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View Full Version : pic: ARJ-101 full view

asid61
11-05-2016, 08:59
[cdm-description=photo]43822[/cdm-description]
Ari423
11-05-2016, 09:00
This looks really cool! I would very much like to see the CAD for it so I can get a closer look.
Basel A
11-05-2016, 10:29
Awfully difficult to tell from this view how possible it would be, but you could introduce more reduction using a planetary gearbox, which would also give you a larger shaft to work with for the ball shifting. Of course, that would increase the footprint substantially.
Kevin Ainsworth
11-05-2016, 11:07
Cool stuff. Sometimes ideas that you decide are not feasible later get you thinking about other ways to do what you want. Our in wheel swerve design from 2014 got more attention than our coaxial from 2015, but was heavier, only a single speed, made speed feedback difficult but still everyone liked it better because it was different from the norm. I am now on the coaxial bandwagon since sensing wheel speed and shifting are very difficult with distributed swerve designs. Getting the motor power wires and the pneumatic lines for the shifter cylinder through the steering pivot without requiring steering limit stops would be an issue. Your designs have come a long way and its been fun watching them progress. Keep going and show us something revolutionary!!!
nathannfm
11-05-2016, 11:27
If you use a planitary you could shift like they do in hand drils by engaging or disengaging some of the ring gear.
asid61
11-05-2016, 13:22
This looks really cool! I would very much like to see the CAD for it so I can get a closer look.

CAD is in the 2015 offseason release: https://workbench.grabcad.com/workbench/projects/gcBvYbFAI7TQYHiKMOq7jiSQVQxuTYPyTAXwhy5IZUFIGK#/space/gcvLTQUiZ-c9-szjJsPH3WvpxdeKOB9B1Z2b-tQWAq3gUh
Look under CIMshift -> 101 to find this assembly.

Awfully difficult to tell from this view how possible it would be, but you could introduce more reduction using a planetary gearbox, which would also give you a larger shaft to work with for the ball shifting. Of course, that would increase the footprint substantially.

This is a planetary shifter, actually. You shift between just a 72:25 (?) reduction and a 72:25 x (60:20 + 1) double reduction, by tying the second planetary to the first one.

Cool stuff. Sometimes ideas that you decide are not feasible later get you thinking about other ways to do what you want. Our in wheel swerve design from 2014 got more attention than our coaxial from 2015, but was heavier, only a single speed, made speed feedback difficult but still everyone liked it better because it was different from the norm. I am now on the coaxial bandwagon since sensing wheel speed and shifting are very difficult with distributed swerve designs. Getting the motor power wires and the pneumatic lines for the shifter cylinder through the steering pivot without requiring steering limit stops would be an issue. Your designs have come a long way and its been fun watching them progress. Keep going and show us something revolutionary!!!

I can totally see that. Personally I did like your CIM-in-wheel, but aftermaking some of my own decided the weight and space weren't worth it.
Thank you!

If you use a planitary you could shift like they do in hand drils by engaging or disengaging some of the ring gear.

See above. However, if I were to just disengage one set, the spread will be very low; I'll be moving from a ratio of 4:1 to 5:1, or 3:1 to 4:1 just because of the way planetaries work.
cad321
14-05-2016, 21:57
Would the shifter built into the cim shaft not be considered modification of the motor? I suppose you could argue that if you can put a flat on a shaft, machining a few extra holes in it wouldn't be much different.
roboruler
14-05-2016, 22:02
Would the shifter built into the cim shaft not be considered modification of the motor? I suppose you could argue that if you can put a flat on a shaft, machining a few extra holes in it wouldn't be much different.

R30 A. The mounting brackets and/or output shaft/interface may be modified to facilitate the physical
connection of the motor to the ROBOT and actuated part.

If the output shaft can be cut down to a stub, to inteface with a Versa-planetary, a few holes isn't an issue.

If would be quite interested to see how something like this would hold up under operation, it is a relatively thin shaft, and drilling holes is going to weaken it considerably
asid61
14-05-2016, 23:55
If the output shaft can be cut down to a stub, to inteface with a Versa-planetary, a few holes isn't an issue.

If would be quite interested to see how something like this would hold up under operation, it is a relatively thin shaft, and drilling holes is going to weaken it considerably

Basically this whole design was based off R30 A. :P
I doubt this would hold up as I'm removing most of the material in the CIM shaft, but given that each CIM is only driving one relatively small wheel, it might not be too bad. I didn't bother to do the calculations before because the radial holes for the balls screw up traditional torsion calcs.