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Group 10: THE LIGHTSABER
MONASH UNIVERSITY SUNWAY CAMPUS
THE PEARL
HUNTERECE 3091
KESHAV RAMREKHA 21630283
TRIANDI TANRI 21827559
OMAR ABDULLAH 21837473
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ContentsList of Figures ................................................................................................................................................ 4
List of Tables ................................................................................................................................................. 5
Acknowledgement ........................................................................................................................................ 6
Abstract ......................................................................................................................................................... 7
Chapter 1 : Requirements Definition ............................................................................................................ 8
1.Introduction .......................................................................................................................................... 8
1.1 Objective ......................................................................................................................................... 8
1.2 Capabilities of the final prototype .................................................................................................. 9
1.3 Purpose of this Report .................................................................................................................... 9
CHAPTER 2: LITERATURE REVIEW ............................................................................................................... 10
2. Introduction .................................................................................................................................... 10
2.1 Robot 1: Line following robot (MOBOT competition) ....................................................................... 10
2.2 Robot 2: Hyper Squirrel..................................................................................................................... 11
2.3 Robot 3: The $50 Robot with Sharp IR edge detection .................................................................... 12
2.4 Robot 4: The OMNI-WHEEL ROBOT .................................................................................................. 13
2.4 Literature review conclusion ............................................................................................................ 14
CHAPTER 3: TEAM ORGANIZATION AND MANAGEMENT .......................................................................... 15
Introduction ................................................................................................................................................ 15
3.1 Planning Methods ................................................................................................................................. 15
3.1.1 Work Breakdown Structure ........................................................................................................... 15
3.1.2 Schedule for Network Activities (Critical Path Diagram) ............................................................... 16
3.1.3 Gantt Chart..................................................................................................................................... 17
3.1.4 Responsibility Matrix ..................................................................................................................... 19
3.1.5 Cost Estimation .............................................................................................................................. 20
3.1.6 Risk analysis ................................................................................................................................... 21
CHAPTER 4: THE LIGHTSABER DESIGN (Prototype 1).................................................................................. 224. THE SUB-SYSTEMS ........................................................................................................................... 22
Introduction ........................................................................................................................................ 22
4.1 Mechanical sub-system ................................................................................................................. 22
4.2 Locomotion sub-system ................................................................................................................ 24
4.3 Electronics Sub-system ................................................................................................................. 26
4.4 Pearl Detection and Collection ..................................................................................................... 30
4.5 Assessment of Prototype 1 ........................................................................................................... 34
CHAPTER 5: The Lightsaber (Prototype 2) .................................................................................................. 37
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5.1 Faults identified ................................................................................................................................ 37
5.2 Prototype 2The Design .................................................................................................................. 38
5.2.1 Mechanical sub-system .............................................................................................................. 38
5.2.2 Locomotion sub-system ............................................................................................................. 39
5.2.3 Electronics Sub-system .............................................................................................................. 40
5.2.4 Pearl Detection and Collection .................................................................................................. 42
CHAPTER 6: Evaluation ............................................................................................................................... 46
6.1 Problems and Solutions .................................................................................................................... 46
6.1.1 Hardware ................................................................................................................................... 46
6.1.2 Software ..................................................................................................................................... 47
6.2 Improvements and Optimization ...................................................................................................... 47
6.3 The Final Competition ....................................................................................................................... 48
6.3.1 Match 1 ...................................................................................................................................... 48
6.3.2 Match 2 ...................................................................................................................................... 49
6.3.3 Match 3 ...................................................................................................................................... 50
6.3.4 Match 4 ...................................................................................................................................... 50
Conclusion ................................................................................................................................................... 51
References .................................................................................................................................................. 52
Appendix ..................................................................................................................................................... 53
Appendix ATesting Scheme for Prototype 2 ....................................................................................... 53
i. Chassis strength .......................................................................................................................... 53
ii. Speed .......................................................................................................................................... 54
iii. The 90oleft turn .......................................................................................................................... 54
iv. Battery Life .................................................................................................................................. 55
Appendix BFull Code written for the Arduino Duemilanove .............................................................. 56
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List of FiguresFigure 1: The platform of the black pearl project ......................................................................................... 8
Figure 2: Final Prototype ............................................................................................................................... 9
Figure 3: Design layout of the Pikachu robot .............................................................................................. 10
Figure 4: Design layout of the Hyper Squirrel robot ................................................................................... 11
Figure 5: Design layout of the $50 robot robot .......................................................................................... 12
Figure 6: Design layout of the omni wheel robot ....................................................................................... 13
Figure 7: Work breakdown Chart ................................................................................................................ 15
Figure 8: Critical Path Diagram ................................................................................................................... 16
Figure 9: Gantt Chart Table ......................................................................................................................... 17
Figure 10: Gantt chart Timeline .................................................................................................................. 18
Figure 11: Design layout of the chassis ....................................................................................................... 22
Figure 12: Design layout of the chassis (side view) .................................................................................... 23
Figure 13: Design layout of the chassis (top view) ..................................................................................... 23
Figure 14: Actual view with top layer mounted (side view) ....................................................................... 23
Figure 15: Tamiya Double Gearbox schematics .......................................................................................... 24Figure 16: Actual view with wheels under test ........................................................................................... 25
Figure 17: Initial prototype with wheels mounted on chassis .................................................................... 25
Figure 18: L293D H-bridge .......................................................................................................................... 26
Figure 19: H-bridge circuit connection ....................................................................................................... 27
Figure 20: H-bridge circuit connected to wheels ........................................................................................ 28
Figure 21: IR sensor circuit .......................................................................................................................... 29
Figure 22: Arduino Duemilanove microcontroller ...................................................................................... 29
Figure 23: The main circuitry as seen on top of the Lightsaber .................................................................. 30
Figure 24: Pearl Detection and Collection method ..................................................................................... 31
Figure 25: Flowchart for algorithm of Prototype 1 ..................................................................................... 32
Figure 26: Pearl detection and collection ................................................................................................... 33
Figure 27: The new design for the chassis (widened chassis) ..................................................................... 38
Figure 28: The new design for the chassis (increased stability) ................................................................. 39
Figure 29: Addition of ball casters to the chassis ....................................................................................... 39
Figure 30: Use of the Sharp IR rangefinder for wall and robot detection and avoidance .......................... 40
Figure 31: Use of the Sharp IR rangefinder for wall and robot detection and avoidance .......................... 41
Figure 32: Flowchart for Prototype 2 .......................................................................................................... 42
Figure 33: Start of Algorithm (Path 1) ......................................................................................................... 43
Figure 34: Path 2 ......................................................................................................................................... 44Figure 35: Path 3 ......................................................................................................................................... 44
Figure 36: Path 4 ......................................................................................................................................... 45
Figure 37: Lightsaber Prototype 2 ............................................................................................................... 48
Figure 38: Inability to return to base after getting stuck ............................................................................ 49
Figure 39: New path taken after confusion ................................................................................................ 50
Figure 40: Deflection of chassis frame ........................................................................................................ 53
Figure 41: The 90oleft turn ......................................................................................................................... 54
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List of Tables
Table 1: Tabular Comparison of the 4 robots ............................................................................................. 14
Table 2: Responsibility Matrix ..................................................................................................................... 19
Table 3: Cost Estimation ............................................................................................................................. 20Table 4: Risk Assessment ............................................................................................................................ 21
Table 5: Table of number of pearls collected ............................................................................................. 34
Table 6: Table showing drop in voltage levels of batteries (powering H-bridge and sensors) ................... 35
Table 7:Table showing drop in voltage levels of battery (powering Arduino)............................................ 35
Table 8: Table describing faults identified in Prototype 1 .......................................................................... 37
Table 9: Table for hardware problems and solutions ................................................................................. 46
Table 10: Table for software problems and solutions ................................................................................ 47
Table 11: Table of improvements and Optimization performed ................................................................ 47
Table 12: Table of weight v/s deflection ..................................................................................................... 53
Table 13: Speed v/s stability ....................................................................................................................... 54
Table 14: Table of speed v/s angle .............................................................................................................. 55
Table 15: Battery life of LiPo battery .......................................................................................................... 55
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Acknowledgement
First and foremost, we would like to thank Dr. Melanie Ooi, the lecturer for ECE 3091. Dr. Ooi proved
to be very helpful and was a constant source of encouragement and motivation which helped
towards the completion of this project. Our thanks and gratitude also goes to the lab technicians, Mr.
Paremanan and Mr. Hasnan, for always being ready to help us with our needs and providing us with
all the necessary assistance required in the lab. Last but not least, our thanks go to our friends, who
have been constantly helping us out in any way possible, be it to solve a technical problem, or to
hang out and relax for a while.
--
Members of Group 10:
Keshav Ramrekha
Triandi Tanri
Omar Abdullah
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Abstract
Autonomous robots are intelligent machines capable of performing tasks pre-programmed into
them. But for them to perform, proper research, planning, testing and debugging must be carried
out. Some people ask themselves Who would we be without machines? and the answer is often
another question: What would machines be without men? Food for thought? The following report
gives an insight about the behind-the-scenes of this project which sees The Lightsabercoming to
life. From a single rough sketch to a fully operational robot, this report is the work of three young
minds put together.
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Chapter 1: Requirements Definition
1. Introduction1.1 Objective
The objective of this project is to design and build a robot which has the ability to collect allpolystyrene balls provided in the platform and bring them back to base within a specified time limit,
while at the same time preventing other enemy robots from stealing from the home base. The base
is defined as one of the corner encircled by an arc line. The purpose of this project is to apply the
acquired knowledge in circuit theory and programming onto real life application likewise building
the robot in this Pearl Hunter project. Furthermore, students are able to develop problem solving,
self-independent and cooperative skills throughout this project.
Figure 1: The platform of the black pearl project
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1.2Capabilities of the final prototype
Figure 2: Final Prototype
In this project, sensors are used as guidance to navigate the robot and also to locate the polystyrene
balls. A number of implementation issues did surface, but were solved. The final prototype is
capable of navigating its way in the arena and carry the polystyrene balls back to the base. It is also
able to prevent wall collision and avoid being hit by enemy robots.
1.3 Purpose of this Report
This report comprises the summarized version of the project planning, design description, algorithm,
testing scheme and also the problems that the group has encountered during the brainstorming
stage circuit design stage assembly stage test and evaluation stage debugging and
optimization stage. Moreover, this report explains the required specification for all components in a
very clear manner that errors and risk can be identified easily so improvements and optimizations
can be conducted to increase the reliability of the complete system. .
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CHAPTER 2: LITERATURE REVIEW
2.IntroductionThis section will provide information about the research carried out in order to gather ideas andbrainstorm for solutions as to how to build and improve The Lightsaber. Research was carried out on
various platforms and ideas gathered were then put together for a selection.
2.1 Robot 1: Line following robot (MOBOT competition)
The robot was initially built to compete in the MOBOT competition. The robot is a line following robot
capable of following a white strip line on different surfaces in an outdoor environment without its
performance being compromised by external conditions (lighting, wind, surface).
The robot chassis was made out of plastic board with servo motors used as wheels. A custom
microcontroller was used, with the circuit design soldered on a veroboard to minimize use of space and
to be very light.
The robot was fitted with color sensors to detect the white line and to be move forward.
While the overall performance of this robot was quite impressive, there were quite a number of issues
to solve before finally getting a decent overall performance. IR emitter/detector can easily be flooded by
Figure 3: Design layout of the Pikachu robot
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sunlight and be made useless. Without these, performance of robot is compromised. It is essential to
make sure the sensors are well shielded to get good results.
Varying surfaces and levels were also a problem, as the robot needs to adapt to its surroundings and be
able to brake to avoid collisions or going off-track. A DC motor braking technique can therefore be usedin this case.
The robots performance can be improved by adding a camera to navigate through the course. This,
while being a good idea, will increase workload and increase complexity of design and coding.
While this robot is fairly easy to understand and make, it lacks a few features required as part of what
the robot to be designed for ECE 3091 needs.
2.2 Robot 2: Hyper Squirrel
The Hyper Squirrel is a robot which can perform high speed reactive mapping. The robot travels at fast
speeds while making decisions on directions based on input from its sensors.
The robot makes use of 2 Sharp IR Rangefinders mounted on a servo motor which scan the environment
the robot is placed in and can navigate on its own.
The robot was built using acrylic as chassis and treads from a toy car for wheels. This enabled it to
navigate through any rough surfaces without any problem.
While the rangefinders were used to navigate around, 2 sets of IR emitter-detectors were used as
bumper sensors to avoid any collisions with unwanted objects or walls.
Figure 4: Design layout of the Hyper Squirrel robot
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The Hyper Squirrel is a very interesting project and surely can be used as base for comparison for this
current project. The treads make interesting motion wheels and the high-tech advanced mapping
technique used by this robot is a very interesting prospect that could be used to find and collect the
balls for this current project. The design will however need to be customized and modified so that a ball
collection mechanism can be added to the robot which has to fit in the specific constraints set for this
project.
2.3 Robot 3: The $50 Robot with Sharp IR edge detection
This is by far the easiest and perhaps the most interesting robot of its kind. It is made up of easy to find
materials and costs less than $50.
The robot uses a piece of acrylic as chassis, and 2 pieces of cardboard cut in circular shape for wheels.
These are rotated by means of 2 servo motors.
The Sharp IR rangefinder is used to make the robot go through its surroundings while avoiding obstacles
and walls.
Main advantages of this robot were the low costs of building and fairly easy level on of understanding
required to build it. The performance on the other side was very basic while not having great purpose.
The robot could however be easily modified and improved once built and working.
Figure 5: Design layout of the $50 robot robot
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2.4 Robot 4: The OMNI-WHEEL ROBOT
This robot is one of the most interesting in its kind and perhaps the most complicated as well. It uses a
series of Omni-wheels that can move in any direction at any angle without any prior rotation. This
mechanism can be considered for the current project as the polystyrene balls are scattered all over thearena, and our robot needs to be able to move in any direction to move and collect them.
The Omni-wheel robot is a very advanced piece of robotics, including 3 Sharp IR rangefinders
performing 2D mapping as part of an intelligent navigation system. In addition to those, 3 sonars acted
as obstacle detection and avoidance system, while 2 pairs of infrared emitter/detector sets were used
for line following system.
The omni-wheel robot is one of the best of its kind and built for a specific purpose. But while its superb
features make it a hard-to-neglect choice, the cost of purchasing all the items needed to build it by far
exceeds the budget limit we are allocated. Budget aside, the fuzzy logic algorithm and coding knowledge
required to make it function is sadly one of the qualities we lack for now and would prove a very
challenging task to get it right at the very first attempt.
Figure 6: Design layout of the omni wheel robot
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2.4 Literature review conclusion
Table 1: Tabular Comparison of the 4 robots
Key points identified during literature review:
Size:
Lightsaber needs to be small in size to enable all sorts of movements. Also, as per the set requirements
of the project, the robot needs to fit a 20cmX20cm size.
Speed:
Lightsaber needs to be fast to be able to collect as many balls as possible during the allowed 5 minutes
time limit.
Consistency:
Lightsaber needs to be consistent in the runs, being able to bring the pearls back to base on as many
runs as possible.
Cost:
Lightsaber needs to be built by using materials which do not exceed the set limit of RM300.
Robot Advantages Disadvantages
Line Follower Small Simple design Ability to detect white
lines and help with
motion
Inability to perform morecomplex operations
No ball catching mechanismHyper Squirrel System uses high speed
reactive mapping
Very robust design Can easily detect objects
around the arena and
move to them
Complex software Conveyor belt wheels provide
too much friction and limit
motion
Heavy chassis$50 robot Simple design
Cheap Materials readily
available
No specific function Not robust No ball collection system Movement limited by cardboard
wheels
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CHAPTER 3: TEAM ORGANIZATION AND MANAGEMENT
Introduction
No teamwork can be a one-man show and this project was not an exception. To achieve the aims set,
the team members worked closely together to be able to be successful. This chapter will detail the work
to be done by each team-member and provide a work timeline as well as a proper budget breakdown of
the project.
3.1 Planning Methods
3.1.1 Work Breakdown Structure
Group Members:
- Keshav Ramrekha (KR)- Triandi Tanri (TT)- Omar Abdullah (OA)
Figure 7: Work breakdown Chart
"Black PearlProject"
Hardware
Assembling frameof robot - KR, TT, OA
Assembling motorgearbox - KR
Electrical
Build sensors/leverswitches- OA
Build H-driversmotor circuit - TT
Software
Programming - KR,TT
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3.1.2 Schedule for Network Activities (Critical Path Diagram)
This is also another project modeling technique that is used to determine the priority of each element and the most effective path or critical
path that must be undertaken for the project to develop according to the proposed time.
Figure 8: Critical Path Diagram
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3.1.3 Gantt Chart
This is a type of a bar chart that displays the data of the project schedule. They include the start and
finish dates of each element in the project schedule. They also include the amount of time required to
be spent on each element of the project and identifies the team members responsible for each element
in the project schedule. The summary elements comprise of the work breakdown structure.
ID Task Name Start Finish Duration
11d8/12/20117/29/2011Research/Planning
6d8/5/20117/29/2011Motor Gear Ratio
10d8/11/20117/29/2011Robot Design and Layout
8d8/9/20117/29/2011IR sensors
8d8/9/20117/29/2011Phototransistors
2d8/11/20118/10/2011Assembly
1d8/9/20118/9/2011Motor Assembly
1d8/10/20118/10/2011Toggle Switch
10d8/23/20118/10/2011Design
1d8/10/20118/10/2011Robot Dimensions
9d8/23/20118/11/2011Framework
5d8/18/20118/12/2011Testing
1d8/12/20118/12/2011Wheel balancing
4d8/17/20118/12/2011Sensor Sensitivity
6d8/22/20118/15/2011Robot Construction
3d8/17/20118/15/2011Circuit building
3d8/19/20118/17/2011Circuit Troubleshooting
35d9/30/20118/15/2011Software
10d8/26/20118/15/2011Research Algorithm
10d9/23/20119/12/2011Testing
10d9/9/20118/29/2011Coding
5d9/28/20119/22/2011Debugging
15d10/19/20119/29/2011Finishing
5d10/3/20119/27/2011Coding Finalization
6d10/10/201110/3/2011Robot Finalization
15d10/19/20119/29/2011Final Testing
7d8/18/20118/10/2011Requirement Analysis
11d8/29/20118/15/2011Design Specifications
Figure 9: Gantt Chart Table
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18Figure 10: Gantt chart Timeline
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3.1.4 Responsibility Matrix
This is a matrix that identifies all the elements in the project schedule and displays the priority
of the team members effort in each and every element. This management technique allows
you to clarify the team members responsibilities in each task and displa ys whether there was
efficient communication between the assigned team members by viewing their priority in the
each specific task.
Task KR OA TT
Brainstorming
Layout of Robot P S P
Algorithm P S P
Components S P P
Hardware
Motor Gear Box P S S
Robot Frame P P P
Electrical
Sensors S P P
H-Bridge S S P
Software
Ball Detection Algorithm P S P
Ball Collecting Algorithm P P S
Testing
Wheel Balancing Test P S S
Sensor Sensitivity Test S P S
Ball Collecting Algorithm P P S
Full Testing P P P
Documentation
Requirement Analysis P P P
Design Specification P P P
Presentation P P P
Final Report P P PTable 2: Responsibility Matrix
Note:Primary Responsibility (P)
Secondary Responsibility (S)
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3.1.5 Cost Estimation
This method was done in order to estimate the cost of all the products that had to be bought in
the implementation of the robot. This method gives us a rough estimate of the costs of each
product for future reference and also determines the budget of the robot.
Table 3: Cost Estimation
Tools Quantity Price/unit (RM) Suppliers Price(RM)
Diagonal Cutting Pliers 1 - Monash -
Wire Cutter 1 - Monash -
Wire Stripper 1 - Monash -
Solder Sucker 1 - Monash -
Precision Screwdrivers (set) 1 - Monash -
Duwell Needle Files (set) 1 - Monash -
Insulation Tape 3 1.00 Ace Hardware 3.00
Materials Quantity Price/unit Suppliers
Plastic-board 2 3.00 Popular 6.00Polystyrene board 1 5.00 Popular 5.00
Bolts and Nuts several - Monash -
Bread Board 3 - Monash -
AAA Battery 6 - Monash -
AA Battery (rechargeable) 2 - Monash -
9V Battery (rechargeable) 1 - Monash -
9V Battery connector 1 - Monash -
Ball Caster 2 10.00 Cytron 10.00
Battery Holders 3 2.004.00 Ace-hardware 8.00
Gear Box 2 - Monash -
Electrical components Quantity Price/unit Suppliers
Micro-controller Board 1 - Monash -Sharp IR Rangefinder 1 55.00 Cytron 55.00
Ribbon Cable 3 - Monash -
9V Battery Connector 1 - Monash -
IC (H-drivers) 1 - Monash -
Push Switches 4 0.50 Ace Hardware 2.00
Sensors 7 2.00 JalanPasar 14.00
Servo Motor 2 20.00 E-shore 40.00
Maximum budget : RM 300.00 Total 143.00
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3.1.6 Risk analysis
Hazard
No.Description of Hazard Corrective Actions/ Risk Controls
H4 Electrical hazard such as contact with any electrical
conductor resulting in current flow to the body
Consequence Likelihood Risk
Severe Injury Unlikely Low
Make sure everything is assembled properly before switching on
the power supply
Timing Responsibility
During wire connection KR, OA, TT
R34 Cause burns
Consequence Likelihood Risk
Minor Injury Unlikely Low
Wear protective gloves and glasses
Timing Responsibility
During soldering KR, OA, TT
E3 Prolong repetitive movement/position
Consequence Likelihood Risk
Minor Injury Unlikely Low
Take 5 minutes break for every hour sitting in front of computer
Proper lighting, comfortable working environment
Timing Responsibility
During programming KR, OA, TT
Table 4: Risk Assessment
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CHAPTER 4: THE LIGHTSABER DESIGN (Prototype 1)
The Initial Design
4. THE SUB-SYSTEMSIntroduction
No project consists of one main system, no matter what the nature of the project is. To facilitate work
distribution and verification and problem solving, a problem is always broken down into sub-systems. In
the case of The Lightsaber, the project was divided into four main sub-systems; the mechanical sub-
system, locomotion sub-system, electronics sub-system and the pearl detection and collection sub-
system. The following sections describe the system in greater details.
4.1 Mechanical sub-system
After a brainstorming session, the mechanical sub-system was the first issued tackled by the group. The
mechanical part is one of the most important parts of the Lightsaber. This will be the whole body of the
robot and needs to be very stable and reliable. All other sub-system will be linked to the mechanical part
enabling proper functioning of the robot. As the need to be light and fast was clearly identified, the
materials chosen to build the chassis were plastic-board, polystyrene and tape (double-sided and
normal). These materials are readily available and are cheap.
Figure 11: Design layout of the chassis
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Figure 12: Design layout of the chassis (side view)
Figure 13: Design layout of the chassis (top view)
Figure 14: Actual view with top layer mounted (side view)
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4.2Locomotion sub-systemThe main aim of this project is to have an autonomous robot which is to be used to detect and collect
the pearls and return back to base. To be able in this task, motion of the robot is essential. For the robot
to move, wheels with a proper gearbox are used.
In this case, the group was provided with a set of Tamiya Double Gearbox system with adjustable gear
ratios for different scenarios.
The main aim of the project was to get a fast moving robot. Therefore, the gear ratio to be chosen had
to be enough to be able to provide enough torque for the Lightsaber to move fast.
Figure 15: Tamiya Double Gearbox schematics
There are four different gearbox designs that are shown in the above diagram and out of this four, two
were tried out and tested. The two choices that were considered are Aand B.
A344:1This is the design that provides the highest torque but results in a very slow rotationof the wheel.
B- 114.7:1- This is the design that provides the second most torque but provides a largerincrease in speed than A.
The other two were not chosen since the speed of the wheel would be too fast for easy smoothnavigation.
A
B
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Figure 16: Actual view with wheels under test
Figure 17: Initial prototype with wheels mounted on chassis
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4.3Electronics Sub-systemThe electronics sub-system acts like the bridge between the microcontroller and the mechanical system.
It is the part that allows all motion to be possible, and at the same time is the carrier of messages from
one component to the other.
To power the wheels, a dual H-bridge was used.
H-Drivers are used for the motor circuit as an integrated chip acts as a controller that connects the
batteries, motors and I/O pins from the micro-controller in just one IC. One H-Driverchip can control up
to two motors at the same instance.
Figure 18: L293D H-bridge
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Figure 19: H-bridge circuit connection
In the design of the robot, only one L293D quadruple half H-Drivers were used. After some trials, it is
found that both the motors for the wheel and also the servo motor could be controlled by just one H-
Drivers.
From the diagram above, the input voltage to the H-Driver is at pin 1, 8, 9, and 16. The minimum voltage
that must be supplied to the H-Driver in order to get the robot moving is around 5V and above to ensure
movement stability as some task that the robot has to perform requires more power from the motor
than the others.
This can be seen when the robot is doing a turn in which one of the motor have to turn clockwise and
the other, counter clockwise. From all the trials performed, it is noticed that when the input voltage to
the H-Driver is less than 4V the robot is unable to turn accordingly thus by making sure that the input
voltage is at least 5V and above, the problem is eliminate
Pins 2, 7, 10, and 15 are the I/O pins connected to the micro-controller. These pins are used for
controlling the direction of movements of the motors. For example, if pin 2 is set to 1 and pin 7 is set to
0 digital outputs, the motor will turn clockwise whereas if pin 2 is set to 0 and pin 7 is set to 1, the motor
will turn counter clockwise.
A dual H-bridge is a system component which allows control of 2 motors and allows rotation in both
clockwise and anti-clockwise direction. In the case of the Lightsaber, a L293D chip was used to control
rotation of motors.
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Figure 20: H-bridge circuit connected to wheels
The electronics subsystem also consists of the sensor circuits. In the case of the Lightsaber, sensors were
used for ball and wall detection. The sensors were connected to the main circuitry of the robot system
and powered through a common 5V rail.
The sensors used in this project are of infrared type and it is of the 5mm category. It works by the
photodiode sensing the amount of reflected energy/light, which is radiated by the transmitter, off any
surface. The photodiode will have distinctive output reading across its terminals for different colour
surface.
The IR sensor used in the design is based on the schematic provided by the school. The only variation did
to the schematic was the value of the pair of resistors used. The resistor used for the IR transmitter is
120 and the resistor used for the IR receiver is 4.7k .
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Figure 21: IR sensor circuit
After performing some test on the micro-controller to determine its threshold between logic 1 and 0,
the comparator is ignored and the output of the sensor is connected directly to the micro-controller.
The threshold voltage for the given micro-controller is 1.07 V. Any values lower than 1.7 V will be
interpreted as logic 0 and those above it will be logic 1.
The Arduino Duemilanove was used as the main microcontroller for the Lightsaber due to its small size
and lightweight.
The board is very small in size and is very light as well. This would be an advantage as it would not add
too much weight or take up too much space on the chassis. In addition to that, the Arduino, despite
being small in size, has a decent number of I/O ports, some of which can be used as PWM ports to
control speed/motion.
1204.7k
Figure 22: Arduino Duemilanove microcontroller
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Figure 23: The main circuitry as seen on top of the Lightsaber
4.4Pearl Detection and CollectionThis section is the most important section of the project as the main objective is to gather as many
pearls as possible in the home base. The initial design made use of the sensory feedback as main source
of information about pearls and their position.
The Sharp IR rangefinder was used to locate the pearls as the robot moved and calculated the distance
separating the distance from the robot to them. This helped the robot keep moving until it reached the
pearls. Once it reached the pearls, they would get into the holding area of the Lightsaber, where they
would cross the signal between the IR emitter and detector circuit.
This would in turn activate two servo motors, which acted like flaps to close and hold the pearls inside
the robot. This action would indicate to the robot to start the process of returning to base to drop the
pearls safely back into the home base.
Arduino DuemilanovH-Bridge
Sensors connected to common rail Battery holder for batteries to power circuit
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Figure 24: Pearl Detection and Collection method
Sharp IR
rangefinder used
to locate pearls
IR emitter/detector
to detect whether
pearl was inside
holding area
Pearl
Servo Motors close flaps
upon detection of pearls
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3.4.1 Ball Collection Algorithm
Start
Move Forward
Detect ball?Keep moving
Forward
Close Flaps
Turn 180 degrees
Move forward
Detect wall
Stop and release
balls
Reverse with preset
delay
NO
YES
YES
NO
Figure 25: Flowchart for algorithm of Prototype 1
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The algorithm on the previous page gives an overall idea of how the Lightsaber performed its task of
detecting and collecting the ball. It worked using a simple system of detection by using the Sharp IR
rangefinder and the IR emitter/detector pair was used to help holding on to the ball.
The robot will start moving and as soon as it detects a pearl, it will close the flaps, turn 180 o clockwise
and return to base. When it detects the wall of the base, it will stop, release the pearl by opening the
flaps, and then move backwards, turn to face the arena, but this time at another preset angle.
Pearls
Home
Base
Figure 26: Pearl detection and collection
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4.5.2 Battery Life
Battery life greatly affects performance of machines and the Lightsaber was no exception. As the testing
was done, battery life was considerably reduced and had to be replaced constantly. Rechargeable
batteries avoided extra cost of buying new ones, but at the expense of long waiting hours for charging to
be complete. The battery levels were regularly monitored to assess performance of the robot.
Set 1 Set 2 Set 3 Set 4 Set 5
Initial
Voltage
(Volts)
Final
Voltage
(Volts)
Initial
Voltage
(Volts)
Final
Voltage
(Volts)
Initial
Voltage
(Volts)
Final
Voltage
(Volts)
Initial
Voltage
(Volts)
Final
Voltage
(Volts)
Initial
Voltage
(Volts)
Final
Voltage
(Volts)
Trial 1 5.28 5.02 5.31 5.11 5.16 4.99 5.23 5.02 5.11 4.88
Trial 2 5.24 5.12 5.27 5.10 5.20 4.86 5.18 4.83 5.13 4.92
Trial 3 5.16 4.96 5.18 4.93 5.23 5.01 5.21 4.82 5.23 4.85
Table 6: Table showing drop in voltage levels of batteries (powering H-bridge and sensors)
Set 1 Set 2 Set 3 Set 4 Set 5
Initial
Voltage
(Volts)
Final
Voltage
(Volts)
Initial
Voltage
(Volts)
Final
Voltage
(Volts)
Initial
Voltage
(Volts)
Final
Voltage
(Volts)
Initial
Voltage
(Volts)
Final
Voltage
(Volts)
Initial
Voltage
(Volts)
Final
Voltage
(Volts)
Trial 1 9.66 9.36 9.58 9.21 9.67 9.35 9.59 9.32 9.55 9.12
Trial 2 9.55 9.15 9.52 9.07 9.36 9.01 9.32 8.99 9.30 9.06
Trial 3 9.35 8.95 9.23 8.93 9.21 7.96 9.17 8.23 9.13 8.29
Table 7:Table showing drop in voltage levels of battery (powering Arduino)
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4.5.3 Testing of individual components
4.5.3.1(IR emitter/detector circuit)
These components were responsible to check whether pearls were inside the holding area of the arena
or not. The result of that operation would then enable to servo motors to close the flaps. To check this
part, the same concept was used as for the previous section and the number of times it worked was
noted.
Again, a set of 5 runs over 2 minutes was carried out and repeated.
From the tests, it was noted that over the number of runs, only 6 times the sensors had failed to detect
a ball inside the holding area. This was either due to a wire coming out hence causing an open circuit or
the robot moving too fast and pushing the ball away before the sensors could react to the voltage
change.
4.5.3.2 Servo motors (flaps)
The servo motors were used to open or close the flaps to either keep hold of the pearls or release them
when in the home base.
Results were collected over the same number of runs as in the above section
From the tests, it was noted that over the number of runs, 9 times the servos had failed to open or close
the flaps. This was either due to a wrong connection out hence causing an open circuit or wrong output
from sensor readings causing the robot to ignore the decision.
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CHAPTER 5: The Lightsaber (Prototype 2)
After the old design was tested over and over again, a number of faults were identified and corrective
measures were to be taken to improve the performance of the robot.
5.1 Faults identified
Components Faults
Chassis Chassis started bending under weight of all other
components mounted on it. Caused robot to move in a
curved path.
Holding area not wide enough to hold many pearls at
one go.
Batteries The batteries proved a major issue with them
discharging fast and not providing enough power to the
wheels. Motion of robot became erratic after power
drops below full operating limit.
Pearl collection using sensory feedback The detection of pearls using data obtained from
sensors was not always reliable, since the number of
pearls detected and collected was low.
Servo motors Servo motors were found to be under the influence of
fluctuating voltage and often were found to close
without any signal sent to them. This caused the
Lightsaber to miss the pearls.
Table 8: Table describing faults identified in Prototype 1
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5.2 Prototype 2 The Design
For the prototype 2, the overall layout of the subsystems remained the same, with the same 4
subsystems as mentioned for prototype 1. However, some changes were made to the design and
components and are detailed below. The changes were made in order to correct and reduce the faultsidentified in the previous section
5.2.1 Mechanical sub-system
From the previous section it was observed that the chassis of the robot was not strong enough to
withstand heavy testing. It was then modified in order to make it stronger and more resistant.
The second issue noted was the fact that the holding area for pearls was not as wide as expected, and it
was therefore widened to allow more pearls to be held.
Figure 27: The new design for the chassis (widened chassis)
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To assist the robot in moving around the arena, a Sharp IR rangefinder was placed at the top of the
robot. It was programmed to detect walls and other robots, and stop and change directions if ever they
came into contact. The Sharp IR rangefinder also helped in the path algorithm used for ball collection,
which is described further down in this report.
Figure 30: Use of the Sharp IR rangefinder for wall and robot detection and avoidance
5.2.3 Electronics Sub-systemThe main components of the electronics sub-system were kept unchanged, although a few changes
were made. The servo motors were removed as well as the IR emitter/detector circuits. The
rechargeable batteries used for prototype 1 were all replaced by a single LiPo battery.
The main reason for replacing all the batteries with a single LiPo battery was the improved performance,
greater power and longer running hours on a single charge. The robot was found to be able to run
smoothly for 2.5 hours on a single charge.
Both the Arduino and the H-bridge circuitry were powered by the LiPo battery. This also helped reduce
overall weight of the robot and with the battery placed at the center of the bottom layer of the robot;
the center of gravity was made lower, thus improving stability of the robot.
Sharp IR
rangefinder, for
wall and robot
detection
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Figure 31: Use of the Sharp IR rangefinder for wall and robot detection and avoidance
Arduino
Microcontroller
H-bridge
Switch to ON/OFF
the robot
Sharp IR rangefinder
powered straight
from Arduino
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5.2.4 Pearl Detection and CollectionFor the prototype 2, the whole algorithm for ball collection changed, as this time a pre-defined motion
path was programmed into the microcontroller.
It was noted that in the case of prototype 1 that allowing the robot to move by using the sensors was
erratic and a lot of errors were introduced due to unstable chassis, incorrect wheel alignment and wrong
return to base movement.
The use of a predefined path allowed a more consistent navigation of the robot, with it moving
according to the program and returning to base before moving out again. The path algorithm is shown in
the pictures below.
Figure 32: Flowchart for Prototype 2
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The robot starts to move from point A in the above diagram until it reaches the wall where it turns 900
anti-clockwise. It then detects a second wall where again it turns 90 Oanti-clockwise. It will then move
until it reaches the wall of the home base, and will reverse until it reaches point B.
A
B
Figure 33: Start of Algorithm (Path 1)
Home
Base
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From point B, it will turn 90oand move forward for 5 seconds and again turn 90o degrees anti-clockwise
and move forward until it reaches the wall. It will turn and follow the motion defined by the arrows until
it reaches point C.
B
C
Figure 34: Path 2
D
Figure 35: Path 3
Home
Base
Home
Base
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From Figure 30, the robot will move from position C, turn 90 o, follow a straight path for 7 seconds, and
then again turn left 90o and move until it reaches the wall. The same procedure is used to reach the
home base again with turning left each time the Sharp IR rangefinder detects a wall.
In path 4 (Figure 31), the robot will follow the path indicated by the arrows after it reaches point D in
Figure 30. The purpose of path 4 is to be able to steal the pearls from the enemy base and increase the
chances of winning.
In the end, the robot covers the area of the arena by covering it section by section using the algorithm
showed in the previous figures and each time returns to base to deposit any pearls collected on its way.
Home
Base
Figure 36: Path 4
Enemy
Base
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CHAPTER 6: Evaluation
One of the main issues about this project was the random scattering of the pearls all over the arena and
how to collect the pearls and come back to the home base. The whole competition depended on the
final number of pearls collected and brought back to base. The main concern was therefore to find theoptimized path and method to collect the most number of balls. After trying prototype 1 and noticing its
shortcomings, the design was changed to Prototype 2 and test runs were carried out.
It was found out that, after extended testing that the Lightsaber performed better while being on a pre-
defined course than on a to-and-fro path using sensor feedback. Prototype 2 was also found out to
move in a straight line better than prototype 1 due to its improved chassis and enhanced weight
distribution.
After the removal of the rechargeable AA and AAA batteries and the 9V battery, and replacing them
with the new LiPo battery, it was found out that robot performed in a more consistent way with the
drop in voltage levels not as considerable as the previous batteries. The absence of the need to
constantly charge up the batteries made it easier to keep testing the robot and also maintaining
constant performance for long hours.
6.1 Problems and Solutions
6.1.1 Hardware
Table 9: Table for hardware problems and solutions
No Hardware
Problems
Cause & Evolved Solution
1 Sensor values
changing too fast
This was due to the motion of the robot. The sensor was secured properly with tape
and values smoothened out.
2 Driving motors
not rotating
This occurred mainly due to wires coming out of the breadboard. Proper connectors
were used to solve the problem.
3 Dying Batteries If the voltage supplied by the batteries is too low, the driving motors rotation speed
decreases, resulting in a slow forward motion of the robot and sometimes getting
stuck in one position while turning 90 degrees. All the batteries were replaced by a
single LiPo 8.4V battery which solved these problems.
4 Gearbox The initial gear-ratio chosen was for a light robot, however even when the robot
chassis was changed, performance did not drop so no change was made to the
gearbox.
6 Servo Motors The servo motors had faults of jerking without even a microcontroller input. This is
due to the connection between the servo and microcontroller not being fixed
properly. Servo motors were taken off for Prototype 2.
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6.1.2 Software
Number Software Problem Cause & Solution
1 Usage of delay in
coding to createPWM.
This is because the delay causes the drving motor rotation to
decrease. Therefore, the delay may cause the robot to move inadifferent speed for old batteries, likely slower and if new
batteries, it would increase the speed causing the hardware
problem stated before.
Solved by replacing batteries with a more powerful LiPo battery
which kept voltage at an almost high and constant level.
2 Coding issues and
inability of robot to
follow instructions
There were issues where the robot did not follow the code
programmed into the microcontroller. This problem was solved
by breaking down the whole software into small pieces and
testing individually and then compiling the whole code together
once issues were resolved.Table 10: Table for software problems and solutions
6.2 Improvements and Optimization
Prototype I Prototype II
Components one set of IR sensorsone Sharp IR rangefinderTwo wheel motorsOne ball caster as third wheelTwo servo motors as flaps
One Sharp IR rangefinderWidened holding area
Functions Capable of performing a to-and-for pearl detection and collection
Able to detect wallAble to return to base accurately
Weakness Unreliable motionDoes not always return to base At certain angle, wall or robotdetection may not work
Changes from
previous
prototype
N/A Servo flaps removedIR sensor circuit removedWidened holding areaImproved chassisNew LiPo batteryNot
applicable
reason
Inconsistency of sensors andunreliable chassis was major
issues.
No flaps to capture the polystyreneballs
Table 11: Table of improvements and Optimization performed
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6.3 The Final Competition
The final competition was the means by which the overall performance of the robot was to be tested in
matches against different opponents. In the competition everything ranging from robustness, creativity
to performance was assessed.
Prototype 2 competed in the competition and had the following specifications.
Size: 19x18cm (fits within preset 20x20cm limit) 1 IR rangefinder Arduino Duemilanove Microcontroller Breadboard containing connections and circuitry for H-Bridge Tamiya Dual Gearbox with gear ratio 114.7:1 1 Lipo 8.4V 1200maH battery
6.3.1 Match 1
During match 1, Lightsaber performed very well, managing to go through the entire path and algorithm
preset and collecting pearls on its way back to base. In the end, it collected 14 pearls with a minimum
amount of human interventions needed to help its motion. Eventually it ran out as winner of its match.No notable difficulty in navigation was observed. Design and algorithm was preserved.
Figure 37: Lightsaber Prototype 2
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6.3.2 Match 2
Match 2 was a totally different scenario, where the enemy robot had a different approach to the match.
This changed the game plans and soon after the match started, the 2 robots collided and had to be
taken back to base. However collision was not the only problem faced in this case. The Lightsaber got
stuck amongst pearls and therefore could not come back to base and had to be taken out. The same
situation repeated itself and the match was lost in the end as the opponent team collected more pearls.
In this match, there was also an example of preventing enemy robots stealing from the home base. The
strategy was to time the predefined paths in such a way that Lightsaber returned to home base at
regular intervals after completing the path motions. If ever an enemy robot were to come steal, it would
either collide on the way to the base or collide in the base, in which case, no pearls could be taken off
the home base.
Figure 38: Inability to return to base after getting stuck
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6.3.3 Match 3
Match 3 started well, with path 1 (mentioned earlier) completed well. However in this match versus
team Tornado, there was little that could be done to prevent the fan from blowing off all the pearls
from our home base and from the arena into the enemy base. Attempts were made to steal from enemy
base after path 4, but with the fan blowing hard the match was lost.
6.3.4 Match 4
Match 4 was a repeat of the scenario from match 2 with the Lightsaber again getting stuck due to a
collision with a few pearls at an angle. This prevented it from moving correctly and not returning to base
but instead moved to a second loop. It did however work after a human intervention was required, but
in the end lost the match due to a smaller number of balls collected compared to the opponent.
New path taken by
Lightsaber, after
getting confused.
Did not return to base
initially.
Figure 39: New path taken after confusion
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Conclusion
Throughout this project, electrical knowledge learned in Monash University is put to practice. Besides,
skills and teamwork cooperation are developed during the progress of the project.
The planning of the project is arranged properly that every group member has the fair responsibility in
this project. And the total cost used for this project is relatively affordable where it does not exceed the
maximum planned budget.
Although performance in the competition was not as successful as expected in terms of collection of
pearls, the robot has considerably high reliability in straight line motion and wall or robot detection and
avoidance. Have we had a little more chance to make a few more modifications to the robot, we would
have been able to achieve far better results.
In conclusion, we are successful in building a robot that is capable of fulfilling every requirement for this
project thus we feel a great sense of achievement in it.
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ReferencesSociety of Robots. (2011). Sensors: Sharp IR rangefinder. [Online]. Available:
http://www.societyofrobots.com/sensors_sharpirrange.shtml
Acroname Robotics. (2011). Sharp GP2Y0A21YK0F IR Package.[Online]. Available:
http://www.acroname.com/robotics/parts/R301-GP2Y0A21YK.html
Tamiya. (2011). Double Gearbox.[Online]. Available:
http://www.tamiyausa.com/product/item.php?product-id=70168
C. McManis. (2006). H-Bridges: Theory and Practice.[Online]. Available:
http://www.mcmanis.com/chuck/robotics/tutorial/h-bridge/
Price, D. A. Monash Minibot Version 1.0. 2005
Elecrom. (2008). How to make simple Infrared Sensor Modules. [Online]. Available:
http://elecrom.wordpress.com/2008/02/19/how-to-make-simple-infrared-sensor-modules/
Ikalogic. (n.d.). Line Sensors. [Online]. Available:
http://www.ikalogic.com/tut_line_sens_algo.php
HPhy. (n.d.). Schmitt Trigger. [Online]. Available:
http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/schmitt.html
OP AMPS. LF 324 Datasheet.(2010).
Silicon Labs. (2011). MCU Development Kits.[Online]. Available:
http://www.silabs.com/products/mcu/Pages/C8051F020DK.aspx
Arduino. (2011).ArduinoDuemilanove.[Online]. Available:
http://www.arduino.cc/en/Main/ArduinoBoardDuemilanove
Society of Robots. (2011). Mobot Competition.[Online]. Available:
http://www.societyofrobots.com/competitions_mobot.shtml
Society of Robots. (2011). Mobot 2007 Line follow robot tutorial.[Online]. Available;
http://www.societyofrobots.com/robot_mobot_2007.shtml
Society of Robots. (2011). Hyper Squirrel.[Online]. Available:
http://www.societyofrobots.com/robot_hyper_squirrel.shtml
Society of Robots. (2011). The $50 Robot.[Online]. Available:
http://www.societyofrobots.com/robot_50_robot_sharpIR.shtml
Society of Robots. (2011). Omni-Wheel Robot Fuzzy.[Online]. Available:
http://www.societyofrobots.com/robot_omni_wheel.shtml#fuzzy
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Appendix
Appendix A Testing Scheme for Prototype 2
The following pages will describe the testing procedures carried out on Prototype 2 and the discussion
of the results obtained.
i. Chassis strengthTo test the new chassis and whether it would be able to support the weight of the breadboard,
microcontroller and battery, a simple test was done whereby objects of varying weight were placed on
the chassis and the robot made to move. After a series of 10 test runs for each weight set, the chassis
was checked for deflection.
Figure 40: Deflection of chassis frame
Weight Deflection, (cm)
125g -
245g 0.2
330g 0.4
Table 12: Table of weight v/s deflection
The above table shows the deflection observed when different weights were applied. For small weights
the deflection was negligible. When the weight was increased, the deflection was about 0.2-0.4cm,
which was still very low. The total weight of the circuits, Arduino and battery did not exceed 300g and
therefore was well within the limit of negligible deflection.
Chassis was therefore reliable for operation with all the components integrated on it for the test runs.
Deflection,
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ii. SpeedTo test the speed of the robot, it was tested over a number of test runs. The test was to test the robot
with all the components on it and allow it to complete the predefined path. The robot having a
considerable weight now was tested at different PWM speeds to find an optimum PWM value to ensure
enough speed and stability in motion.
PWM Value Time taken to complete path Stability/Issues
150 3min 08s Too fast. Unstable
120 3min 48s Fast. Motion not entirely straight
100 4min 10s Stable
80 4min 32s Very Stable. Straight line motionTable 13: Speed v/s stability
From the above table it can be seen that the robot was found to move perfectly well in a straight line
motion with a PWM speed of 80. That speed was chosen for the competition as it offered great stability
and enabled the robot to move well within the time limit of 5minutes.
iii. The 90oleft turnTo be able to make the 90o left turn, a lot of testing was done to find the optimum PWM value that
would enable the robot to turn at 90o. A reference mark was set and deviation and angle calculated
from there.
Figure 41: The 90oleft turn
90oreference
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PWM value Delay Angle (estimated)
120 500 110
150 300 25
100 550 80
80 600 90
Table 14: Table of speed v/s angle
From the above table, the speed of 80 and delay of 600 was chosen to make the robot turn at 90O.
iv. Battery LifeThe battery life of the LiPo battery was tested over a series of test runs with initial value and final value
noted.
No of test runs Initial Value (V) Final Value (V)
15 8.34 8.30
20 8.28 8.17
25 8.23 7.99
50 8.20 7.64
Table 15: Battery life of LiPo battery
From the above table it can be noted that the voltage drop is not that considerable and the voltage level
still being above the average operating limit, the robot performed well even at a high number of test
runs. Charging time was only 25minutes for full charge, and was therefore an advantage over normal
rechargeable AA, AAA batteries which have a charging time of 8 hours for full recharge.
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Appendix B Full Code written for the Arduino Duemilanove
//18th October 2011
//Written by Triandi Tanri
//Modified by Keshav Ramrekha
#include
int motor_left[] = {3, 5}; //Define pins for left motor
int motor_right[] = {6, 11}; //Define pins for right motor
int wall = 4; //Initialize a counter for walls
int counter = 0; //Initialize counter
void setup() {
Serial.begin(9600);
pinMode(motor_left[1], OUTPUT); //Pin definitions
pinMode(motor_left[0], OUTPUT);
pinMode(motor_right[0], OUTPUT);
pinMode(motor_right[1], OUTPUT);
;
}
void loop(){ //Main loop
float walls = analogRead(wall)*0.0048828125; // Converting reading from sensor to voltage
Serial.println(walls);
forward();
if(counter2.5){
path_1();
}
else if(counter==2 && walls>2.2){
path_2();
}
else if(counter>2 && counter 2.5){
path_1();
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}
else if(counter==5 && walls>2.2){
path_3();
}
else if(counter>5 && counter2.5){
path_1();
}
else if(counter==8 && walls>2.2){
path_4();
}
else if(counter>8 && counter2.5){path_1();
}
else if(counter==12 && walls>2.2){
backward();
delay(750);
left(80,80);
delay(600);
forward();delay(1500);
left(80,80);
delay(600);
forward();
delay(500);
counter = 0;
}
}
void path_1(){
counter++;
// backward();
// delay(400);
left(80,80);
delay(650);
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motor_stop();
delay(500);
forward();
delay(500);
}
void path_2(){
counter++;
backward();
delay(750);
left(80,80);
delay(620);
motor_stop();
delay(200);
forward();
delay(3000);
left(80,80);
delay(700);
forward();
delay(500);
}
void path_3(){counter++;
backward();
delay(750);
left(80,80);
delay(620);
motor_stop();
delay(200);
forward();
delay(4500);
left(80,80);
delay(700);
forward();
delay(500);
}
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void path_4(){
counter++;
backward();
delay(750);
left(80,80);
delay(500);
motor_stop();
delay(200);
forward();
delay(500);
}
//-----------MOTOR FUNCTIONS----------------//
void motor_stop(){
digitalWrite(motor_left[0], LOW);
digitalWrite(motor_left[1], LOW);
digitalWrite(motor_right[0], LOW);
digitalWrite(motor_right[1], LOW);
//delay(2000);
}
void forward(){
analogWrite(motor_left[0], 80);
digitalWrite(motor_left[1], LOW);
analogWrite(motor_right[0], 80);
digitalWrite(motor_right[1], LOW);
}
void left(byte a, byte b){
analogWrite(motor_left[1], a);
digitalWrite(motor_left[0],LOW);
analogWrite(motor_right[0], b);
digitalWrite(motor_right[1], LOW);
//delay(1000);
}
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void right(byte a, byte b){
analogWrite(motor_left[0], a);
digitalWrite(motor_left[1], LOW);
analogWrite(motor_right[1], b);
digitalWrite(motor_right[0], LOW);
}
void backward(){
analogWrite(motor_left[1], 90);
digitalWrite(motor_left[0], LOW);
analogWrite(motor_right[1], 90);
digitalWrite(motor_right[0], LOW);
}