Title: Modelling of electrohydraulic servo drive used in very low velocity applications

Authors: A. Milecki, A. Myszkowski

Addresses: Institute of Mechanical Technology, Poznan University of Technology, Ul. Piotrowo 3, 61-138 Poznan, Poland. ' Institute of Mechanical Technology, Poznan University of Technology, Ul. Piotrowo 3, 61-138 Poznan, Poland

Abstract: In the paper, the discussion is focused on modelling of the electrohydraulic servo drive with stepping motor and electric feedback linkage, which is capable of obtaining very low velocity. The main features of drive operation are described and some specific problem areas, due to the nature of very low velocity movement, are considered. Some important features of the servo drive flow control valve construction are outlined, with reference to modelling possibilities. For all drive elements i.e., the stepping motor unit, hydraulic valve and cylinder theoretical equations, characteristics and a simulation model were proposed. In particular, the shapes and characteristics of hydraulic flow valve window are given in detail. A prototype electrohydraulic servo drive with stepping motor has been designed, constructed and investigated. The investigation results (curves) of valve dead zone and clogging process are included into the model. Finally, the whole servo drive investigations results are compared with results obtained by simulation. Both results are very similar, which means that the proposed simulation model in the paper corresponds quite well to the real servo drive.

Keywords: modelling; electrohydraulic drives; servo drives; stepping motor; low velocity; simulation; electrohydraulic valves; motion control; valve gaps clogging; cold moulding presses; simulation.

DOI: 10.1504/IJMIC.2009.027211

International Journal of Modelling, Identification and Control, 2009 Vol.7 No.3, pp.246 - 254

Published online: 17 Jul 2009 *

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