Host based stepper motor phase controller and method therefor

Abstract

The invention is a host-based stepper motor controller that reduces velocity overshoot and settling time. A typical embodiment of the invention will include a stepper motor, a carrier mechanically coupled to the stepper motor, a processor for controlling the stepper motor and a driver circuit allowing communication between the processor and the stepper motor. The processor control reduces velocity overshoot and settling time by guaranteeing that each move begins on the stepper motor phase that optimally reduces velocity overshoot and settling time. The processor generates an initial value indicative of the extent of a current move of a carrier mechanically coupled to a stepper motor. Next, the start phase of the current move is determined along with the direction of the next move. Based on the initial value, the current move start phase and the next move direction, the initial value is adjusted to a new value where the new value is indicative of a move that causes the next move to begin on the optimal start phase of the stepper motor predetermined to minimize velocity overshoot and settling time. The new value is communicated directly or after translation to the driver circuit causing the stepper motor to move the carrier the appropriately.