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Za prenašanje velikih sil in navorov pogosto uporabljamo hidravlične sisteme. Ti nam omogočajo kompaktno obliko, dolgoročno stabilnost in samo mazalnost. Hidravlični valj je eden glavnih sestavnih delov hidravličnih sistemov in se uporablja za kontroliran prenos moči. Različne dajalnike pomika uporabljamo predvsem pri avtomatiziranih sistemih. Glede načina merjenja se merilniki delijo na optične, induktivne, magnetne in tiste s principom vrtinčnih tokov. Glede na izhodni signal pa jih delimo na inkrementalne, absolutne in navidezno absolutne merilnike. Nogi obstoječega humanoidnega robota sta sestavljeni iz šestih hidravličnih valjev. Za nadaljnji razvoj humanoidnega robota je nujno potrebna vgradnja merilnikov pomika v vse njegove hidravlične valje. V okviru naloge so bile pregledane vse možnosti merjenja pomika batnic hidravličnih valjev na trgu. Izdelan je bil tridimenzionalni model hidravličnih valjev ter predvidena vgradnja različnih merilnikov pomika. Primerjana je bila cena in funkcionalnost posameznih rešitev ter izbrana najprimernejša. Izbran merilnik je bil vgrajen v hidravlična valja, preizkušeno je bilo njegovo delovanje in ocenjena uporabnost. We often use hydraulic systems to transmit large forces and torques. These enable us to have a compact design, long-term stability and self-lubrication. The hydraulic cylinder is one of the main components of hydraulic systems and is used for controlled power transmission. Various feed encoders are mainly used in automated systems. Regarding the measurement method, gauges are divided into optical, inductive, magnetic and those with the principle of eddy currents. According to the output signal, they are divided into incremental, absolute and quasi-absolute meters. The legs of the existing humanoid robot consist of six hydraulic cylinders. For the further development, it is necessary to install displacement gauges in all its hydraulic cylinders. As part of the task, all options for measuring the displacement of the pistons of hydraulic cylinders on the market were examined. A three-dimensional model of the hydraulic cylinders was made and the installation of various displacement gauges was planned. The price and functionality of individual solutions were compared and the most suitable was selected. The selected gauge was installed in the cylinder, its operation was tested and its usefulness was evaluated.

Trend razvoja hidravličnih sistemov stremi k vedno bolj zanesljivim, preciznim sistemom. V skladu s tem razvojem in namenom preprečevanja potencialnih poškodb občutljivih komponent naraščajo zahteve po čistoči sistemov. V kolikor se vgrajenih in generiranih nečistoč ne odstrani, krožijo po sistemu in povzročajo poškodbe hidravličnih sestavin. Sistem se učinkovito očisti nečistoč z izpiranjem. Literatura si ni enotna, katere komponente se lahko izpira in kakšna je spodnja vrednost Reynoldsovega števila Re, s katerim sistem temeljito očistimo oprijete kontaminacije. Naš namen je bil definirati najnižjo vrednost Reynoldsovega števila Re s katerim je možno sistem temeljito očistiti in katere komponente se lahko izpira skupaj s sistemom. V ta namen smo eksperiment strukturirali v več faz. Na preliminarnem sistemu smo preizkušali in primerjali različne metode izpiranja, in sicer: izpiranje z vročim oljem, izpiranje z vročim oljem in nizkim pretokom ter izpiranje s turbulentnim tokom. Na realnem sistemu smo ugotovili, da se hidravličnega valja in ohišja filtra ne da izprati s sistemom. Realni sistem smo nato izpirali z različnimi vrednostmi Re in primerjali učinkovitost izpiranja s posameznim Re. Ugotovili smo, da je spodnja vrednost Re za temeljito izpiranje sistema 4000, optimalna vrednost Re za obravnavan sistem pa je bila 10000. Recent trends in hydraulic systems have shown that precision and reliability are among the most desirable characteristics. To minimize potential damage to sensitive components, special attention should be paid to the cleanliness of hydraulic systems. If contaminants generated during manufacture and maintenance processes, or generated during operation, are not removed from the system, they can cause damage to components. The hydraulic system can be cleaned by flushing, but various sources are unclear about which components of the system can be cleaned by flushing. The objective of our study was to determine the minimum value of Reynolds number Re at which the system can be effectively cleaned and to determine which components within the system can and should be flushed. We set up our experiment in several stages. On a preliminary system, we tested different flushing methods – flushing with hot oil flushing with hot oil and low flow and flushing using turbulent flow. On a real system, we found that the filter housing and the hydraulic cylinder could not be cleaned by flushing. In an effort to optimize the cleaning method, we tested various Re values and finally concluded that the minimum Re value for effective cleaning is 4000, but the optimum Re value for our system is 10 000.

Varnostni ventil je prisoten v vsakem hidravličnem sistemu, saj ščiti pred tlačno preobremenitvijo. Ker se s spreminjanjem števila zaporedno delujočih aktuatorjev spreminja tudi tlak, moramo hidravlični sistem v vsaki situaciji ustrezno tlačno zaščititi. Gre za varnostni ventil, kateremu je možno s pomočjo krmiljenja spremeniti nivo nastavljenega tlaka. Raziskali smo več konceptov rešitve problema, jih vrednotili in izbrali najprimernejšega. Pri tem so bili ključni kriteriji kompaktnost, enostavnost izdelave in cena. Izbrani koncept rešitve smo natančno dimenzionirali ter izdelali prototip in opravili meritve. Zaključili smo z ugotovitvijo pomanjkljivosti glede na meritve in montažo prototipa ter s predlogi za izboljšavo. A pressure relief valve is part of every hydraulic system because it protects against pressure overload. When the actuators in the system change, the pressure also changes, so it is necessary to protect the system from the new pressure that is created. This is a pressure relief valve, that can be modified by controller to change the level of set pressure. We studied several concepts to solve the problem, evaluated them and selected the most suitable one. The main criteria were compactness, ease of manufacture and price. The selected solution concept was carefully designed, a prototype was developed and measurements were performed. We completed the identification of deficiencies in terms of measurements, installation of the prototype and suggestions for improvement.

Jadrnica Shipman 63 v dolžino meri približno 20 metrov. Zaradi svoje velikosti ima jadrnica veliko komponent, ki jih ni moč upravljati ročno, pač pa potrebujemo pomoč hidravličnih oz. električnih sistemov. V diplomski nalogi je predstavljen opis jadrnice in že obstoječih komponent, ki potrebujejo hidravlično krmiljenje. Predstavljen je opis delovanja posameznih komponent ter zasnova hidravlične sheme. Določene so hidravlične črpalke, ventili, rezervoarji in ostale hidravlične komponente. Izdelan je 3D model hidravlične napeljave, predstavljen je opis krmiljenja posameznih aktuatorjev ter podana finančna ocena celotnega hidravličnega sistema. The sailboat Shipman 63 measures approximately 20 meters in length. Due to its size, the sailboat has many components that cannot be operated manually, but we need the help of hydraulic or electrical systems. The thesis presents a description of the sailboat and existing components that need hydraulic control. A description of the operation of individual components and the design of the hydraulic scheme are presented. Hydraulic pumps, valves, reservoir and other hydraulic components are specified. A 3D model of the hydraulic installation is made, a description of the individual actuators is presented, and a financial assessment of the entire hydraulic system is given.

Pri žaganju z vertikalno tračno žaga ima pomembno vlogo črpalka, s pomočjo katere se opravi premik debla proti žagi. Pri visokih tlakih daje črpalka zadosten pretok za hiter gib debla, pri nizkih tlakih pa je hitrost nižja. Zaključno delo raziskuje delovanje aksialne batne črpalke s spremenljivo iztisnino, vzrok za omenjen problem in rešitve. Pumps play an important role at sawing with vertical band sawmill, because it helps with moving trunk toward saw. At high pressures the pump gives a sufficient flow for quick movement and at low pressure flow is lower. The final work examines operation of the axial piston pump with variable displacement, the cause of the called problem and solutions.

Microtransat Challenge je mednarodno tekmovanje prečkanja Atlantika z avtonomno jadrnico brez človeškega nadzora. Ta mora prepluti Atlantski ocean med Evropo in Ameriko. Največji izziv predstavlja krmilni sistem, ki skrbi da jadrnica pride do cilja. V diplomski nalogi je predstavljeno konstruiranje krmilnega sistema ter poleg tega rešitev problema oddušnika. Predstavljen je nov hidravlični sistem jadrnice ki vsebuje hidravlično črpalko, tri hidravlične valje, povezovalne cevi ter vrvenico za krmiljenje dveh jamborov in krmila. Izdelan je 3d model novega hidravličnega sistema jadrnice ter izvedene meritve porabe električnega toka. V diplomskem delu je prikazana vgradnja celotnega krmilnega sistema. The Microtransat Challenge is an international race crossing the Atlantic with a selfpropelled yacht without human control. It must cross the Atlantic Ocean between Europe and America. The biggest challenge is the steering system, which ensures that the boat reaches its destination. The thesis presents the design of the control system and the solution to the vent problem. A new hydraulic sailboat system is presented, featuring a hydraulic pump, three hydraulic cylinders, connecting tubes and a rope for steering two masts and rudders. A 3d model of the new hydraulic system of the sailboat has been made, as well as a measurement of electricity consumption. The diploma thesis shows the installation of the complete control system.

V magistrski nalogi je opisan postopek od začetne faze projekta, projektnih zahtev do delujočega prototipa. Potrebno je bilo razviti nizkotlačni recipročni hidravlični sistem, ki bo deloval pri tlakih do 1 MPa, pri pretoku 5 l/min in frekvenci preklapljanja 10 Hz. V prvem delu naloge je predstavljeno stanje tehnike in začetki razvoja hidravličnega sistema za kontrolirano recipročno gibanje kapljevine. Ovrednoteni so koncepti, ki so bili kasneje bolj podrobno analizirani. V nadaljevanju so predstavljeni izdelani prototipi. Na končnem prototipu so bile opravljene meritve in analiza padca v odvisnosti od pretoka. Pri meritvah smo izmerili padec tlaka med priključkoma P in A 0,072 MPa, med priključkoma P in B pa 0,131 MPa. Izračunani padec tlaka med priključkoma P in A 0,38 MPa ter med priključkoma P in B 0,44 MPa. Zaradi odstopanja meritev in izračunanih rezultatov smo ponovno izdelali numerično analizo po metodi CFD za ugotovitev, koliko se je bat dejansko odmaknil od sredinske lege. Ugotovili smo, da je bil problem v hidravličnem batu, ker se je odmaknil za 1,5 mm, namesto 3 mm. Na koncu so podane še smernice za nadaljnji razvoj. In the Master's thesis is presented the process from the initial stage of the project, from the design requirements to the working prototype. During the project duration it was necessary to develop low-pressure reciprocating hydraulic system, which will sustain pressures up to 1 MPa, flow 5 l/min and be able to change direction of fluid at frequency 10 Hz. The first part presents the state of the art and the beginning of the development of the hydraulic system for hydraulic fluid flow control in the desired direction. Evaluated concepts were later analysed in details. In continuation of the thesis are presented working prototypes. On the final prototype measurements and analysis of the fluid pressure drops were made. We measured pressure drop between ports P and A 0,072 MPa and between ports P and B 0,131 MPa. The calculated pressure drop between ports P and A was 0,38 MPa and between ports P and B 0,44 MPa. As a result of the large deviation measured and calculated data, we made another CFD numerical analysis, to determine the distance hydraulic piston made during operation. We have determined that the problem was in the hydraulic piston, which moved only for 1,5 mm from centreline instead of 3 mm as expected. At the end of the thesis we presented guidelines for further development.

Na področju energijske učinkovitosti industrijskih pogonskih sistemov se pojavljajo vedno strožji predpisi in zahteve za zmanjšanje porabe energije in izpustov toplogrednih plinov pri čemer hidravlični sistemi niso izvzeti. Energijsko učinkovitost hidravličnih sistemov lahko izboljšamo tako, da izboljšamo izkoristek posameznih sestavnih delov hidravličnega pogona, in tudi tako, da izboljšamo koncept vodenja oziroma regulacije takšnega sistema. V smislu slednjega so v doktorski disertaciji predstavljeni trije možni pogonski sklopi, ki temeljijo na volumetričnem principu regulacije hidravlične energije. Zasnovani so matematični modeli vseh komponent pogonskih sklopov, tako da je omogočena statična in dinamična simulacija izkoristka vseh pogonskih sklopov. Rezultati, pridobljeni s simulacijo, so nato preverjeni še na preizkuševališču pogonskih sklopov. Na podlagi rezultatov so zasnovani različni regulacijski koncepti, med drugim tudi nov koncept, ki omogoča sledenje najvišjemu izkoristku hidravličnega sistema. Regulacijski koncepti so med seboj primerjani tako v simulaciji kot tudi praktično na preizkuševališču. Doktorska disertacija se dotakne tudi ionskih tekočin, ki imajo velik potencial, da postanejo hidravlične tekočine prihodnosti. Ker se stisljivost ionskih tekočin razlikuje od stisljivosti hidravličnega olja ter ima velik vpliv na dinamiko in energijsko učinkovitost hidravličnih sistemov, je poudarek predvsem na stisljivosti in merjenju stisljivosti ionskih tekočin. Na koncu disertacije je predstavljen še modul za brezžični zajem podatkov, ki ga je možno preprogramirati tudi tako, da lahko izvaja vse predstavljene regulacijske algoritme. In the field of energy efficiency of industrial drives new strict energy regulations for minimizing energy consumption and carbon footprint and hydraulic systems are no exeption. Energy efficiency of hydraulic systems can be either improved by improving efficiency of all the components used in such a system or by improving control concept of such system. This dissertation presents all three possible drive concepts, which are based on volumetric principle of hydraulic energy control. Mathematical models of all of the components used are created. A static and dynamic simulation of efficiency of all concepts can be predicted using these models. Results obtained using the simulations are later verified on a test-stand. Some new control concepts are developed based on the acquired data. This new control concept is designed in such way, that it can track maximum efficiency of the hydraulic system. All the control concepts are also compared in simulation and on the test stand. Doctoral dissertation also evaluates ionic liquids, which have a great potential to become hydraulic fluids of the future. Since the compressibility of ionic liquid differs from the compressibility of hydraulic oils and has a great impact on the dynamics and energy efficiency of hydraulic systems, dissertation focuses on the compressibility measurements of the ionic liquids. At the end, a module for wireless data acquisition is presented. This module can be also reprogrammed to execute all of the presented control concepts.