The control current for the pressure control valve it reads out the set point control current (i) for

摘要

PROBLEM TO BE SOLVED: To avoid the influence of a manufacture error in the operation characteristic of a hydraulic system operating by means of a pressure control valve and/or the influence of a change owing to operation time by correcting a control current characteristic map so that a difference between the actual value and the target value of pressure amplitude is reduced when it exists. ;SOLUTION: Modulation current having prescribed amplitude is overlapped with control current and pressure amplitude generated by modulation current is detected. It is compared with the target value of pressure amplitude corresponding to prescribed amplitude. When a difference exists between the actual value of pressure amplitude and the target value of pressure amplitude, a control current characteristic map is corrected so that the difference is reduced. In the device, the characteristic map is stored in a controller 26 controlling a pressure control valve 12. A current target value Is which is to be supplied to the pressure control valve 12 from the controller 26 is shown in the characteristic map. The intensity of current supplied to the pressure control valve 12 is measured by a current measuring device 40 and it is controlled by feeding it back to the controller 26.;COPYRIGHT: (C)2000,JPO