UWE Bristol Engineering showcase 2015

NUR SAFWANAH MOHD AZHARI
MEng ELECTRICAL AND ELECTRONIC ENGINEERING
MODELLING AND CONTROL THE SPEED OF DC MOTOR SYSTEM IN
SIMULINK
Introduction
The underlying concept of an automatic control system has played an important role in the advance of engineering and science. Control
methods are used whenever some quantity, such as velocity, speed, temperature, altitude or heat flow, must be made to behave in
some desirable way over time. Moreover, the automatic control system is much better than the human-controlled operation in terms of
efficiency, accuracy and reliability. The system will be demonstrate by using computer simulation . The controller is required to obtain
the required parameters such as to minimize the steady state error and to control the maximum overshoot of the system. The design &
simulation studies used to demonstrate the basic theoretical feasibility of the system used by PID controller and state-space method
approach.
The DC motor modelling is done by summing the torques acting on the rotor
inertia and integrating the acceleration to the velocity and also Kirchhoff’s laws
to armature circuit. The mathematical modelling of DC motor can be
constructed by using four basic equations of DC motor [24] . Therefore, the
dynamic parameters of the motor are explained and described by the following
equations:
dd
vv aa = RR aa II aa tt + LL iiii tt
aa
dd tt
+ ee bb tt --- (1)
ee bb tt = KK bb ww tt --- (2)
TT mm tt = KK tt ii aa tt --- (3)
dd
TT mm tt = JJ ww tt
mm
dd tt
+ BB mm ww tt --- (4)
GG ss =
rrrrrrrrrrrrrrrrrrrr ssssssssss
aaaaaaaaaaaaaaaa vvvvvvvvvvvvvv
(9)
Therefore the transfer function can be simplified into below expression:
GG ss = WW(ss)
=
--- (10)
VV aa (ss)
KK tt
rrrrrr/ssssss
LL aa ss+RR aa JJ mm ss+BB mm + KK bb KK tt VVVVVVVV
dd
dd tt
ww
ii
=
−BB mm
JJ mm
−KK bb
LL mm
yy = 1 0 ww ii
KK tt
JJ mm
−RR aa
LL aa
ww
ii
+ 0 VV --- (12)
+ 0 1
LL mm
VV --- (11)
Parameter PI controller PID controller State-space: state feedback
Steady-state error Less Less Less
Settling time (Ts) 7.28sec 8.24sec 4.0sec
Overshoot 34% 28.4% 10%
Rise time (Tr) 1.13sec 0.907sec 0.855sec
Step response Stable Stable More Stable
Project Supervisor
PROF. QUAN MIN ZHU
Project summary
This thesis is dedicated on the control system design
in modelling and controls the speed of DC motor
system in simulink, with the goal of obtaining a
reliable speed control system. The speed control is
regarded as one of the most important element in
industrial field, for instance in process control,
electrical system in home and especially in electromechanical
system. Dynamic DC motor speed
simulations include all the design parameters that
influence the way in which a DC motor responds to
the external environment. It can be done by
demonstrating the mechanism and dynamics of the
speed of DC motor for a period of time. In order to
obtain required parameters, there are two methods
that have been chosen as a control method which
are; PID controller and State-space method. Several
modes can be represented as feedbacks (speed, input
voltage, velocity, etc.) to optimize the severity of
performance. Both the model of the flowing process
and of the control law is validated by a virtual
detailed simulation environment.
Project Objectives
-Implement one of the matured control
strategies by using Matlab software
-Define the mathematical modelling to find
the equations and transfer function of the
plant system. Modelling and analyst the
system without controller.
-Design and implement two methods of controller for
DC Motor to improve the performance
Project Conclusion
-The designing and simulating of DC motor speed
control system has been done using the MATLAB
software, most of the vital calculated results have
also been double checked using the MATLAB
simulation to prove the physical parameters of the
system.
-Discuss about the comparison of two controllers
between PID controller and state space method
approach