A Cavitation Avoidance Strategy in Hydraulic Switching Control Based on a Nonlinear Oscillator

In hydraulic switching control a cavitation critical phase is the switching from the pressure to tank line. A high tank line pressure can generate a fast onset of the flow from the tank line into the system and can avoid cavitation in this way. But for energetic reasons the tank pressure should be kept low. In this paper a method to boost the tank pressure considerably by applying a nonlinear oscillator is presented. Its performance is studied in combination with a `Hydraulic Buck Converter`. The mechanisms of generating cavitation are explained and rules for a proper dimensioning are derived by simplified mathematical models. Due to the nonlinearity a complex system behaviour may occur, like for instance a non periodic response of the oscillator.