pic: 2399 Inspired Octocanum Module -- Looking For Feedback



2399 Inspired Octocanum Module -- Looking For Feedback - CAD - Chief Delphi

Great Job!
Compact and with 2 wheel speeds.

Can you post some additional pics showing the rotational point.
What gears did you use?

Dave

Sure, I’ll post some additional pics soon, but it basically just rotates around the colson hex shaft. As for the gears, the cims gears as 12t, the main center gear is 72t, the one from the main gear to the mecanum is a 48t, the two that go to the colson are 44 and 60. Gives us ~20FPS on the mecanum and ~6 on the colson.

Cool!
I don’t really see where the clevis of the pneumatic cylinder will go? I like that the colson shaft gets reused as the pivot and loss of pressure will drop you into pushbot mode.

Personal preference - I hate shaft collars, they’ve failed me too many times. Machined flanges with undersize bearings, threading the end for a 1/4-20 bolt, even (shudder) e-clips and retaining rings with in-tolerance retaining grooves all have worked better.

Watch out for high-current-draw issues running 20fps on the mecanum wheel - those systems use a surprising amount of torque, you might want to get some reliability testing in or plan for current limiting on the CIMs (easily done on Talons, harder on simple PWM controllers).

The diameter of your standoffs combined with all the cantilevered gears make me nervous about the stiffness of the case to react your gear loads, but that’s probably because I tend towards the overbuilt side in transmission design. Ultimately you only need it to last about 6 hours or so, after all.

The CIM rings don’t appear to actually add any stiffness (*from what i can see in this view), but they sure are pretty. I’d take them out and increase my standoff diameters, as a design exercise you could consider going tighter tolerance there, and adding a bolt to lock the CIMs into place. Either as a single piece that flexes like a shaft collar, or as a separate yoke that bolts down onto the back gear plate. In any case - trying to get more stiffness out of the setup will be a dangerous game, if you’re not careful you’ll just overconstrain the motor and tear up the pinion gear. Maybe with a rubber or foam gasket to add some compliance?