Experimental analysis of instability and self-oscillations in an electrohydraulic servo drive

The tendency to self-oscillations is one of the most important problems of closed-loop hydraulic systems. In actual systems losses occur, variation of the transmitted energy and the strength of the system structural elements are always limited. This is the reason why self-oscillations are most often present. The main purpose of the research is to reveal the mechanisms of instability and self-oscillations in an electro-hydraulic servo drive to make a numerical simulation of the drive characteristics. A servo drive has all the conditions for the generation of self-oscillations: the oscillatory element – the movable member of the drive and a column of elastic liquid, the source of energy. Regular oscillations in a drive are maintained due to the energy of compressed liquid, feedback, non-linear character of generated and absorbed energy etc. An experimental analysis of a servo system of the FESTO training simulator was carried out. The aim of the research was to accumulate materials for the development of mathematical models that would adequately represent the main properties of actual systems.