This is my first post this year as myself (PedroR) so HI to all of you. FYI I've been doing some posting under 'Robosavvy' in the last months but this is the first one (and an important one) as PedroR again.
To the point of the post, Robobuilder has finally released the Official brochure and details about a new line of their servos.
http://robosavvy.com/RoboSavvyPages/Rob ... LDER-3.pdf
The servos include important and relevant features, and are real competition to the Robotis offer:
- 32 bit processor
- RS232 Full Duplex or RS485 Half Duplex interface. (as far as I understand the same model can do either one or the other).
This means 4 wire connectors (2 for power and 2 for data: RX, TX using RS232 and a differential pair (2 wires for half duplex) using RS485)
- We have also been told there is a proper current measurement chip onboard which offers a very linear relation between current and force. (see the image bellow).
This is something requested in Robotis servos for quite a long time
- Servo torques up to 150kfg.cm
- Speeds of up to 130~140rpm (check the base SAM-7 with only 7kg but 130rpm which is quite an upgrade from the wCK 1108 at only 55 rpm I think)
- Advanced Encoders including Optical and Magnetic for much higher resolution
(on this front one thing we weren't thrilled about was that these are available only for the 150kgf.cm version; we'd like to see at least optical encoding in the 110kgf.cm version and maybe on lower torque versions as well).
- There seems to be a new Protocol (or at least extended) according to the docs we got.
- Servos will ship with Joint sets and the joint assembly will be the preferred mechanism during the release phase. (Metal brackets _may_ be released later.)
Personally I I believe this is a good approach as Joints allow for Rapid Prototyping and projects for high end applications usually have the frames designed and manufactured to their own specs.
- Finally, one of my favorites, the GPIO port is now exposed externally on all servos so each servo can receive an A/D sensor (readable via the protocol) and includes two DIO pins.
The current (and cheap) wCK modules already include such a port, fully supported by the protocol, but it's hidden inside the case and hard to use which is a pitty.
Graphic Showing Current Measurement versus Load feedback reported by the Servo protocol.
According to the information we received, servos have an onboard current sensing chip.
I leave the discussion open for your thoughts and opinions.
Have a look at the brochure
http://robosavvy.com/RoboSavvyPages/Rob ... LDER-3.pdf
as it seems to promise quite a lot.
I've also personally got a lot of expectation about the new Roboard 050 so it could be quite a cool project to combine these with this new Roboard model to build a custom Humanoid.
We're also doing some work here at RoboSavvy with Gumstix as well which can also be a nice option.
Pedro.
Statistics: Posted by PedroR — Fri Mar 18, 2011 7:26 pm
]]>