glee robotic arm team members: william jaynes ted schnittgen dana navarra samuel langfield feng...

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

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Electrical Work DetailsElectrical Design

• Detailed Micro Block Diagram

GLEEGreater Lafayette Elementary

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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!