| 摘要 |
A motor grader has a control system in which the manner of controlling the blade position differs depending upon whether the blade is to be moved vertically or is to be maintained at a generally constant level and cross slope. First and second hydraulic valves control the flow of hydraulic fluid to the first and second hydraulic cylinders which raise and lower respective ends of the blade. An inclinometer provides an inclinometer output indicating the inclination of the blade along its length with respect to horizontal. The control system includes a first hydraulic cylinder position sensor for determining the extension of the first hydraulic cylinder. The control system further includes a control that is responsive to a control input specifying the desired height and cross slope of the blade, to the first hydraulic cylinder position sensor, and to the inclinometer output. The control provides valve control signals to the first and second hydraulic valves. The control provides a first valve control signal to the first hydraulic valve in dependence upon a desired height specified by the control input, and the control provides a second valve control signal to the second hydraulic valve in dependence upon the inclinometer output and upon the cross slope specified by the control input. However, when the blade is to be moved upward or downward with the retraction or extension of the first cylinder, the control provides the second valve control signal to the second hydraulic valve in dependence upon the first hydraulic cylinder position sensor such that the second hydraulic cylinder retracts and extends with the first hydraulic cylinder, maintaining the cross slope angle of the blade as a constant.
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