Automatic Guided Cart.
ABSTRACT
The present invention related to automated guided cart (AGC) particularly to costeffectiveness, light duty vehicle, which is specifically adapted for use in light
manufacturing shop floor. This AGC followed a magnetic guide taped on floor to
move goods or material from one point to another under PIC control. The AGC
system employ specifically designed carts, which are configured particularly to carry
components such as automobile chassis or assembly components in an automobile
assembly operation. Generally, the method to achieve the objectives, it consists of
designation stage, procurement preparation stage, material preparation stage,
fabrication stage, and examination stage. This project involved design and
development of the AGC system through the engineering skills via mechanical
calculation and analysis, material selection, electrical circuit design, and
programming of the PIC controller. In the implementation stage, a light duty AGC
produce and applicable to industrial environment to accomplished the project.
i
ABSTRAK
Ciptaan projek berautomatik panduan kereta (Automated Guided Cart) terutamanya
untuk keberkesanan kos, kenderaan tugas ringan dan khususnya disesuaikan oleh
penggunaan dalam tingkat pembuatan ringan. AGC ini diikuti satu panduan yang
magnetik merakamkan di atas lantai untuk bergerak barangan atau bahan di
sepanjang lorong yang ditentukan. Ia dikawalkan oleh PIC mengawal untuk bergerak
dan pelbagai fungsi. Sistem AGC reka bentukan mengatur corak yang tatarajah
terutamanya untuk melaksanakan komponen-komponen ibarat casis kereta atau
komponen-komponen
pemasangan
dalam
operasi
automobil
pemasangan.
Umumnya, kaedah untuk mencapai matlamat-matlamat, ia mengandungi peringkat
gelaran, ia itu, tahap persiapan pemerolehan, tahap persiapan bahan, peringkat
pembuatan, dan peringkat peperiksaan. Rekabentuk dan pembangunan AGC terlibat
dalam projek ini melalui kemahiran-kemahiran kejuruteraan adalah pengiraan dan
analisis mekanikal, pemilihan bahan, rekabentuk litar elektrik,dan pengaturcaraan
PIC mengawal. Untuk mencapaikan matlamat projek ini, dalam peringkat
pelaksanaan, AGC yang bertugasan ringan menghasilkan dan bersedia digunakan
untuk persekitaran perindustrian dicipta.
ii
ACKNOWLEDGEMENT
I would like to express my gratitude to all those who gave me the possibility to
accomplish this project of manufacturing engineering bachelor’s degree entitled
automated guided cart. I want to thank the Department Managemtnt Faculty of
Manufacturing of Universiti Teknikal Malaysia Melaka (UTeM), Prof. Dr. Mohd.
Razali b. Muhamad and giving me permission to commence this project in the first
instance, approved the title of project proposed. I have furthermore to thank the
Management of Project Sarjana Muda, Sivarao a/l Subramonian, and Head of
Department of Robotic and Automation, Dr. Zamberi bin Jamaludin who gave and
confirmed this permission and supported me to progressing with my project.
I am deeply indebted to my supervisor, Puan Nur Aidawaty bt. Rafan and principle
co-supervisor, Puan Silah Hayati bt. Kamsani from the Department of Robotic and
Automation of UTeM whose help, stimulating suggestions, technical information,
and encouragement helped me in all the time of project and writing of this report.
My colleagues from 4BMFA of UTeM supported me in my research work. I want to
thank them for all their help, support, interest and valuable hints. Especially I am
obliged to Mr. Lim, Lee Wai Keong, Tan Sia Peng for the great help in difficult
times and suggestions for improvement.
Especially, I would like to give my special thanks to my wife Karen whose patient love
enabled me to complete this work.
iii
TABLE OF CONTENT
Abstract
i
Abstrak
ii
Acknowledgement
iii
Table of Content
iv
List of Tables
vi
List of Figures
vii
List of Abbreviations
viii
1. INTRODUCTION
1
1.1
Introduction
1
1.2
Problem Statement
2
1.3
Objectives
4
1.4
Scope
5
2. LITERATURE REVIEW
6
2.1
Vehicle Guided Technology
6
2.1.1
Imbedded Guided Wires
6
2.1.2
Paint Strips Guidance
7
2.1.3
Self Guided Vehicle
8
2.2
2.3
Mechanical Review
8
2.2.1
Material in Mechanical Design
9
2.2.2
Electrical Motors
13
2.2.3
Kinematic of Gears
18
Electrical Review
20
2.3.1 Sensors
20
2.3.2 PIC Microcontroller
23
3. METHODOLOGY
26
3.1
Methodology Flow Chart of project AGC
26
3.2
Functions of the Cart
27
iv
3.3
Design Requirement
28
3.4
Evaluation Criteria
29
3.5
DC Motors
30
3.6
Drive Mechanism
30
3.7
Frame
31
3.8
PIC Microcontroller
33
3.9
Sensors
35
4. DESIGN AND DEVELOPMENT
38
4.1
DC Motor Selection
38
4.2
Drive Mechanism
40
4.2.1
Gear Geometry Computation
41
4.2.2
Shaft Design
42
4.2.3
Bearing Selection
44
4.3
Frame Design
45
4.3.1
Technical Drawing
48
4.4
Motor Drive Circuit Board Designation
51
4.5
Microcontroller Electronic Circuit Designation
53
4.6
Magnetic Sensor
54
5. RESULT AND DISCUSSION
56
5.1
Mechanical Structure
56
5.2
Controller
58
5.2.1
Microcontroller Electronic Circuit Board
58
5.2.2
Microchip Pin Assignment
61
5.2.3
Motor Control Electronic Circuit Board
62
5.3
Magnetic Sensor Electronic Circuit Board
64
5.4
PIC Comment Programs
67
5.4.1
Microcontroller Language (C Language)
67
5.4.2
Program Burning
71
v
6. CONCLUSION AND RECOMMENDATION
74
6.1
Conclusion
74
6.2
Recommendation
75
REFERENCE
76
APPENDIX A
APPENDIX B
APPENDIX C
APPENDIX D
APPENDIX E
APPENDIX G
vi
LIST OF TABLES
1.1
Comparison of the Methods of Material Handling.
2.1
Uses of Some Steels
2.2
Aluminum Alloy Groups
2.3
Common Aluminum Alloys and Their Uses
2.4
AC Motor Voltage.
2.5
AC Motor Speeds for 60 Hertz Power
2.6
DC Motor Voltage Ratings
3.1
Characteristics of the Material Elements.
3.2
Alloy Steel and Aluminum General Physical Properties.
3.3
Microcontrollers Device Overview and Its Properties
3.4
Microcontroller Features As Guide to Selection
3.5
Characteristics and the Features of Unipolar Type Magnetic Sensors.
3.6
Characteristics and the Features of Bipolar Type Magnetic Sensors.
4.1
Summary of the Comparison between Desired Value and Selected Value.
4.2
Pin assignment and its function.
4.3
General electrical and magnetic specifications.
5.1
Result comparison from designed specification to actual specification
vii
5.2
DIP switch operation direction
5.3
Logic function of the motor driver
LIST OF FIGURES
1.1 Production Layout Illustrated the Material Handling System in Present Practice.
2.1
Plan View of an Exemplary Embodiment of the Information Sensing
Portion of the Guided System.
2.2
The Diagrammatical Perspective View of the AGV Adapted to Move
Automatically Along an Optically Defined Path for Carrying a Load From
a Starting Point to an Arrival Point.
2.3
A Diagrammatic Side Elevation View of a Self Guided Vehicle
2.4
Single-phase AC Power and Three-phase AC Power
2.5
General Form of Motor Performance Curve
2.6
Pair of Spur Gears. The Pinion Drives the Gear
2.7
Hall-Effect Principle With No Magnetic Field Present
2.8
Hall-Effect Principle With Magnetic Field Presents
2.9
Circuit of an IR Emitter and IR Phototransistor
2.10
3.1
Circuit and Diagram of an Infrared Reflectance Sensor.
Basic Draft of the Options for the Drive Mechanism of Automated Guided
Cart.
3.2
Design Concept of the Frame of the Automated Guided Cart.
3.3
Comparison of the Properties between Alloy Steel and Aluminum.
viii
3.4
Force Distributed on the Cart.
4.1
Design Sketch of the Drive Mechanism (Single Stage Gear System) and
Its Main Components.
4.2
Power Flow Through the Gear.
4.3
Direction of Force Distribution on Gear.
4.4
Graphical Representative of Force, Shearing Force and Bending Moment
of the Gear.
4.5
Force Distortion on the Frame of the Cart.
4.6
Graphical Representative of Force, Shearing Force and Bending Moment
of the Frame.
4.7
COSMOSX Analysis of the Aluminum Square Hollow Bar (20x20x1/4)
4.8
Assembly CAD Drawing of the AGC.
4.9
Frame CAD Detail Dimension Drawing.
4.10
Detail CAD Drawing of the Drive Mechanism.
4.11
Pin connection of the dual-bridge microchip Multiwatt15
4.12
Full-bridge circuit electronic circuit diagram.
4.13
Design circuit of the microcontroller board associated with the burner
function.
4.14
Mechanism of turning performed by three magnetic sensors.
4.15
Dimension of the magnetic sensor.
4.16
Designation of the magnetic sensors circuit
5.1
Top view of the structure of Automated Guided Cart
5.2
Dimension of the Automated Guided Cart
5.3
Gear mechanism using spur gear system to drive the cart
5.4
Microcontroller electronic circuit board
5.5
Dual Interchange Pin (DIP) Switch
5.6
Voltage regulator 7805
5.7
Microchip 16F877A pin assignment to the programming.
5.8
Motors controller electronic circuit board.
5.9
Result from the testing on the PWM signal generation.
5.10
Magnetic sensor circuit board.
ix
5.11
Typical output characteristics with various values of external bias resistors.
5.12
Solid-state sensor response graph.
5.13
PIC 16F877A pin-out descriptions.
5.14
New project and its setting in microC.
5.15
Source code build into machine code (.hex file).
5.16
Detection of the microchip 16F877A.
5.17
Burning operation of .hex file to microchip.
5.18
Finish burn of the microchip.
LIST OF ABBREVIATIONS
AC
-
Alternative Current
ADC
-
Analog Digital Convertor
AGC
-
Automated Guided Cart
AGV
-
Automated Guided Vehicle
AGVS
-
Automated Guided Vehicle System
AISI
-
American Iron and Steel Institute
CAD
-
Computer Aided Drawing
CCP
-
Capture and Compare Module
CPU
-
Central Processing Unit
DC
-
Direct Current
DIP
-
Dual Interchange Pin
EEPROM -
Electrically Erasable Programmable Read-only Memory
FMS
-
Flexible Manufacturing System
GND
-
Ground
I/O
-
Input / Output
IC
-
Integrated Circuit
IDE
-
Integrated Development Environment
IR
-
Infra-Red
JIT
-
Just In Time
LED
-
Light Emitting Diode
NEMA
-
National Electrical Manufacturers Association
x
PIC
-
Programmable Intelligent Computer
PWM
-
Pulse Width Modulation
R
-
Resistor
RAM
-
Random Access Memory
RPM
-
Radius per Minute
SCR
-
Silicon Controlled Rectifier
UNS
-
Unified Numbering System
USART
-
Universal Asynchronous Receiver / Transmitter
USB
-
Universal Serial Bus
xi
CHAPTER 1
INTRODUCTION
This chapter introduced the general information regarding to this title of project and
problem statement to state reason to develop the research and implementation of
Automated Guided Cart. Brief declaration of Automated Guided Cart discussed.
1.1
Introduction
Automated guided vehicle system (AGVS) is a material handling system that uses
independently operated, self-propelled vehicles guided along defined pathways
(Groover, 2008). The vehicles are powered by on-board batteries that allow many
hours of operation. An AGV is suitable applies on automating material handling in
batch production and flexible manufacturing system.
In this project, automated guided cart (AGC) developed in the application of material
handling to light duty industry as assembly line applications, storage and distribution
and logistics. There are three main tasks to carry out the project, which are
mechanical structure, controlling electronic circuit components and comments
programming. From designation, material selection, implementation and evaluation
stages, discussed.
1
1.2
Problem Statement
Material handling equipment is usually assembled into a system. The system must be specified and configured to satisfy the requirement of a
particular application. It depends on the materials to be handled, quantities and distance to be move, type of production facility served by the
handling system, and other factors, included available budget.
Station #401
Station #301
Roof and Cowl-Top
Transferred from SubAssy Station #304
Side Member Transferred From Station
#201/2 with Overhead Conveyor System
Coaster Return Conveyor
Plate Fender Transferred
with Overhead Conveyor
Shell part (doors,
hoods and screws)
delivery manually
Figure 1.1: Production layout illustrated material handling system in present practice (Perodua, 2007)
2
In current practice, progress of welding to form a Main Body of KENARI (station
#301) presently is perform in a completely automated process line as shown in
Figure 1.4. In the #301 process, it involved robot welding and the main body delivery
automatically by the conveyor. When the main bodies proceed to the station #401,
which is assembles of the doors and hood. Screws and nuts, doors and hoods are
delivery manually by the tow tractor from the storage. Due to the tow tractor delivery
not in time, downtime of the operation occurred. Furthermore, extra cost of man
power and diesel needed to perform delivery process.
Every point affects the manufacturing cost. Especially man power operated required
labor costs and petrol and diesel consumption due to prices crisis increment.
Therefore, a reasonable adjustment and development required to encounter these
circumstances.
There are several alternatives to modification from manual supply to automated
supply to the station #401, which are automated guided cart system and conveyor
system.
Table 1.1: Comparison of material handling methods
Automated
Guided Cart
Initial Investment
Cost
Labor,
Maintenance and
Power
Consumption
Costs
Manual
Transport
Cart & Magnetic
/ Wire Tape
Installation
Labor Cost = 0
Maintenance =
Average A
Month Once
Power
Consumption =
Electrical
Powered
Productivity &
High
efficiency
Material Flow (JIT Point to Point
System & FMS)
Fork Lifter /
Towing Truck
Labor Cost =
Each per
Transports
Maintenance =
Average 6
Month Once
Power
Consumption =
Fuel
Consumption
Medium
Point to Point
3
Conventional
Conveyor
System
Building
Construction and
Modification
Labor Cost = 0
Maintenance =
Average 2 Month
Once
Power
Consumption =
Electrical
Powered
High
Station to Station
To implement automation to a process, several facts and consideration stated as
following based on the problems indicated, summarized of the AGC system
responded to its problems are:
•
Cost effectiveness and Labor Free: Automated Guided Carts are in fact, required
no labor other than periodic and remedial maintenance. They can operate 24
hours a day without supervision, injuries, pensions, vacations or sick days.
Furthermore, electrical power drives the movement of AGC is much more
environment friendly and zero fuel consumption needed depend to fork lifter and
towing truck.
•
Space Efficient: AGC require little more space than the material they are carrying
and since they are mobile and equipped with on-board safety equipment, they can
co-exist with people, manual material handling and processes such as assembly.
•
Increase productivity while reduce costs:
A prime for cost saving in
manufacturing is through in-process inventory reduction and facilities
investment. Simply by adding or removing the AGC from the line, assembly
production rate can be adjustable. This fits to company which applied Just-InTime System and Flexible Manufacturing System. In an addition, the load
handling is easy to modify to fits the materials or products needed to carries.
Therefore, it protecting the initial investment of the product.
1.3
(a)
Objectives
To develop and produce a cost-effectiveness and flexible autonomous
Automated Guided Cart (AGC).
(b)
To develop and produce an Automated Guided Cart which is controlled by
Programmable Intelligent Computer (PIC) Microcontroller.
(c)
To develop and produce an Automated Guided Cart, which is, could be applied
into industrial environment included safety aspects.
4
1.4
Scope
(a) Design and fabricate the structure of the Automated Guided Cart.
When the materials selected to be used for the frame fabrication, dimensions design
and draw through computer aided design (CAD) drawing or technical drawing
prepared for the assisting to the fabrication stage. There is also needed to inspect the
function of the frame is supportable.
(b) Design and develop the controller of the Automated Guided Cart PIC
microcontroller.
In electrical construction, PIC microcontroller is the main component to control the
function of the AGC. In the programming stage, several hardware needed to be
prepared, they are: (1) burning circuit that transferring the source codes to computer
and convert to machine codes and load into the PIC microchip, (2) programming
software used to complies the source code, (3) computer used as the input and output
module between the microchip and the designed source code.
(c) Design the electrical circuit of the motor driver circuit board and magnetic circuit
board.
For the electrical circuit, it required to design and develops a workable electronic
circuit board that is able to interface to the microprocessor circuit board. Selection to
the magnetic sensors that meet to the microprocessor as input devices needed.
5
CHAPTER 2
LITERATURE REVIEW
In this chapter, the review of information is to support the knowledge and skills
before started the project. There are two major section contained, which are
mechanical section, and electrical section. Due to the information, it ensure the
research and development of the project accomplish.
2.1
Vehicle Guided Technology
The guidance system is the method by which AGC pathway is defined and cart is
controlled to follow the pathways. In this section, it discusses three technologies that
are common used for the vehicle guidance: (1) imbedded guided wires, (2) paint
strips, and self-guided, and (3) self-guided vehicles.
2.1.1 Imbedded Guided Wires
A guided system for a self-guided vehicle features an electrical conductor and
permanent magnets embedded together in an elongate groove formed in a vehicle
supporting surface such as a factory or warehouse floor. The electrical conductor
provides steering guidance while the permanent magnets embedded with the
conductor provide other information without distorting the magnetic field of the
electrical conductor. To prevent such distortion, the permanent magnets are selected
for their low magnetic permeability and high electrical resistivity. Magnetic field
sensors are provided on the vehicle for determining exact position of the vehicle
6
along its path of travel by sensing deviation, or lack thereof, with respect to such
permanent magnets. (Laid, 1987)
Hall-effect sensor
Magnetic field
Floo
Permanent magnet
Figure 2.1: Plan view of an exemplary embodiment of the information sensing portion of the guided
system. (Laib, 1987)
2.1.2
Paint Strips Guidance
The self-propelling vehicle is adapted to carry a load and has steering-wheels and a
central driving-wheel as well as optical detectors designed to read an optical track
laid out on the ground and furnishing passive driving signals, the vehicle also being
provided with an ultrasonic emitter-receiver assembly working as a radar and
operative to detect obstacles along the path of movement of the vehicle.
(Deplante, 1982)
Figure 2.2: The diagrammatical perspective view of the AGV adapted to move automatically along an
optically defined path for carrying a load from a starting point to an arrival point. (Deplante, 1982)
7
2.1.3
Self Guided Vehicle
A navigation system for use in a self-guided material handling vehicle provides
guidance during operation in areas having densely stacked rows of containers and
reduces the potential of deviation of the self-guided vehicle from the desired path
travel. A laser-signaling device is mounted on the vehicle and rotatable about an axis
of the rotation extending generally perpendicularly to the longitudinal axis of the
self-guided vehicle. The laser-signaling device is adapted to delivery a light beam
signal at the first preselected angle relative to the axis of rotation of the lasersignaling device, at a second different preselected angle relative to the axis of
rotation. Receiving devices a reflection of the light beam signal and delivers a
position signal in response to the light beam signal received. The navigation system
is particularly suited for use in automation storage and retrieval systems.
(Wible, 1990)
Figure 2.3: A diagrammatic side elevation view of a self guided vehicle (Wible, 1990)
2.2
Mechanical Review
Design of automated machine always consists of two major elements, which is
mechanical and electrical element. In mechanical design, it creates device or system
to satisfy specific needs. Mechanical devices typically involve moving parts that
transmit power and accomplish specific pattern of motion. Mechanical systems are
composed of several mechanical devices.
8
2.2.1
Material in Mechanical Design
It needed to specify suitable material for each component of a mechanical device
before further designation. The initial efforts in specifying a material for a particular
component of a mechanical design should be directed to the basic kind of material to
be used. Function of the component, kinds and magnitudes of loads it will carry, and
the environment in which it will operate should be specified. (Mott, 2002)
Machine elements are often made from one of the metals or metal alloys such as
steel, aluminum, cast iron, zinc, titanium or bronze. Strength, elastic, and ductility
properties for metals usually determined and considered in the stage of design.
(a) Carbon and Alloy Steel
Steel is possibly the most widely used material for machine elements because of its
properties of high strength, high stiffness, durability and relative ease of fabrication.
Many types of steel are available.
The term steel refer to an alloy of iron, carbon, manganese, and one more other
significant elements. Carbon has very strong effect on the strength, hardness, and
ductility of any steel alloy. The other elements affect hardenability, toughness,
corrosion resistance, machinability, and strength retention at high temperature. The
primary alloying element present in the various alloy steels are sulfur, phosphorus,
silicon, nikel, chromium, molybdenum, and vanadium. (Mott, 2002)
General Form of Designation
AISI
X X XX
Carbon content
Specific alloy in the group
Alloy group: indicates major
alloying elements
The AISI uses a four-digit designation system for carbon and alloy steel as shown
above. The first two digits indicate the specific alloy group that indentified the
primary alloying element other than carbon in steel. The last two digits indicate the
amount of carbon in the steel (Mott, 2002).
9
The present invention related to automated guided cart (AGC) particularly to costeffectiveness, light duty vehicle, which is specifically adapted for use in light
manufacturing shop floor. This AGC followed a magnetic guide taped on floor to
move goods or material from one point to another under PIC control. The AGC
system employ specifically designed carts, which are configured particularly to carry
components such as automobile chassis or assembly components in an automobile
assembly operation. Generally, the method to achieve the objectives, it consists of
designation stage, procurement preparation stage, material preparation stage,
fabrication stage, and examination stage. This project involved design and
development of the AGC system through the engineering skills via mechanical
calculation and analysis, material selection, electrical circuit design, and
programming of the PIC controller. In the implementation stage, a light duty AGC
produce and applicable to industrial environment to accomplished the project.
i
ABSTRAK
Ciptaan projek berautomatik panduan kereta (Automated Guided Cart) terutamanya
untuk keberkesanan kos, kenderaan tugas ringan dan khususnya disesuaikan oleh
penggunaan dalam tingkat pembuatan ringan. AGC ini diikuti satu panduan yang
magnetik merakamkan di atas lantai untuk bergerak barangan atau bahan di
sepanjang lorong yang ditentukan. Ia dikawalkan oleh PIC mengawal untuk bergerak
dan pelbagai fungsi. Sistem AGC reka bentukan mengatur corak yang tatarajah
terutamanya untuk melaksanakan komponen-komponen ibarat casis kereta atau
komponen-komponen
pemasangan
dalam
operasi
automobil
pemasangan.
Umumnya, kaedah untuk mencapai matlamat-matlamat, ia mengandungi peringkat
gelaran, ia itu, tahap persiapan pemerolehan, tahap persiapan bahan, peringkat
pembuatan, dan peringkat peperiksaan. Rekabentuk dan pembangunan AGC terlibat
dalam projek ini melalui kemahiran-kemahiran kejuruteraan adalah pengiraan dan
analisis mekanikal, pemilihan bahan, rekabentuk litar elektrik,dan pengaturcaraan
PIC mengawal. Untuk mencapaikan matlamat projek ini, dalam peringkat
pelaksanaan, AGC yang bertugasan ringan menghasilkan dan bersedia digunakan
untuk persekitaran perindustrian dicipta.
ii
ACKNOWLEDGEMENT
I would like to express my gratitude to all those who gave me the possibility to
accomplish this project of manufacturing engineering bachelor’s degree entitled
automated guided cart. I want to thank the Department Managemtnt Faculty of
Manufacturing of Universiti Teknikal Malaysia Melaka (UTeM), Prof. Dr. Mohd.
Razali b. Muhamad and giving me permission to commence this project in the first
instance, approved the title of project proposed. I have furthermore to thank the
Management of Project Sarjana Muda, Sivarao a/l Subramonian, and Head of
Department of Robotic and Automation, Dr. Zamberi bin Jamaludin who gave and
confirmed this permission and supported me to progressing with my project.
I am deeply indebted to my supervisor, Puan Nur Aidawaty bt. Rafan and principle
co-supervisor, Puan Silah Hayati bt. Kamsani from the Department of Robotic and
Automation of UTeM whose help, stimulating suggestions, technical information,
and encouragement helped me in all the time of project and writing of this report.
My colleagues from 4BMFA of UTeM supported me in my research work. I want to
thank them for all their help, support, interest and valuable hints. Especially I am
obliged to Mr. Lim, Lee Wai Keong, Tan Sia Peng for the great help in difficult
times and suggestions for improvement.
Especially, I would like to give my special thanks to my wife Karen whose patient love
enabled me to complete this work.
iii
TABLE OF CONTENT
Abstract
i
Abstrak
ii
Acknowledgement
iii
Table of Content
iv
List of Tables
vi
List of Figures
vii
List of Abbreviations
viii
1. INTRODUCTION
1
1.1
Introduction
1
1.2
Problem Statement
2
1.3
Objectives
4
1.4
Scope
5
2. LITERATURE REVIEW
6
2.1
Vehicle Guided Technology
6
2.1.1
Imbedded Guided Wires
6
2.1.2
Paint Strips Guidance
7
2.1.3
Self Guided Vehicle
8
2.2
2.3
Mechanical Review
8
2.2.1
Material in Mechanical Design
9
2.2.2
Electrical Motors
13
2.2.3
Kinematic of Gears
18
Electrical Review
20
2.3.1 Sensors
20
2.3.2 PIC Microcontroller
23
3. METHODOLOGY
26
3.1
Methodology Flow Chart of project AGC
26
3.2
Functions of the Cart
27
iv
3.3
Design Requirement
28
3.4
Evaluation Criteria
29
3.5
DC Motors
30
3.6
Drive Mechanism
30
3.7
Frame
31
3.8
PIC Microcontroller
33
3.9
Sensors
35
4. DESIGN AND DEVELOPMENT
38
4.1
DC Motor Selection
38
4.2
Drive Mechanism
40
4.2.1
Gear Geometry Computation
41
4.2.2
Shaft Design
42
4.2.3
Bearing Selection
44
4.3
Frame Design
45
4.3.1
Technical Drawing
48
4.4
Motor Drive Circuit Board Designation
51
4.5
Microcontroller Electronic Circuit Designation
53
4.6
Magnetic Sensor
54
5. RESULT AND DISCUSSION
56
5.1
Mechanical Structure
56
5.2
Controller
58
5.2.1
Microcontroller Electronic Circuit Board
58
5.2.2
Microchip Pin Assignment
61
5.2.3
Motor Control Electronic Circuit Board
62
5.3
Magnetic Sensor Electronic Circuit Board
64
5.4
PIC Comment Programs
67
5.4.1
Microcontroller Language (C Language)
67
5.4.2
Program Burning
71
v
6. CONCLUSION AND RECOMMENDATION
74
6.1
Conclusion
74
6.2
Recommendation
75
REFERENCE
76
APPENDIX A
APPENDIX B
APPENDIX C
APPENDIX D
APPENDIX E
APPENDIX G
vi
LIST OF TABLES
1.1
Comparison of the Methods of Material Handling.
2.1
Uses of Some Steels
2.2
Aluminum Alloy Groups
2.3
Common Aluminum Alloys and Their Uses
2.4
AC Motor Voltage.
2.5
AC Motor Speeds for 60 Hertz Power
2.6
DC Motor Voltage Ratings
3.1
Characteristics of the Material Elements.
3.2
Alloy Steel and Aluminum General Physical Properties.
3.3
Microcontrollers Device Overview and Its Properties
3.4
Microcontroller Features As Guide to Selection
3.5
Characteristics and the Features of Unipolar Type Magnetic Sensors.
3.6
Characteristics and the Features of Bipolar Type Magnetic Sensors.
4.1
Summary of the Comparison between Desired Value and Selected Value.
4.2
Pin assignment and its function.
4.3
General electrical and magnetic specifications.
5.1
Result comparison from designed specification to actual specification
vii
5.2
DIP switch operation direction
5.3
Logic function of the motor driver
LIST OF FIGURES
1.1 Production Layout Illustrated the Material Handling System in Present Practice.
2.1
Plan View of an Exemplary Embodiment of the Information Sensing
Portion of the Guided System.
2.2
The Diagrammatical Perspective View of the AGV Adapted to Move
Automatically Along an Optically Defined Path for Carrying a Load From
a Starting Point to an Arrival Point.
2.3
A Diagrammatic Side Elevation View of a Self Guided Vehicle
2.4
Single-phase AC Power and Three-phase AC Power
2.5
General Form of Motor Performance Curve
2.6
Pair of Spur Gears. The Pinion Drives the Gear
2.7
Hall-Effect Principle With No Magnetic Field Present
2.8
Hall-Effect Principle With Magnetic Field Presents
2.9
Circuit of an IR Emitter and IR Phototransistor
2.10
3.1
Circuit and Diagram of an Infrared Reflectance Sensor.
Basic Draft of the Options for the Drive Mechanism of Automated Guided
Cart.
3.2
Design Concept of the Frame of the Automated Guided Cart.
3.3
Comparison of the Properties between Alloy Steel and Aluminum.
viii
3.4
Force Distributed on the Cart.
4.1
Design Sketch of the Drive Mechanism (Single Stage Gear System) and
Its Main Components.
4.2
Power Flow Through the Gear.
4.3
Direction of Force Distribution on Gear.
4.4
Graphical Representative of Force, Shearing Force and Bending Moment
of the Gear.
4.5
Force Distortion on the Frame of the Cart.
4.6
Graphical Representative of Force, Shearing Force and Bending Moment
of the Frame.
4.7
COSMOSX Analysis of the Aluminum Square Hollow Bar (20x20x1/4)
4.8
Assembly CAD Drawing of the AGC.
4.9
Frame CAD Detail Dimension Drawing.
4.10
Detail CAD Drawing of the Drive Mechanism.
4.11
Pin connection of the dual-bridge microchip Multiwatt15
4.12
Full-bridge circuit electronic circuit diagram.
4.13
Design circuit of the microcontroller board associated with the burner
function.
4.14
Mechanism of turning performed by three magnetic sensors.
4.15
Dimension of the magnetic sensor.
4.16
Designation of the magnetic sensors circuit
5.1
Top view of the structure of Automated Guided Cart
5.2
Dimension of the Automated Guided Cart
5.3
Gear mechanism using spur gear system to drive the cart
5.4
Microcontroller electronic circuit board
5.5
Dual Interchange Pin (DIP) Switch
5.6
Voltage regulator 7805
5.7
Microchip 16F877A pin assignment to the programming.
5.8
Motors controller electronic circuit board.
5.9
Result from the testing on the PWM signal generation.
5.10
Magnetic sensor circuit board.
ix
5.11
Typical output characteristics with various values of external bias resistors.
5.12
Solid-state sensor response graph.
5.13
PIC 16F877A pin-out descriptions.
5.14
New project and its setting in microC.
5.15
Source code build into machine code (.hex file).
5.16
Detection of the microchip 16F877A.
5.17
Burning operation of .hex file to microchip.
5.18
Finish burn of the microchip.
LIST OF ABBREVIATIONS
AC
-
Alternative Current
ADC
-
Analog Digital Convertor
AGC
-
Automated Guided Cart
AGV
-
Automated Guided Vehicle
AGVS
-
Automated Guided Vehicle System
AISI
-
American Iron and Steel Institute
CAD
-
Computer Aided Drawing
CCP
-
Capture and Compare Module
CPU
-
Central Processing Unit
DC
-
Direct Current
DIP
-
Dual Interchange Pin
EEPROM -
Electrically Erasable Programmable Read-only Memory
FMS
-
Flexible Manufacturing System
GND
-
Ground
I/O
-
Input / Output
IC
-
Integrated Circuit
IDE
-
Integrated Development Environment
IR
-
Infra-Red
JIT
-
Just In Time
LED
-
Light Emitting Diode
NEMA
-
National Electrical Manufacturers Association
x
PIC
-
Programmable Intelligent Computer
PWM
-
Pulse Width Modulation
R
-
Resistor
RAM
-
Random Access Memory
RPM
-
Radius per Minute
SCR
-
Silicon Controlled Rectifier
UNS
-
Unified Numbering System
USART
-
Universal Asynchronous Receiver / Transmitter
USB
-
Universal Serial Bus
xi
CHAPTER 1
INTRODUCTION
This chapter introduced the general information regarding to this title of project and
problem statement to state reason to develop the research and implementation of
Automated Guided Cart. Brief declaration of Automated Guided Cart discussed.
1.1
Introduction
Automated guided vehicle system (AGVS) is a material handling system that uses
independently operated, self-propelled vehicles guided along defined pathways
(Groover, 2008). The vehicles are powered by on-board batteries that allow many
hours of operation. An AGV is suitable applies on automating material handling in
batch production and flexible manufacturing system.
In this project, automated guided cart (AGC) developed in the application of material
handling to light duty industry as assembly line applications, storage and distribution
and logistics. There are three main tasks to carry out the project, which are
mechanical structure, controlling electronic circuit components and comments
programming. From designation, material selection, implementation and evaluation
stages, discussed.
1
1.2
Problem Statement
Material handling equipment is usually assembled into a system. The system must be specified and configured to satisfy the requirement of a
particular application. It depends on the materials to be handled, quantities and distance to be move, type of production facility served by the
handling system, and other factors, included available budget.
Station #401
Station #301
Roof and Cowl-Top
Transferred from SubAssy Station #304
Side Member Transferred From Station
#201/2 with Overhead Conveyor System
Coaster Return Conveyor
Plate Fender Transferred
with Overhead Conveyor
Shell part (doors,
hoods and screws)
delivery manually
Figure 1.1: Production layout illustrated material handling system in present practice (Perodua, 2007)
2
In current practice, progress of welding to form a Main Body of KENARI (station
#301) presently is perform in a completely automated process line as shown in
Figure 1.4. In the #301 process, it involved robot welding and the main body delivery
automatically by the conveyor. When the main bodies proceed to the station #401,
which is assembles of the doors and hood. Screws and nuts, doors and hoods are
delivery manually by the tow tractor from the storage. Due to the tow tractor delivery
not in time, downtime of the operation occurred. Furthermore, extra cost of man
power and diesel needed to perform delivery process.
Every point affects the manufacturing cost. Especially man power operated required
labor costs and petrol and diesel consumption due to prices crisis increment.
Therefore, a reasonable adjustment and development required to encounter these
circumstances.
There are several alternatives to modification from manual supply to automated
supply to the station #401, which are automated guided cart system and conveyor
system.
Table 1.1: Comparison of material handling methods
Automated
Guided Cart
Initial Investment
Cost
Labor,
Maintenance and
Power
Consumption
Costs
Manual
Transport
Cart & Magnetic
/ Wire Tape
Installation
Labor Cost = 0
Maintenance =
Average A
Month Once
Power
Consumption =
Electrical
Powered
Productivity &
High
efficiency
Material Flow (JIT Point to Point
System & FMS)
Fork Lifter /
Towing Truck
Labor Cost =
Each per
Transports
Maintenance =
Average 6
Month Once
Power
Consumption =
Fuel
Consumption
Medium
Point to Point
3
Conventional
Conveyor
System
Building
Construction and
Modification
Labor Cost = 0
Maintenance =
Average 2 Month
Once
Power
Consumption =
Electrical
Powered
High
Station to Station
To implement automation to a process, several facts and consideration stated as
following based on the problems indicated, summarized of the AGC system
responded to its problems are:
•
Cost effectiveness and Labor Free: Automated Guided Carts are in fact, required
no labor other than periodic and remedial maintenance. They can operate 24
hours a day without supervision, injuries, pensions, vacations or sick days.
Furthermore, electrical power drives the movement of AGC is much more
environment friendly and zero fuel consumption needed depend to fork lifter and
towing truck.
•
Space Efficient: AGC require little more space than the material they are carrying
and since they are mobile and equipped with on-board safety equipment, they can
co-exist with people, manual material handling and processes such as assembly.
•
Increase productivity while reduce costs:
A prime for cost saving in
manufacturing is through in-process inventory reduction and facilities
investment. Simply by adding or removing the AGC from the line, assembly
production rate can be adjustable. This fits to company which applied Just-InTime System and Flexible Manufacturing System. In an addition, the load
handling is easy to modify to fits the materials or products needed to carries.
Therefore, it protecting the initial investment of the product.
1.3
(a)
Objectives
To develop and produce a cost-effectiveness and flexible autonomous
Automated Guided Cart (AGC).
(b)
To develop and produce an Automated Guided Cart which is controlled by
Programmable Intelligent Computer (PIC) Microcontroller.
(c)
To develop and produce an Automated Guided Cart, which is, could be applied
into industrial environment included safety aspects.
4
1.4
Scope
(a) Design and fabricate the structure of the Automated Guided Cart.
When the materials selected to be used for the frame fabrication, dimensions design
and draw through computer aided design (CAD) drawing or technical drawing
prepared for the assisting to the fabrication stage. There is also needed to inspect the
function of the frame is supportable.
(b) Design and develop the controller of the Automated Guided Cart PIC
microcontroller.
In electrical construction, PIC microcontroller is the main component to control the
function of the AGC. In the programming stage, several hardware needed to be
prepared, they are: (1) burning circuit that transferring the source codes to computer
and convert to machine codes and load into the PIC microchip, (2) programming
software used to complies the source code, (3) computer used as the input and output
module between the microchip and the designed source code.
(c) Design the electrical circuit of the motor driver circuit board and magnetic circuit
board.
For the electrical circuit, it required to design and develops a workable electronic
circuit board that is able to interface to the microprocessor circuit board. Selection to
the magnetic sensors that meet to the microprocessor as input devices needed.
5
CHAPTER 2
LITERATURE REVIEW
In this chapter, the review of information is to support the knowledge and skills
before started the project. There are two major section contained, which are
mechanical section, and electrical section. Due to the information, it ensure the
research and development of the project accomplish.
2.1
Vehicle Guided Technology
The guidance system is the method by which AGC pathway is defined and cart is
controlled to follow the pathways. In this section, it discusses three technologies that
are common used for the vehicle guidance: (1) imbedded guided wires, (2) paint
strips, and self-guided, and (3) self-guided vehicles.
2.1.1 Imbedded Guided Wires
A guided system for a self-guided vehicle features an electrical conductor and
permanent magnets embedded together in an elongate groove formed in a vehicle
supporting surface such as a factory or warehouse floor. The electrical conductor
provides steering guidance while the permanent magnets embedded with the
conductor provide other information without distorting the magnetic field of the
electrical conductor. To prevent such distortion, the permanent magnets are selected
for their low magnetic permeability and high electrical resistivity. Magnetic field
sensors are provided on the vehicle for determining exact position of the vehicle
6
along its path of travel by sensing deviation, or lack thereof, with respect to such
permanent magnets. (Laid, 1987)
Hall-effect sensor
Magnetic field
Floo
Permanent magnet
Figure 2.1: Plan view of an exemplary embodiment of the information sensing portion of the guided
system. (Laib, 1987)
2.1.2
Paint Strips Guidance
The self-propelling vehicle is adapted to carry a load and has steering-wheels and a
central driving-wheel as well as optical detectors designed to read an optical track
laid out on the ground and furnishing passive driving signals, the vehicle also being
provided with an ultrasonic emitter-receiver assembly working as a radar and
operative to detect obstacles along the path of movement of the vehicle.
(Deplante, 1982)
Figure 2.2: The diagrammatical perspective view of the AGV adapted to move automatically along an
optically defined path for carrying a load from a starting point to an arrival point. (Deplante, 1982)
7
2.1.3
Self Guided Vehicle
A navigation system for use in a self-guided material handling vehicle provides
guidance during operation in areas having densely stacked rows of containers and
reduces the potential of deviation of the self-guided vehicle from the desired path
travel. A laser-signaling device is mounted on the vehicle and rotatable about an axis
of the rotation extending generally perpendicularly to the longitudinal axis of the
self-guided vehicle. The laser-signaling device is adapted to delivery a light beam
signal at the first preselected angle relative to the axis of rotation of the lasersignaling device, at a second different preselected angle relative to the axis of
rotation. Receiving devices a reflection of the light beam signal and delivers a
position signal in response to the light beam signal received. The navigation system
is particularly suited for use in automation storage and retrieval systems.
(Wible, 1990)
Figure 2.3: A diagrammatic side elevation view of a self guided vehicle (Wible, 1990)
2.2
Mechanical Review
Design of automated machine always consists of two major elements, which is
mechanical and electrical element. In mechanical design, it creates device or system
to satisfy specific needs. Mechanical devices typically involve moving parts that
transmit power and accomplish specific pattern of motion. Mechanical systems are
composed of several mechanical devices.
8
2.2.1
Material in Mechanical Design
It needed to specify suitable material for each component of a mechanical device
before further designation. The initial efforts in specifying a material for a particular
component of a mechanical design should be directed to the basic kind of material to
be used. Function of the component, kinds and magnitudes of loads it will carry, and
the environment in which it will operate should be specified. (Mott, 2002)
Machine elements are often made from one of the metals or metal alloys such as
steel, aluminum, cast iron, zinc, titanium or bronze. Strength, elastic, and ductility
properties for metals usually determined and considered in the stage of design.
(a) Carbon and Alloy Steel
Steel is possibly the most widely used material for machine elements because of its
properties of high strength, high stiffness, durability and relative ease of fabrication.
Many types of steel are available.
The term steel refer to an alloy of iron, carbon, manganese, and one more other
significant elements. Carbon has very strong effect on the strength, hardness, and
ductility of any steel alloy. The other elements affect hardenability, toughness,
corrosion resistance, machinability, and strength retention at high temperature. The
primary alloying element present in the various alloy steels are sulfur, phosphorus,
silicon, nikel, chromium, molybdenum, and vanadium. (Mott, 2002)
General Form of Designation
AISI
X X XX
Carbon content
Specific alloy in the group
Alloy group: indicates major
alloying elements
The AISI uses a four-digit designation system for carbon and alloy steel as shown
above. The first two digits indicate the specific alloy group that indentified the
primary alloying element other than carbon in steel. The last two digits indicate the
amount of carbon in the steel (Mott, 2002).
9