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