Open-loop step motor control system

摘要

A motor control system that reduces noise while reducing power requirements but providing sufficient torque. A one-phase-on drive mode modified to microstep between "one phase on" positions is used to accelerate the motor in a non-linear manner to a maximum speed. The microstep drive modes have a constant period, and the step rate of the motor is increased by decreasing the number of microsteps in succeeding steps of the motor. A modified full step waveform maintains the motor at the maximum speed, where the current to one winding of the step motor changes polarity within one motor step while the other remains approximately constant providing increased smoothness in the drive and reduced noise. The polarity changes in accordance with the inductance and the compliance voltage of the motor. A one-phase-on waveform modified to include microsteps between "one phase on" positions later decelerates the motor in a non-linear manner, and the motor stops in a detent position until another waveform of steps in delivered to the motor.