@cloudcake8

finally figured out why my 2 phases werent looking right

so the feaaturescript im using to generate the cyclodial profile only generates it with one tooth fully “in”, making it so that if i want another disc exactly 180 degrees out of phase, i need to have an even amount of pins and an odd amount of teeth for it to work

so instead of 16:1 i’m running 15:1

and im switching from 2 bearings to 1 pressfit bearing because i thought about it and there really isn’t any thrust forces present in the gearbox so its probably fine, i might add some sort of bearing retainment though just in case, otherwise its just going to be retaining compounded in

ok so i want to run ball bearings for all of my pins on the cycloid, did some preliminary research and right now with my cycloid disc setup it would have required 196 individual bearings (but i think i can get it down by a lot by narrowing my cyclodial discs)

theres a lot im confused about but im working it out slowly, specifically how do i make sure my output shaft is strong enough to support a whole joint

figuring out what motors and how the structure of the gearbox will look like

doing some research on motors, i am choosing the WK8110 frameless outrunner
frameless because i want to fit a cyclodial reduction inside of it (mini cheetah style)
outrunner because they have more torque (i am trying to target high torque without too much of a reduction ratio so i can have some backdrivability so whatever joint this is on acts as if its connected directly to the motor, hence the “quasi” direct drive)

i think i’ll also use some cheap motor controller, most likely a simpleFOC board of some sort (aliexpress clones), because they are super cheap and i think they should be good enough for at least testing on a desk. if i do testing and they explode on me or can’t handle the current or something, i’ll splurge on some vesc based motor controller OR maybe an odrive board (or odrive clone on aliexpress) for the complete robot of whatever i’m making (quadruped?)

i’ve found i want to target around ~16:1 for the ratio, because lowkey these motors have like no torque from their spec sheets so i need a higher ratio than ideal (to get all the benefits of “quasi direct drive” its ideal to have a lower ratio so its a more direct connection to the motor kinda), this ratio should get me around 40 ish max nm of torque (woah! lowkey a lot!) so maybe i can do some jumps or something if the robot is light enough

not sure about what encoder setup i’ll use,
did some digging on amazon for bearings and bushings to support everything, i think i’ll do m4 or m3 sleeve bushings for the outer pins and the inner pins, and some random bearing for the inner eccentric bearing
and i’ll support everything with massive bearings so that the outrunner is properly alligned to the stator (need to find 90mm id bearings that arent really expensive, or figure out how to package cheaper smaller bearings to constrain the motor)

i just spent a lot of time thinking about how everything will package and rotating around the model to think about it from different angles

not sure what material i will do the cycloid discs out of (probably just 6061 alu, laser cut from some online service), and for the enclosure i think i’ll do some nylon composite filament for strength and heat resistance (or maybe just PLA for this prototype)

otherwise, i think this session gave me a pretty solid mental image of what the whole actuator will look like and i’m excited to design the rest of it