Open loop control of stepper motors reduces system cost and complexity for positioning systems. To produce a precise current waveform, a novel open loop control implementation of a hysteresis current controller (HCC) is presented and compared to the existing pulse width modulation (PWM) method. The new method extends the resolution available for a given sampling rate, allowing finer control of the motor current. Applications for precision positioning minimize external disturbances but a real, nonideal, motor introduces vibration and non-uniform motion. Microstepping of the drive waveform approximates a continuous motion to reduce these effects but they are not fully modelled or understood. The proposed current controller is assembled with a hybrid stepper motor to verify the method experimentally. A differential evolution (DE) optimizer is applied with the complete physical system in the loop. To measure vibration, a low cost contact microphone is used, eliminating the requirement for expensive rotational sensors. This method is shown to reduce vibration across different speeds. Comparing the microstep positions of a standard sinusoidal waveform and the waveform optimized to reduce vibration, an improvement in position accuracy is also found.

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