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FTC Build a Better Robot Cougar Robotics 4251

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FTC Build a Better Robot. Cougar Robotics 4251. Design Principles and Strategies. Design Principles and Strategies . KISS Keep It Super Simple Tool Design First Leapfrog Development Never go backwards Repetitive Testing Repetitive Testing Repetitive Testing Repetitive Testing - PowerPoint PPT Presentation

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Page 1: FTC  Build a Better Robot

FTC Build a Better Robot

Cougar Robotics 4251

Page 2: FTC  Build a Better Robot

Design Principles and Strategies

Page 3: FTC  Build a Better Robot

Design Principles and Strategies

• KISSo Keep It Super Simple

• Tool Design First• Leapfrog Development

o Never go backwards

• Repetitive Testingo Repetitive Testingo Repetitive Testingo Repetitive Testing

• Competitive Development

Page 4: FTC  Build a Better Robot

Practical Applications

Page 5: FTC  Build a Better Robot

Chassis/Drivetrain• Stiff & Stable Frame

• Maneuverabilityo Rocker in a 6 wheel tank-drive chassiso Omni wheels on corners or one end

• Ability to go where you want/need to for the game

• Going the right speed

• Practice driving before the tournamento Be prepared to drive on all parts of the field

Page 6: FTC  Build a Better Robot

Other

• Isolate your motors from impacts

• Torque > Traction

• Mechanical Alignment

• 8 motors, 3 lego motors, 12 servos

Page 7: FTC  Build a Better Robot

Motor Power Table

Motor Name Speed (RPM)

Speed (Radians/Second)

Torque (oz/in)

Torque (Newton/meters)

Power (Watts)

DC 12 volt Motor 150 16 300 2.12 33.26

PF XL 220 23 56 0.40 9.11

NXT Servo 170 18 70 0.49 8.80

PF M 405 42 15 0.11 4.49

180 Servo 60 6 84 0.59 3.73

PF E 780 82 5 0.04 2.88

Continuous Servo 43 5 39 0.27 1.24

Page 8: FTC  Build a Better Robot

Double Drilled vs Regular

Page 9: FTC  Build a Better Robot

Tools, and Using them

• Color coding tools• Good mechanics have their own tools• Removing cross-threaded machine screws

o Vice gripso Drill out

• Removing rounded out machine screwso Vice gripso Easy outs

Page 10: FTC  Build a Better Robot

Building Practices

• Keeping screws and set screws ino Nylockso Lock-tite and pre-nylon threaded set screws

• Don’t transmit loads thru axles• Understanding friction/traction

o Surface area doesn’t change frictiono F=µFn

• Components under tension & compression

Page 11: FTC  Build a Better Robot

Regular Wheel With Sprocket

Page 12: FTC  Build a Better Robot

Calculating Loads on Lever Arms

• Margin of Safetyo At least a 2:1

• Exerciseo Use a lever arm on your robot or make one

including: A DC motor At least one gear change A lever arm on the end

o Using your setup, calculate the reasonable max weight your lever arm could elevate

Page 13: FTC  Build a Better Robot

Custom Parts

Page 14: FTC  Build a Better Robot

CAD Programs

• PTC Creo Pro

• Autodesk Inventor

• Gear Generatoro http://woodgears.ca/gear/index.html

Page 15: FTC  Build a Better Robot

Tools

• Laser Cutter• CNC Machine• Sheet Metal Shear

o Metalo Polycarb and PETG

• Sheet Metal Brake• Machine Lathe

Page 16: FTC  Build a Better Robot

Steel and Plastic

• When to use steel• Your best plastics

o PETGo Delrino Polycarbonate

Page 17: FTC  Build a Better Robot

3D Printing

• When to print your own parts• Web order 3D printing (Shapeways)

o Some companies can print steel

Page 18: FTC  Build a Better Robot

Useful Websites• Official Game Forum

o http://ftcforum.usfirst.org/forum.php

• Chief Delphio http://www.chiefdelphi.com/forums/forumdisplay.php?f=146

• ROBOTC Forumo http://www.robotc.net/forums/viewforum.php?f=52

• Xander Soldaato http://botbench.com/blog/

• Cougar Roboticso http://cougarrobot.com/

• Landroidso http://landroids.org

Page 19: FTC  Build a Better Robot

More Useful Websites

• Hitechnico http://www.hitechnic.com/

• Lego Educationo http://www.legoeducation.us/

• Digikey o http://www.digikey.com/

• McMaster-Carro http://www.mcmaster.com/#