glee robotic arm team members: william jaynes ted schnittgen dana navarra samuel langfield feng...
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GLEE
Robotic Arm
Team Members: William Jaynes Ted Schnittgen
Dana Navarra Samuel Langfield
Feng Shuang Stamme Jeha Lee
Aaron Fry Targoon Siripanichpong
Greater Lafayette Elementary Education
Overview• Robotic Arm
– Models the human arm – Six degrees of motion– Teaches concepts of anatomy, robotics,
teamwork, mathematics, and engineering • Interactive environment
– Students will use the Robotic Arm to do multiple different tasks
GLEEGreater Lafayette Elementary
Education
Project History• Originated in Spring 2004• Fall 2008: Project was restarted as a
maintenance project• Spring 2009: All electrical components were
destroyed, new parts were ordered• Spring 2010: Started new design and created
enclosure due to safety constraints and preservation
• Spring 2011: New design involved using the best of 2010 and 2009’s pieces
GLEEGreater Lafayette Elementary
Education
Shoulder Rotation Shoulder Lift
Elbow Extension Forearm Rotation Wrist Rotation
Mechanical OverviewGLEE
Greater Lafayette Elementary Education
Mechanical Overview (cont.)GLEE
Greater Lafayette Elementary Education
• The arm is too heavy for the vertical shoulder servo to hold it up without issues, so the spring was added.
• This semester the spring has been relocated due to the lack of elbow motion.
• Mount for elbow servo is in the works and is almost identical to the others already in place.
Electrical WorkGLEE
Greater Lafayette Elementary Education
Sub Project Leader: William Jaynes
GLEEGreater Lafayette Elementary
Education
• Overall schematic
Electrical Work DetailsElectrical Design
Arduino Nano v3.0
(ATMega16)
GLEEGreater Lafayette Elementary
Education
Electrical Work DetailsElectrical Design
• Detailed Micro Block Diagram
GLEEGreater Lafayette Elementary
Education
Electrical Work Details(cont.)• Using an old computer power source
taken directly from the tower which allows us a variety of voltages and currents for the servos, micro, and controllers
• This is important because each servo takes approximately 1 amp of current when there is no load on the servo
Electrical Design
GLEEGreater Lafayette Elementary
Education
Electrical Work Details(cont.)• We are going to be working with voltage
regulators because the power from the power source fluctuates a bit which causes some instability
• We will be soldering the micro and control components to a board when the code has a final pinout design
• The wiring is to be cased similar to how it is now, which will make is more robust
Electrical Design
GLEEGreater Lafayette Elementary
Education
Electrical Work Details(cont.)• Servos used (all by Hitec)
– HS-645MG (4)• Used for all but lift and rotation of shoulder
Operating Voltage: 4.8-6.0 VoltsOperating Speed (4.8V): 0.24sec/60° at no loadOperating Speed (6.0V): 0.20sec/60° at no loadStall Torque (4.8V): 106.93 oz/in. (7.7kg.cm)Stall Torque (6.0V): 133.31 oz/in. (9.6kg.cm)
– HS-805BB (2)• Used for lift and rotation of shoulder
Operating Voltage: 4.8-6.0 VoltsOperating Speed (4.8V): 0.19sec/60° at no loadOperating Speed (6.0V): 0.14sec/60° at no loadStall Torque (4.8V): 274.96 oz/in. (19.8kg.cm)Stall Torque (6.0V): 343.01 oz/in. (24.7kg.cm)
Electrical Design
GLEEGreater Lafayette Elementary
Education
Electrical Work Details(cont.)
HS-645MG:
HS-805BB:
Electrical Design
GLEEGreater Lafayette Elementary
Education
Electrical Work Details(cont.)• Wiring from each servo contains a
ground, a power (+5) and a control wire• Since it works from 0 – 6v, we do not
have to deal with negative voltage which makes it easier when writing code to control these servos
Electrical Design
Accomplishments• Noise from servos is no longer a problem
due to the fix involving having two power sources and keeping the servos separate
• Developed a method to keep the fluctuating voltage from the power source more stable (Early Stage)
• Tested all servos with the lab power supply and made sure all wires to servos were connected correctly
GLEEGreater Lafayette Elementary
Education
Electrical Design
Accomplishments(cont.)• Developed, with Ted, a way to sense the
force being placed on the closing hand (More about this in Problems section)
• Cased wiring since arm is not mounted at the moment. This will keep the wiring that is complete safe
• Developed, with mounting team, a servo bracket design to mount the elbow servo onto the arm
GLEEGreater Lafayette Elementary
Education
Electrical Design
Ongoing Issues• Soldering the board requires me to wait
for a final pinout• Hand servo still fights itself and overheats
(Fix in the works)• As of now, power source still fluctuates,
but fix is designed, and will be implemented soon
• Elbow servo is still not attached, but the servo itself now works
GLEEGreater Lafayette Elementary
Education
Electrical Design
Controller team
Jeha LeeFeng Shuang Stemme
GLEEGreater Lafayette Elementary Education
Controllers Overview
• Arm consists of 6 individually controlled joints
• 6 students can manipulate the arm at one time
• Each joint is operated by 1 joystick box• Each joint has 2 directions of movement
GLEEGreater Lafayette Elementary
Education
Design Process
• Reason for 6-person operation of arm:– Reinforces importance of team work.
All joints of arm must work together to complete a task
– Demonstrate complexity of human brain– Exemplify endless possibilities of technology
GLEEGreater Lafayette Elementary
Education
Joystick Specifications• 2 directions of movement (1 axis control) • Switched 0 Volts, 5V, and 2.5 V output
Exterior Casing Specifications• Average 11 yr. Old's hand length is 6.1”• Total weight of controller < 5 lbs.• Durable material: wood, hard plastic,
metal
GLEEGreater Lafayette Elementary
Education
Electrical Design
Price per unit
Specs Handle color
Micro switch
Box
1 18.00 2-way Black Yes No
2 14.95 2-4-8 way Green Y N
3 8.00 2-4-8 way Red Y N
4 14.85 4-way Black Y N
GLEEGreater Lafayette Elementary
Education
Electrical Design
Required box dimension to fit joystick= 4 x 4 x 2.75 (in inches)
Box we are going to order and use(from Radio Shack)= 7 x 5 x 3(in inches)
GLEEGreater Lafayette Elementary
Education
Electrical Design
Assembly schematicGLEE
Greater Lafayette Elementary Education
Electrical Design
J S T1 J S T2 J S T3 J S T4 J S T5
Controller
I/C
LK
1
I/O
E1
3
I/O
14
I2
I3
I4
I5
I6
I7
I8
I9
I1
1
I/O
15
I/O
16
I/O
17
I/O
18
I/O
19
I/O
20
I/O
21
I/O
22
I/O
23
I1
0
0 0 00 0
5V
Robotic Arm
Wiring schematicGLEE
Greater Lafayette Elementary Education
Electrical Design
Controller Controller ControllerController Controller
Schematic for inside the Joystick
5VR 1
330 ohms
R 2
330 ohms
0
2.5V
Multiple Switch 1
Multiple Switch 2
No Movement
15 mA current goes through two resistor. Therefore between two resistor voltage drop will be 2.5V.
GLEEGreater Lafayette Elementary
Education
Electrical Design
2.5V
5VR 5
330 ohms
R 6
330 ohms
2.5V
0
Multiple Switch 2
Up direction
Multiple Switch 1
The current passing through one resistor and for the up direction out put voltage will be 5V.
Greater Lafayette Elementary Education
GLEEElectrical Design
5V
5VR 3
330 ohms
R 4
330 ohms
0
2.5V
Multiple Switch 1
Down direction
Multiple Switch 2
The current through one bottom resistor and the out put voltage will be 0V.
GLEEGreater Lafayette Elementary
Education
Electrical Design
0V
Reference
• Joystick Vendor– http://na.suzohapp.com/joysticks/ultimate_joy.
htm
• Children’s hand size– http://
ovrt.nist.gov/projects/anthrokids/images1975/pcc043.gif
– http://www.ergonomics4schools.com/lzone/anthropometry.htm
GLEEGreater Lafayette Elementary
Education
Mounting System
Team Members: Targoon Siripanichpong
Aaron Fry
GLEEGreater Lafayette Elementary
Education
Old Mounting System
• Previous mounting system was a desktop tower case
• Meant for temporary use• Unstable and too large for its casing environment
GLEEGreater Lafayette Elementary
Education
Mounting
Problem
We need to create a permanent mounting system able to support the robotic arm.
Criteria for Success:– Cost-effective– Durable– Maximum range of motion– High stability without swaying– Must not interfere with robotic arm maintenance
GLEEGreater Lafayette Elementary
Education
Mounting
Constraints• Arm must be able to touch the floor at its full
extension.• Time Constraint: 5 weeks (Finished)• Cannot attach to the Plexiglas
GLEEGreater Lafayette Elementary
Education
Dimensions:Length- 53.5 inchesDepth- 34 inchesHeight- 48 inchesFalse Bottom Height- 6 inches
Mounting
Conceptual Design: Basic Ideas• Brainstormed by individual basic
components• Divide the designs into 3 parts:
– Base– Supporting Column– Plate
GLEEGreater Lafayette Elementary
Education
Mounting
Base DesignsGLEE
Greater Lafayette Elementary Education
Mounting
Supporting Column DesignsGLEE
Greater Lafayette Elementary Education
Mounting
Plate Designs
GLEEGreater Lafayette Elementary
Education
Single Plate Hybrid PlateDouble Plate
Mounting
Decision Matrix• Simplest method for conveying ideas• Allows team member feedback• First basic quantitative evaluation• Two Designs Matrices:
- Model Design Matrix- Materials Selection Matrix
GLEEGreater Lafayette Elementary
Education
Mounting
Decision matrix Criteria• Time: Total time for developing and fabricating• Cost: Relative category to other designs, how
much in comparison to other designs• Functionality: How well the design performs its
task, including design flexibility• Durability: How well the design handles physical
stress• Aesthetics: Which designs is the most visually
appealing• Maintenance: Ease of repairing the design
GLEEGreater Lafayette Elementary
Education
Mounting
Blank MatrixGLEE
Greater Lafayette Elementary Education
Mounting
Result of Team Survey
GLEEGreater Lafayette Elementary
Education
Mounting
Feedback from Mechanical Engineer
• Design the false floor first• Identify stresses and forces on system• Metal material may be overkill• L-shape bracket and gussets
GLEEGreater Lafayette Elementary
Education
Mounting
Interior Design Sub team GLEE
Greater Lafayette Elementary Education
Team members: Dana Navarra Samuel Langfield
Activities Demonstrating Proficiency
– Honking a bike horn– Building with blocks– Stacking and sorting colored shapes– Dunking a small basketball– Doing a math problem on a huge
calculator– Ringing a bell
GLEEGreater Lafayette Elementary
Education
Interior Design
Decoration in Casing
• Block “P”• Field Design• Black and Gold• Possibly HHES colors for school pride
GLEEGreater Lafayette Elementary
Education
Interior Design
Casing Representation
GLEEGreater Lafayette Elementary
Education
Interior Design
Arm’s Mounting Location
The boundaries of this Semi-sphere is the approximated range of motion
Stack and Sort Board
GLEEGreater Lafayette Elementary
Education
Interior Design
Accomplishments
• Produced a multitude of ideas for the decoration of the casing
• Brainstormed activities to test the use of the robotic arm
• Analyzing “corner cases” that could pose issues with our design
GLEEGreater Lafayette Elementary
Education
Interior Design
Problems with Design
• The arm’s movement is still undetermined.
• Unknown possible locations of activities.
GLEEGreater Lafayette Elementary
Education
Interior Design
Upcoming Plans
• Start designing and building the activities the children will manipulate
• Create corner case analysis of design limitations
• Verify and test locations of objects are in adequate places
GLEEGreater Lafayette Elementary
Education
Interior Design
MicrocontrollerGLEE
Greater Lafayette Elementary Education
Sub Project Leader: Ted Schnittgen
Initial Problems
• Unstable control of the servos• “Jumpy” movement of servos• No code flexibility• Uncommented code
GLEEGreater Lafayette Elementary
Education
Microcontroller
Accomplishments
• Created a steady state design for unstable servos
• Used variables that are reused throughout the code.– Easier changing of large amounts of code– Easier understanding of code with helpful variable
names
• Commented code and gave explanations of coding decisions
GLEEGreater Lafayette Elementary
Education
Microcontroller
Additions & More Problems
• Proper gripping action– How to recognize holding an object– Best way to regulate servo movement– Force Sensing Resistor (FSR) vs. Micro Switches
• Added an external LCD display– Displays the angle of movement for each servo– Allows users to see exactly where they are moving the arm– Gives added resources to the teachers for math related curriculum– Great Diagnostics Tool
• Problems with LCD– Baud rate between LCD and microcontroller were not the same.– LCD uses “true” serial communication– Microcontroller uses “inverted” serial communication
GLEEGreater Lafayette Elementary
Education
Microcontroller
GLEEGreater Lafayette Elementary
Education
Microcontroller
Flow Chart
Start Initialize Variables
Initialize Serial Communication
(LCD)
Read Controller
Voltage
What is the
Voltage?
Keep Servo Motor the
same
Increase Servo
Position
Decrease Servo
Position
Update LCD Screen
2.5 V
5 V0 V
GLEEGreater Lafayette Elementary
Education
Microcontroller
Code Examples
GLEEGreater Lafayette Elementary
Education
Microcontroller
Code Examples Cont
//TODO:
• Test the newly assembled controllers with the code.
• Verify that the servos work as expected• Determine movement increments for the
various servos• Create a demo simulation for the arm to
complete a simple task• Regulate available movement in the case.
GLEEGreater Lafayette Elementary
Education
Microcontroller
To Do:
• Combine sub components cohesively • Create documentation for end users
– DFMEA– User manuals– Educators Guide
• Video• Written Packet
• Display Purdue, EPICS logo, and School’s logo within project
GLEEGreater Lafayette Elementary
Education
QuestionsGLEE
Greater Lafayette Elementary Education
Please ask us questions!