A Novel Method of Controlling a Hydraulic Actuator with Four Valve Independent Metering Using Load Feedback

A revolution in mobile hydraulic equipment is occurring. Conventional hydraulic spool valves with hydromechanical pressure compensators are being replaced by valve assemblies with four valve independent metering with electronically-controlled pressure compensation. In the system described here, two of the four independent valves are active during metering. This new topology offers significant advantages due to the two degrees of freedom provided.

In this paper, the theory behind a new method of flow control based upon load feedback is presented for two of the five distinct metering modes. In addition, a new algorithm for setting the supply pressure is presented which is also based upon load feedback.