Patent ID: 9644651
Date: 2017-05-09
CPC Classifications: E02F,F02D,F04B,F15B

Claim:
1. A method for controlling a hydraulic system of construction machinery, the method comprising: a maximum value setting step, in which when a required torque value for a pump is generated, the required torque value is set to a maximum value; a power conversion step, in which a power value matched to a current load mode and the maximum value is output; an inclination limit step, in which a conversion speed of the power value per hour is limited; an engine speed prediction step, in which a virtual engine speed value is predicted based on a previously input engine speed; a PID control step, in which proportional integral derivative control is performed so that the actual engine speed converges toward the virtual engine speed; and a final power output step, in which the pump is controlled with a final power value obtained by adding a first power value determined by the current load mode, a second power value determined by the required torque value for the pump, and a third power value deduced by the PID control.