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

2.1 Mechanical Factors

These are related to the construction of the stepper motor arising from imperfections in the magnetic and mechanical construction of the motor, and are not under control of the stepper motor driver.

  • The precision to which the stator and rotor are punched and assembled.
  • The concentricity of the air gap between the rotor and the stator. If the variation in the airgap increases, step error also increases proportionally.
  • Higher torque stiffness of the rotor causes oscillations back and forth between steps.
  • Motor linearity refers to how the motor moves between its intended locations. In practice, all stepper motors exhibit some non-linearity, meaning the microsteps bunch together rather than being spread evenly over the span of a full step. This leads to poor stopping accuracy.