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    Investigation of a Digital Hydraulic Valve Operated by Servo Motors
    (Eos Assoc, 2021) Ozalp, Adem Fatih; Polat, Refik; Cetinkaya, Celalettin; Cetin, Muhammet Huseyin
    This paper describes a new type of digital hydraulic valve run by two servo motors. Digital hydraulics is a cutting edge technology, which saves more exhausted energy than conventional hydraulic valves. It includes conventional valves, but its working principle is different. Similar or different size valves constitute a digital hydraulic valve assembly. When the assigned valves are opened, a certain amount of flow is obtained from the output of the valve assembly. To control a digital hydraulic valve, Pulse Number Modulation (PNM) Control technique is used for equal valve flow rates, while Pulse Code Modulation (PCM) is used for different valve flow rates. Valves are exerted by independently launched electric coils. Previous studies used controller board and external power booster circuits for coils. In this study, a new type of digital hydraulic valve is designed, manufactured, and tested with the PNM method. The studied valve body has two different valve groups. Every group includes 16 equal valves and 1 camshaft rotated by 1 servo motor. The servo motors are controlled by a PLC. The calculated performance index is found to be 5.1ms which is similar to the results of previous studies. The experimental results showed that the cam and servo motor controlled digital hydraulics is applicable to variable speed control hydraulic systems.
  • Küçük Resim Yok
    Öğe
    Investigation of a Digital Hydraulic Valve Operated by Servo Motors
    (Eos Assoc, 2021) Ozalp, Adem Fatih; Polat, Refik; Cetinkaya, Celalettin; Cetin, Muhammet Huseyin
    This paper describes a new type of digital hydraulic valve run by two servo motors. Digital hydraulics is a cutting-edge technology, which saves more exhausted energy than conventional hydraulic valves. It includes conventional valves, but its working principle is different. Similar or different size valves constitute a digital hydraulic valve assembly. When the assigned valves are opened, a certain amount of flow is obtained from the output of the valve assembly. To control a digital hydraulic valve, Pulse Number Modulation (PNM) Control technique is used for equal valve flow rates, while Pulse Code Modulation (PCM) is used for different valve flow rates. Valves are exerted by independently launched electric coils. Previous studies used controller board and external power booster circuits for coils. In this study, a new type of digital hydraulic valve is designed, manufactured, and tested with the PNM method. The studied valve body has two different valve groups. Every group includes 16 equal valves and 1 camshaft rotated by 1 servo motor. The servo motors are controlled by a PLC. The calculated performance index is found to be 5.1ms which is similar to the results of previous studies. The experimental results showed that the cam and servo motor controlled digital hydraulics is applicable to variable speed control hydraulic systems.
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    Öğe
    Investigation of the vibration effect of using single or double eccentric mass in the trunk shakers used in fruit harvesting
    (Elsevier - Division Reed Elsevier India Pvt Ltd, 2022) Cetinkaya, Celalettin; Polat, Refik; Ozalp, Adem Fatih
    Trunk shakers are widely used in the harvesting of tree fruits. The vibration produced by trunk shakers is obtained by rotating eccentric masses. In trunk shakers, a single eccentric mass is used as well as a double eccentric mass. However, there is no study on their effectiveness relative to each other if these eccentric masses are used single and double. In this study, the vibration effect of eccentric masses in trunk shakers is compared when they are operated in axial or parallel positions as a double mass instead of a single mass. For this purpose, a trunk shaker was designed for a stiff trunk tree and manufactured after mod-eling in 3D. The 3D model of the trunk shaker is simulated in ANSYS software. Afterward, experiments are carried out with the manufactured trunk shaker assembly. A trunk model (steel pipe) is vibrated by operating the eccentric masses at frequencies of 16.5 Hz and 25 Hz. Vibration graphics are obtained by making measurements for 2 s in the x and y axes directions at two different points of the tree model. The vibration results obtained in the simulations in ANSYS software are compared with the results obtained in the experimental study. In both simulations and experimental studies, it has been found that when double mass is used instead of single mass on trunk shakers, there is a decrease in the vibration values they produce. The vectorial resultant of the acceleration values produced by the masses at differ-ent positions in the x and y axes were compared proportionally. When the dual mass is used instead of a single mass, the greatest reduction in acceleration was obtained in dual-mass experiments (-14.6 % in experiments and-14.2 % in simulations) placed in parallel positions at 25 Hz frequency. These results show that the positions of the eccentric masses as well as their frequencies are critical for harvesting in a shorter time without damaging the tree trunk. It was concluded that the use of single eccentric mass trunk shakers may be more efficient for fruit harvesting on trees with very stiff trunks.(c) 2022 Karabuk University. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).