An improved method and apparatus for making an accurate cut with a crop shear (12) while the workpiece (11) speed is changing and the shear knife (24, 26) is in an acceleration phase. A shear acceleration factor based on the change in the speed of a workpiece (11) during the acceleration phase for the shear drive (28) is added to a 'position trim' value to adjust the speed and position of the shear knife (24, 26) in order to compensate for the change in the workpiece speed during the acceleration of the shear knife (24, 26). The 'position trim' value is derived based on the calculated angular velocity reference to the shear drive speed controller (18) at the moment when the velocity of the workpiece (11) changes during the acceleration process, and based on a desired angular velocity of the shear knife in view of the change of workpiece (11) speed.
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