Nonlinear Behaviour, Including Jump Resonance, of Hydraulic Servomechanisms

Abstract

The harmonic response of an electrohydraulic servomechanism operated under certain conditions is investigated. Its nonlinear characteristics are apparent in the experimental results and include among its peculiarities the jump phenomenon. It is shown that the nonlinear effects of interest are contained in the equations which are formulated. The mathematical model is modified to a form which allows of a simplified analogue programme and of analytical treatment by the application of Duffing's method to the open loop. Closed loop behaviour is then predictable by the use of the authors' general method. Finally, general criteria are obtained for the occurrence of the jump phenomenon and for the boundaries of linear operation in hydraulic servos.