True, but we're finally starting to see a few devices that aren't just variants of R/C airplane parts. The important innovation is that some of the newer servos will read back position and torque to the controlling computer. That advances control from blind positioning to force feedback.
John Nagle
Yeah, but no gears (that fit on the servo shaft) that I could find. They do have sprockets and chains, which could serve the same purpose, but in a bulkier and more Rube-Goldbergish way.
Best,
- Joe
I have also milled new bottom plates out of Delrin (a very durable plastic), adding the missing stud an allowing for the idler. It is alos easy to add a channel and cutout for the wires, so they come out at the other end.
This works great, but it is a lot of work and an new (or modified) CAD file needs to be created for every servo type. For my particular machine, I also need to do four manual tool changes, so at 20 bottom plates, I am busty for two hours and I mill away 80% of the Delrin which then becomes toxic waste.
The obvious way would be to mill a negative instead and have these plates injection molded, but again, that would be different for every servos type. Something I would highly recomend to a servo manufacturer.
Finally, there is a project on the web, OpenServo, that gives instructions, pcb layout and the firmaware to build drop-in servo electronics that are controlled via i2c (a high speed two wire serial bus, making the controller obsolete) and knows everything and anything about the servo (power consumption, own ID, position to 12 bit resolution, temperature inside the servo, etc., etc.).
To sum this up, I would generally be willing to organize injection molding and pcb production and soldering, but we would need to agree on a single servo type, and we would need to be able to organize the sale of 1000 or more servos.
Matthias
Hmmmm. They used to sell gears that incorporates splines for attaching to servos. Convenient though it's usually not hard to use a standard servo disc and just mount the exact gear you want over it.
-- Gordon
If you don't have the catalogs of
Small Parts, Inc. Stock Drive Products Berg
you should. They're full of gears, shafts, collars, and related mechanical parts. That's where you get such things. Prices are higher than in the R/C world, but the quality is higher.
John Nagle
But none of these have servo splines, so there's still that issues, and when we're talking about R/C servos, I wonder if it makes sense to spend more on the gear than it does on the servo. You can get a nice nylon or Delrin gear replacement Traxxas gear, for example, for $3-4 retail.
-- Gordon
Oops, my mistake -- I just found them via a Google search:
So this does offer a potential solution -- if your frame had all the joint hinges built into it, with a gear on each joint shaft, then you could use these to drive the joint from a servo, without the servo experiencing any lateral force at all.
Thanks,
- Joe
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