Imagine you are  texting a friend on your smartphone. If your phone's keyboard (motors) just sent the keypresses without showing you what you typed (sensors), you wouldn’t know if you made mistakes. But, with the screen showing your text (feedback system), you can see and correct typos immediately. Similarly, a robot needs a feedback system to adjust its actions based on real-time information, ensuring it performs tasks accurately, just like you typing correctly by seeing and correcting mistakes as you go.

Meet Sam, the smart robotic arm that assembles smartphones. Sam is a closed-loop robotic system, which means he constantly checks and adjusts his actions to ensure everything is perfect. One day, you give Sam a task: pick up delicate glass screens from a tray and place them on the phone bodies on the conveyor belt. Sam starts by receiving your instructions (the controller), and his sensors (like eyes and touch) keep an eye on every movement. He uses his amplifiers (muscles) to make sure his actions are strong and precise enough. As Sam reaches for a screen, his actuators (joints and motors) move his arm smoothly, calculating the exact angles (kinematics) and planning the safest path (trajectory) to avoid any obstacles.

While Sam works, he’s constantly checking if everything is going as planned. If his sensors detect that a screen is slightly out of place or he’s using too much force, they send this information back to his controller, which immediately makes corrections (local feedback and sensor errors). It’s like Sam has a built-in quality control system. So, if there’s any disturbance, like a slight shake or an unexpected object in his way, Sam adjusts his movements to keep everything on track. By continually checking and correcting his actions, Sam ensures that each screen is placed perfectly every time, just like you would carefully place a delicate piece of art in a frame, adjusting your grip and position to make sure it’s just right. This continuous loop of sensing, acting, and adjusting is what makes Sam so reliable and precise in his work.