1. Automatic Control Theory School of Automation NWPU Teaching Group of Automatic Control Theory

2. Excecies(26) 5 — 32 ， 33 ( 用坐标纸 ) Automatic Control Theory

3. （ Lecture 26) §5. Analysis and Adjustments of Linear Systems in Frequency-Domain §5.1 Concept of Frequency-Response Characteristics §5.2 Amplitude and phase Frequency Characteristics §5.3 Bode Diagrams §5.4 Nyquist Stability Criterion §5.5 Stability Margins §5.6 System Analysis by Frequency Response Characteristics of Open-Loop Systems §5.7 Nichols Chart §5.8 System Analysis by Frequency Response Characteristics of Closed-Loop Systems §5.9 Control Systems Design by Frequency Response

4. Automatic Control Theory §5.9 Control Systems Design by Frequency Response 5.9.1 Lead Compensation 5.9.2 Lag Compensation 5.9.3 Lag-Lead Compensation 5.9.4 PID Design （ Lecture26 ）

5. Compensation: Add proper devices with adjustable structure and parameters to improve the system performance meeting the requirement. Compensation methods ： Cascade compensation ， Feedback compensation ， Composite compensation §5.9 Control Systems Design by Frequency Response （ 1 ）

6. §5.9 Control Systems Design by Frequency Response （ 2 ） Process of system design by Fre. Resp. Reasonable expectation (Specifications) Priority of Specifications No unpractical Specifications

7. Middle band Tri-Band in Frequency Higher band Lower band Corresponding performance Expectation L()L() The ability of anti-high-frequency noise Open-loop gain K System type v e ss Cutoff frequency  c Phase margin  Dynamic Performance Steep ， High Moderate, Wide Low ， Steep Frequency Band Tri-Band does not give the steps to design systems, but it show the way to adjust the system structure for better performance. §5.6 Analysis by Frequency Response of O.L. Systems （ 12 ）

8. §5.9.1 Lead Compensation （ 1 ） §5.9.1 Lead Compensation (1) Lead Circuit

9. §5.9.1 Lead Compensation （ 2 ） (1) Lead Circuit Thus,

10. §5.9.1 Lead Compensation （ 3 ） (1) Lead Circuit  Features: Phase lead, Magnitude increased  Maximum Phase lead for a network 60º  Effetive range

11. §5.9.1 Lead Compensation （ 4 ） (2) Lead Compensation Essential — Use the phase lead of the network to increase the phase. ① From ③ Determine ④ Design ⑤ Check if satisfy the requirements ② From Algorithm (Given index )

12. §5.9.1 Lead Compensation （ 5 ）

13. §5.9.1 Lead Compensation （ 6 ） Example2

14. Summary §5.9.1 Lead compensation For ： Essential — Use the phase lead of the network to increase the phase. Steps ： ① ③ ④ Design ⑤ Check ② Effects ： Lower band unchanged Middle band altered Higher band raised Incapable of anti-high-frequency noise To Satisfy to improve dynamic performance

15. Excecies(26) 5 — 32 ， 33 ( 用坐标纸 ) Automatic Control Theory