HYDRAULIC PUMP DRIVING SYSTEM CONTROLLER

PURPOSE:To change it to an input torque limited value commensurate to working details or working surroundings as well as to aim at economy in energy without entailing any drop in operation efficiency, by installing a desired displacement setting device, which sets the desired displacement of a discharge controlling device in accordance with a signal out of a compensating device for a revolving speed deviation, in a controlling part. CONSTITUTION:A deviation DELTAN between a desired revolving speed Nr and an output revolving speed N is inputted into a function setting part 24. And, a functional value RN and a functional value RM made up of inputting the said revolving speed Nr into a function setting part 23 are both inputted into a minimum value selecting part 25. Of which the side of the value being smaller is outputted as a rack command value RL. And a deviation DELTAR between th command value RL and a signal value R of a signal 10a is amplified at an amplifier 26, outputting it to a rack driving device, and the deviation DELTAR is approximated to zero, namely, the desired revolving speed Nr. On the other hand, when a compensating command signal 7a (a signal value S) of a deviation DELTAN is inputted into a function setting part 27, a compensating command value DELTAS is outputted whereby a deviation compensation value DELTAN' is outputted to both function setting parts 28 and 29, outputting regulator desired deflections XL1 and XL2. Deviations DELTAX1 and DELTAX2 between these deflections and a tilting value are controlled to be adjusted to zero.