DEWBOT VIII Drive-train Team Page
Student Lead: Molly
Head Mentor: Ben Kellom
Students:
Mentors:
Pivot drive Steering Motor selection
The BaneBots RS540 motors used in 2011 are not available for the 2012 robot. Alternatives are BaneBots RS395 and BaneBots RS550 motors. After analysis, BaneBots RS395 motors with 132:1 reduction were selected, primarily based on their lower contribution to robot mass.
Motor/Gearbox for Barrier crossing
Early prototype testing using DEWBOT VI demonstrated that raised, 8" diameter KitBot wheels are incapable of allowing a pivot drive chassis being driven over the mid-field barrier. An alternative is the use of driven, 8" diameter pneumatic wheels. What motors & gearboxes are needed to drive these wheels? Analysis indicates that FisherPrice motors and Gearbox's will do the job (one should alone, in fact, if the power transmission to the two wheels is managed).
FRC Team 1717's awesome pivots
Team 1640 is generally considered a competent practictioner of pivot (a.k.a swerve, unicorn,...) drive. I was, however, humbled when I saw team 1717's (D'Penguineers) pivot module at St. Louis. More so afterwards when I watched videos of how they move. If we ue Pivot again, we've got a new performance target. My photos from Championships are below (original 4368 x 2912 pixel photos are available upon request).
While the 1717 pivot module design is mechanically impeccable (albeit at 9 lbm a bit heavier than ours), the videos make it crystal clear that their primary benefit comes from control and software, not mechanics.
D'Penguineers, of course, were made famous by Neal Bascomb's book, The New Cool, Crown Publishers (2011).
From the photos, I deduce that 1717 has discrete left & right pivot modules.
There appears to be seven (7) discrete vertical axles in the module (supporting two drive trains - wheel drive & steering). There are two parallel horizontal axles in the pivot (wheel drive). Two vertical module axles contain coaxial elements (the gear shift and the pivot itself). Instrument take-offs are provided for CIM motor speed (not reduced) and pivot angle.
Gear shift with independent pivot drive is very cool and probably useful under many conditions. By taking much of the drive reduction with gears, a smaller difference between drive & driven pulleys are needed.
