pic: Back-in-Black 4-speed Top View

[unclewaldo]

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[yongkimleng]

wow nice.. ever since a few years back, it has been two-speed transmissions.. then three.. then now 4..
I guess sooner or later it'll be a norm to have multi-speed transmissions with motor-optimizing PID loops to switch gears, keeping the motor spinning at optimum rpm
Its like the drive system being a large subsystem by itself

[AdamHeard]

Originally Posted by yongkimleng

wow nice.. ever since a few years back, it has been two-speed transmissions.. then three.. then now 4..
I guess sooner or later it'll be a norm to have multi-speed transmissions with motor-optimizing PID loops to switch gears, keeping the motor spinning at optimum rpm
Its like the drive system being a large subsystem by itself

Team 33 had this gearbox in 2004 with everything you just described. It was amazing then, and is still impressive now.

[yongkimleng]

Originally Posted by AdamHeard

Team 33 had this gearbox in 2004 with everything you just described. It was amazing then, and is still impressive now.

hmmm any links? not sure if I've seen it before.. my mind is hazy and my abovementioned description may have been due to fragments of thoughts from such stuff in the past lol

[EricH]

http://www.chiefdelphi.com/media/papers/1580 is the whitepaper. I'm not sure if it details their programming techniques for automatic shifting, though.

[AdamHeard]

Originally Posted by EricH

http://www.chiefdelphi.com/media/papers/1580 is the whitepaper. I'm not sure if it details their programming techniques for automatic shifting, though.

There is an excel associated with the whitepaper which tells you the rpm's to shift at based on motor input and ratios. Not sure where to get it anymore besides contacting team 33. Once you have those shift points it is a little bit of a challenge. We haven't done it yet, but we think a big case statement where each gear is a case. In each gear, it compares the current rpm to the shift points to determine whether to stay in gear, or shift up/down.

[yongkimleng]

Originally Posted by AdamHeard

There is an excel associated with the whitepaper which tells you the rpm's to shift at based on motor input and ratios. Not sure where to get it anymore besides contacting team 33. Once you have those shift points it is a little bit of a challenge. We haven't done it yet, but we think a big case statement where each gear is a case. In each gear, it compares the current rpm to the shift points to determine whether to stay in gear, or shift up/down.

Hmm since we have 4 ranges, for each of the possible gear combinations, I think a binary nested if-else block suffices and should run fast enough
very interesting setup there.. next best thing to variable belt drives

[Rick-906]

have you guys heard about the infinite gear transmission? it was in PopSci. it consists of two rotating discs with two spheres connecting them, and by varying the angle of the spheres you can achieve any gear ratio you desire.

i will be seriously impressed if anyone somehow gets something like this onto a robot

[Cory]

Originally Posted by Rick-906

have you guys heard about the infinite gear transmission? it was in PopSci. it consists of two rotating discs with two spheres connecting them, and by varying the angle of the spheres you can achieve any gear ratio you desire.

i will be seriously impressed if anyone somehow gets something like this onto a robot

Already been done. 190 in 2002. I believe 494 made one as well. 217 made something close to a CVT. There might be others I've overlooked.

[Rick-906]

ach its hard to be innovative in first...

i'd love to see a robot equipped with one of these in action

[mman1506]

woops,wrong thread
sorry