quadrature-encoder-course/lessons/02-using-encoder-feedback/02-closing-the-loop-with-a-pid/closing-the-loop-with-a-pid.md

title	summary	chapter	order	tags	estimated_minutes
Closing the Loop with a PID	Use encoder speed feedback to hold a target wheel speed with a simple controller.	Using Encoder Feedback	2	control pid robotics	12

Closing the Loop with a PID

With encoder speed feedback in place, you can command a target speed and adjust motor output based on error.

The basic control loop is:

• measure current speed
• compute error = target - measured
• update the controller
• send the new motor command

Start simple. A proportional controller is often enough to prove the loop works before adding integral or derivative terms.

What good behavior looks like

• the wheel reaches the target speed quickly
• overshoot stays limited
• the response remains stable when load changes

Checkpoint

Tune a controller so the wheel returns to the target speed after you briefly drag on the tire by hand.