Abstract: A motor 12 (FIG. 2) is controlled to move at a demanded velocity, input at 29, by sampling the position of the motor at sample intervals, digitally determining the demanded change in position per sample interval, modifying each position sample by the addition of said demanded change, comparing the modified position value with the previous modified sample to derive a position error signal representing the position error between the instantaneous position and that demanded by motion at the demanded velocity, and applying the position error signals from successive sample intervals to motor drive means.