Abstract
Feedback controllers are what allow robots to move intelligently and with precision; by sensing the environment and updating their outputs at every instant, robots can carry out complex tasks (Jiang et al., 2022). This chapter will introduce you to the basics of open and closed loop controllers. You will learn about how feedback can keep systems operating accurately, even in the presence of disturbances or parameter changes. We will also spend a good amount of time diving into a special type of controller called a PID controller. This type of controller is very common, and it attempts to correct error as it occurs. You will learn about important performance characteristics like overshoot, steady-state error, and stability. Not only will we go over what they are, but we will give examples of how they relate to robots. Examples of these concepts include industrial robot arms holding their position, keeping a heavy payload balanced, and preventing themselves from falling down. These all use feedback loops to keep the robot working safely. By learning about these concepts, you will be able to understand how robots know where they are and how to move about their environment with certainty.