Dealing with input delay and switching in electrohydraulic servomechanism mathematical model

Abstract

Electrohydraulic servomechanisms represent a field of maximum attractiveness in many industrial fields for about 70 years, but special attention is paid in particular to the performance and quality of these automatic systems in flight controls of aircraft. Electrohydraulic servomechanism considered in this paper is modeled by five dimensional switched nonlinear systems of differential equations. Intrinsically, the mathematical model of the electrohydraulic servomechanism has several shortcomings: critical case for stability and switching type nonlinearity. The shortcoming of the critical case of stability was eliminated in this paper by naturally introducing the internal leakage between the two chambers of the hydraulic cylinder in the mathematical model. Instead, the control delay was introduced, also naturally. It is worth mentioning that this mixed problem, of the electrohydraulic servomechanism switching type delayed mathematical model, is quite difficult in itself and has not been considered, as far as we know.