University of Baghdad College of engineering Ele . & Com. Dept. 3 rd Year Matlab

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University of Baghdad College of engineering Ele . & Com. Dept. 3 rd Year Matlab

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University of Baghdad College of engineering Ele . & Com. Dept. 3 rd Year Matlab

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University of Baghdad

College of engineering

Ele. & Com. Dept.

3rd Year

Matlab

Report of

POSITION AND SPEED CONTROL SYSTEM

Part I

Part II

By Ahmed Alaa

Position and Speed

Objectives

The general characteristics of a closed loop system provided by speed and position control for an electric motor using MATLAB

Procedure

- PART ONE: POSITION CONTROL SYSTEM
- Run the MATLAB program on a PC
- Give the simulink for the block diagram shown in fig.4
- For the gain KA=3 set the feedback gain K1 to: 0,0.2,0.4,0.5,0.6,1,3,5,10
- Draw the output response with the step input signal for each case
- From the output response calculate the following time constants values (Delay time td ,tr,tp,ts, and the maximum %OS (Mp) (only for cases that k=0 up to 0.6)
- PART TWO: SPEED CONTROL SYSTEM
- Give the simulink for the block diagram shown in fig.5
- Set the step i/p of a final value of 1 and step time of 0 with k=10 ; kg=1
- Draw the o/p response with step i/p signal
- From the o/p response calculate the following time constants values (Delay time td,ts,tr,Mp,tp)
- Repeat 3 and 4 for the following values of a step input final values (2,3,4,5,6,7,8,9,10)

Page 1

Position and Speed

Discussion

What is the benefits of using feedback paths in control system, is it good to increase the feedback paths in these systems ? Why ?

Derive the overall transfer function of the position control CLS from the basic equations.

the most important advantages is available when negative feedback used

increasing stability , bandwidth

and for +ve feedback ; an oscillation is probably occurs when BA=1

if we increased the number of feedback paths , a great stability is composed with this case but with an increasing noise i.e if the number of passive elements is increased in a circuit a noise will happen

For a CLS:

G(s)=A/1+BA

A is OLTF for fig 2-b

A=Km/s(1+Ts)

KA is the preamplifier gain

Om is the gear unit gain

At=KA(A)(Om)

At=KAKmOm/s(1+Ts)

G(s)=KAKmOm/s(1+Ts)+KAKmOm

Page 2

Position and Speed

What is the effect of changing the values of KA and K1 on the response of the positioncontrol system?

Reason out why the error decreases as the system gain increases in speed control system

Increasing k1 will increase Tsi.e the time is taken by system to reach its steady state is increased ; if k1=0 i.ef.b path removed . An oscillation is occurred before the system reaches steady state ; increasing KA will increase the Mp (max. %OS)

Increasing KA if K1 exists make no difference

For KA=1 ; K1=0 For KA=3 ; K1=0

For KA=10 ; K1=1

System gain k is directly proportional with error constant i.eKv

Kv=limskG(s) as s approaches 0

And error(ramp)=1/Kv

Hence the error will decrease if k increased

Page 3

Position and Speed

Compare between the theoretical and practical results for both systems and comment on your results.

For step II

Ts=4/zWn; z=0.5 and Wn=1

Ts=8 sec [equal to the practical]

from these experiments we found that k of feedforward of a system with unity one path feedback will affects the Mp .. Oscillation is increased when k is increased ; the other k i.e of feedback is affects the o/p magnitude . Unity case is preferred for control systems . Adding another path of feedback will increase the stability . Adding with a value of k ( of the feedback) will decrease Ts.( for procedure step 1)

Mp,Ts,Tp and Tr remains constant even if we increased the final value of a step i/p

Page 4