15/08/2026
Control systems are widely used in electronics, automation, robotics, and motor drives to control a desired output. In an open-loop system, such as a TV remote, the command is sent to the TV without measuring whether the desired result was achieved. A closed-loop system, such as DC voltage regulation, measures the output and uses feedback to correct errors. In P control, such as LED brightness control, the control action depends on the size of the error. PI control, commonly used for battery charging and current regulation, adds integral action to reduce steady-state error. PID control, used in applications such as drone attitude control, combines proportional, integral, and derivative actions for faster and more stable correction. Cascade control uses two control loops; for example, a motor drive can use an outer speed loop and a faster inner current loop. Feedforward control measures a disturbance before it affects the system and applies corrective action early, as in active noise cancellation. Understanding these control methods helps us design accurate and stable electronic and automation systems.