When studying the control law of the controller, the controller is disconnected from the system, that is, the characteristics of the controller itself are studied only when the loop is opened. Different control laws adapt to different production requirements, and appropriate control laws must be selected according to production requirements. Improper selection will not play a good role, but will worsen the control process and even cause accidents. To select a suitable controller, first of all, we must understand the characteristics and use conditions of several commonly used control laws. Then, according to the quality index requirements of the transition process, we can make the correct choice in combination with the characteristics of specific objects.
