Abstract
The velocity of the load of the excavator working equipment is all the time variability. It makes harmfulness to operator and complex construction machinery. There are two ways in which flow control can be accomplished: using a variable displacement pump and using an orifice opening via a proportional valve. The load sensing system acts to reduce the supply pressure to the pressure compensated flow control valve reducing pressure losses across the valve. The pressure compensated flow control valves act to respond quickly to changes in the loads and to act as isolation valves for multiple loads. Velocity of the load is controlled by the variable displacement pump. In such a system, the transient response of the load is often unsatisfactory because it is difficult to quickly and accurately manipulate the pump displacement or change shaft speed. One way to achieve constant velocity is controlling the pressure drop across the valve and limiting it to a small value, independent of load pressure applied to a pressure compensated valve. A servo valve is added into the hydraulic system to realize the active control of working equipment velocity. The goal of this research is to explore how combine of servo valve and pressure compensated valve can be applied to control excavator working equipment velocity .
Keywords: Velocity, Load Sensing Pump, Servo Valve, Pressure Compensator, Control