Glossary · Motion control and drives
Microstepping
Also known as: Microstep mode, Microstep operation
German: Mikroschrittbetrieb
In stepper motor control, microstepping is the operating mode in which the driver sets the currents in the motor phases to intermediate values, typically along a sine and cosine curve, so that each full step is divided into smaller microsteps, up to 256 microsteps per full step in current motion control ICs.
- Motion control
In one sentence
Microstepping divides each full step into smaller steps, up to 256, by setting sine-shaped phase currents; it raises resolution, not accuracy.
Example
A microscope stage axis runs with 256 microsteps per full step, giving 51,200 microsteps per revolution and very smooth, quiet motion.
How it applies
- Engineering: Microstepping makes motion smoother, reduces noise and resonance and increases the commanded Resolution. It does not increase absolute Accuracy: step angle tolerance, Cogging torque, load and friction still shift the real rotor position.
- Commissioning: The incremental torque per microstep drops sharply with the subdivision, roughly holding torque × sin(90° / microsteps). At 256 microsteps a single microstep carries well under 1 % of the holding torque, so a small load can keep the rotor from following individual microsteps.
- Operation: Some ICs interpolate a coarse step input internally to 256 microsteps, so the motor runs smoothly even when the controller sends only 16 steps per full step.
- Documentation: Never write that microstepping makes a positioning system "more accurate" or "precise to 0.007°". Say that it refines resolution and smoothness, and state the achievable accuracy separately, from measurement.
Microstepping vs. higher accuracy
A finer microstep setting adds commanded positions between the full steps. Whether the rotor actually reaches each of them depends on motor linearity and load. Positioning that must be accurate to a value needs feedback, for example an Encoder or a Closed-loop stepper.