ArbotiX Beta 3 Released!

It's finally here! PyPose V0.91 is a complete rewrite of the software, using wxPython as the GUI package. It's world's better than the old release.

One of the great new features is that we finally have a sequence engine.

Features coming later this week (hopefully):

• Live sequence playback
• Drop-down selection of serial ports
• Pose & Capture over a USBDynamixel
• Encoders library

All of these features have been in the works for a bit, just need finishing touches. I'll also have a video shortly walking through the whole process of creating poses and sequences to make a little droid walker.

-Fergs

Issy Goes Fire Fighting

I've been talking lately about building a walking fire fighter, but I've now finally started transforming Issy from a mech into a Fire Fighter.

Issy's new body is about 2" shorter in both the width and length direction, a necessary adjustment to get him under the 12"x12" rule (yes, I know the Trinity contest allows walkers to be 12"x18", but I intend to take Issy to CNRG, and possibly RoboGames next year, and neither contest has a walker division, so the 12"x12" rule had to be followed).

Issy has a head similar to what I had on GMR. The head has an IR ranger for 99% of his navigation, a sonar ranger mainly for approaching the candle (since the IR gets wiped out), an IR photodiode for fire detection (similar to Crater's sensory), and a ducted fan for fire extinguishing. Issy is sporting a new arbotiX robocontroller, and power is from an 11.1V 2200mAh LiPO. Early tests with IK have shown quite a bit of promise as far as odometry from walking - I've still got a ways to go as far as implementing a geometrically stable gait.

Issy's code will basically be another rework of Crater's (cause heck, it works).

-Fergs

Bioloid Build Tips, #2

The Bioloid kits from Robotis are amazing. They're an excellent prototyping tool, but there are also a few improvements that could be made. My biggest gripe (and I think most people agree), are the tiny little screws... eesh. 2MM phillips heads are not fun. I've taken to replacing all of my screws with socket head cap screws, this lets me use a hex driver during assembly, and saves a ton of time. Unfortunately, each screw will run you $0.03-0.07, but it's well worth it in the long run. I've been buying my 2mm SHCS in 6mm and 10mm length, and also 3x10mm for the big screws opposite the servo horn, from McMaster-Carr:

M2x6mm: http://www.mcmaster.com/#91292A006 (the most common ones you'll need)
M2x10mm: http://www.mcmaster.com/#91292A011
M3x10mm: http://www.mcmaster.com/#95263A134

These fairly cheap upgrades save a lot of time, I think I've cut the amount of time spent on assembly by at least 50%. Just make sure you have a GOOD set of hex drivers.

-Fergs

Bioloid Build Tips, #1

How to install nuts in the servos:
Line the nut up, use a flathead screwdriver to push the nut into place.

-Fergs

arbotiX Prototypes

The first full batch of arbotiX prototypes is finally done after a summer of development and testing with the 2 original prototypes (1 of which was used in IssyDunnYet, champion at Mech Warfare 2009).

While prototype boards have gone out to early adopters, we're still working on some of the desktop software. A V1.0 release of PyPose is expected around late September, or the same time that boards should be available from Trossen Robotics.

More information can be found here.

-Fergs

Report from Robogames

Robogames 2009 is now over. Both of my bots faired quite well.

IssyDunnYet, my entry into the inaugural Mech Warfare event, won the gold medal. We didn't ever get in a real ladder competition, too many bots had major issues, but Issy really did quite well in all of his matches. I've posted a tutorial on how Issy was built, over at the Trossen Robotics Community.

GMR made another appearance, taking second in the Fire Fighting Competition. I'm not too disappointed about that second, he lost to a team from an Indonesian University. They were greeted at home by the Minister of Education apparently. GMR was using a reworked version of Crater's code, including head panning and all sorts of other audience pleasers....

-Fergs

UPDATE: I've posted a tutorial over on the Trossen Robotics Community, that walks through building IssyDunnYet, and is a fairly good reference on building an AX-12 based mech:
http://forums.trossenrobotics.com/tutorials/build-articles-130/build-your-own-issydunnyet-3257/

Viva La Crate

Trinity 2009: What a whirlwind... It was not the weekend I had expected.

The Green Machine Reloaded won the poster contest. I finished first in the Olympiad. But then the wheels fell off the whole operation... GMR didn't complete a single of his competition runs on Sunday. I was disappointed to say the least.

While I'd spent countless hours working on GMR, on the side I had built Crater, what was supposed to be a contender for the low-cost prize. I didn't expect much from a robot built out of $118 in parts, built out of a small crate, using a single distance sensor. He was slow. Really slow. Like almost slow enough that the judges would fall asleep. But he ended up being reliable. Really reliable. He finished all 3 of his runs. He hit the candle each time, which make his scores appear to be even slower (who knew such a thing was possible).

The senior division was split between 2 arenas for competition day. Crater's score was 3rd on the leader board, then 5th. It then became apparent that our arena was running quite a bit faster than the other arena, even though all three of Crater's runs were over, some bots in the other arena had only made 1 run.

As the afternoon continued on, bots in the other arena failed their runs. Suddenly Crater, was back to third on the leader board. But wait! That includes both robots in the Unique and Kit division.. a quick look at the entry list. #1 and 2 on the leader board are KITS! Crater, the cheap, slow, really slow, painfully slow robot had won the Senior Division. He outperformed robots that probably cost 10x as much. He outperformed robots that probably got 10x as much attention from their creators. As would be expected, Crater also won the cost-effective prize. His 189 second final time for three runs probably couldn't have won any other year in the past decade, but this year it worked just fine.

I should have noticed something going on Saturday. The "crate on wheels" was hugely popular.. the little green guy got almost no attention (his custom controller board, and wireless debugging turned some heads, but he got no love...). There's just something people like about animating everyday objects. His moving head, required by his lack of sensory, was also popular.

This just further exemplifies, that reliability generally trumps speed in robotics, and that reliability in robotics is really hard to come by. And of course, if the robot can look cute or anthropomorhize itself all the better.

-Fergs