Docsity
Docsity

Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity


Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan


Guidelines and tips
Guidelines and tips

Temperature Control System - Linear Control Systems I - Past Exam Paper, Exams of Linear Control Systems

Main points of this exam paper are: Phase Margin, Proportional Plus Integral, Respective Transfer Functions, Locations, Poles, Zeroes, Damping Ratio, Measurements, Open-Loop Conditions, Polar Plot

Typology: Exams

2012/2013

Uploaded on 03/26/2013

sarman
sarman 🇮🇳

4.4

(54)

206 documents

1 / 5

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
EE318 Linear Control Systems I Page 1 of 5
Semester I Examinations 2011/2012
Exam Code(s)
3BEI, 3BN, 3BM, 3BSE, 4BEE
Exam(s)
Third Engineering Innovation – Electronic
Third Electronic Engineering
Third Mechanical Engineering
Third Energy Systems Engineering
Fourth Sports & Exercise Engineering
Module Code(s)
EE318, EE439
Module(s)
Linear Control Systems I
Paper No.
1
Repeat Paper
No
External Examiner(s)
Prof. G. W. Irwin
Internal Examiner(s)
Prof. G. Ó Laighin
Dr. M. Duffy
Instructions:
Answer any three questions from four.
All questions carry equal marks (20 marks).
Duration
No. of Pages
Discipline
Course Co-ordinator(s)
Requirements:
MCQ
Handout
Statistical Tables
Graph Paper
Yes: mm graph paper
Log Graph Paper
Other Material
Nichols Chart Paper
pf3
pf4
pf5

Partial preview of the text

Download Temperature Control System - Linear Control Systems I - Past Exam Paper and more Exams Linear Control Systems in PDF only on Docsity!

Semester I Examinations 2011/

Exam Code(s) 3BEI, 3BN, 3BM, 3BSE, 4BEE

Exam(s) Third Engineering Innovation – Electronic

Third Electronic Engineering

Third Mechanical Engineering

Third Energy Systems Engineering

Fourth Sports & Exercise Engineering

Module Code(s) EE318, EE

Module(s) Linear Control Systems I

Paper No. 1

Repeat Paper No

External Examiner(s) Prof. G. W. Irwin

Internal Examiner(s) Prof. G. Ó Laighin

Dr. M. Duffy

Instructions: Answer any^ three^ questions from four.

All questions carry equal marks (20 marks).

Duration 2hrs

No. of Pages 5

Discipline Electrical & Electronic Engineering

Course Co-ordinator(s)

Requirements :

MCQ

Handout

Statistical Tables

Graph Paper Yes: mm graph paper

Log Graph Paper

Other Material Nichols Chart Paper

The following standard formulas are given and may be freely used:

Ziegler-Nichols Rules : Proportional control : K = 0.5 K c

P+I control : K = 0.45 K c , T i = 0.83 T c

PID control: K = 0.6 K c , T i = 0.5 T c , T d = 0.125 T c

M (^) p M (^) o

=

1 2 ζ 1 −ζ (^2) ( ζ ≤ 0. 707)

ω (^) r =ω (^) n 1 − 2 ζ (^2) ( ζ ≤ 0. 707)

ω (^) d =ω (^) n 1 −ζ 2

ω (^) b =ω (^) n (1− 2 ζ 2 ) + (1− 2 ζ 2 ) + 1

T (^) r (0 − 95%) ≅ 3 / ω (^) b ( ζ > 0. 4)

T (^) r (0 − 100%) =

π − sin−^1 1 −ζ 2

ω (^) n 1 −ζ (^2) ( ζ < 1)

Overshoot = 100 exp −

πζ

1 −ζ 2

( ζ < 1)

T (^) s (±2%) ≤

ζ ω (^) n

ln

1 −ζ 2

^ ( ζ < 1)

T (^) s (±5%) ≤

ζ ω (^) n

ln

1 −ζ 2

^ ( ζ < 1)

1. Results of the open-loop frequency response measured on a temperature control system as

shown in Figure 1 with K = 1, are given in Table 1.

Table 1

(a) Write an expression for the output signal you would expect to measure for an input

signal, r(t) = 0.1 sin(0.5t), applied to the open-loop system with K = 1. [ 4 marks ]

(b) Using mm graph paper, sketch the open-loop data of Table 1 on a polar plot.

[ 5 marks ]

(c) What value of gain, K, will result in a gain margin of 6 dB for the given system?

(Hint: the gain may be less than 1.) [ 3 marks ]

(d) With the gain set equal to the value found in part (c), sketch a new Polar Plot for the

system and determine the phase margin. [ 8 marks ]

Figure 1

2. The block diagram of a position control system used in a CD player is shown in Figure 2.

Figure 2

(a) Write the closed-loop transfer function for the given system in terms of the gain

parameter, K. [ 2 marks ]

(b) Sketch the root locus of the system for K, including a calculation for the location of

the breakpoint from the real axis. [ 12 marks ]

(c) Using the root locus of part (b), determine the maximum value of K that would

result in the system complex poles having a damping factor, ξ = 0.5. [ 6 marks ]

ω (rad/s) 0.2^ 0.3^ 0.5^ 0.7^ 1.0^ 1.

Gp(j ω ) –^5 –^ j 7.6^ –^4 –^ j 3.7^ –^ 2.4^ –^ j 0.8^ –^ 1.4^ –^ j 0^ –^ 0.6 + j 0.2^ –^ 0.15 + j 0.

_

R(s) C(s)

K^ Gp(s)

_

R(s)

(s 3 )

s(s 2 )

K(s 1 )

C(s)

3. Results of the open-loop frequency response of an industrial automation system using PID

control are given in Table 2.

Table 2

(a) Plot the results of Table 2 on a Nichols chart. Determine the bandwidth (BW) of

the closed loop system and use it to estimate the 0 – 95% rise time. [ 6 marks ]

(b) In order to reduce the system response time, the gain parameter is increased by 6

dB. Show how this increase in gain changes the Nichols chart for the system, and

use it to determine the new 0 – 95% rise time. [ 4 marks ]

(c) Using the Nichols chart of part (b), calculate (i) the percentage step response

overshoot and (ii) the ±5% settling time. [ 8 marks ]

(d) Suggest an alternative method for reducing the system response time which would

have greater stability than that proposed in part (b). [ 2 marks ]

4. A DC motor is connected into the tachometric feedback loop shown in Figure 3, and the

gain of the power amplifier is set at K = 3.6.

Figure 3

(a) Confirm that without tachometric feedback, i.e. with β = 0, the system of Figure 3

has closed-loop poles located at s = − 0.5 ± j 0.975. [ 3 marks ]

(b) Given that the poles in part (b) are the dominant system poles, determine (i) the

percentage overshoot, (ii) the (0–100%) rise time and (iii) the ±5% settling time

for a unit step input. [ 8 marks ]

(c) With tachometric feedback in operation, find the value of β which will locate one

of the closed-loop poles at s =− 2 and determine the locations of the other two

poles. [ 4 marks ]

(d) For the system of part (c), estimate values of (i) percentage overshoot and (ii) (0–

100%) rise time for a unit step input, and comment on the effectiveness of

tachometric feedback. [ 5 marks ]

ω (rad/s) 0.05^ 0.1^ 0.2^ 0.3^ 0.

G p (jω) (dB )^20 3.5^ –^ 3.7^ –^ 8.8^ –^ 16.

∠G p (jω)(o ) − 95^ − 115^ − 136^ −154^ −

C(s)

K

R(s)^ +

1+βs

s(s 4s 4.2)

G (^) p (s) 2