Abstract: According to the present invention, a hydraulic system of construction equipment is implemented as a close center system, which converts an input signal of an electric or hydraulic joystick into a speed signal of a work apparatus, and controls a speed of the work apparatus regardless of an external load condition, thereby minimizing fatigue of a worker to improve work efficiency, improving a work apparatus operation ability of an unskilled person, and patterning standardized work to implement automation of construction equipment.

Abstract: According to the present invention, a hydraulic system of construction equipment is implemented as a close center system, which converts an input signal of an electric or hydraulic joystick into a speed signal of a work apparatus, and controls a speed of the work apparatus regardless of an external load condition, thereby minimizing fatigue of a worker to improve work efficiency, improving a work apparatus operation ability of an unskilled person, and patterning standardized work to implement automation of construction equipment.

Abstract: An independent flow rate controlling hydraulic system for pressure control of an excavator, in which a hydraulic system of the excavator can be variably controlled via independent flow rate control. The hydraulic system includes a plurality of actuators which actuate a working apparatus, a pressure control-type hydraulic pump which feeds working fluid to the actuator, first and second electronic proportional control valves which are disposed at a piston-side inlet flow path and a load-side inlet flow path connected from the hydraulic pump to the actuators, third and fourth electronic proportional control valves which are disposed at a piston-side outlet flow path and a load-side outlet flow path connected from the actuators to a hydraulic tank, and a control unit which variably controls areas of the flow paths by controlling the first, second, third and fourth electronic proportional control valves depending on an amount by which a control stick is manipulated.