The propositional scope of north china university of technology's automatic control principle and the knowledge points examined.

1 Basic concept of automatic control

1) Three basic control modes of automatic control system: open-loop control, closed-loop control and compound control;

2) feedback control mechanism;

3) Basic composition of closed-loop control system;

4) Basic requirements of control system.

2 Mathematical model of control system

Differential equation, transfer function and structure diagram are three main forms to describe the mathematical model of the system, with the emphasis on:

1) definition and properties of transfer function, concept of structure diagram;

2) The method of obtaining the transfer function of a specific physical system and drawing the system structure diagram;

3) By simplifying the structure diagram, the open-loop transfer function, closed-loop transfer function, error transfer function and closed-loop transfer function under the action of interference signal are obtained;

4) Understand the establishment of signal flow diagram and the application of Mason formula.

Time domain analysis of linear systems

This paper focuses on the analysis methods of candidates' performance such as system stability, steady-state error and dynamic quality.

1) Definition of system performance index;

2) The concept of system stability, Routh stability criterion and its application;

3) Dynamic performance analysis of first-order and second-order systems (mainly second-order), step response analysis of second-order systems and calculation of dynamic performance indicators;

4) the definition of system type, the definition and calculation method of static error coefficient, and the static error of the system is calculated by using the static error coefficient;

5) The concept of dominant pole, and generally understand the analysis method of dynamic performance of high-order systems.

Root locus method of four linear systems

1) Master the basic concept of root trajectory and the relationship between root trajectory and system performance;

2) Master the basic rules of root trajectory drawing, and flexibly apply the basic rules to draw the root trajectory of the system;

3) Analyze the performance of the system by using the root trajectory;

4) Understand the concepts of parametric root locus and zero-degree root locus.