Learn about stepper motors in one article

This experiment: drives a stepper motor. The experiment requires that one button can control the start and stop of the stepper motor, and one button controls forward and reverse rotation.

1. Experimental Phenomenon

2. Experimental Code

3. The concept of stepper motor

A stepper motor is an actuator that converts electrical pulses into angular displacement. When the stepper driver receives a pulse signal, it drives the stepper motor to rotate a fixed angle in the set direction (this angle is called the step angle). We can control the angular displacement of the motor by controlling the number of pulses, thereby achieving the purpose of precise positioning; at the same time, we can also control the speed and acceleration of the motor by controlling the pulse frequency, thereby achieving the purpose of speed regulation.

4. Phase, line, polarity

"Phase" means how many coils (also called windings) the stepper motor has.

"Line" means how many connection ports the stepper motor has.

"Polarity" is divided into unipolar and bipolar. If the coil of the stepper motor can conduct electricity in both directions, then the stepper motor is bipolar. On the contrary, if the coil of the stepper motor is only allowed to conduct electricity in one direction, then the stepper motor is unipolar.

1. A five-wire four-phase stepper motor has five wiring ports and four coils.

Since there are five terminals, that is, the number of terminals is an odd number, that is, one terminal is a common terminal, so the conduction mode of its coil is only allowed to be unidirectional, that is, this stepper motor is unipolar.

2. A four-wire bipolar stepper motor has four wiring ports, and the conduction method allows bidirectional operation.

Since there are four wiring ports and the conduction method is bidirectional, this stepper motor is two-phase.

5. Stepping mode: single shot, double shot, single and double shot

1. Single shot: (single four-shot working mode)

The single-shot working mode means that only one coil is energized at a time, and the stepper motor rotates by changing the coil that is energized each time.

Let's talk about the five-wire four-phase stepper motor first. Assuming that its four coils are called A, B, C, and D, then in the single-shot working mode, the coils are energized in the following order: A, B, C, and D;

Then there is the four-wire bipolar stepper motor. Assuming its two coils are called A and B, then in the single-shot working mode, the coils are: A, B, -A, -B;

【Note】A and B refer to the forward current flowing through the A and B coils, and -A and -B refer to the reverse current flowing through the A and B coils.

Since the five-wire four-phase stepper motor cannot pass reverse current, there are only A, B, C, and D.

2. Double shot: (double four shot working mode)

The double-shot working method is: energize the two coils each time, and make the stepper motor rotate by changing the energized coil.

Five-wire four-phase stepper motor: In the double-beat working mode, the coils are energized in the following order: AB, BC, CD, DA;

For a four-wire bipolar stepper motor, in the double-beat working mode, the coils are energized in the following order: AB, BA, -AB, -BA;

3. Single and double beats (eight-beat working mode)

The single-double-shot working mode is to alternate between the single-shot working mode and the double-shot working mode.

Five-wire four-phase stepper motor: A, AB, B, BC, C, CD, D, DA;

Four-wire bipolar stepper motor: A, AB, B, BA, -A, -AB, -B, -BA;

4. Step angle: