Method of controlling hydraulic device

A method of controlling a hydraulic device, comprising:

• a comparison step of comparing a measured load of a hydraulic device driven by a hydraulic pump with an allowable load of the hydraulic device;
• and
• a control step of controlling a flow rate of the hydraulic pump based on a result of comparison between the measured load and the allowable load,
• wherein an engine drives the hydraulic pump, and the hydraulic pump drives a hydraulic motor,
• wherein an engine torque calculation value is calculated based on a discharge pressure of the hydraulic pump, a suction pressure of the hydraulic pump, and a rotation speed of the hydraulic motor or a flow rate of the hydraulic motor,
• wherein an allowable engine torque value is predetermined based on a rotation speed of the engine or an amount of operation of an operation unit for operating the engine,
• wherein in the comparison step, comparison is performed between the engine torque calculation value as the measured load and the allowable engine torque value as the allowable load, and
• wherein in the control step, when the engine torque calculation value is expected to exceed the allowable engine torque value, the flow rate of the hydraulic pump is reduced by adjusting a control valve.