Battle Ready Robot

fiercebunΗλεκτρονική - Συσκευές

2 Νοε 2013 (πριν από 3 χρόνια και 9 μήνες)

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Battle
Ready Robot



Final Report



Submitted to


The Faculty of Operation Catapult LX
X
X
II


Rose
-
Hulman Institute of Technology


Terre Haute, Indiana







Group
33



Gavin Darroca

W.T. Woodson High School

Fairfax, Virginia


Rick Dempsey

Billerica Me
morial High School

Billerica, Massachusetts


Nik Francis

St. Pius X

High School

Spring, Texas


July 28, 2007


33
-
1


Introduction


The purpose of our project is to design and build a remote controlled battle ready robot.
The embedded control section of the ele
ctrical engineering at Operation Catapult is made up of
many different factions of projects. The most popular choice this session of Catapult was the
Smart Car. Seeing as Operation Catapult is an engineering camp, this can’t possibly be the
hardest route t
here is, so the group decided to mold their own project loosely based on the Smart
Car idea.
Instead of normally following the common path of creating a smart car, we chose to
develop a battle ready robot.

Usually
, the control

of
the car
would be
through
autonomous
means

however,

we chose to
use a
remote control
.

The PIC would instead of interpreting its
surroundings would only listen to its infrared sensor.

Objectives

This vehicle

has wheels powered by servos, a
weapon for engaging
in combat, and the car

is

remote
controlled.
One of the main goals of the
battle ready
robot was to

d
esign and construct a chassis. W
e
chose to make it out of wood and a clear plastic,
acrylic

(Figure 1)
. Another goal is to figure out how
to make the PIC to interact with the VC
R remote
control. Once that has been achieved, we needed to
decide on a combat element

and how
to integrate it
into the robot.


Procedure

The battle ready robot
is a very arduous project to construct. There are so many hurdles to get
past that the origina
l Smart Car did not have. The main differences between the two projects are
the weapons and the remote control as opposed to autonomous control. The battle
robot
came
together as a result of a number of systems running together. The systems that make up th
e battle
robot

are the chassis, the power supply and microcontroller, the drive train, the flipping
apparatus, and the infrared controller.


The first system constructed for the
battle robot

is the chassis. The chassis is the basis of
the entire car and ph
ysically holds everything together. Available materials for the construction
of a chassis include acrylic and wood. The wood chassis appears to be the easiest and most
versatile material to work with. A design of a wooden wedge went into play to accommodat
e for
the car's internals, the car's weapon, and to keep the overall size of the car down. A four piece
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2


wooden chassis was created with an open top which will later be covered

(Figure 2)
. After the
chassis, a power supply and a microcontroller have to be c
rafted.


The power supply and microcontroller comprise the second system pieced together for
the
battle robot
. A MicroChip PIC microcontroller

(Figure 3)

is the common controller in the
embedded control project. The
microcontroller has 32 I/O ports availa
ble for
use and a daughterboard to allow for an easy
wiring set up. It is also easily programmable
with use of a computer and an ICD
-
2
programmer. Getting power to the
microcontroller is the difficult task in this
system. An array of eight AA batteries is
attached to the back of the vehicle and run to
the PIC microcontroller. The PIC has a
voltage regulator to turn down the voltage put
out by the batteries and
to
prevent the chip
from shorting out itself and its accessory
components. The next three systems
in the
battle robot

are all accessory components of the PIC microcontroller.


A drive train is required by the
battle robot

for locomotion. It is an accessory to the PIC
microcontroller and is therefore controlled solely by the PIC. The
battle robot
's driv
e train is
comprised of two MAXX MX
-
400 servos which have wheels attached to them. The servos have
three speeds both clockwise and counterclockwise and grant the drive train versatile movement.
The wheels can move forwards and backwards, and by slowing dow
n one side, can pivot to turn
the vehicle. In short, the drive train is a minimalist set up that still has a large amount of
versatility.


Weapons are what set the
battle robot

apart from the original smart car design. The
battle
robot
's weapon can be des
cribed as a flipping apparatus that contours to the chassis's wedge
shape. A cover made of one eighth inch thick acrylic
is attached to the wooden chassis via a large hinge.
This acrylic piece covers the internals of the
battle
robot
. It is also tipped wit
h a rectangular aluminum
piece in order to give it a more effective way to get
under its target. Attached to the underside of the
acrylic piece is a lifting arm with teeth on one side.
This lifting arm is interl
ocked by its teeth to a gearbox
(Figure 4)

Th
is gearbox is driven by a third servo and
provides a larger amount of torque for the flipping
apparatus. In short, a servo with a gearbox powers a
wedge to push the
battle robot
's opponents and flip
them over.

The final system that is required by the
battl
e robot

is the infrared sensor. An Everlight
IRM 8420 infrared sensor is a small device that picks up and decodes infrared pulses. In
conjunction with a PIC microcontroller, the sensor can be set as an input and control the
microcontroller with the pulses
it receives. Naturally, a simple VCR remote control can be used
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3


to send infrared pulses to the sensor and
programmed to control the microcontroller. To
program the microcontroller to read the pulses, the
pulses must first be decoded. Using an oscilloscope
attached to the infrared sensor, the pulses are able
to be captured and decoded into a binary string.
With the correct binary string and a state system
program, the remote control

s output can be picked
up by the infrared sensor and used as an input for
th
e microcontroller. The drive train and flipping
apparatus are controlled by the microcontroller by
inputs from the infrared sensor. The Everlight IRM
8420 allows the
battle robot

to be controlled by an outside source and not autonomously.

Results

The
fina
l product of the
battle robot

is
a complete wooden and plastic menace to the other
robots
. First, the chassis made of wood proves to be stu
rdy enough for the parts the robot

requires to run, and it has suf
ficient space to contain the robot
’s internal worki
ngs.
T
he PIC
microcontroller is in perfect working condition in addition with the daughterboard to provide the
wiring to the accessory components. The voltage regulator chip on the daughterboard is able to
reduce

the

twelve volts from the batteries into a
five volt

supply so that no accessories short out.
T
he most important accessory, the infrared sensor, is

a wonderful addition provided you can aim
the remote at it. It has a range of about 10 feet as long as the sensor is angled correctly and able
to pick
up the infrared pulses. The remote used to control the
battle robot
, and

has 8 working
buttons that can be used for different functions. In addition,
the PIC microcontroller runs
a state
machine
program
to decode the remote’s infrared pulses which works al
most flawlessly t
o
eradicate the small anomalies

and interference in the pulses.
In conclusion the
battle robot

is
fully functional and can be directly controlled by anyone who has the 22 year old VCR remote!

Lessons Learned

Operation Catapult is primaril
y a summer program to introduce high school students to
engineering and have them learn more regarding some specific fields of engineering. The
electrical and computer engineering portions of the program offer a lot as far as learning is
concerned. Groups
enter the program with little to no knowledge on the subject and walk away
with a very clear understanding of many different activities. First, the most basic building blocks
of electr
ical and computer engineering are

dealing with wires and circuit boards.

The students
must learn how electricity flows and with that knowledge be able to wire together circuits,
whether they are simple or complex, on a circuit board. The next step was to actually wire in
some electrical device and get it to work, such as a ser
vo
.
After, a PIC board was the next
obsta
cle to master. A PIC board

assist
s

in controlling any functions regarding the electrical
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4


devices in use.

PIC boards can be controlled by external inputs such as a switch or a sensor.
Infrared sensors can be wired to

a PIC board and read as an input. However, with a sensor, one
must get something to provide
data to define controls. A remote control can be used to send
signals to the sensor, and the signals it sends transmits to the sensor can be picked up and read by
an oscilloscope. In summary, to set up an infrared sensor input there must be proficient
knowledge of a sensor, a remote, an oscilloscope and a PIC board. Last
ly
,
the final lesson wasn’t
necessarily in the field of electrical or computer engineering. In or
der to create the body and the
gearbox fo
r the flipping apparatus servo some mechanical engineering is called for.

The
mechanical engineering is accomplished simply by communicating to that department, as all
departments are open to all projects.


Conclusi
ons

The battle ready
robot

is a project that has never been undertaken. So we have some
higher level of difficulty to complete our project than the regular smart car groups.

Figuring out
what the shape of robot took a lot of critical thinking. The comba
t system was also hard to
decide on since its effectiveness is determined by the chassis of the robot.

Creating the wedge
-
shaped frame out of wood with an acrylic top, plus minor details, was simple yet time
consuming. Programming dragged on for hours to

encode
the infrared pulses

of each button of
the VCR remote into the PIC and
molding the flipping apparatus brought the whole group to a
breaking point.