Servos with feedback, next generation stuff

[Mjolinor]

https://www.youmagine.com/designs/dc...gn-information

[Marm]

Explain to me how this is an improvement? I've seen servo's with feedback feeds for a while now. Is it the fact that there is more power than a normal servo? Watching the video, I see all the drawbacks of servos and DC motors in one, with few advantages aside from power. Isn't a stepper a better choice here, as steppers are supposed to lock into place? I'm not seeing the point here, please enlighten me.

[Mjolinor]

No reason to not still use steppers if you prefer. The advantage is in absolute positioning, not relative so a missed step cannot ever happen. The other big advantage is speed. A well tuned PID controller can move like greased weasel droppings and stop on a pin head.

[truly_bent]

Wow! Is that ever a great find. A dirt cheap servo with 888 line encoder feedback. In theory, that could mean 3552 (888*4, quadrature) pulses per rev. That far surpasses the (actual) resolution of steppers at 200 ppr. I was surprised to see the price of the little motor at $5.98 ea., including the built in encoder. Have to wonder how durable those little puppies are, but since they're intended for toys, they might just be fine. Someone will no doubt design a proper housing to protect the encoder disk.



Motors are pretty high speed:
5V, 60mA, 1600rpm
12V, 80mA, 4300rpm
24V, 120mA, 8600rpm

I wonder if the Arduino program has any provision for ramping...

[richardphat]

I call a farce on that price, last time I tried to buy from the germany, the strip alone in my quote worth 30+$ just for the strip and rotary plastic ....

Ruhlatec something, unless I've been completely screwing by browsing, but 5$ for that ammount of LPI is really cheap.

Alternatively, I've taken habit of scraping encoder printers and their motors. I end up accumulating encoder.
Just beware though, finding the pinout is a pain in the butt.