Controls and Counterbalance Team MIEUX – ASME Design Competition October 7, 2004 Stefan Campbell Carlos Celada Chris Villani Laurel Weiske TEAM MIEUX

Controls-Motors Motor Driver Jameco #: Double Throw Double Pole On-Off-On $1.29 –One position for Forward, Reverse and stop position Emergency Stop Jameco #: Single Throw Single Pole On-Off $1.15

Controls-Counterbalance & GrainDelivery CounterBalance Jameco #: Double Throw Double Pole On-Off-On $1.29 –One position for Forward, Reverse and stop position Grain Delivery Jameco #: Single Throw Single Pole On-Off $1.15 –Two On-Off switches physically linked to avoid burning out motor TEAM MIEUX

L MAX = 7.5 inches l = 3.6 inches Ø = 21.79° d w = inches (d,h) = (2.566,1.816) Maximum Length of Counterbalance Arm Length constrained by ASME size requirements Size of package Estimated counterweight dimensions subtracted Pythagorean Theorem utilized TEAM MIEUX

X = moment arm = 4.64 inches W cb >= 2.8 lb Minimum Counterbalance Weight Rotation of counterbalance arm constrained by the line y = tan(40)*x Vehicle must rotate through 40° in order to surpass 4 inch stair during ascension Counterbalance must not touch ground in vehicle’s raised position TEAM MIEUX

Required Weight for Target Rotation Times Used an estimated mass moment of inertia of the vehicle and the angular acceleration for each target time to calculate the required weight Concluded that a counterbalance weight of approximately 3 lbs. would be optimal TEAM MIEUX

Crank-Rocker versus Crank-Slider Four Bar Crank-Slider Advantages of Crank Slider Lower torque requirements – 8in-lbs vs 10+ in-lbs Larger range of motion - 20° vs 148° Smaller links – Four bar linkage would not meet ASME requirements

Force Analysis TEAM MIEUX Height Implications Height has no effect on the torque requirement Height chose to be 3.25” Half distance counterbalance distance Crank length geometrically determined to be 3.12”

TEAM MIEUX Torque Requirements Implications Highest torque occurs at rotation angle of 30° (in-lb) Start-up torque requirements are very high Torque decays linearly from 30° to 90°