Research on Root Locus Correction Algorithm in Automatic Control System

2.1. Composition of Automatic Control System (Trentin et al., 2020; Zhao et al., 2018)

The automatic control system is mainly composed of the following parts:

• 1.

  Controlled object;

• 2.

  Setting element: it is used to generate reference input or setting value in conventional instrument control;

• 3.

  Controller: receive deviation signal or input signal, give control quantity through certain control law, and send it to the execution element;

• 4.

  Actuator: sometimes the output of the controller can directly drive the controlled object;

• 5.

  Measuring transmission element: it is also called sensor, which is used to detect the output of controlled object, such as temperature, pressure, flow, position speed and other non electric physical quantities, which are transformed into standard signals and sent to the controller as feedback quantities;

• 6.

  Comparison element: it is used to generate deviation signals to form control. Some systems are equipped with special comparators in the form of standard devices, most of which are incorporated into other control devices in a hidden way.

2.2. Working Principle of Automatic Control System

When the controlled object is given, we should first understand the working principle and characteristics of the controlled object, such as which parameters need to be controlled, through which mechanisms they can be adjusted, which parameters can be measured, measurement accuracy requirements, as well as the working environment and interference of the controlled object. Then select the type, characteristics and parameters of the actuator, select the appropriate measurement transformer, and design the preamplifier and power amplifier. These elementarily selected elements and controlled objects constitute the invariable part or inherent part of the system. The purpose of the control system design is to combine the components and the controlled object properly, so that it can meet certain performance requirements (Ru, 2013; Sun & Shen, 2018).