solution: homework 8

Dr.-Ing. Erwin SitompulPresident University

Lecture 11

Introduction to Neural Networksand Fuzzy Logic

President University Erwin Sitompul NNFL 11/1

http://zitompul.wordpress.com


Solution: Homework 8Fuzzy ControlFuzzy Logic


FC with 5 Rules

Solution: Homework 8 (Cont.)Fuzzy ControlFuzzy Logic

Rule 1: IF level is okay, THEN valve is no change.Rule 2: IF level is low, THEN valve is open fast.Rule 3: IF level is high, THEN valve is close fast.Rule 4: IF level is okay AND rate is negative,

THEN valve is open slow.Rule 5: IF level is okay AND rate is positive,

THEN valve is close slow.

Rule 1: IF error is zero, THEN valve is no change.Rule 2: IF error is positive,THEN valve is open fast.Rule 3: IF error is negative,THEN valve is close fast.Rule 4: IF error is zero AND error rate is positive,

THEN valve is open slow.Rule 5: IF error is zero AND error rate is negative,

THEN valve is close slow.

error = reference – levelrate of error = – rate of level



Valve control signal [%/s]

no

chan

ge

ope

n fa

st

clos

e fa

st

–30 –20 –10 0 10 20 30

1 o

pen

slow

clos

e slow

Rate of level error [cm/s]

zero positivenegative

–4 –0.5 0 0.5 4

1

Level error [cm]


–5 –4 0 4 5

1

1st Set of Membership Functions



Level error [cm]


–5 1 0 1 5

1

2nd Set of Membership Functions


no

chan

ge

ope

n fa

st

clos

e fa

st

–30 –20 –10 0 10 20 30

1 o

pen

slow

clos

e slow



–4 –0.5 0 0.5 4

1



Level error [cm]


–10 –4 0 4 10

1

3rd Set of Membership Functions


no

chan

ge

ope

n fa

st

clos

e fa

st

–30 –20 –10 0 10 20 30

1 o

pen

slow

clos

e slow



–4 –0.5 0 0.5 4

1


PID-like Fuzzy Controllers

Fuzzy P Controller

u+–

e r y

Fuzzy ControlFuzzy Logic


PID-like Fuzzy Controllers

Fuzzy PD Controller

u+–

e ry



Fuzzy Control of Single Tank

Fuzzy PID Controller

ue r y+–

• Weakness: too many rules




Fuzzy PD+I Controller

r+–

eyDu




r u+–

e y++

Du






r u+–

e y++



End of the LectureFuzzy ControlFuzzy Logic

solution: homework 8

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