Proposed Dewbot V Chassis Clem Mc Kown Team

Proposed Dewbot V Chassis Clem Mc. Kown Team 1640 December 21, 2008

Why 6 wd? n n This summer’s prototyping and follow-up analysis demonstrated that 6 wheel drive robots have a significant advantage in maneuvering vis-à-vis a 4 wd robot Omni-wheels facilitate 4 wd turning, but make a robot easier to push around 6 wd middle wheels are key for turning performance Also a plus for ramps

Good practices n n 6 wd has no advantage in traction or stability, but… For traction, n n all wheels should be driven; robot should be at maximum weight; and traction tread material should be used For stability, n n Maximize wheelbase Keep center of mass low and central

The Specs n (6) 6” Andy. Mark Plactron Wheels n (4) CIM Motors n (2) modified 2 -speed Andy. Mark Shiftboxes n 9. 4: 1 & 24: 1 Overall Gear Ratios n 14. 8 & 8 ft/s maximum speed n 24. 26 x 30” wheelbase

Isometric View “Grease Guard” 1/ ” PC partition 16 to keep electronics compartment clean c. RIO Controller Battery

Isometric View (showing Jags) Jaguar (PWM) motor controllers mounted on front panel

Front / Rear Elevations

Right / Left Elevations

Plan View

Plan View (Showing Jaguars)

Direct drive to Middle Wheels n n n Middle wheels are direct, geardriven from the gearbox Front & Rear wheels are slavedriven via chains & sprockets from the middle wheel Benefits n n n Reliability Keeps motor & gearbox (and center of mass) low Weight savings

Customized (Team 1640) Direct-Drive Andy. Mark Shiftbox Sprockets replaced w/ 20 tooth gear Spacer bolts (now ¼-20) also serve as mounting bolts Additional axle = wheel axle w/ 45 tooth drive gear New front & back plates

Identical left & right drive units We could build & bring a spare

Design Performance n n Acceleration curves are with wheels slipping High gear provides adequate power for turning (enough to make wheels slip)

Weight n Current Mass is 68. 9 lbm, which includes n n n Chassis w/ Drivetrain Pneumatic System up to & including Regulator Panel mounts for electronics Battery Mount c. RIO controller with: n n n n c. RIO w/ 5 modules Alalog bumper Pneumatics bumper Digital side-car & cable Distribution Block Radio Does not include: n n Jaguar (PWM) Motor Controllers Battery Bumpers (not the electronic bumpers) Oh, yeah, whatever we actually need to play the game

Center of Mass n 4. 4 in above grade n 4. 5 in aft of chassis center (w/ battery) n 1 in left of chassis center (w/ battery)

A reminder n n This is a still work in progress Any suggestions or critique will be appreciated