UNIVERSITI TEKNIKAL MALAYSIA MELAKA
Study on DC Motor Control System
Thesis submitted in accordance with the requirement of the Technical University Malaysia, Melaka for the Degree of Bachelor of Engineering (Honours)
Manufacturing (Robotic & Automation)
By
Moahamad Ariff bin Mohd Arshad
DECLARATION
I hereby, declare this thesis entitled “Study on Dc Motor Control System” is the result of my own research except as cited in the reference.
Signature : ………
APPROVAL
This thesis submitted to the senate of KUTKM and has been accepted as fulfillment of the requirement for the degree of Bachelor of Manufacturing Engineering (Honours) (Robotic and Automation). The members of the supervisory committee are as follows:
……….. (MR SHARIMAN BIN ABDULLAH)
Main supervisor
ABSTRACT
This case study describes the physics of a standard dc motor. From this general
understanding, differential equations are developed to describe the motor’s dynamic
behavior. State space equations and Laplace transforms are then developed for further
analysis. Typical data for a specific motor are included within a Matlab/Simulink
program to illustrate the basic time domain behavior of the system. System modeling
methods for analysis, design and regulation purposes have conventionally employed
lumped linear and non-linear methods to provide the dynamic and steady state
information required. Adequate though this may be when the components employed are
largely concentrated, physically, as system dispersion and slenderness ratios increase, the
dynamics arising from spatial distribution assume increasing relevance. Recognition of
this and attempted accommodation, via the promotion of approximation and empiricism,
ABSTRAK
Tesis ini adalah kajian mengenai instrumentasi dan kawalan motor arus terus. Motor arus
terus digunakan bersama dengan gear, alat penghubung, dan power screw untuk
membentuk satu elektro-mekanikal sistem. Seterusnya mencari transfer function utuk
sistem tersebut. Simulasi menggunakan perisian MATlab digunakan untuk menganalisis
sistem tersebut berdasarkan transfer function yang telah diperolehi. Keputusan yang
diperolehi dikaji untuk melihat sama ada apabila motor arus terus berkuasa 12 voltan
dibekalkan, apakah jumlah yang terhasil. Sistem dianalisis dan dipertingkatkan untuk
mendapatkan hasil yang terbaik dimana jumlah voltan yang dibekalkan sama dengan
ACKNOWLEDGEMENTS
Appreciations are expressed to those who have given generous contributions within the
period of this thesis development to fulfill the requirement of the Degree of Bachelor of
Engineering (Honours) Manufacturing (Robotic and Automation) program.
Here I would like to express my deepest appreciation to my supervisor, Mr.
Shariman, also acts as chief of department robotic and automation of faculty of
manufacturing engineering in Universiti Teknikal Malaysia Melaka.
His constant guidance and support during my thesis writing is invaluable to me.
His continuous direction and opinion regarding the flow of the project has a mass
contribution to achieve the objective of the project. Furthermore, the guide and help of
him on how to make this thesis a more effective reference are followed with my sincere
gratitude.
Finally, I would like to thank to all lectures, technicians and colleagues who had
involved directly or indirectly in my thesis.
Mohamad Ariff Mohd Arshad
TABLE OF CONTENTS
Abstract i
Acknowledgement iii
Table of Contents iv
List of Figure viii
List of Table xi
Sign and Symbols xii
1 INTRODUCTION 1
1.1 Introduction to the project 1
1.2 Problem Statement 2
1.3 Objectives, Aims and Scopes of the Research 3
1.3.1 Objectives 3
1.3.2 Aims 4
Scopes of the Project 4
1.4 Gantt Chart 5
2 LITERATURE REVIEW 7
2.0 Introduction 7
2.1 Dc Motor 8
2.1.1 Wound field DC motor 10
2.1.2 Theory 11
2.1.3 Speed control 12
2.2 Introduction to Control System 14
2.2.1 History of Control System 14
2.2.2 Classical control theory: the closed-loop controller 15
2.2.3 Stability 17
2.2.5 Derivation of a Schematic for a DC Motor 19
2.3 Mathematical Model 23
2.3.1 Electrical Characteristics 24
2.3.2 Mechanical Characteristics 25
2.3.3 Step Response of a DC Motor 30
2.3.4 Matlab Commands 31
2.4 Performance Characteristics 36
2.4.1 Block Diagram 40
2.4.2 Closed-Loop Control 43
2.5 Gear 44
2.5.1 Spur Gear 45
2.5.2 A Gear System 46
2.5.3 The Transfer Function 46
2.6 Coupling 47
2.7 Power Screw 47
3 METHODOLOGY 51
3.1 Flowchart 52
3.2 Details 53
3.3 Detailed design 54
3.3.1 DC Motor 54
3.3.2 Coupling Specification 55
3.3.3 Lead Screw Specification 55
3.4 The Design Process 56
3.4.1 Transform Requirement into a Physical System 56
3.4.2 Draw a Functional Block Diagram 56
3.4.3 Create a Schematic 57
3.4.4 Developed a Mathematical Model (Block Diagram) 57
3.4.5 Reduce the Block Diagram 58
3.5 Simulink 59
3.5.1 Simulink Basics 60
3.5.2 Opening Models 61
3.5.3 Using the Simulink Toolbar to Enter Commands 61
3.5.4 Simulink Windows 62
3.5.5 Saving a Model 63
3.5.6 Running a Simulation Programmatically 63
3.5.7 Modeling Dynamic Systems 64
3.6 System Model 67
3.7 Calculation of the Parameter 67
4 RESULTS 71
4.1 System Model Schematic Diagram 71
4.2 Calculation of the Transfer Function 72
4.3 Descriptions of the Blocks 75
4.3.1 Step 75
4.3.2 Transfer Fcn 77
4.3.3 Scope 78
4.4 Modeling Equations 80
4.4.1 Running the Model 82
4.5 Modelling Simulink With Gain 83
4.5.1 Gain 83
4.5.2 Running the Model 85
4.6 Modelling Simulink with Gain and Feedback 87
4.6.1 Feedback 87
4.6.2 Sum 87
4.6.3 Running the Model 89
4.7 Designs via Root Locus 91
4.7.1 Improving Transient Response 91
4.7.3 Improving Steady-State Error via Cascade Compensation 93
4.7.3.1 Ideal Integral Compensation (PI) 93
4.7.4 Improving Transient Response via cascade Compensation 95
4.7.4.1 Ideal Derivative Compensation (PD) 96
4.7.5 Improving Steady-State and Transient Response 96
4.7.5.1 PID Controller Design 97
4.8 Creating the Simulation Model 98
4.8.1 Integrator 99
4.8..2 Derivative 103
4.8.3 Running the Model 103
5 DISCUSSION 107
6 CONCLUSION AND RECOMMENDATION 113
7 REFERENCE 114
LIST OF FIGURES
2.0 A simple DC electric motor. 9
2.1 The armature continues 9
2.2 When the armature becomes horizontally aligned, the commutator
reverses the direction of current through the coil, reversing the magnetic
field. The process then repeats.
10
2.3 A simple feedback control loop 16
2.4 Current-carrying wire in a magnetic field 19
2.5 a. Current-carrying wire on a rotor
b. current-carrying wire on a rotor with commutation and coils added to
the permanent magnets to increase magnetic field strength
20
2.6 Magnetic flux density passing through a loop of wire on an armature 22
2.7 DC motor circuit diagram 23
2.8 Electrical representation of a dc motor. 24
2.9 Block diagram representation of equations 28
2.10 Block diagram of the dc motor as modeled in this study 29
2.11 Overall transfer function for the dc motor 29
2.12 Block diagram produced within Simulink 30
2.13 Step response of a dc motor for the Case 1 and Case 2 simulations 31
2.14 Dc Motor Representation 36
2.15 Rated Values of Speed, Torque And Power 39
2.16 The block diagram of a dc drive 40
2.17 Spur gear 45
2.18 A gear system 46
2.19 a. angular displacement in lossless gears
b. torque in lossless gears
46
2.20 Coupling 47
2.22 Type Of Power Screw 50
3.1 Sketching Of the Mechanical Design Diagram 54
3.2 Simulink library 60
3.3 Model Window 62
3.4 inputs and/or output 64
3.5 Diagram Illustrates Some of the Tools Provided By The Mathworks 66
3.6 Schematic diagram 67
4.0 System Model Schematic Diagram 71
4.1 Step 75
4.2 Block Parameter of the Step 76
4.3 Transfer Fcn 77
4.4 Block Parameter of the Transfer Fcn 78
4.5 The Scope Block 79
4.6 The Scope Window 79
4.7 The Blocks Gather Into Model Window 81
4.8 Complete and connected block circuit 82
4.9 The Step Response from the Scope 83
4.10 The Gain Block 84
4.11 Block Parameter of the Gain Block 84
4.12 Simulink Block With Gain 86
4.13 The Step Response With Gain 86
4.14 The Sum Block 88
4.15 Block parameter of sum 89
4.16 Workspace model of the simulation with Gain and Feedback 90
4.17 Step response of the output. 90
4.18 Pole at A is on the root locus without compensator 94
4.19 Pole at A is not on the root locus with compensator pole added 95
4.20 Approximately on the root locus with compensator pole and zero added. 95
4.22 Model workspace with added block, Gain, Integrator, Derivative, and
Sum.
99
4.23 Integrator Block 99
4.24 Block Parameter: Integrator 100
102
4.25 Derivative Block 103
4.26 Complete circuit of the simulation with PID controller. 104
4.27 Steady-state response output 104
4.28 Voltage reach 12V 105
4.29 cmax decrease to cfinal 106
5.0 The Step Response from the Scope for the linear system 108
5.1 The Step Response from the Scope for the linear system with gain. 109
5.2 The Step Response from the Scope for the closed-loop system with gain. 110
5.3 The Step Response from the Scope for the closed-loop system with PID
controller
LIST OF TABLES
4.0 Maxon Dc Motor Data 72
4.1 Coupling specification 73
LIST OF ABBREVIATIONS, SYMBOLS, SPECIALIZED NOMENCLATURE
DC - Direct Current
EMF - Electric Motive Force
PWM - Pulse Width Modulation
AC - Alternating Current
SISO - Single-Input-Single-Output
MIMO - Multi-Input-Multi-Output
BIBO - Bounded-Input-Bounded-Output
PDF - Pseudo-Derivative Feedback
PID - Proportional-Integral-Derivative
SCR - Silicon Controlled Rectifier
RPM - Revolution per Minute
SM - Single loop Margin
DM - Double loop Margin
MM - Multi loop Margin
y(t) - Output Of The System
r(t) - Reference Value Through The Measurement Performed By A
Sensor
C and P - Linear And Time-Invariant For A Simple Feedback Control Loop
C(s) and P(s) - Transfer Function For A Simple Feedback Control Loop
x[n] - Impulse Response
i - Electric Current
l - Flowing In A Wire Of Length
B - Magnetic Field Of Strength
F - Force
Kt - Equivalently
Ia - Current Flow
A - Area
ia(t) - Wire Carrying Current
Tm(t) - Torque for DC Motor
Ra - Resistance
La. - Inductance
θm(t) - output angular displacement for DC Motor
Va - Voltage Source In Electrical Characteristic
kv - Velocity Constant Determined By The Flux Density Of The
Permanent Magnet
ωa - Rotational Velocity of The Armature
Te - Electromagnetic Torque in Mechanical Characteristic
Tw - The Torque Due To Rotational Acceleration of The Rotor
in Mechanical Characteristic
Tw’ - Torque Produced From The Velocity Of The Rotor
in Mechanical Characteristic
TL - Torque Of The Mechanical Load in Mechanical Characteristic
Ωref - Speed In Closed-Loop Ωf - Speed Feedback Signal CS - Critical Speed
D - Root Diameter Of Screw (Inches) for Power Screw
L - Length Between Supports (Inches) for Power Screw
CHAPTER 1
INTRODUCTION
1.1 Introduction to The Project
modeling was investigated for mechanical, power transmission system modeling, were also researched and accurate, compact, computationally efficient realizations, for controller design and real-time diagnostics, were derived. At this time single loading effects and the dynamics arising from flexible beams, shafts and rotor-bearing assemblies were addressed. Whirling speed applications studies continued in parallel with this work using frequency response and numerical minimization methods. In this contribution previous work will be advanced with a novel combined torsion and tension loading, machine tool modeling method. The technique involved will be to describe significantly distributed elements of the machine, such as the lead screw, using distributed parameter procedures. This approach to the mathematical construction process enables greater reality, accuracy and integrity to be achieved. Essentially, the system dynamics arising from the combined, distributed lumped description enable all of the incident, traveling and reflected waveform effects to be replicated in the final realization. Effectively, the response signatures generated by the model will be shown to correspond closely with those from the actual system. In particular, the effects of spatial dispersion and combined, lead screw, torsion and tension loading provide a broadband realization, capable of generating the low and high frequency behavior of the system’s, x-axis dynamics. This is enhanced by the incorporation of lumped nonlinear effects. Details of these characteristics were obtained, in this study, from manufacturer’s data and from measured, experimental results. Following, the detailed derivation for the x-axis traverse, motor drive and the multivariable lead screw model, for combined torsion and tension loading will be presented. Thereafter, an overall, interactive representation, for the complete distributed–lumped system configuration, will be derived. Finally, the simulated response transients for the system, following voltage step changes on the lead screw, motor drive, will then be computed.
1.2 Problem Statement
the system. The objective of this project was to study and analyze a simple test that had all the relevant attributes of the more complicated machines. The dynamics and control of a load driven by a DC motor was to be investigated in the context of high-speed high precision motion control. High performance was desired without risking close-loop stability. One particular addition of interest is a Simulink graphical model which automatically performs the appropriate block diagram arithmetic and generates a state space model for use in a standard Matlab simulation. This model is used here to relate the output angular velocity of the motor to the input applied voltage. It is also used as a subsystem in a Simulink model of the complete the simple mechanical design.
1.3 Objectives, Aims and Scopes of the Project
1.3.1 Objectives
1. To demonstrate the use of electrical blocks, in combination with Simulink blocks, in the simulation of an electromechanical system with a control system. The electrical part of the DC motor drive, including the DC source, and the DC motor, is built using blocks from the Elements, Machines, and Electronics libraries in the Matlab Software. The DC Machine block models both electrical and mechanical dynamics. The load torque-speed characteristic and the control system are built using Simulink blocks.
2. Describe various methods of controlling the speed and direction of a DC motor.
3. Learn the operation and modeling of DC motor systems. 4. Learn the driver circuitry for DC motors.
1.3.2 Aims
Analyze the output voltage of DC motor that produce for the simple mechanical design that have power screw. Be able to using the Matlab software to simulate the design and test to see that the requirements and specification are met.
1.3.3 Scope of the Project
This project is to study on ‘Dc Motor Control System’. The project scope is to ‘Study the Control Element in Single Axis Positioning with Consist of Motor, Gearing, Coupling, and Power Screw’. The software that recommended in this research is Matlab 6.5.1. The main of this research is to explore and design the mechanical element. From the mechanical equations, transfer to the control system equations. Then, find the specification of the element at calculate the value of the dc motor output voltage. Construct the block diagram using Matlab software and simulate the design.
1.6 Gantt Chart
Table 1 Gantt Chart PSM 1.
CONTENTS W
1 W 2 W 3 W 4 W 5 W 6 W 7 W 8 W 9 W 10 W 11 W 12 W 13 W 14 W 15 W 16 Project Selection Information research
Write a literature review
Discuss on simple robot that using dc motor
Draft the objective and select the instrument that need to be used in the project
Study on MATlab Software
Design and solve mechanical diagram
Draft report preparation
Final draft report preparation
Presentation and report submission
Table 2 Gantt Chart PSM 2.
CONTENTS W1 W2 W3 W4 W5 W6 W7 W8 W9 W10 W11 W12 W13 W14 W15 W16
Find the specifications
Find the transfer function
Simulation using MAtlab software
Analysis the result
Make a discussion
Gathering all information and sources
Draft report preparation
Final draft report preparation
Presentation and report submission
CHAPTER 2
LITERITURE REVIEW
2.0 Introduction
