There are various types of control systems, but here are three common types:
1. Open-loop control system: In this type of system, the control action is determined solely by the input signal. The output of the system is not compared to the desired output or reference signal. An example of an open-loop control system is a washing machine with a timer that runs for a fixed duration regardless of the state of the clothes inside.
2. Closed-loop or feedback control system: In this type of system, the output of the system is measured and compared to the desired output, and the control action is adjusted accordingly. This type of system uses feedback to continuously adjust the output to match the desired value. An example of a feedback control system is a thermostat that measures the temperature of a room and adjusts the heating or cooling system to maintain a desired temperature.
3. Digital control system: In this type of system, the control variables are processed digitally. The input and output signals are sampled and converted to digital signals, and then the control algorithm is executed using digital processing techniques. This type of system is commonly used in modern industrial control systems and robotics.