What is closed-loop?

A closed-loop is when something keeps going around and around because it uses what happens next to decide what to do next.

Imagine you're on a swing. You start by pushing yourself forward, and then you pump your legs to go higher. Each time you push, you feel how high you are, if you’re not high enough, you keep pumping. That’s like a closed-loop: it uses the result of what just happened to know what to do next.

Think of a toy that moves on its own, like a robot dog. If it sees something in front of it, it stops, and if it doesn’t see anything, it keeps moving forward. It checks what’s happening around it every second and decides whether to stop or keep going. That's a closed-loop too! The robot uses the information from its eyes (or sensors) to know what to do next.

It’s like having a friend who helps you ride the swing, they tell you when to push harder or slower, based on how high you go. That way, you keep swinging without needing anyone else to help.