Observer-based and energy saving control of single-rod electro-hydraulic servo system driven by servo motor

This paper addresses the energy saving problem in single-rod electro-hydraulic servo system (EHSS) driven by servo motor. Firstly, the performance of key components in EHSS is analyzed and tested locally and globally to pursue better control effect. Then, an energy saving controller containing three control variables is proposed. The servo valve controller is designed based on ARC to guarantee a prescribed output tracking transient performance and final tracking error. The relief valve controller is constructed based on disturbance observer to estimate the unknown disturbance-load force without a force sensor. The servo motor controller is designed via a grey model to predict the displacement of load. From these three sub controllers, the supply pressure and supply flow rate can be derived and controlled to achieve energy saving. Finally, the proposed method was validated by comparative experiments, which shows this control strategy can reduce about half of the power consumption.