pic: Cobra box

[ratdude747]

Originally Posted by Jeffy

The often better way than using worm gears.

However, sometimes you really just need that worm gear or anti back-drive pins (like on a winch for hanging), but often you can get away with "passive assistance."

Just wanted to make sure this option was considered. Best of luck, it looks pretty awesome.

I can attest that passive assistance works. My team's 2011 arm had two extension springs attached to a "sissy bar" above the lower arm joint... two BB 550 attached to 1:123 planetaries were overkill, as one of the two motors was would move the arm... the two at full power would rais the arm in a second (0 to 10 ft), so in practice the the motors see at most (via PID) 70% power at any given moment.

on a side note, sissy bars also make good tilt camera mounts...