mae3_team presentation
TRANSCRIPT
Team 30 - Team Fi
Seán Craddock, Joseph Dillon, Madeline Ocampo, and Nathalie Romero
MAE 3 - SPRING 2014
What drives Fi-bot?
● Friction - rotates circular base
o Motor 1 mounted at rear
● A belt - rotates lower arm
o Motor 2 mounted on the left
● Tension - rotates upper arm
o Motor 3 mounted in front
● Pressure - knocks ball down to score
o Surface area of upper arm
FIGURE
Design Process
● Initial robot design:
o Two rods - lift ball - create track
o Required two lower components
o Failure - Insufficient torque
● Modification:
o Attack from below
o Allows for one arm design
o Decreased necessary moment
o Increase contact area
FIGURE
Fi Robot starting point in Field
Final Design: Fi-Bot
Turntable
Spool
Sprockets
with timing
belt
Friction keeps Fi-bot Spinning
● Rotational Vs. Lateral movement
o Degrees of freedom
o Accuracy of arm
o Defensive risk
o Complexity of design
● Chosen design specifications
o High gear ratio (2:7)
o Friction drive
o Circular track
FIGURE
CIRCULAR TRACK
BASE
GEARED MOTOR
ROTATING
WHEEL
Initial Design Fails to the ground
● Torque failures:
o Initial opposing moment
o Resulting moment when vertical
o Counter-clockwise rotation
● Accuracy inadequacies:
o Brackets & first axle
o Lower arm components
o Forklift/ramp components
ARMS
PIVOT
POINT SPROCKETS
Difficulties of Hitting Balls
● Accessibility
o Constricted from below
o Difficult to see and be precise
● Accuracy
o Inaccurate attempts add deficit
o Placement of constraints
● Force Application
o Excessive force = control loss
o Low force = unable to hit ball
FIGURE
ARM
BALL
TARGET
MISSED
● Counter weight - decrease opposing
moment of upper component
● String applies force to a 1.5in radius
disc on axis creating torque
● Torque maximized by counter weight
and decrease of mass
● Curved contact surface to allow
proper pressure distribution for
control
Arm Hits Ball with Face
CURVED FACE
PIVOT POINT
STRING
COUNTER WEIGHT
Gear Ratio Increases Torque
● Accuracy or Power?
o Gears Vs. Sprockets
Available torque
Mounting accuracy
adaptability
Sprockets Degree of Safety:
● Max torque required 0.135Nm
● Output shaft torque 0.512Nm
● D.O.S.= 0.512/0.315 = 1.625
Machine in Action
Points scored without
opponent: an infinite amount
of cool points