23 DOF Project. Which platform? AT-01, Bioloid or KHR-1HV

[NullARC]

I'm sure, by now, most of you have heard of the Cycloid II by Robotis, from the same people who brought us the Bioloid. (if not, look here http://www.tribotix.com/Products/Robotis/Robotis.htm )

If you have seen the videos of this biped you also know that it has 23 DOF and is capable of some great movements. (videos: http://www.tribotix.com/Videos/Videos.htm click the 'Robotis' tab at the top of the page) Unfortunately it carries a reported $20,000 USD price tag! Well out of the reach of most hobbyists / experimenters budget.

I would like to build a biped similar to the Cycloid with 22 or 23 DOF. This brings me to the question, which robot kit would be the best platform for this project? The Manoi AT-01, Robotis Bioloid or the new Kondo KHR-1HV?? I guess the most important aspects would be (1) servo torque, to carry the additional weight of 4 to 6 additional servos. And (2) ease of construction with existing parts. (3) I also want it to be powerful enough to execute EMMA-U0A's 'standing up' maneuver. It can be viewed in the video at the bottom of this page: http://www.robots-dreams.com/2006/12/em ... .html#more VERY COOL MOVE!!


As I see it, here are the pro's and con's of each biped for this application:


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Robotis Bioloid:
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Pro's:

1. Similar construction method to Cycloid. (uses same bracket system, though in aluminum)
2. Additional servos only roughly $50.00 USD.
3. Servos have 300 degree rotation range.
4. One has been built already, though it has not been tested yet. Look here: http://forums.tribotix.info/forum1/54.html
5. Comes with 19 servos out of the box.
6. Great price Approx. $900.00 USD.
7. Servos created for robotic use, with many more features than other standard biped kits.

Con's:

1. Currently no gyro support for added stability.
2. Relitively low torque servos (16.5 kg/cm). Though higher than 1HV & AT-01.
3. Higher torque servos (DX-117's 28 kg/cm) are approx. $195.00 USD. ouch!
5. Would need M5 controller board if upgrading to the 14.4v DX-117 servos. ?? not sure ??

Additional considerations:

The little brother to the Cycloid II, the Cycloid III, uses DX-113 servos listed at only 10.2 kg/cm and seems to work fairly well though obviously over matched in a bout with a Cycloid II. (video of match can be found at link above) So servos with a torque of around 10 to 15 kg/cm might be adequate.



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Manoi AT-01:
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Pro's:

1. Can be upgraded to 21 DOF fairly easily. (tempusmaster states that manual has instructions for adding 4 DOF arms / legs)
2. Has gyro support.
3. Additional KRS-4024 HV servos only roughly $60.00 USD.
4. Can be easily upgraded to KRS-4014HV servos for a massive 40 kg/cm torque!
5. Servos have 260 degree rotation range.

Con's:

1. KRS-4014 servos cost approx. $145.00 USD. again, ouch! (though less than DX-117's)
2. Servos only have a torque rating of 10.5 kg/cm. Is that enough??
3. Only comes with 17 servos out of the box.
4. $1,500.00 USD Price.

Additional Considerations:

Has the advantage of being created by some of the best minds in the RoboOne / biped world!!



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Kondo KHR-1HV:
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Pro's:

1. Comes with 19 DOF out of the box. (with 2x KRS-4024HV servos)
2. Has gyro support.
3. Additional KRS-788HV servos only roughly $50.00 USD.
4. $1,091.00 USD price. (according to Trossen Robotics Blog http://blog.trossenrobotics.com/index.php )

Con's:

1. KRS-788HV servos only have a torque rating of 10 kg/cm.
2. Servos can't be upgraded to higher torque.
3. Additional frame pieces would have to be manufactured.
4. Who knows when Kondo might release it??



Ok, that's how I see it. I can't make up my mind though!!

This is where you come in! If I have missed something, or something is wrong, PLEASE let me know.

And finaly WEIGH IN on your vote for the best platform for this project and why! I WANT YOUR OPINIONS!!

Thanks for your time and expertise everyone!!

- Marc

P.S. - I have posted this in the Kondo & Bioloid discussions for a broader range of opinions. Sometimes 'Kondo guy's' just say Kondo and sometimes 'Bioloid guy's' just say Bioloid. Know what I mean?!?!

[tempusmaster]

1. Can be upgraded to 21 DOF fairly easily. (tempusmaster states that manual has instructions for adding 4 DOF arms / legs)

I probably wasn't clear enough in my description. Let me clarify things a bit. The documented upgrades are-

Arms: Replace a plastic arm segment with a KRS-4024S-HV servo plus a few other small stock pieces and some screws. This results in an addition DOF for each arm.

Hip: The stock body is disassembled slightly and a single KRS-2035S-HV servo is installed between the two assemblies. This provides hip rotation, not an additional DOF for each leg. Just as a side note - EMMA has both hip and leg rotation.

In total, the AT01 can be upgraded from 17 to 20 DOF without any frame mods. I've heard about some owners doing additional, non-stock hacks to add additional DOF but haven't seen any of them in person yet. The Kyosho Athlete Humanoid Cup is next Sunday, so we'll be able to see first hand what people have been up to.

[NullARC]

1. Can be upgraded to 21 DOF fairly easily. (tempusmaster states that manual has instructions for adding 4 DOF arms / legs)

Hip: The stock body is disassembled slightly and a singe KRS-2035S-HV servo is installed between the two assemblies. This provides hip rotation, not an additional DOF for each leg. Just as a side note - EMMA has both hip and leg rotation.

Ok, I get it. When I was reviewing the AT-01 manual I couldn't find the instructions for the 2 extra DOF. This makes more sense. Still the hip rotation is great. Hopefully adding the leg rotation won't be too hard.

What do you think tempusmaster, how much torque would be needed to execute EMMA's 'stand up' move? Also, on Robots-Dreams it mentions that EMMA uses GWS servos. Do you know where I can find documentation on these servos?

Once again thanks for your time and expertise!

[tempusmaster]

1. Can be upgraded to 21 DOF fairly easily. (tempusmaster states that manual has instructions for adding 4 DOF arms / legs)

Hip: The stock body is disassembled slightly and a single KRS-2035S-HV servo is installed between the two assemblies. This provides hip rotation, not an additional DOF for each leg. Just as a side note - EMMA has both hip and leg rotation.

Ok, I get it. When I was reviewing the AT-01 manual I couldn't find the instructions for the 2 extra DOF. This makes more sense. Still the hip rotation is great. Hopefully adding the leg rotation won't be too hard.

The option sections are towards the back of the manual, after all the body shell preparation. The exploded assembly drawings and parts list make it pretty straightforward to understand.

What do you think tempusmaster, how much torque would be needed to execute EMMA's 'stand up' move?

Not that much. Keep in mind that EMMA is pretty short and light. Since torque is force*distance if you keep the size small enough then you can really decrease the necessary torque. That's how Takara/TOMY was able to design their tiny biped and keep the target price under $350.

Also, on Robots-Dreams it mentions that EMMA uses GWS servos. Do you know where I can find documentation on these servos?

Nakano told me the servos are GWS Micro-MG 2BB. Here's the GWS webpage with the specs-

http://www.gws.com.tw/english/product/servo/micro.htm

Once again thanks for your time and expertise!

You're very welcome. Feel free to point other robot fans to Robots Dreams if you think they would be interested.