APC 2009 MATLAB Demo 1 Slides

7/22/2019 APC 2009 MATLAB Demo 1 Slides

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MATLAB / SIMULINK

Lab Demonstration No.2by Faye & Shahin 2009

ChE 411/558 Advanced Process Control



Contents

Simulink ® Control Design Graphical User

Interface (GUI):1. Configure the model and GUI for controller

design

2. Design a PID controller using Ziegler-Nichols tuning and Bode graphical design.

3. Simulate the closed-loop system.



1. Problem

Cascade control: CST composition mixer

AC

AT

Product, C

FT

FC

F1, C1

F2, C2



CV: Product composition, MV: F1 flow rate,

DV: Changes in F1 flow rate

Aim: To eliminate the disturbance from F1 flow

rate, and good setpoint tracking.Tuning Criteria:1.The fluctuations after tuning for disturbance

rejection should lie within 5%.2.Whereas for setpoint tracking, the overshoot

less than 50%, and

3.The rise time less than 5 seconds.



Process transfer functions:

Gpp: Product composition subject to changes in F1flowrate:

Gps: Valve stem position subject to changes in F1

flowrate:

Assume negligible sensor dynamics.

s

PPe

ssF

sC G 19.0

1 165.0

73.0

)(

)( −

+

==

s

PS e

ssF s X G

02.0

111.0

1

)(

)( −

+

==



Note

Model configuration in Simulink:

‘Continuous’ Transfer Function, Transport Delay

‘Sources’ Step, Clock ‘Sinks’ To Workspace, Scope

‘Math Operations’ Sum (double-click to change

the signs) ‘Simulink Extras’ ‘Additional Linear’ PID

Controller

NOTE:

Don’t forget to change all ‘To Workspace’ blocks to array format





1. Open-loop step test

2. Design the controllers using Ziegler-Nicholsmethod:

Select Tools > Control Design > Compensator

Design

Click ‘Select Blocks’ tick the controllers - OK

Right click on the input line to the closed loop

Select ‘Linearization Points > Input Point’ .

Right click on the output line from the closed loop

Select ‘Linearization Points > Output Point’.

Click ‘Tune Blocks’.

2. Controller Design & Tuning



• Under the tab ‘Analysis plot’, select ‘Step’

and tick the closed loop box.• Under the tab ‘Automated tuning’, select

any of the design method, in this case, we

have chosen PID tuning ZN open loop Update compensator Update simulinkblock parameters

• Alternatively, you can use ‘Graphicaltuning’/ ‘Compensator editor’.

• Check if the responses meet the tuning

criteria



After tuning: ‘Store Design’



Disturbance Rejection:

Fluctuationsappro. 3%

when subjectto a unit stepchange in

D(s).

0 1 2 3 4 5 6 7 8 9 10-0.04

-0.03

-0.02

-0.01

0

0.01

0.02

0.03

0.04

0.05



>> stepinfo(y)

ans =

RiseTime: 3.8370SettlingTime: 139.7210

SettlingMin: 0.8769SettlingMax: 1.4054Overshoot: 40.4407

Undershoot: 0Peak: 1.4054

PeakTime: 22

Criteria achieved~

Setpoint Tracking:

0 2 4 6 8 10

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1

1.2

1.3

1.4

1.5



3. Stability Analysis

Carry out at least 1 stability analysis, such as

open-loop bode plot, root locus, nyquist,nichols, etc.

Describe.



4. Performance Evaluation Disturbance

rejection +5 and +10

increase in

D(s): Others: +5 and

-5,

Etc. Describe.

0 2 4 6 8 10-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

D(s)=+5

D(s)=+10

Can your controller eliminate large

disturbances? What range?

>> plot(t,y,t1,y1) > > legend('D(s)=+5','D(s)=+10')



Setpoint tracking

+1, +2 and +5step changesin Ysp(s):

Others: -1,-2, -5changes

Etc.

Describe. Can work well for

large setpoint

changes?

0 1 2 3 4 5 6 7 8 9 100

1

2

3

4

5

6

7

8

Ysp(s)=+1

Ysp(s)=+2

Ysp(s)=+5

0 2 4 6 8 10 12 14 16 18 20-4

-3

-2

-1

0

1

2

3

4

5



Have fun~!

Reference: [1] The MathWorksTM

Do free out some time to go through this tutorial:

http://www.mathworks.com/access/helpdesk/help/toolbox/slc

ontrol/index.html?/access/helpdesk/help/toolbox/slcontrol/gs/ brrzwxv.html

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APC 2009 MATLAB Demo 1 Slides

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