Progress of actuator design

Did you get your Lua code to work yet?

Hi

I have the older code working now, still struggling with the new. My newer pcb with almost all smt on one-side was ok, the pad was not too close to the via. I have moved it a bit further away though, so i’ll get the pull request updated.

Wow! Is that flex spine gear printed via DLP process?
Really nice! only thing I would have concerns about would be that the hinges will keep the tension under torque without breaking. But the idea is great!
If my steppers could provide more torque this would be an idea to improve the toothplay of my gearchains, too.


Thank you for sharing!

MechaMind

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Here’s a technique (not sized in this application for your needs!) that does not put the encoder at the center; it uses a ring-shaped diametric magnet:

John,

Deciding on print settings and material for my final version of actuator prints. What is the max rpm that your code it going push the small actuators too? I want to test at that RPM.

I have a PLA version working fine, it takes a lot of gear tuning though.

I also got a 100% (Gears and body) Nylon version going, no work on the gears at all, works right out of the printer. I am leaning towards going 100% nylon for the actuators, for the finished product . Only concern is the collector arms are pretty flexible.

Can you foresee anything wrong with that?

Completed a couple proto runs on assembling the actuator circle, finally happy with my resistor soldering technique, and overall quality. Going to go into production on the boards for the finished product.

Looks like there has not been any changes to your design posted on Git Hub in the last two months, correct?

I tested the BOM motor from moons and from Ali, seemed like the motor from Ali got hotter, but also did not stall as often. I ran them both at 20V, did you wind up with a preference on motors between the two?

Thanks,
Rod

I found that I went back to PLA after trying PETG. Ultimately I think they both work fine. This actuator does not do high RPM. I’m more interested in precise movements anyway. On the final output I think you only end up with maybe max 20 RPM.

I have not posted much code lately as work has been consuming me, but it’s all up there for folks to play with and even modify or extend. I’m all for pull requests too.

On the motor getting hot, what current setting do you have it at on the DRV8825? I use a banggood power supply that shows me the mA and I would run the motors around 250 to 300mA.

Okay, I think I have good enough prototypes, had been testing them to 300 RPM, haha, any missteps/stalls were happening at over 200 RPMs. Was setting Vref to .4 so theoretically 800mA, will tune that down.
Thank you John.

2 posts were split to a new topic: Help getting started with (metric) robot arm actuator?