Header height correction system and method

An agricultural machine for rapidly moving a header to a harvesting position comprising:

• a main frame supported above the ground by ground engaging mechanisms;
• a rockshaft pivotably coupled to the main frame for rotation about a first axis;
• a lift actuator coupled at a first end to the main frame and at a second end to the rockshaft to facilitate pivoting motion of the rockshaft relative to the main frame;
• a lift arm pivotably coupled to the main frame for rotation about a second axis parallel to the first axis;
• a header configured to harvest crop, the header being coupled to and supported above the ground by the lift arm;
• a float actuator pivotably coupled to the lift arm for rotation about a third axis, the third axis being parallel to the first axis, wherein the float actuator provides an upward force to the lift arm, thereby cooperating with the lift arm to support the header above the ground;
• at least one valve fluidly coupled to the float actuator and configured to move between open and closed positions to change the pressure in the float actuator;
• and
• a controller configured to send electrical signals to the at least one valve to execute a rapid height correction algorithm, which extends or contracts the float actuator causing a change in height of the header relative to the ground, in response to receiving terrain data including ground contours and receiving correction data associated with at least one of a current height of the header and a current pressure of the float actuator;
• wherein contraction of the float actuator is configured to occur independent of pivoting motion of the rockshaft relative to the main frame.