Stabilization problem: Given a plant, select a sensor and an actuator, and design a controller so that the output of the closed-loop system has good stability.
If we take a closer look at a human feedback system when driving a car, we can see that the human actually has to perform several subtasks:
- Sensing: Observe the car position.
- In general, a sensor measures a physical variable that can be used to deduce the behavior of the concerned output, such as the deviation of the car position, and turn it into a signal, usually an electrical signal, that the controller can read. The controller, often a computer or an electric circuit, takes the reading from the sensor, determines the action needed to correct the car position, and sends the decision to an actuator.
- Control: Make decisions regarding which actions to take
- The controller is typically a computer or an electric circuit that the reading from the sensor, determines the action needed to correct the car position, and sends the decision to an actuator.
- Actuation: Exercise his/her decision and influence the motion of the car.
- The actuator then generates the quantity which influences the plant.