| 摘要 |
<p>A method and apparatus for controlling an agricultural harvester (200) having a cut crop receiving header (202) coupled to a hydraulic (206). The header (202) applies a force against the ground that is adjusted by applying pressure to the cylinder (206). Proportional raise and lower valves (118, 120) control the pressure in the cylinder. A pressure signal representing cylinder pressure is received. The difference between the measured pressure and the setpoint is used to compute input signals, which are transmitted to the valves (118, 120). Cylinder pressure is maintained substantially at a setpoint, the setpoint being adjustable in response to varying terrain (220). The setpoint is set to a first value in falling terrain and a second value in rising terrain. At the top of a hill, the setpoint is reduced below the first value until ground contact is regained, and the pressure is recharged above the second value.</p> |
