BOT HEADS

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BOT HEADS
David Weaver Great start!

• Pardip, Blanche, and Cathy

2
Objective

• Complete two separate assignments, using TI
  Calculator and Logger Pro.
• 1 RC Truck
• 2 Robot Sam

3
THE RC CAR
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RC Truck

• Program Signals in TI
• Use the program to control the movements of the
  truck.
• Eventually get the truck to sign your name.

5
Whats Inside?

• Inside the car, you will find a circuit board
  with several capacitors, resistors and diodes, as
  well as the IC that controls the motors. The
  radio receiver consists of a crystal that
  oscillates at a specific frequency, inductors and
  an antenna.
• The electric motors receive power from the
  batteries. The flow of the power is regulated by
  the IC.

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Basic Movements

• Forward
• Reverse
• Forward and Left
• Forward and Right
• Reverse and Left
• Reverse and Right

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MOTORS

• DC MOTOR
• SERVO MOTOR
• STEPPER MOTOR

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DC MOTORS
David Weaver You need to give credit for all
images, quotations, paraphrases, etc.
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DC MOTORS
David Weaver This slide is kind of confusing,
dont you think?

• Main idea come from Michael Faraday
• Faraday concluded that emf induced in a coil of
  N loops depends on the time rate of change of the
  magnetic flux through all the loops.
• Considered the universal motor
• Mostly used on power tool, food mixers, and car
  starter
• First current goes through the field of the
  armature and is polarized
• The interaction with the windings make the core
  rotate the electricity generates mechanical force
  
• The principal is the magnetic field of the field
  windings of the motor and the armature interact
  to create mechanical motion
• The magnetic field alternates and reverses
  polarity creating rotation
• When the coil is powered a magnetic field is
  generated around the armature. The left side of
  the armature is pushed away from the left magnet
  and drawn toward the right, causing rotation.

Faraday's idea any induced voltage has the
polarity that opposed the change causing the
induction.
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DC MOTOR PARTS
David Weaver Your explanation of the armature
construction is not quite right. Splain
commutator function better.
Armature
Commutator and brushes
North and South Windings and permanent magnets

• Armature- assembly consists of a shaft and iron
  metal core
• Brushes-provide rotating contact for commutator
  which convey current
• Commutator-is the rotating switch

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DC MOTORS
David Weaver What sort of maintenance are you
referring to? How short of a life span (I
havent heard this before).
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Servo Motors
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What is a Servo Motor?

• Servo motor is a little device that has an output
  shaft. The shaft can be positioned to specific
  angular positions. To do this, you have to send
  the servo a coded signal. As long as the coded
  signal exists on the input line, the servo will
  maintain the angular position of the shaft.
• When the coded signal changes, so does the
  angular position of the shaft. However, the servo
  motors are used in radio controlled airplanes to
  position control surfaces like the elevators and
  rudders. They are also used in radio controlled
  cars, puppets, and robots.

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Potentiometer
How servo works

• The servo motor has some control circuits and a
  potentiometer that is connected to the output
  shaft. The potentiometer is located on the right
  side of the circuit board. (Doesnt it depend on
  what direction you are looking at it?) The
  potentiometer lets the control circuitry to
  monitor the current angle of the servo motor.
  When the shaft gets to the right angle, then the
  motor shuts down. However, if the circuit
  discovers that the angle is not right, it will
  keep on turning the motor until the angle is
  right.
• The output shaft of the servo has a capability of
  traveling about 180 degrees. The servo is used to
  control an angular motion of between 0 and 180
  degrees. However, a servo is mechanically not
  capable of rotating any farther due to a
  mechanical stop that is built on the main output
  gear. (this seems like its bordering on
  plagiarism. Should be in own words)

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• Enough power is applied to the motor until it is
  proportional to the distance it needs to travel.
  (What does this mean?)
• The control wire (white wire) is used to
  communicate the angle. The angle is determined by
  the duration of a pulse that is applied to the
  control wire, also called Pulse Coded Modulation.
  The servo has to see a pulse every .02 seconds.
  The length of the pulse however determines how
  far the motor will turn. For example, If you have
  a .0015 second pulse, it will make the motor
  rotate to the 90 degree position. However, if the
  pulse is shorter than .0015 seconds, then the
  motor will rotate the shaft closer to 0 degrees
  and if the pulse is longer than .0015 second, the
  shaft will rotate closer to 180 degrees.

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Servo Parts
Cover
Motor
Control Circuit
Power, (5volts)
Control Wire
Ground wire
Gears
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Stepper Motor

• Electric motor that divides a full rotation into
  a large number of steps.
• Used as a positioning system usually when
  digitally controlled as part of a servo system.
• Stepper motors are used in floppy disk drives,
  flatbed scanners, printers, plotters and many
  more devices. (How about the SAM robot???)

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How it Works
David Weaver Charges interact with charges,
magnets interact with magnets, charges and
magnets do not interact. So, you shouldnt be
talking about a magnet being charged. Why are the
top four teeth attracted at first and then the
nearest 4 teeth? What is the sprocket made of?
Why does what you just described translate to a
3.6 degree rotation?

• The top electromagnet (1) is charged, attracting
  the topmost four teeth of a sprocket.
• The top electromagnet (1) is turned off, and the
  right electromagnet (2) is charged, pulling the
  nearest four teeth to the right. This results in
  a rotation of 3.6.

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Continued..
David Weaver Im not getting this if each
electromagnet causes a 3.6 degree rotation, then
the cycle of 1-2-3-4 would result in14.4 degrees
which is 1/25th of a complete rotation but then
are 4 teeth being attracted but it only moves 1
tooth and there are 100 steps Please try to
clarify this further.

• The bottom electromagnet (3) is charged another
  3.6 rotation occurs.
• The left electromagnet (4) is enabled, rotating
  again by 3.6. When the top electromagnet (1) is
  again charged, the teeth in the sprocket will
  have rotated by one tooth position since there
  are 25 teeth, it will take 100 steps to make a
  full rotation.

20
THE SAM ROBOT
David Weaver This slide seems out of sequence.

• TRIALS
• BASIC MANUAL SYSTEM
• MANUAL VELOCITY CONTROL SYSTEM
• BASIC AUTOMATIC SYSTEM
• AUTMOATIC VELOCITY CONTROL

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PARTS OF SAM
David Weaver You should really show all the
parts of SAM, not just the stuff that controls
SAM. That means that you need images (and some
explanations) of all the stuff underneath. The
LoggerPro is the green device beneath the
calculator (you should briefly describe what it
is and does). The blue device is an ultrasonic
motion detector/ranger (you should briefly
explain how it works too).
Logger pro
Calculator TI 83
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What is Sam?
David Weaver Some grammar issues with this
slide. BTW, SAM isnt really a life-sized model
of a microbot, that was just part of the story
introduced by a memo from a fictional person.

• The Sam Robot is a life size model of micro-
  robots
• These micro robots (in theory) are used for
  medical purpose going inside human veins and
  unclogging clots
• The robots are to stand at a set distance from
  its target and maintain that stand off distance
  even if the targets is moving
• The group was given four different system
• Our job was to determine which system worked more
  efficiently

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BASIC MANUAL SYSTEM
David Weaver What does open loop mean?

• The basic manual system is the first system we
  used for the Sam robot. The way we used it was
  simply by using the TI and the lab pro that was
  attached to Sam. Also, a sensor was used for Sam
  to see the target.
• First, we placed Sam between 200 and 1000mm.
• Second, we put in the distance where Sam was
  standing.
• Third, we put in the target distance for Sam to
  stop.
• Forth, we pushed the up arrow on the TI for Sam
  to start moving. When it got closer to the
  distance, we pushed the left or right arrow for
  Sam to stop within the 10mm allowed distance from
  the target.
• Open loop

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BASIC MANUAL SYSTEM
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MANUAL VELOCITY SYSTEM
David Weaver Explain why you had to use trial
and error. What happened with a tolerance of 10?
BTW, 10 whats?

• This system is considered an closed loop system
  (the robot will constantly collect data about it
  position and use the data to readjust the
  position)
• This system does require human intervention being
  able to control the speed of the robot as well as
  its direction of motion
• The robot was placed between 200 to 1000mm in
  front of the wall
• The tolerance was tested
• Which proved to be trial and error
• Started out with a tolerance of 10
• Tolerance of 57 proved to be the best

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MANUAL VELOCITY SYSTEM
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Basic Automatic Control System

• Needs human operator however instruction software
  does not require complete human control.
• Tolerance is needed to keep Sam within required
  distance of target.
• Took Sam 14 seconds to move 494 mm.
• Stayed within required tolerance

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Basic Automatic Control System

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AUTOMATIC VELOCITY-CONTROL SYSTEM
David Weaver It would be better to keep your
fonts consistent.

• The automatic velocity control system does not
  require much human work. The system runs Sam the
  robot all by it self.
• To run the program, all we had to do was to enter
  the distance where Sam was starting from in the
  TI.
• Then we entered the target distance and also the
  tolerance distance.
• After it was all done, Sam moved to the correct
  distance without any problems.
• Closed loop

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AUTOMATIC VELOCITY-CONTROL SYSTEM
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COMPARE/CONTRAST
David Weaver Within the story, the basic manual
system was the cheapest to buy and the automatic
velocity control was the most expensive. The
instructions also indicated that open loop
systems are more expensive to operate.

• Of the system, automatic velocity controlled
  proved to be the most efficient.
• This system obtained the required distance in a
  short amount of time with the least amount of
  errors

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Conclusion

• In conclusion working on this project helped the
  group better understand the complexity of remote
  controls
• We also the different motors and setting up
  programs in the calculator
• Overall this project was a lot of funwho gets to
  experiment with RC trucks for a project in
  college?

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The Groups completeIn the Right Place Assignment
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