Post on 22-Jul-2015
Three Legs are Better than Four
Joseph CaluzaAerospace Engineering
Daniel KaminskiMechanical Engineering
Tyler StearsEnvironmental Engineering
Project Objective
• Simplicity: As a team of three, we did not want a risky design.
• Reproducibility: Controlling the robot is kept simple with just two degrees of freedom.
• Exceptional Fabrication: Implementation of Design for Manufacture methods
Tyler Stears
Lock and Load
• The shim stock component acts as a high-powered spring to deploy the robot arm. The small rubber band aids in auxiliary deployment of the arm and deploys the reaping fork.
Tyler Stears
Compressed Shim stock
Stretched small rubber band
Small rubber band puts fork under tension
….RELEASE!!
Fork slips out from friction drive shaft when the wheel make a small rotation
Small rubber band aids the shim stock pin to lock in place
Decompressing Shim stock
Fork rotates out of position
Fork held in place by rubber band
Shim locks into rear arm notch
Daniel Kaminski
Reaper’s Deployment
• The shim reverts to its original straight position to release the Reaper.
Sliding Screw locks into notch in the slide
Arm Locks into place with linear slider with help of rubber band
Shim fixed on upper portion of arm
Notch locks the arm in place
Rubber band tension holds pin in notch
Rubber band keeps fork forward
Daniel Kaminski
Parts of the Design Process: Design for Manufacturability
Slots
Universal width to interchange forks
Clearance Holes
Rotating WheelFore arm
Daniel Kaminski
You’ll Get a Kick Out of This
How to get the tree monkeys?
Get Lifted!!
Kick slips out and reaper claims ground monkeys
Get Un-lifted!!
Joseph Caluza
Wheel Torque Analysis
Tfriction = A*(umg/A)*r = umg*rTfriction = (0.8)(0.186 kg)(9.81m/s^2)(0.0813m) = 0.119 N*mTfriction needed = F.S. * Tfriction = 1.5 * 0.119 N*m = 0.179 N*mActual Torque Generated = (.75N)*(.235m) = 0.176 N*m
Motor FBD Friction Normal FBD Wheel FBD
Mass of robot arm with max load of three monkeys (m) = 0.186 kgRadius of Circle Piece (r) = 3.2 in = 0.0813 mCoefficient of friction of acrylic on acrylic (u) = 0.8Factor of Safety = 1.5 Note: Lubricant reduces coefficient
friction value
Joseph Caluza