Control method on serial type pump-valve coordinated electro-hydraulic servo system

In order to compromise the conflicts between control accuracy and system efficiency of conventional electro-hydraulic servo systems, a novel pump-valve coordinated electro-hydraulic servo system was designed and a corresponding control strategy was proposed. The system was constituted of a pump-controlled part and a valve-controlled part, the pump controlled part is used to adjust the flow rate of oil source and the valve controlled part is used to complete the position tracking control of the hydraulic cylinder. Based on the system characteristics, a load flow grey prediction method was adopted in the pump controlled part to reduce the system overflow losses, and an adaptive robust control method was adopted in the valve controlled part to eliminate the effect of system nonlinearity and parametric uncertainties due to variable hydraulic parameters and system loads on the control precision. The experimental results validated that the adopted control strategy increased the system efficiency obviously with guaranteed high control accuracy.