Dyne's LD-F1 (D-O concept) build

[Dyne]

I installed the parts to do some testing, as you can see just below the black bogie carrier arms either side of the main body.  In the process, I discovered that they are somewhat sensitive to the diameter of the hole for the M5 bolts. Too wide and it will likely easily spin around the bolt. Too narrow and the precise threading of the bolt in the hole matters -- whether it self-taps or you tap the plastic manually, if the threads don't align with the threaded insert at the right point, the bolt won't be tight when the part is at the correct angle ... so either the angle will be wrong or it will be loose and the belt tension will make it spin in the threaded insert instead.






To be honest, while it certainly had an effect, I'm not sure how significant of an effect it is. Trying to turn the droid on carpet now sometimes causes the power draw to exceed the current limit I'd set on my power supply (a relatively low 2 amps), which was not previously happening.  That tells me the belts are staying engaged a little bit longer instead of immediately skipping teeth and letting the motor freewheel when more (mechanical) power is needed.  Consequently, the current draw to overcome the motor's stall can go higher than it was going before, hitting the max I set.**

On the other hand, it still mostly ends up skipping teeth instead of turning (or accelerating too quickly), regardless whether I'm using the actual battery or a raised max current on the bench, so it's not a huge improvement.

On the gripping hand, the carpets I'm testing on do have deeper piles than the carpet at e.g. dragon con, so it may still improve things in the real world.  Due to weather, I have yet to test it outdoors on concrete, which is another situation where it sometimes skips when turning, albeit not as often.

I could maybe continue tweaking this part to add more tension, but beyond that the logical next step I see is to switch to a chain drive for the second stage. I know little about chain drive hardware beyond that it would likely mean integrating off the shelf sprockets into my intermediate and drive roller parts. (I suspect printed sprockets wouldn't cut it, though I've been wrong before.)



** I'm not sure what the stall current on these things is supposed to be.  Specs have always been hard to find in general because iflyrc's website is terrible, and I believe the product has since been discontinued so the semi-broken page I knew about has also been removed.  I had to resort to the internet archive copy.  I'm just going to screenshot that here for posterity in case I haven't already done so somewhere else: