| 摘要 |
PURPOSE:To raise the followability and accuracy of a power shovel by using a system in which the first insensitive zone to be varied with the number of engine revolutions and the pressure of oil-pressure circuit is put out by a compensatory voltage generated by a compensating circuit having a sufficiently smaller second insensitive zone than the first insensitive zone. CONSTITUTION:A master lever 10 is provided with angle sensors 11 and 12 to detect the corresponding angle of boom angle alpha and arm angle beta, and the operating section of the boom 1 and arm 2 of the actual device is provided with angle sensors 21 and 22. In the detection of boom angle, for example, the signals of the sensor 11 and the sensor 21 as the target value of boom angle are added to a compensating circuit 33 by taking a deviation at the adding point 31. When the deviation voltage exceeds the insensitive zone, step voltage corresponding to the number of engine revolutions and the circuit pressure is generated to put out the insensitive zone, a compensatory voltage is added through an amplifier 51 to a servo valve 52, a flow rate control valve 61 is moved, and a given flow rate of pressure oil is supplied to the boom cylinder 4. |
