Stepper motor principle and drive

Stepper motor principle and drive

1, stepper motor is a special motor used as a control, the electrical pulse signal converted into angular displacement or linear displacement of electromechanical components. The input amount of stepping motor is the pulse sequence, and the output amount is the corresponding increment displacement or step motion. Its rotation is at a fixed angle (known as "step angle") step-by-step operation, which is characterized by no accumulation error (100% accuracy), so widely used in a variety of open-loop control. Stepper motor operation to have an electronic device to drive, this device is a stepper motor driver, it is the control system issued by the pulse signal into the angular displacement of the stepper motor, or: The control system every pulse signal, through the drive to make the stepper motor rotation step angle. Therefore, the speed of the stepper motor is proportional to the frequency of the pulse signal. Therefore, the control of the frequency of the step pulse signal, the precise speed of the motor can be controlled, the number of stepping pulses, the precise positioning of the motor can be targeted. In normal motion, it has a fixed number of steps per week, and the rotational speed of the continuous stepping motion maintains a strict correspondence with the frequency of the input pulse, and is not affected by voltage fluctuation and load change. Because the stepper motor can directly accept the digital control, it is particularly suitable to use microprocessor control. 
2, stepper Motor drive through the subdivision drive, the step angle becomes smaller, such as the drive in the 10 subdivision state, its step angle is only the "motor Natural Step angle" of one-tenth, that is to say: ' When the drive is not subdivided in the full-step state, the control system every step pulse, motor rotation 1.8 While working with a subdivision drive in 10 subdivision, the motor only rotates the 0.18° ', which is the basic concept of subdivision. The subdivision function is entirely generated by the phase currents of the actuator by precisely controlling the motor, independent of the motor.

3. What are the advantages of drive subdivision, why it is recommended to use the subdivision function.
The main advantage after the drive subdivision is that the low frequency oscillation of the motor is completely eliminated. The low frequency oscillation is the intrinsic characteristic of the stepper motor (especially the reactive motor), and the subdivision is the only way to eliminate it, if your stepper motor sometimes to work in the resonant zone (such as walking arc), select the subdivision drive is the only choice. The output torque of the motor is increased. Especially for the three-phase reactive motor, the torque ratio does not subdivide when the increase of about 30-40%. Improves the resolution of the motor. It is self-evident to increase the resolution of the motor by reducing the step angle and increasing the uniformity of the step distance.

The stepper motor controls the
number of pulses required to send the driver to the stepper motor, and the
drive-driven stepper motor rotates according to the number of pulses sent. The specific rotation position and speed are set by the drive.

Usually the driver module of the stepper motor is controlled by the gpio level of the microprocessor, the general interface has a sleep hardware pin that controls the driver's sleeping or working state, a model pin of the subdivision driver is set up for the input pulse control motor rotation mode, and the step pin that accepts the number of input pulses The direction pin that controls the direction of rotation of the stepper motor. After initializing the rotation direction and turning the subdivision controller, the sleep pin is set to the active state, the input pulse queue, and the motor rotation frequency is proportional to the frequency of the input pulses.