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 Competitive Development Joey Questions / Discussion Leapfrog so you never go backwards Strategy, build your robot to complement partners...

Practical Applications

Chassis/Drivetrain Stiff & Stable Frame Maneuverability Rocker in a 6 wheel tank-drive chassis 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 tournament Be prepared to drive on all parts of the field Nathan -don’t go in-depth on rocker -omni wheels on the corners or at one end

Other Isolate your motors from impacts Torque > Traction Mechanical Alignment 8 motors, 3 lego motors, 12 servos Joey Note for Joey: Put program on brick that tells robot to drive straight for 10 seconds or so.

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 39 0.27 1.24 Evan Need motor stats/limits Should bring Ring It Up! arm

Double Drilled vs Regular

Tools, and Using them Color coding tools Good mechanics have their own tools Removing cross-threaded machine screws Vice grips Drill out Removing rounded out machine screws Easy outs Sean

Building Practices Keeping screws and set screws in Nylocks Lock-tite and pre-nylon threaded set screws Don’t transmit loads thru axles Understanding friction/traction Surface area doesn’t change friction F=µFn Components under tension & compression Joey Build both examples

Regular Wheel With Sprocket

Calculating Loads on Lever Arms Margin of Safety At least a 2:1 Exercise 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 Using your setup, calculate the reasonable max weight your lever arm could elevate Evan Should bring Ring It Up! arm

Custom Parts

CAD Programs PTC Creo Pro Autodesk Inventor Gear Generator http://woodgears.ca/gear/index.html Evan

Tools Laser Cutter CNC Machine Sheet Metal Shear Sheet Metal Brake Polycarb and PETG Sheet Metal Brake Machine Lathe Evan

Steel and Plastic When to use steel Your best plastics PETG Delrin Polycarbonate Joey

3D Printing When to print your own parts Web order 3D printing (Shapeways) Some companies can print steel Sean

Useful Websites Official Game Forum http://ftcforum.usfirst.org/forum.php Chief Delphi http://www.chiefdelphi.com/forums/forumdisplay.php?f=146 ROBOTC Forum http://www.robotc.net/forums/viewforum.php?f=52 Xander Soldaat http://botbench.com/blog/ Cougar Robotics http://cougarrobot.com/ Landroids http://landroids.org Sean

More Useful Websites Hitechnic http://www.hitechnic.com/ Lego Education http://www.legoeducation.us/ Digikey http://www.digikey.com/ McMaster-Carr http://www.mcmaster.com/# Sean

Contact Information Coach Jamie- coach@cougarrobot.com Coach Judy- scientist@cougarrobot.com Kids- joey@cougarrobot.com evan@cougarrobot.com sean@cougarrobot.com nathan@cougarrobot.com reeve@cougarrobot.com