Basic Notions - Feedback Loops
For any control to happen, the system needs to have some sort of a sensor to detect, encode, and feed information from the environment or system itself into the system, some form of logic to process the information and compare it against a set of parameters (i.e., goals, targets) and understand the deviation, a decision-making mechanism to choose between options to correct the deviation, and finally, some acting parts that can act upon the selected option and thereby change the state of the system.
The flow of information, from sensing to comparing, to choosing, acting, and back again to sensing, is known as Cybernetic Feedback Loops and is depicted in figure above. Each part of the system receives an input from the previous part and produces an output to feed into the next part. The flow continues and feeds back into the system to form a continuous loop: A Feedback Loop.
Feedback loops are building blocks of control systems that enable the system to continuously evaluate its status against its target, find options to correct its course to get closer to the target, and probe again to check the effect of its actions in closing in its target, evaluate the deviation, and on it goes until the target is achieved.