let’s jam team 35: jason chen, justin ho, andrew wilkinson presenting: the jammer
TRANSCRIPT
Let’s JAM
Team 35: Jason Chen, Justin Ho, Andrew Wilkinson
Presenting: The Jammer
Components of Robot
Andrew Wilkinson
Objective
Get balls onto own field
White balls = 1 ptYellow balls = 2 pts
meh... Oooh! Shiny!
Andrew Wilkinson
Robot in Three Pieces
Friction Drive
Arms
Elevator
Andrew Wilkinson
Step One: Getting In Position
Increase vertical height
starting position arms raise up robot at maximum height
Controlled by one geared motor
Justin Ho
Step Two: Driving to Balls
Use friction drive to move forward
Robot ready to get balls
Justin Ho
Step Three: Dragging Off Balls
Score points!
Give me that! Mine mine mine
I got one, but it’s not enough!
Grasp balls using arms
Drive backwards to pull ball back
Ball falls onto soccer field!
Justin Ho
In Real Life!
Justin Ho
Initial Design: Scissor Lift
Problems● Difficult to extend scissor lift with
only 1 motor● Complex design; aiming for
simplistic design● prone to jamming
After our risk reduction test, we decided to use an elevator mechanism to raise our robot instead.
Jason Chen
Key Feature #1: A Reliable Improvement
Initial Position
Final Position
Elevator for reaching yellow balls
Walls removed to show inner workings
small gears rotate against track
Large gears mesh with each other so lifting force is equal on both sides of robot Jason Chen
Key Feature #2: Pivoting Arms
Jason Chen
Key Feature #2: Pivoting Arms
● Pulling from top
● Requires less accuracy
● One geared motor
● Compact Design
● Simple
● One gear drives all
Jason Chen
Key Feature #3: Drivetrain
● Front wheel friction drivetrain
● Two non-gear motors
● High gear ratio
● Medium torque
● Simple
Friction drivetrain
Inner workings of drive train
Check out them shoes!
Friction drive on front
Jason Chen
Driving Around: An Analysis on the Drivetrain
Left friction drive Left friction drive schematic
Jason Chen
Friction Drive: Force Analysis
Given:● Robot Weight: 1.444 kg● Distance from Rear Wheel
to Center of Mass: 8.89 cm (2.5 inch)
● Distance from Front Wheel to Center of Mass: 6.35 cm (3.5 inch)
Assumption:● Quasi-Static Motion● No Friction between acrylic
and axles● Non-geared motor does not
slip● Motor is strong enough to
not stall
Testing shows robot can actually push with 5.6 N!
How much force can it actually output?
Analysis Objective:How much force can our robot push with?
Andrew Wilkinson
Friction Drivetrain
Elevator Analysis: Rising UpAnalysis Objective:Can one geared motor lift half our robot?
Given:● Robot Top half Weight: 0.44 kg● Torque from motor: 0.32Nm● Gravity: 9.81m/s^2● radius of gear: 0.6in=0.015m● FS:2
Assumption:● Energy loss to friction is
negligible● Quasi-Static analysis● Gears do not jump
Andrew Wilkinson
Final PerformanceAdvantages:
● Easy to design and build● Easy to maneuver● Able to get whites on own side and
yellow balls
Disadvantages:● Can’t get balls into own goal● May accidentally knock balls to
opponent’s side● Elevator can jam sometimes
Andrew Wilkinson
Best Score: 10 points4 white balls and 3 yellow balls on own side with no opponents
