We've received the first "real" pictures of the first units of SAM servos.
These pictures include the Accessories available with each servo:
SAM 140/170; versions with Potentiometer/Optical Encoder/Magnetic Encoder:
Robobuiilder SAM-140-170EO-170EM Servos
, on Flickr
The joint in the picture is the only model available at the moment.
Robobuiilder SAM-20-28 Servo
, on Flickr
We believe these are the candidates to the most popular servo model as they offer nice price/performance ratio and let you build fairly tall humanoids (about the size of a DARwIn).
The difference here is that these are only available with Potentiometer (ie there is no version with Optical Encoder).
Robobuiilder SAM-5 servo
, on Flickr
These resemble the wCK modules used in Robobuilder a lot. They have however much less torque (and slightly higher price) offering improved bus speeds.
Both SAM 5 and SAM 3 were designed to build the hand/finger structures on their TITAN robot and are noticeably smaller than current wCK servos and significantly smaller than AX-12.
Robobuiilder SAM-3 Servo
, on Flickr
This is a miniature servo (same size as SAM-5; probably different gear reduction). With only 3kgf.cm was designed to build "finger" articulations although its application is not limited to this.
It has the advantage of small size and reduced weight and retains the same high end features of other servos (same High Speed bus and Protocol) with the possibility of being daisy chained with all other (higher torque) servos.
There are some unique advantages to these servos compared to Dynamixel:
- The bus is Full Duplex
and by default Operates at 1.5Mbps
A full duplex bus makes integration with Microprocessors a LOT easier than Dynamixel.
Dynamixel, being Half Duplex, means you need to Short RX and TX on the processor and write code to filter out want you send or otherwise add hardware (Tri State buffers)
- Wider range of Servos, from 3kgf up to 170kgf including minuature servo models
: the 3kgf and 5kgf versions are interesting solutions for fingers or compact Pan&Tilt and other applications where space and weight are at a premium.
They can be mixed and matched on the same bus with all other servo models up to 170kfg.cm
- Full Metal Gears
on all servos from 5kgf.cm on.
The only exception is SAM-3 that mixes and matches Metal with Plastic.
- Finally, I believe the ratio of price per kfg.cm
will also be a factor to consider.
We've received pricing for these servos already (although we won't be disclosing it yet) and we can say they're slightly less expensive than the equivalent Dynamixel model (ie the price per kgf.cm is more competitive on SAM servos).
Robotis has also given us a heads up that pricing for Dynamixel should increase in 2012 which should make this difference even more expressive.
- The only downside I can anticipate on SAM servos is the lack of Magnetic Encoders on the lower end models.
We've discussed this with Robobuilder without great response from them (we're getting used to this from Korean companies)
Only real world experience and applications will tell if this has a significant impact in both adoption and performance.
There is no doubt that Dynamixels are the standard in this market segment and that their quality and reliability are undisputed.
We've seen attempts from other manufacturers to challenge the dominance of Dynamixels with no success so far.
Although we know and expect Dynamixels to continue being a great choice, we have hopes that these new servos from Robobuilder present a viable alternative to Robotis.
Competition is always nice for the end customer: performance improves and prices come down