1. Automatic controllers refer to the use of machine equipment or systems to replace humans in completing a certain production task, implementing a certain process, or carrying out transaction management work. Strictly speaking, an automatic controller refers to a machine, equipment, or production management process that automatically achieves the expected operating equipment through automatic detection, information processing, analysis, and judgment without direct human participation. 2. A system in which an automatic controller can complete a certain control task. The composition and working principle of an automatic controller have many similarities with the composition and working mechanism of the human body: there are sensors in the automatic controller that are equivalent to human sensory organs, control devices that are equivalent to human brain and nervous system, and execution mechanisms that are equivalent to human hands, legs, and muscles. Sensors are used to detect command information, external changes, and state information of the controlled object, and convert them into electrical signals for transmission to the control device. The control device calculates the difference between the current state of the controlled object (referred to as the controlled quantity, or the output of the system) and the desired state (referred to as the input signal), and generates a control signal according to a certain law based on this deviation (referred to as the error signal), which is then amplified and sent to the operating executing mechanism. The operation execution mechanism is used to drive the motion of the controlled object until its state reaches the desired state. The control formed by comparing the output of the system or other controlled variables with the input of the system is called closed-loop control or feedback control