Hey everyone, I was one of the people that spent some time beta testing the Arbotix, and I thought it would be a good idea to start and "ultimate" thread for it. I have noticed that there are several people that have already bought an arbotix, and from the sound of things they are having a lot of fun with them. I personally think that this board is awesome, and cant wait to see what projects people come up with using it.
I have been working on getting a mech ready for next year, but I haven't had much success with my previous designs. I got bored today and threw this bot together in a couple hours. I haven't had much time to do any walking or anything but I figured I could post a few little videos of what I have so far. Please excuse the fact that this thing looks like a mess, its not a very good layout and I hacked it together pretty fast. Hopefully I will have it looking a little better in a few weeks.
Anyway, please post your thoughts on the arbotix, your questions, and at least a link to your arbotix based projects on here. Above all keep building!
I just got a chance to work on my mech over the weekend, I changed a few things up as far as the leg design goes. What I really wanted everyone to see was some poses being exported to the board, as well as using some of the boards IO. I basically have three ir sensors hooked up and poses are triggered when and IR sensor detects something in front of it. For some stupid reason I was having trouble getting the poses exported properly but after a little sleep my brain started working better and I got things going.
I just sent a PM response about the protocol used by PyPose, and how to connect using a custom application, so I figured I would copy my response here for all to learn from:
Quote:
All of our programs are open source. If you have the PyPose program -- you already have the source. Python is just a scripting langauge, open PyPose.py or any of the .py files in a text editor and you'll see. (alternatively, you can browse the source on arbotix.googlecode.com, click on Source tab).
The TEST command is basically our in-house way of checking out an ArbotiX before shipping it. To trigger it, send out:
0xff 0xff 253 2 25 231
The protocol is the same as talking to an AX-12 itself (basically, the PyPose sketch acts as a bus pass through, or, given special instructions, it executes commands). The first two 0xff are the header for the packets (just like an AX-12 would recieve). The 253 is the ID, your servos are IDs 1-X, 253 tells the arbotiX this packet SHOULD NOT be passed through, and that it instead should interpret the packet itself. 25 is the instruction (arbotiX test or ARB_TEST). The 2 is the length of the packet (see the AX-12 datasheet or the PyPose.py source for details, but general format = # of parameters + 2, test takes no parameters). The 231 is a checksum (255 - ((id + length +instruction + any parameters)%256)). All of the other special arbotiX commands, such as loading a sequence, loading the poses that are part of a sequence, or playing it, follow this format.
Also, for fun, here's a quick video of early work on my Salamander-inspired walker, Sally:
Hey man, Sally looks very nice, cool gait too, show us more! (also, if i may ask, can you currently show anything from NUKE yet? i'd love to see how that goes, did you use it for sally?)
Last edited by Suicidal.Banana; 11-09-2009 at 07:55 AM.
Hey man, Sally looks very nice, cool gait too, show us more! (also, if i may ask, can you currently show anything from NUKE yet? i'd love to see how that goes, did you use it for sally?)
That's all there is to show right now -- Sally just got up and running. It's all pose and caputre (6 poses for that forward walk). I'm actually not certain at this time if there IS a closed form solution to the IK for Sally. There's a few issues that need to be worked out before continuing with the bot, those Lynxmotion tubes are shaking themselves loose as the bot walks and I'll need to do some serious weight distribution work to get it to walk on surfaces like carpet.
As for NUKE, there is an image of the GUI in the PyPose documentation. The program is basically converging from two ends: there's the GUI that's mostly done, and there is the actual IK and gait generating code which is also mostly done, and then in the middle is the meshing of the two -- which is where most work is now needed.
Okay thanks for the info on PyPose/NUKE, good luck on that middle part (ye i recently ran into the gui pic, which caused me to ask about NUKE ) and nice job on achieving that walk with 'just' pose usage, 'props' man.
Sthmck and I got a chance to sit down and run the pre-alpha version of NUKE on his quad, Jeff, this weekend at the Canadian National Robot Games. In about 30 minutes we had a full IK solution customized to his bot, and a default gait. Since we only started about an hour before the competition, he didn't have time to get the sensors attached to the bot, so he used just dead reckoning -- here's the third and final run, with a time of about 49s, which took third place behind Issy and Roz, two other arbotiX/NUKE powered robots.
) and nice job on achieving that walk with 'just' pose usage, 'props' man.
Linear Mode
