| 摘要 |
PURPOSE:To attain to enhance detection accuracy, by constituting the titled apparatus so that the distance up to the end surface of a piston is operated on the basis of the ratio of detection values by both ultrasonic sensors mounted to both ends of a cylinder and detecting the distance up to the end surface of the piston. CONSTITUTION:Ultrasonic sensors 10, 10 for detecting the distance up to the end surface of a piston 8a are respectively mounted to both end surfaces of the cylinder tube 8b of a hydraulic cylinder 8 and the distance up to the piston 8a is operated on the basis of the detection values of both sensors 10, 10. The detection signal of an inclination sensor 9 is inputted to a first operation circuit 11 to operate the extension and contraction quantity of the hydraulic cylinder 8 necessary for making a rotary plowing apparatus 4 horizontal as an objective control value L0. In parallel to this operation, the time required before the ultrasonic sensors 10, 10 receive an ultrasonic wave is inputted to a second operation circuit 12 to operate the actual stroke value (l) of the cylinder 8. Values L0, (l) are inputted to a control circuit 13 and an order signal for driving the cylinder 8 is outputted to a drive circuit 15 until the coincidence of both values is discriminated.
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