to detect a number of defects and imperfections of the structure, unpredictable at the design stage. The article describes the research procedure certified by Polish Centre for Accreditation and discusses examples of technoclimatic research carried out recently in the thermoclimatic chamber of Laboratory of Technoclimatic Research and Heavy Duty Machines of Cracow University of Technology.
2
Content available Effectiveness of the active pneumatic suspension of the operator’s seat of the mobile machine in depend of the vibration reduction strategies
Chwastek S., Pobędza J.
Journal of KONES
|
2018
|
Vol. 25, No. 4
43--48
EN
Low speeds of heavy mobile machines combined with large inertia result in the excitation of low frequency vibrations. Dissipation of vibration energy in the case of unsprung machines is performed only through tires, which slightly reduces the intensity of vibrations. Effective reduction of vibrations of mobile machines is possible only with active or semi-active methods. In unsprung mobile machines, on the way of propagation of vibrations between the source of vibrations and the protected object (machine operator), are vibroisolation systems located. These are most often controlled seat suspensions. In the case of the active suspensions, it is necessary to provide external energy, e.g. in the form of compressed air. The compressed air has the advantage that it is generally available in working machines as the working fluid and has its environmentally friendly properties (leaks do not contaminate the environment). This article is the result of the continuation of work on active methods of vibro-activity lowering in mobile machines, which resulted in, among others, elaboration of simulation model of the active operator’s seat suspension with controlled pneumatic actuator and its experimental identification. In particular, it was verifying the effectiveness of the adopted solution made the identification the friction model and thermodynamic phenomena in the controlled pneumatic cylinder. The aim of this work is parametric optimization of the suspension system and searching for the optimal control strategy. Experimental tests were carried out under conditions of harmonic excitations, coming from the electromechanical vibration exciter with controllable pitch and frequency. Data acquisition system and control circuit of the proportional directional control valve, supplying compressed air to the actuator were implemented using MATLAB-Simulink Real-Time software.
3
Content available Effectiveness of the active pneumatic suspension of the operator’s seat of the mobile machine in depend of the vibration reduction strategies
Chwastek S., Pobędza J.
Journal of KONES
|
2018
|
Vol. 25, No. 3
93--98
EN
Low speeds of heavy mobile machines combined with large inertia result in the excitation of low frequency vibrations. Dissipation of vibration energy in the case of unsprung machines is performed only through tires, which slightly reduces the intensity of vibrations. Effective reduction of vibrations of mobile machines is possible only with active or semi-active methods. In unsprung mobile machines, on the way of propagation of vibrations between the source of vibrations and the protected object (machine operator), are vibroisolation systems located. These are most often controlled seat suspensions. In the case of the active suspensions, it is necessary to provide external energy, e.g. in the form of compressed air. The compressed air has the advantage that it is generally available in working machines as the working fluid and has its environmentally friendly properties (leaks do not contaminate the environment). This article is the result of the continuation of work on active methods of vibro-activity lowering in mobile machines, which resulted in, among others, elaboration of simulation model of the active operator’s seat suspension with controlled pneumatic actuator and its experimental identification. In particular, it was verifying the effectiveness of the adopted solution made the identification the friction model and thermodynamic phenomena in the controlled pneumatic cylinder. The aim of this work is parametric optimization of the suspension system and searching for the optimal control strategy. Experimental tests were carried out under conditions of harmonic excitations, coming from the electromechanical vibration exciter with controllable pitch and frequency. Data acquisition system and control circuit of the proportional directional control valve, supplying compressed air to the actuator were implemented using MATLAB-Simulink Real-Time software.
4
Content available Model identification of active pneumatic vibration reduction operator’s seat of mobile machines
Chwastek S., Pobędza J.
Journal of KONES
|
2016
|
Vol. 23, No. 4
55--62
EN
Low-frequency vibrations, generated in mobile machines during their driving, could be reduced only by use of active or semiactive methods. In conditions of low-frequency vibrations, energy dissipation in the machines tires slightly reduces the intensity of the vibration. Unsprung mobile machines are usually equipped with system of vibration isolation, which is located on the way of vibration propagation, between the vibration source and the protected object (the operator of the machine). Generally, controlled seat suspension is used. In the case of the active suspensions, it is necessary to provide external energy, e.g., in the form of compressed air. The compressed air has the advantage that it is generally available in working machines as the working fluid and has its environmentally friendly properties (leaks do not contaminate the environment). This article is the result of the continuation of work on active methods of vibro-activity lowering in mobile machines, which resulted in, among others, elaboration of simulation model of the active operator’s seat suspension with controlled pneumatic actuator. Currently aim of the study was experimental verification of the theoretical results; this verification was performed on the laboratory test bench. In the stand tests, special attention was paid on the assumed models of friction and thermodynamic phenomena in pneumatic actuator, as well as on the control system. Experimental tests were carried out under conditions of harmonic excitations, coming from the electromechanical vibration exciter with controllable pitch and frequency. Data acquisition system and control circuit of the proportional directional control valve, supplying compressed air to the actuator were implemented using Matlab-Simulink Real-Time software. Identification of the simulation model allows for getting the right parameters of the seat suspension. In addition, parametric optimization of the seat suspension system and functional optimization of control strategy would be possible in the next step.
5
Content available remote Innovative approach to postgraduate education in the field of fluid power technology
Pobędza J., Guzowski A.
Czasopismo Techniczne. Mechanika
|
2015
|
Y. 112, iss. 4-M
103--116
EN
The article presents the developed, innovative model of postgraduate education in the area of fluid drive and control technology, launched in the Cracow University of Technology. The program of postgraduate studies was elaborated in accordance with the CETOP guidelines. Characteristics of education on hydraulic and pneumatic systems are presented together with the proposed model of studies and its innovative components.
PL
W artykule przedstawiono opracowany i uruchomiony na Politechnice Krakowskiej innowacyjny model kształcenia podyplomowego z napędów i sterowania płynowego zgodny z wytycznymi CETOP. Pokazano charakterystykę kierunku, zaproponowany model studiów oraz jego innowacyjne elementy, zweryfikowane w zrealizowanych już dwóch edycjach zajęć.
6
Układ rekuperacji energii w mechanizmie obrotu koparki
Pobędza J.
Zeszyty Naukowe. Mechanika / Politechnika Opolska
|
2014
|
z. 103
151--152
EN
Excavator swing mechanism is one of the systems in which there is possibility to recuperate kinetic energy. This paper presents simulation model of hydrostatic system with hydraulic accumulator and valve control block, working as a secondary energy source. Based on simulation calculation it is possible to determine properties of such system, to calculate energy savings and also to test different energy management strategies.
PL
Dążąc do minimalizacji zużycia energii w maszynach roboczych prowadzo¬ne są różnorodne prace, zarówno nad poprawą sprawności poszczególnych ele¬mentów i podukładów jak również nad odzyskiem i ponownym wykorzystaniem energii potencjalnej i kinetycznej zmagazynowanej w poszczególnych mechani¬zmach w trakcie pracy maszyny [1, 2]. Mechanizm obrotu nadwozia koparki, obok mechanizmu jazdy, jest jednym z napędów, w którym występuje cykliczne rozpędzanie i hamowanie bryły o dużej bezwładności. Jest to zatem układ, w którym poszukiwać można odzysku energii kinetycznej w fazie zmniejszania prędkości kątowej nadwozia.
7
Układ rekuperacji energii w mechanizmie obrotu koparki
Pobędza J.
Transport Przemysłowy i Maszyny Robocze
|
2014
|
Nr 3
89--92
PL
Dążąc do minimalizacji zużycia energii w maszynach roboczych, prowadzi się różnorodne prace, zarówno nad poprawą sprawności poszczególnych elementów i podukładów, jak i nad odzyskiem oraz ponownym wykorzystaniem energii potencjalnej i kinetycznej generowanej w poszczególnych mechanizmach w trakcie pracy maszyny [1-3].
EN
Excavator swing mechanism is one of the systems in which there is possible to recuperate kinetic energy. This paper presents simulation model of hydrostatic system with hydraulic accumulator, working as a secondary energy source and valve control block. Based on simulation calculation it is possible to determine properties of such system and evaluate amount of saved energy, as well as, testing different energy management strategies.
8
Sterowanie silnika tłokowego zasilanego sprężonym powietrzem
Pobędza J.
Logistyka
|
2014
|
nr 6
8838--8845
PL
W artykule przedstawiono model symulacyjny tłokowego silnika pneumatycznego, przeznaczonego do napędu lekkich pojazdów o masie kilkuset kilogramów. W rozważanym silniku zastosowano układ rzędowy trzech cylindrów, przy czym przewidziano zastosowanie typowych siłowników dostępnych na rynku elementów pneumatycznych. W opracowanym modelu symulacyjnym szczególną uwagę zwrócono na opis procesów sprężania i rozprężania powietrza w komorach roboczych siłowników oraz na właściwe określenie natężenia przepływu przez zawory sterujące. W obliczeniach wykazano bardzo istotny wpływ wielkości zaworów na szybkość zmian ciśnienia w siłownikach. Przy opracowani układu sterowania, zastosowanych w silniku zaworów, wprowadzono dwa sygnały sterujące: sygnał nastawczy i kąt wyprzedzenia. Wykorzystując zbudowany model symulacyjny opracowano charakterystyki prędkości kątowej w funkcji sygnałów sterujących, dla różnej wartości momentu napędowego silnika oraz charakterystykę mocy. Wykazano istotny wpływ omówionych sygnałów sterujących na pracę silnika, w szczególności wyznaczono wartości kąta wyprzedzenia, przy których uzyskuję się maksymalną moc.
EN
The article presents a simulation model of the piston pneumatic motor, designed to drive light vehicles, weighing several hundred pounds. In the considered engine, system of three cylinders installed in one line, was used, wherein typical actuators, available on the market of pneumatic components were installed. In the developed simulation model, special attention was paid to the description of the processes of air compression and expansion in the cylinders chambers, as well as on appropriate determination of the control valves flow rate. The calculations showed a highly significant effect of the size of the valves on the rate of change of pressure in the actuators. The control system of valves, used in pneumatic engine, introduces two control signals: the degree of filling and the angle of advance. Based on developed simulation model, characteristics of the angular velocity as a function of the control signals for different values of engine torque and power characteristics has been elaborated. The significant effect of discussed control signals, on the engine operation, has been illustrated, in particular values of advance angle, at which maximum power is effected, was determined.
9
Content available The wireless hydrostatic transmission control by the use of mobile technology
Kucybała P., Pobędza J., Sobczyk A.
Journal of KONES
|
2014
|
Vol. 21, No. 2
169--175
EN
The paper presents the concept of a new approach for remote control and monitoring of parameters of mobile or stationary machines in real time on the example of the hydrostatic transmission drive test stand. The proposed system control and monitoring is the mobile system which is closely related with the three applications written in a different programming languages, such as: java (Android) – mobile application runs on the tablet, C language – server application joins xPC Target with tablet, PHP – admin panel to manage mobile control platform. Controlling of the hydrostatic drive stand is implemented using an application installed on the tablet. This application is connected with computer’s real-time (xPC Target) module, generated in Matlab. The computer with xPC Target is equipped with a measuring-control card, to which the control signals are transmitted. This hardware-software component plays the connecting role between machine and operator of the mobile platform installed on the tablet. The application allows observe important parameters such as pressure, volumetric flow rate, temperature, velocity, torque in real-time, as well as, it enable, by use of special graphic slider on the tablet’s screen, to set control parameters such as: speed of electric motor, the opening and switching positions of the directional valve, as well as, setting the load by pressure relief valve. Based on this system research related to the verification of system operation were performed for different setting of the hydrostatic transmission drive speed controller, and selected results are presented in the paper.
10
Content available Simulation of pneumatic motor used in pneumobile
Flis K., Pobędza J.
Journal of KONES
|
2014
|
Vol. 21, No. 3
89--96
EN
One of the alternative powertrain systems of cars, commercial vehicles and mobile machines are hybrid drives with pneumatic motors for compressed air. This paper presents a mathematical model and the results of simulation calculations of piston pneumatic motor. Mathematical model was based on the fundamental principles of mechanics, thermodynamics and rights of airflow. For simulation model parameterization, prototype of such engine was built and installed on dedicated test stand. Performed experimental research allowed achieving values of coefficients and components characteristics used for model estimation. One of the important tasks of this study was to create the control system of the compressed-air supplied engine. For this purpose an appropriate pneumatic and electronic component were selected and also an algorithm was created which would facilitate changing of the engine settings in order to obtain the best performance. Using elaborated simulation model, series of calculation were performed for different parameters of pneumatic motor, like cylinders diameter and stroke, length of the crank, compressed air pressure and valves size. A lot of attention was devoted to determine the influence of control system settings, such as valves opening and closing in reaction to crankshaft position, on motor properties. When discussing the results of calculations considerable attention was paid to the power, torque and efficiency values. To illustrate performance of designed engine, simplified model of light vehicle was used to calculate possible to achieve acceleration, velocity and travel distance.
11
Content available An analog-digital hydraulic cylinder velocity control system for mobile machines
Czyrek J., Pobędza J.
Journal of KONES
|
2014
|
Vol. 21, No. 3
59--66
EN
Hydrostatic drive systems with linear actuators are commonly used in variety of mobile machines and vehicles. One of important aspect of its operation is cylinder velocity control in variable operating conditions, such as different load, pump pressure and engine rotational velocity. The aim of this article is to create an algorithm, which would control velocity of a hydraulic cylinder used in such systems. One way to create cylinder velocity control system is to perform an identification, which would characterize this system. To do this work it was appropriate to use test stand with excavator equipment. The first part of the article includes the description of the stand and enumerates parts that compose it. Correct work of the control system is possible through use of a proper controller. For achieving a desired purpose, a PID controller was used with some modifications improving system's operation. The controller parameters were tuned based on the model of the system, obtained on the basis of estimation, for different operational conditions. To do this, a tool of MATLAB Simulink called Parameter Estimation was used. The control algorithm, in automatic mode, makes system tuning based on coefficients array. The final stage of the research work was to conduct verification tests, which let to assess a correctness of the created and proposed control system.
12
Rozdzielacze zaworowe z pokryciami powierzchni do układów hydrauliki wodnej
Pobędza J., Sobczyk A.
Hydraulika i Pneumatyka
|
2013
|
nr 1
9--13
13
Energy recuperation in hydrostatic transmission system
Kucybała P., Pobędza J.
Hydraulika i Pneumatyka
|
2008
|
nr 6
31-33
EN
The objective of this research is to elaborate simulation model of hydrostatic transmission with energy recuperation system of fork lift. Mathematical model of the system consists of motion and flow continuity equations as well as formulas determining hydro-pneumatic piston accumulator behaviour. Exemplary simulation results illustrate hydrostatic transmission system operation with energy recuperation.
PL
Opisano zagadnienia dotyczące zastosowania systemu odzyskiwania energii w układzie jazdy wózka widłowego z przekładnią hydrostatyczną. Przedstawiono model matematyczny przekładni hydrostatycznej z akumulatorem gazowym tłokowym. Podano wyniki badań symulacyjnych działania napędu jazdy z odzyskiwaniem energii.
14
Właściwości mechatronicznego układu sterowania z zastosowaniem wody jako cieczy roboczej w układzie wykonawczym manipulatora
Chwastek S., Pobędza J., Sobczyk A.
Hydraulika i Pneumatyka
|
2002
|
nr 6
49-51
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