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Linear Actuator Resolution Calculator

Calculate encoder pulses required per mm of linear travel.

Actuator Parameters

Linear distance per one revolution of the screw.

Linear Resolution

1.0 μm / pulse
Resolution in mm 0.001000 mm / pulse
Pulses per mm 1000 pulses
info
Disclaimer of Liability: This calculator is provided for educational and estimation purposes only. By using this tool, you agree to discharge AutomationView of any liability for direct, indirect, or consequential damages resulting from its use. It is your strict responsibility to independently verify all calculations, validate the results against official manufacturer documentation, and ensure compliance with all applicable safety and engineering standards before implementing any parameters in a production environment.

What is Linear Actuator Resolution?

To calculate the linear resolution (or step size) of a ball screw actuator driven by a stepper motor, you need to determine how much linear distance the nut travels for every single step or microstep of the motor. This determines the finest positioning capability of your linear motion system.

The Core Formula

The linear resolution (Smin) is calculated using the ball screw lead and the total steps per revolution of your motor system:

Resolution = Lead / Total Steps per Revolution

Step-by-Step Calculation Guide

1. Identify the Lead of the Ball Screw

The lead is the linear distance the nut moves in one full 360° revolution of the screw. Note that lead is different from pitch; pitch is the distance between adjacent threads, while lead is the distance moved per rotation. For single-start screws, lead and pitch are identical.

2. Calculate Total Steps per Revolution

For stepper motors, the total steps per revolution depends on the native step angle and the microstepping drive setting:

  • Native Steps per Rev: Standard stepper motors have a 1.8° step angle, equaling 200 steps per revolution (360 / 1.8 = 200).
  • Microstepping: If the driver uses microstepping (e.g., 1/16th step), multiply the native steps by this factor.

Total Steps = Native Steps/Rev × Microstep Division

3. Calculate Resolution

Plug the values into the formula to find the distance moved per microstep.

Example Calculation

If you have a ball screw with a 5 mm lead, a 200-step motor, and are using 16x microstepping:

  1. Total Steps per Rev = 200 × 16 = 3,200 steps/rev
  2. Resolution = 5 mm / 3,200 steps = 0.0015625 mm/step (or 1.56 µm/step)

Important Considerations

While this formula gives the theoretical commanded resolution, the actual positioning accuracy is limited by the backlash of the ball screw, mechanical tolerances, and the angular accuracy of the motor. Increasing microstepping improves smoothness but does not necessarily increase absolute positional accuracy.