2. Sensor method: Install position sensors such as Hall switch and photodiode at zero position. When the stepping motor returns to the zero position, the sensor gives a detection signal, and when the control circuit detects the signal, the motor stops at the zero position.
3. A special motor driver chip with stall detection is adopted. When the motor stops running, the chip can immediately detect that the motor is in a stall state and determine the zero position.
4. Adjust the duty cycle of PWM signal, construct a sinusoidal driving current whose amplitude decays according to a certain law, and add this current to each winding of the stepping motor with a certain phase difference, so that the stepping motor is driven in micro steps and its torque decays according to the expected law.