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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 Experimental testing of the vehicle heating system
Kucybała P., Gawlik A.
Journal of KONES
|
2017
|
Vol. 24, No. 3
135--141
EN
An important problem in the design of machinery and equipment at the stage of determining their structure is the issue of providing adequate thermal comfort to users while operating in variable climatic and environmental conditions. This issue is of particular importance because all types of machinery and devices are equipped with very expensive and automated control and monitoring system, which should guarantee adequate warming conditions and should work under different climatic conditions. Examples of these tendencies are special solutions for vibroacoustic insulation of the inside of the devices, special air conditioning equipment, special constructions, ergonomic inside solutions. The process of shaping the discussed structural design of vehicles in terms of meeting the relevant technical and operational criteria is currently being increasingly realized through experimental tests of prototypes supported by numerical calculations. The purpose of this paper is to present the methodology of conducting test stand as a stage for the experimental determination and verification of temperature distribution, the location of heating and air conditioning devices in a prototype vehicle in variable climatic conditions (minus 15º C). The research was carried out in a large-scale climate chamber. It covered the process of heating up the passenger area of the bus and the time of temperature stabilization on the inside of the vehicle while operating the heating systems. An additional attempt was made to test the heating system while the vehicle was in motion and to open the vehicle door to simulate the stopping of the vehicle at the bus stop. Another aspect that was analysed was the impact of the installed convector on the vehicle when the liquid heater was off.
3
Content available Dynamic weighing system used in excavator
Gawlik A., Kucybała P.
Journal of KONES
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2017
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Vol. 24, No. 4
31--38
EN
In many industrial applications is taken to consider change of payload potential energy while lifting it. It allows obtained directly benefits. For example, the cost of material loaded on a dump truck in a composition of coal is generally priced by its weight. In this case, the truck has to pass a stationary scale twice to identify its payload, before and after loading. Measuring weight of the material instantly while loading the truck, increases the efficiency of the process and makes a stationary scale unnecessary. In addition, it is possible to prevent overloading of means of transport, which use public roads, and can be weighed by the road service. The typical solutions of the static and dynamic weighing system from market were compared. The theoretical model is presented basing on geometrical and mass parameters of excavator CAT 301.5. The weighing system used in off-road machines is usually based on the measurement of the working fluid pressure in the piston chambers of the hydraulic cylinders, which lift the machine work equipment together with a payload. In this article is shown a solution with load pin, which allows the determination of the load mass independently of the several factors affecting the classic weighing system. The possibility of payload mass measuring on the excavator was estimated during tests on prepared research stand. There were obtained a good agreement of experimental research results with the mathematical model.
4
Content available The use of digital hydraulic to the position control of hydraulic cylinder
Kucybała P., Sobczyk A.
Journal of KONES
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2016
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Vol. 23, No. 3
297--302
EN
The article presents the method of controlling the position of the hydraulic cylinder using hydraulic valves on/off with an appropriate strategy for digital control. Main elements of the hydraulic system under consideration include a group of electromagnetic hydraulic valves and hydraulic cylinder single acting. The control system was implemented in the environment of the real-time system based on MATLAB/Simulink. The digital control strategy is based on a fast enough on and off switching valves causing corresponding motion of the cylinder to the required position. This article presents the advantages and disadvantages of this type of control about the system with the proportional control system. The accuracy of this kind of control depends on the structure, properties of the valves or their static and dynamic characteristics. The results of analysis of the control system have the possibility of controlling the positioning hydraulic cylinder with a rather high accuracy, which can be used in place of proportional control systems. The use of digital control system allows, under certain conditions to obtain cost savings related to a reduction in energy consumption, to get a much better adaptation to variable control systems. This concept is an interesting alternative for the conventional control system and provides opportunities for application in systems, where conventional control is very expensive e.g. water hydraulics or to the clear systems where the use of hydraulic proportional technique is not necessarily, but depends on the user to the possibility of obtaining good quality control at a relatively low cost.
5
Content available Modelling accuracy of a car steering mechanism with rack and pinion and McPherson suspension
Knapczyk J., Kucybała P.
International Journal of Applied Mechanics and Engineering
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2016
|
Vol. 21, no. 3
751--759
EN
Modelling accuracy of a car steering mechanism with a rack and pinion and McPherson suspension is analyzed. Geometrical parameters of the model are described by using the coordinates of centers of spherical joints, directional unit vectors and axis points of revolute, cylindrical and prismatic joints. Modelling accuracy is assumed as the differences between the values of the wheel knuckle position and orientation coordinates obtained using a simulation model and the corresponding measured values. The sensitivity analysis of the parameters on the model accuracy is illustrated by two numerical examples.
6
Content available The control system for a manipulator with two degrees of freedom for water hydrostatic transmission drive
Kucybała P., Sobczyk A.
Journal of KONES
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2015
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Vol. 22, No. 3
125--132
EN
The article presents concepts of control of the manipulator with two degrees of freedom, which uses a water hydraulic power unit to drive the actuators. The proposed control system is based on the use of electromagnetically controlled “rosettes valve” and proportional flow control valve. The control system is implemented using a computer equipped with a module for the real-time operating system (XPC Target) working in connection with the environment Matlab/Simulink. Controlled variable of the drive system is the displacement of the individual hydraulic cylinder and after determining manipulator kinematics, any point of the object in operating space. The positioning error of individual manipulator elements will be determined during the test in terms of different control algorithms, using the PID controller and PWM signal. In addition, it analyses the impact of changes in the velocity of the piston rod for the boom mechanism and the arm mechanism. An important aspect of the presented hydrostatic drive system is the use of water as a medium that physical and chemical properties are different from commonly used hydraulic oil, and which is friendly to the environment and meet the high cleanliness requirements for the fluid used to transfer the hydrostatic energy. Therefore, the control system requires a different approach, tied with synchronous control valves ON/OFF and proportional control flow regulators to achieve high accuracy.
7
Content available The wireless hydrostatic transmission control by the use of mobile technology
Kucybała P., Pobędza J., Sobczyk A.
Journal of KONES
|
2014
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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.
8
Metody modelowania akumulatora hydropneumatycznego stosowanego w układach hydraulicznych
Kucybała P.
Przegląd Mechaniczny
|
2013
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nr 3
37--43
PL
W artykule przedstawiono metodę modelowania akumulatora hydropneumatycznego na przykładzie akumulatora tłokowego stosowanego w układach hydraulicznych m.in. jako wtórne źródło energii. Opracowany został model matematyczny akumulatora ze szczególnym uwzględnieniem równań opisujących zachowanie się gazu w akumulatorze (między innymi równanie Van der Waalsa i Benedicta-Webba-Rubina). Otrzymane wyniki z badań symulacyjnych dla różnych modeli gazu porównano z badaniami uzyskanymi podczas testów doświadczalnych i dokonano oceny, który z przyjętych modeli najlepiej odzwierciedla przebiegi parametrów rzeczywistego akumulatora.
EN
The paper deals with the simulation model of hydro-pneumatic accumulator. Mathematical model of the system uses the motion and flow continuity equations, as well as, formulas determining hydro-pneumatic piston accumulator behavior. A few models of real gas were used to calculate gas parameters in accumulator (eg Van der Waals and Benedict-Webb-Rubin eguations) and numerical model of the accumulator was elaborated. Simulation tests were performed for different work cycles and compared with experimental tests to determine which models accurately reflects the behavior of the real hydro-pneumatic accumulator.
9
Wózek widłowy z hybrydowym układem napędu i odzysku energii
Kucybała P., Soczyk A.
Hydraulika i Pneumatyka
|
2012
|
nr 4
29-32
10
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.
11
Badania komfortu cieplnego w prototypowych kabinach dźwignicowych
Michałowski S., Cichocki W., Kucybała P.
Maszyny Dźwigowo-Transportowe
|
2003
|
nr 3-4
48--55
PL
W referacie przedstawiono metodykę prowadzenia badań komfortu cieplnego kabin operatorów maszyn roboczych, wskazując iż dla celów optymalizacji parametrycznej na etapie komputerowych obliczeń symulacyjnych niezbędnym jest dysponowanie odpowiednią bazą danych szeregu wielkości między innymi takich jak: współczynniki strat cieplnych przez poszczególne elementy struktury konstrukcyjnej kabiny. Prezentacji metody dokonano na przykładzie realizacji badań stanowiskowych prototypowej kabiny dźwignicy, ktore zostały wykonane w komorze termoklimatycznej Politechniki Krakowskiej.
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