Why does the robot design use a stepper motor ?

Stepper motors with low speed and high torque equipment make the transmission shorter which means higher reliability, higher efficiency, smaller clearance and lower cost. It is this feature that makes stepper ideal for robots, since most robot movements are short distances requiring high acceleration to reach low cycle times. Power - weight ratio is lower than DC motor. Usually involves short distance stops and starts. They are ideal robots at low RPM and high torque.

All ST robots have encoder feedback which is counted against the software motor. If no errors can be corrected, the system will stop. As a result, the integrity of the system is much higher.

Therefore, the advantages of stepper motor in robot design are as follows:

1. For the same performance of the stepper motor is cheaper.

2. Stepper motor has longer life than brushless motor etc.

3. As a digital motor it can accurately locate no hunting or overshooting.

4. The driver module is not a linear amplifier which means less heat sink, more efficiency, and more reliability.

5. Driver modules are cheaper than linear amplifiers.

6. There are no expensive servo-controlled electronics because the signal originates directly from the MPU.

7. Software fail-safe. Main control board problem stepping pulse. If the software does not work or crashes the motor stops.

8. Electronic drive fail-safe. If the motor that drives the amplifier fault locks, it will not operate. When the servo drive fails the motor can still run, possibly at full speed.

9. Speed control is precise and repeatable (crystal control).

10. Stepper motors run extremely slowly if needed.