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MID EXAM - ELECTRICAL - Linear System and Control - Muhammad Zubair - SU-20-02-048-004

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Sarhad University, Peshawar


Department: Electrical Engineering Program: M.S Electrical Engineering
Course & Course Code : Linear Systems and Control Examination : Mid Term Spring 2020
*Student Name: Muhammad Zubair
Total Marks: 30 (30% Weightage)
*Registration # SU-20-02-048-004
Instructor: Engr. Dr. Salman Ahmed
*Student Email:zubairksk@gmail.com

IMPORTANT INSTRUCTIONS FOR THE STUDENTS:


Before uploading, save the same file in this format MID EXAM_DEPARTMENT_COURSE_Student Name_Reg#.doc

Upload it at your SUIT PORTAL before the deadline. Answer Sheet sent through EMAIL will not be accepted.

The total size of this file should not exceed 1MB at the time of uploading it at portal

Just type the answers under each question and draw the figures yourself in MS-word, Try to avoid inserting
images. Follow the instructions at SUIT Portal.

Table: To be filled by the Instructor

Question Number 1 2 3 Grand Total


Obtained Marks 0 0 0 0
Total Marks 10 10 10 30
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Sarhad University, Peshawar

Department: Electrical Engineering Program: M.S Electrical Engineering

Student Name: Muhammad Zubair

Registration No SU-20-02-048-004

Student Email: zubairksk@gmail.com

Table: To be filled by the Instructor

Question Number 1 2 3 Grand Total


Obtained Marks 0 0 0 0
Total Marks 10 10 10 30
Page |3

Contents
No. Title Page

1 Answer no 1 4

2 Answer no 2 7

3 Answer no 3 part a 10

4 Answer no 3 part b 11
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Question #1:

Using the canonical form to obtain state-space representation of the


system shown in the given Figure:

Answer1:

Step 1

U(t) Σ 16 S4 −32 S 2+16


y(t)

Step 2
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16(s4 −2 s 2+1)
1+(16 s4 −32 s 2+16)(1)
u(t) y(t)

16(s4 −2 s 2+1)
1+(16 s4 −32 s 2+16)(1)

16 (s 4 −2 s2 +1)
1+(16 s4 −32 s 2+16)

16(s 4−2 s 2 +1)


(16 s4 −32 s 2+17)

16(s4 −2 s 2+ 1)
16 ¿ ¿
y ( t ) s 4−2 s 2+ 1
=
u (t ) 17
s 4−2 s2 +
16
b 0=1 ,b 1=0 , b2=−2 ,b 3=0 , b 4=1

a 0=1.06 , a1=0 ,a 2=−2 , a3=0 , a 4=1

Change into S.S


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b4s 4 +¿
b3 s ¿
¿
G(s)= 3+¿
b
2s 2+¿
b
1s
1+¿
b0 ¿
¿
0s5 + a s4 +a s 3 +a s2 +a s 1+ a
4 3 2 1 0

0 1 0 0

0 0 1 0

A= 0 0 0 1

-a0 -a1 -a2 -a3

0 1 0 0
Or A= 0 0 1 0

0 0 0 1

-1.06 0 2 0

1
0
B= −2 ⌉
⌈ C= ⌈ 10 0 0 0 ⌉
0
1
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Question #2

A capacitive displacement sensor is used to monitor small changes in


work-piece position. The two metal cylinders are separated by a distance
of 1 mm and dielectric constant at 1KHz of 2.5. This sensor is installed
in a system where the sensor outputs the position of the system. The
system has the following state-space equations:

A newly inducted engineer wants to design a controller for this system.


Compute the controllability matrix and check if this system is
controllable.

Answer 2:
First we check Eigen value of Matrix A so we check that the
system is stable or unstable.
det ( λI −A )=0

[ 10 ]
I= 0 1

λ I= [ 0λ 0λ]
[ λ 0] [ 0.5 1]
( λI − A ¿= 0 λ ‒ 0.8 2

Or [ λ−0.5−1 ]
( λI − A ¿= −0.8 λ−2
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det ( λI −A )= λ−0.5−1
[ −0.8 λ−2 ]
det ( λI −A )=¿

det ( λI −A )=(λ2 −2.5 λ+1)−0.8

det ( λI −A )=(λ2 −2.5 λ+1−0.8)

det ( λI −A )= λ2−2.5 λ+ 0.2

λ=−b ± √b 2−4 ac
2a

λ=−(−2.5)± √(−2.5)2 −4 (1)( 0.2)


2(1)

λ=2.5± √ 6.25−0.8
2

λ 1=2.5 ± √ 5.45
2

λ 1=2.5 ± 2.33
2

λ 1=2.5+2.33
2

λ 1=2.415

2.5−2.33
λ 2=
2
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λ 2=0.085

Here it is clear that Eigen Values are positive so the system is unstable

And we need to stabilize it, following the pre-requisite steps for Matrix
C, and the matrix C must be Identity so

Matrix C= ⌊ 0.5 0.1 ⌋

Matrix C is not identity so we cannot make controller for it.


P a g e | 10

STEP 1:
P a g e | 11

C( s) G 1+G 2
=
R( s) 1+G 1+G 2(G 4−G3)

Q3(B)
G1

R(s) G2
C(s)

H1

H2

STEP 1:

G1
P a g e | 12

R(s) G2
C(s)

H1

H2

STEP 2:
G1

R(s)
G2
C(s)

H2-H1

STEP 3:

R(s) G2 C(s)
1+ G2(H 2−H 1)

STEP 4:

G2
R(s) 1+G1 1+ G2(H 2−H 1)
P a g e | 13

C(S)
STEP 5:

(1+ G1)G 2
R(s) 1+ G2(H 2−H 1)
C(S)

STEP 6:
¿¿
R(s)
C(S)

C( s)
=¿ ¿
R( s)

End the paper

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