Copyright © Yokogawa Electric Corporation - 1 - PID Control for the future Haruo TAKATSU Yokogawa Electric Corporation

<PID ‘12 Conference>Copyright © Yokogawa Electric Corporation<March 29th 2012>

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PID Control for the future

Haruo TAKATSUYokogawa Electric Corporation


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Agenda


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Discussion Items

1. Will PID control continue to be used in the future ?– Market Survey in Japan

2. When and why is derivative action used ?– Flexibility of PID Control block in DCS

3. What are alternatives ?– Self-Tuning / Adaptive Control, Internal Model Control

4. What is your favorite tuning method ?– PID Tuning in our system

5. Do we know everything about PID or are there any research needs ?– Introduce Monitoring & Diagnosis


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Needs of PID Control - SICE Report -


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0

200

400

600

800

1000

1200

1400

I-P

D a

nd

2 d

eg

ree

s o

ffr

ee

do

m P

ID

PID

au

to t

un

ing

Ap

plic

atio

ns

Applications

0

10

20

30

40

50

60

70

80

90

Ga

in s

che

du

ling

Mo

de

l pre

dic

tiv

e c

on

tro

l

Fuzz

y c

on

tro

l

De

ad

tim

e c

om

pe

nsa

tio

n

De

cou

plin

g P

ID

Ru

le b

ase

d c

on

tro

l

Op

tim

iza

tio

n

Ka

lma

n fi

lte

r

Ne

ura

l ne

two

rk

Op

tim

al r

eg

ula

tor

Ob

serv

er

infi

nit

y c

on

tro

lＨ

Ad

ap

tiv

e c

on

tro

l

Ex

act

lin

ea

riza

rio

n

Re

pe

titi

ve

co

ntr

ol

Slid

ing

mo

de

co

ntr

ol

Control Technologies

OthersＯ（）

Power pl antＰＷ（）

Engi neeri ngＥ（）

Cement and cerami cＣＲ（）

Pul p and paperＰＰ（）

Chemi cal , fi ber, fi l mＣＦ（）

Petrochemi calＰＣ（）

Refi neryＲ（）

S(Steel and metal ）

Control Technology Survey

Takatsu, H., Itou, T. : Future Needs for Control Theory in Industry – Report of the Control Technology Survey in Japanese Industry, IEEE Transaction on Control Systems Technology, 07, 03 pp.298-305 (1999)


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PID Control Structure - Derivative Action -


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Control Block in DCS


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sTsT

di

1

1PB

100Process

SV PVMV

DV

＋＋

＋-PID

PV

DV

PB

100Process

SV MV ＋＋

＋-

sTd

sTi

11 ＋

-PI-D

I-PD PB

100Process

SV PVMV ＋＋

＋- sTi

1 ＋-

sTd1

DV

sT

sT

d

d

α

1

1

α

Page 8

PID Control


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PID Alternatives - Adaptive / Self-Tuning Control


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PID Control Process

Response Monitoring

Model Estimation

Estimated Model

PID Tuning

MV PVSV

PID parameters

Self-Tuning Control


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- Nonlinear Programming -

Xred

Reflection: Xref = (1+a)Xbar -aXmax

Expansion: Xexp= bXref+(1-b)Xbar

Xmid

Xmax

Xmin

Xref

Xexp

Xbar

Xmax

Xmid

Xred

ReductionXcon

Xmin

Xmax

Xmid

Contraction:

Xcon= cXmax+(1-c)Xbar

In case oscillating and small overshoot, 　

Increase/Decrease P and decrease I.

In case large overshoot and fast convergence,

Increase/decrease P & I.

In case No oscillation, slow convergence,

Decrease P &I.

In case slow oscillation and convergence, Decrease P and increase I.

Self-Tuning Control


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PID Alternatives - IMC Control -


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Controller ： C(s) ， Internal Model ： PM(s) ， Process ：P(s) 　

+

++

-

+

－

SV MV PVC(s) P(s)

DV

PM(s) PM(s)+

－

Q(s)

+

++

-

SV MV PVQ(s) P(s)

DV

PM(s)+

－

C(s)

Internal Model Control


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+

-

SV MV PVP(s)

KPe-Lps

1+TPs

Kc(1+TPs)

1+λTPs

+

+

2012.1.6 - 20

Internal Model Control


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PID Tuning Method- IMC Method -


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Stable Process

Gain Reset Derivative

PI -

PID)t2(

t2

d

d

ετ

K

)t2(

t2

d

d

ετ

K 2

tdτ

2

tdτd

d

t2

t

ττ

Integral Process

Gain Reset Derivative

P - -

PI -

PID

εK1

2)2(

22

ε

ε

d

d

tK

t

2

td

ε2

22 dtε

εK2

K=Process Gain, td=Dead time

=Time Constant

=Desired Closed Loop Response

τε

PID Tuning


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• The Advanced Tuning window is for user to perform detail analysis of each step test data and confirm the final suitable P, I, D parameters.

Loops Pane

Loop Details Pane

Step Pane

Advanced Tuning Pane

displays loops grouped by the “Location” defined in Loop Configuration

most of the important parameters in loop configuration

the list of steps captured under the selected tag and the preview of the step data

the main window that user does the analysis for model and loop simulation

PID Tuning


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PID Tuning is always correct ?


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Research & Development in the Future - Plant Life Cycle Monitoring & Diagnosis -


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Valve Stiction Results: Oscillating

Only

Loop Oscillation & Valve Stiction Dianosis


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Valve Stiction Results: Oscillating & Sticking

Loop Oscillation & Valve Stiction Diagnosis


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• Industry has implemented many projects• Shift from project work towards maintenance• Staff is less appealed by maintenance work • Shortage of skilled staff in process control and optimisation• Maintenance can be tedious and time consuming• Too much focus towards Uptime (Online factor)

Applications do not deliver optimum performance

Reference : - Recent survey of 20,000 loops performance

Excellent 16%

Acceptable 12%

Fair 28%

Poor 11%

Manual mode 33%

What is problem after installation ?


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Thank you for your attention

Documents

Copyright © Yokogawa Electric Corporation - 1 - PID Control for the future Haruo TAKATSU Yokogawa Electric Corporation