Control device for hydraulic machine

A control device for a hydraulic machine comprising a plurality of hydraulic actuators that are driven by oil ejected from a variable displacement type hydraulic pump driven by an engine, wherein:

• the control device is configured to control a flow rate of the oil ejected from the hydraulic pump to achieve a target value of a differential pressure between an ejection pressure of the oil ejected from the hydraulic pump and a load pressure of oil supplied to the hydraulic actuators;
• a control pressure for changing the target value of the differential pressure is generated as a secondary pressure of an electromagnetic proportional valve;
• the control device comprises a first calculation unit and a target engine rotation number detection unit both provided in the hydraulic machine, and a storage unit, a second calculation unit, and a measured value detection unit which are provided outside of the hydraulic machine, the measured value detection unit configured to detect an actual supply oil flow rate or its substitute numerical value for at least one of the hydraulic actuators;
• the first calculation unit is configured to calculate a control output value to become a basis for a current value to be applied to the electromagnetic proportional valve, according to an engine rotation number detected by the target engine rotation number detection unit;
• the storage unit is configured to store, for the at least one of the hydraulic actuators, a designed supply oil flow rate value or its substitute numerical value in a specific drive state for the at least one of the hydraulic actuators, the specific drive state being a state assumed when the at least one of the hydraulic actuators is driven with a specific engine rotation number and a specific manual operation amount;
• the second calculation unit is configured to calculate a correction coefficient for the control output value, by comparing the actual supply oil flow rate or its substitute numerical value detected by the measured value detection unit when the at least one of the hydraulic actuators is actually driven in the specific drive state, with the designed supply oil flow rate value or its substitute numerical value stored in the storage unit;
• and
• the control output value calculated by the first calculation unit is corrected with the correction coefficient calculated by the second calculation unit.