Step motor control with microstepping technique

Nowadays, step motors have especially been preferred in some applications requiring precise positioning since they can easily be controlled. Being open loop controllable in many systems makes step motors superior to other motors. In this study, control of a step motor via micro-step driving technique is realized by the experimental setup. Closed loop control system is designed by micro-step driving technique in order to increase the number of steps of the selected stepper motor. Micro-stepping technique is based on torque control logic performed by measuring the current in the phase of the motor. To measure the phase currents, a current measuring circuit is used for each phase. PWM signal is generated for the phases by evaluating the measured current value via Arduino micro-controller board. Two four-quadrant DC motor drivers called as MC33926 are used in the system. In addition, DC Offset card is designed for adapting the negative feedback voltage to the measurement range of Arduino. The system response for different step splitting values of the step motor such as 1/4, 1/8, 1/16, and 1/32 is obtained by ensuring the control of the designed system. The phase currents are measured and compared for each step splitting value and different supply voltages. Key Words: Step motor, Microstepping, Control.