بسم الله الرحمن الرحيم Advanced Process Control Lecture one

بسم الله الرحمن الرحيم

Advanced Process ControlLecture one

1- Syllabus, Marking Scheme and Reference Books2- Introduction to Single Input – Single Output Control (SISO)

- Feedback Control- Feedforward and Cascade Control

1Lecturer: M. A. Fanaei Ferdowsi University of Mashhad

Syllabus

Review of SISO control Introduction to feedback control theory

Process modeling

Control valve characteristics

Types and modifications of PID controllers

Tuning of PID controllers (offline and online)

Discrete version of PID controllers

Dynamic simulation and control of chemical processes using

MATLAB/SIMULINK2

Syllabus

Advanced SISO control topics Performance and robustness

Cascade control

Feedforward control

Ratio, Override and Selective Control

Predictive control (IMC and Smith predictor)

State-space model (Continuous and Discrete)

3

Syllabus

MIMO control topics Centralized and decentralized control

Interaction and relative gain array

Design of static and dynamic decoupler

Predictive control (DMC)

4

Marking Scheme & Reference Books

Marking scheme Mid-term exam: 35% Final exam: 40% Homework: 25%

Reference books C. A. Smith and A. Corripio, Principles and Practice of Automatic Process

Control, 3rd edition, Wiley, 2006.

K. J. Astrom and T. Hagglund, Advanced PID Control, ISA, 2006. T. E. Marlin, Process Control: designing processes and control systems for

dynamic performance, 2nd edition, McGraw-Hill, 2000. K. Ogata, Modern Control Engineering, 3rd edition, McGraw-Hill, 1997. K. J. Astrom and B. Wittenmark, Computer Controlled Systems, 3rd edition,

Prentice Hall, 1997. C. C. Yu, Autotuning of PID controllers: A relay feedback approach, 2nd edition,

Springer, 2006. 5

Structures

Objectives

01_1Control objectives and structures

SafetyEnvironmental protectionEquipment protectionSmooth plant operation and productionProduct qualityProfit optimization

FeedbackFeedforwardFeedback/FeedforwardCascade

6

Feedback control

Sensor Transmitter

Controller

Final Control Element

Process

Final element

SensorController

Other outputsDisturbances

Controlled variable

Manipulated variable

7

01_1Advantages and disadvantages of feedback control

Advantages

• Very simple technique

• Effective for all disturbances

• Provides zero ss offset

• Works with minimum knowledge of the process

Disadvantages

• Does not take control action until the process output has deviated from set point

• Affects the closed-loop stability

8

01_4Feedforward control

9

01_1Advantages and disadvantages of feedforward control

Advantages

• Compensates for a disturbance before the process output is affected

• Does not affect the stability of the control system

Disadvantages

• Can not eliminate steady-state offset

• Requires a sensor and model for each disturbance

10

01_5Feedback / feedforward control

11

Cascade Control

When the simple feedback control structure don’t have an

acceptable performance, a cascade structure may

improve the performance (speed up the closed loop

response).

A cascade structure can be used, when a process has some

series dynamics and the output variables between theses

dynamics can be measured. 12

Cascade Control (a process example)

13

Cascade Control (a process example)

14