Figure 1: Depicted is the power consumption of open loop vs. closed loop stepper systems. Consider a side-by-side comparison of a traditional, open loop step motor system and a fully closed loop ...

At that point, the motor returns to the open-loop mode and steps normally. After the final step, the rotor tooth returns to align with the torque vector and the accuracy becomes +5 arc min (0.083°).

A system for control of pointing and guiding of the Moore Observatory 21-inch (52-cm) telescope is described. Its key features are open-loop stepper motor positioning, an on-line star catalog and ...