ftc build a better robot
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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 PresentationTRANSCRIPT
FTC Build a Better Robot
Cougar Robotics 4251
Design Principles and Strategies
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
Practical Applications
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
Other
• Isolate your motors from impacts
• Torque > Traction
• Mechanical Alignment
• 8 motors, 3 lego motors, 12 servos
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
Double Drilled vs Regular
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
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
Regular Wheel With Sprocket
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
Custom Parts
CAD Programs
• PTC Creo Pro
• Autodesk Inventor
• Gear Generatoro http://woodgears.ca/gear/index.html
Tools
• Laser Cutter• CNC Machine• Sheet Metal Shear
o Metalo Polycarb and PETG
• Sheet Metal Brake• Machine Lathe
Steel and Plastic
• When to use steel• Your best plastics
o PETGo Delrino Polycarbonate
3D Printing
• When to print your own parts• Web order 3D printing (Shapeways)
o Some companies can print steel
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
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/#
Contact Information• Coach Jamie- [email protected]• Coach Judy- [email protected]• Kids-– [email protected]– [email protected]– [email protected]– [email protected]– [email protected]