SLOA293A September   2020  – October 2021 DRV8424 , DRV8426 , DRV8428 , DRV8434 , DRV8434A , DRV8434S , DRV8436 , DRV8436E , DRV8889-Q1

 

  1.   Trademarks
  2. 1Introduction
  3. 2Various Factors Affecting Stepper Accuracy
    1. 2.1 Mechanical Factors
    2. 2.2 Electrical Factors
      1. 2.2.1 Stepper Driver Channel-to-Channel Current Matching
      2. 2.2.2 Stepper Driver Decay Mode
      3. 2.2.3 Microstepping Levels
      4. 2.2.4 Stepper Driver Current Sense Accuracy
  4. 3Conclusion
  5. 4References
  6. 5Revision History

1 Introduction

The majority of stepper motor systems do not include an encoder to sense the position and provide feedback to the MCU. With traditional stepper drivers, stepper motors can oscillate around their destination, or have a different angular position increment after each microstep, resulting in poor positional accuracy. Stopping accuracy of a stepper motor is the difference between the actual stop position and theoretical stop position. The higher the stopping accuracy, the better the quality of the end product, such as clearer and more crisp printing.

  • In a 3D printer, the quality of printing depends on the position accuracy of the stepper motors controlling movement of the extruder and of the printer bed in the X-Y-Z directions.

  • For a stage lighting module, precise positioning of the light beam is critical; any vibration or speed fluctuations of the stepper motor will make the light unstable.

  • For a security camera, features such as video facial recognition requires the stepper motors to have very accurate positioning and smooth operation over a wide range of speed to prevent image distortion.

The following sections discuss the various factors that affect the accuracy of stepper motors as well as how stepper motor drivers can help improve the accuracy.