The conception of raising dynamic stiffness of electro hydraulic position servo system by flow feedforward compensation is put forward. First, the elementary principle of maintaining piston position unchanged under sudden external force load change by charging additional oil volume is analyzed. Then, a scheme using double servo valves to realize flow feedforward compensation is presented, in wh...

This paper proposes a novel active disturbance compensation framework for exactly positioning control of electro-hydraulic systems (EHSs) subject to parameter deviations, unknown dynamics, and uncertain external load without velocity measurement mechanism. In order accurately estimate then actively compensate the effects these uncertainties disturbances on system combination between an extended...

In order to study the numerical control (NC) servo press hydraulic control system and its control algorithm. The numerical control servo press performance and control principle of hydraulic control system are analyzed. According to the flow equation of the hydraulic control valve, hydraulic cylinder flow continuity equation and the force balance equation of the hydraulic cylinder with load pres...