*1.3.1.1 The concept of adaptive control*

In the 1950s and 1960s, since classic control was difficult to meet the high control performance requirements of aircraft, rockets, and satellites, a highperformance controller capable of automatically adapting to the changing characteristics of the controlled object, an adaptive controller, was needed.

In order to make the controlled object operate according to the predetermined rules, negative feedback control is used. A natural idea is that when the control performance of the controller does not meet the requirements, the negative feedback control idea is also used to control the controller itself to improve the control performance. This is the basic idea of adaptive control. Therefore, the adaptive controller must have two functions at the same time:


The adaptive controller performs system identification and control tasks simultaneously. The essence of the adaptive fuzzy controller is to make a control strategy described in language by observing and evaluating the performance of the

**Figure 4.** *Control surface of the fuzzy rule base.*

#### *Overview of Some Intelligent Control Structures and Dedicated Algorithms DOI: http://dx.doi.org/10.5772/intechopen.91966*

controller. There are two types of adaptive control: direct adaptive control and indirect adaptive control. The principle of direct adaptive control is shown in **Figure 5**. It adds an adaptive mechanism to the basic feedback control system. It obtains signals from the original control system. The control performance changes that it can adaptively modify the controller parameters to make the control. Performance remains the same. The principle of indirect adaptive control is shown in **Figure 6**. It uses online identification to identify the parameters of the object, and then uses the identified parameters to adjust the control parameters through the parameter corrector to continuously improve and improve the control performance.

Direct reference adaptive control includes model reference adaptive control (MRAC), while indirect adaptive control is also called self-correcting control (STC).

Introduce fuzzy logic inference system in traditional adaptive control, or act as an adaptive mechanism, or as an object model, or as a controller, or both, forming different forms of adaptive fuzzy control, or fuzzy adaptive control [5].
