Control engineering is one of the branches of engineering that is based on mathematical models of multiple phenomena and analyzing the dynamic performance of these phenomena using control theory to create controllers capable of making these systems work in a specific way. Where the control system manages, gives orders, directs, or regulates the behavior of devices or other systems using control loops. These systems have significant applications in our daily life, ranging from simple systems such as a thermostat that controls a home heater to large industrial control systems used to control processes or machines. Applications of electrical circuits, digital signal processors, and microcontrollers are used, as well as sensors and devices involved in the implementation of the control process. The control systems are divided into two parts according to the nature of their work, which is the open-loop control system and the closed-loop control system. In an open-loop system, the control action from the controller is independent of the process variable. An example of this is a central boiler-only timer-controlled. The control procedure is to turn the boiler on or off, where the temperature represents the process variable. At the same time, this controller operates the heating system for a fixed period regardless of the building temperature. In the same context, the closed loop controller has a feedback loop that ensures the controller performs a control procedure to set the process variable at the same setting value.
For this reason, closed-loop controllers are also called feedback controllers. On the other hand, control theory is mainly divided into two major parts, classical and modern, which have direct implications for the applications of control systems engineering. The scope of classical control theory is limited to singular input and output as the system is analyzed in the time domain using differential equations in the time domain and using Laplace transforms or in the frequency domain by switching from the time domain. Controllers designed using classical theory often require on-site tuning to correct design approximations. Due to the ease of designing a controller using classical theory compared to modern theory, it is used in most industrial applications. In contrast, modern control theory takes place in a specific space and deals with systems with multiple inputs and outputs. This overcomes the limitations of classical control theory in more complex design problems, such as controlling combat aircraft.