Thinking about trying out a different Hex robot...

[KurtEck]

Over several years I have been having a lot of fun with several different Lynxmotion Hex Robots. I started off with a CH3-R and then added a Phoenix, T-Hex... All of these use Hitec (non digital) servos. Originally all of these were running using Basic Atom Pros or Arc32s, which are fine processors, but I personally perfer working in C/C++. Over the last year+ I have played around and ported the Phoenix code to C. First to run on a library I hacked up for the Basic Atom Pros /Arc32. Later to Arduinos and likewise Chipkit (Pic32)... I am having a lot of fun with this and have lots of projects that I want to and will do, ...

But, I have also been interested in Robotis for a long time (even before there was a US distributer). Every once in awhile I become tempted to try out something different like the PhantomX. Still thinking about it, but had a few questions.

1) Every video and the like I have seen of the Phantom, shows it moving really fast. Can it move Slow and smooth. That is one of things that I really liked when I first saw Zenta's phoenix.

2) The Arbotix Robocontroller, uses an Atmega644p processor, which is not a standard Arduino processor. I am assuming that your configuration is probably Sanguino like. The Sanguino sites talk about installing build 0018 of the Arduino software. Are you limited to this, or can you get this up to Arduino 1.0?

3) When developing code for the Arbotix, do you normally download programs using the boot loader or ISP or I get the impression the Sanguino boot loader allows you to download over the XBEE at 38400.

Again I am not sure yet if I will do this. But it would be fun to try out the Robotis servos and then maybe update the code to be able to control it from my DIY XBee controllers, try the Phoenix code on it...

Kurt

[lnxfergy]

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1) Every video and the like I have seen of the Phantom, shows it moving really fast. Can it move Slow and smooth. That is one of things that I really liked when I first saw Zenta's phoenix.

The gait engine is actually pretty similar to Zenta's, as it is very extensible. Other than just adjusting the gait, you may find you want to a) increase the interpolation rate on the ArbotiX and/or b) turn up the compliance on the servos to further smooth out the servo movement. (By default, the AX12s are pretty snappy and want to go directly to the goal position, which can cause some overshoot when stepping them through a slower motion.)

2) The Arbotix Robocontroller, uses an Atmega644p processor, which is not a standard Arduino processor. I am assuming that your configuration is probably Sanguino like. The Sanguino sites talk about installing build 0018 of the Arduino software. Are you limited to this, or can you get this up to Arduino 1.0?

We started with the Sanguino core a number of years ago, but we actually maintain our own. We currently have releases that work up to Arduino 0023, the libraries/core that are in SVN trunk actually work with 1.0, but there has not yet been a proper release (I'm still updating PyPose/NUKE before the release).

3) When developing code for the Arbotix, do you normally download programs using the boot loader or ISP or I get the impression the Sanguino boot loader allows you to download over the XBEE at 38400.

Depends a lot on style. Personally, I tend to use the ISP -- but that's just because I like the added robustness over FTDI serial ports. You can certainly download to the ArbotiX over XBEE at 38400, but you have to manually reset the board (unless you hack on some external transistors, there is some discussion here: http://code.google.com/p/arbotix/wiki/GettingSetup, including a link to a tutorial on Adafruit). You'll want to have an ISP available if you are downloading over XBEE, as you *can* brick the bootloader.

Again I am not sure yet if I will do this. But it would be fun to try out the Robotis servos and then maybe update the code to be able to control it from my DIY XBee controllers, try the Phoenix code on it...

The exported IK is very easily modified to input commands from a new source (for instance, I';ve built several autonomous fire fighters using NUKE). You basically only have to modify the main loop, the IK is *almost* a library.

-Fergs

[KurtEck]

Thanks Fergs, I did bite the bullet and order one on Wednesday, not sure if it shipped yet as the order status still shows new... Should be a lot of fun! It will be interesting to experiment with your code base as well as experimenting running Phoenix code on it. I have the Phoenix code running on Arduinos with our without the SSC-32. The actual servo code has been slightly abstracted away so it will be fun to try to implement a bioloid version. How much work is it to support the Atmega644? My look through the Arduino 1.0 tree, gives me the impression that some of the underlying stuff is there, but it is not shown in the boards.txt file... One reason I ask, is that I am playing around with a new board design using the 644, to use in my next version of the Lynxmotion DIY remote control. Earlier I ported the code over to run on an Arduino Mega and used a prototype shield, but think it would be better with a single board. The Atmega328 does not have enough and the Atmega1280/2560 is difficult for me to hand solder, so went to the 644... More details in the thread: http://www.lynxmotion.net/viewtopic....p=80725#p80725 Thanks for the hint about programming with XBee. Yes I have an ISP. Also on the board I am designing, I have ISP plus connection for JTAG. You mentioned that the IK code should be easy to modify to allow inputs from other devices. Will be fun to see if I can integrate in to use all of the inputs from the DIY remote. One version has: 2 3dof joysticks (plus buttons), 3 sliders, 16 button keypad, ... Sounds like I have a lot of fun ahead, hopefully it will come soon Kurt

[lnxfergy]

Thanks Fergs, I did bite the bullet and order one on Wednesday, not sure if it shipped yet as the order status still shows new...

Robogames was this past weekend, so I imagine the office was short handed as both Andrew and Matt were onsite here in California.

How much work is it to support the Atmega644? My look through the Arduino 1.0 tree, gives me the impression that some of the underlying stuff is there, but it is not shown in the boards.txt file...

Please see the getting started here: http://code.google.com/p/arbotix/wiki/GettingSetup, which covers installing the custom core. As for 1.0, you'd have to use from trunk of SVN (note that PyPose/NUKE are not yet Arduino 1.0 compatible).

-Fergs

[darkback2]

I got to play with a phantom X hexipod this past summer. It is a really cool and capable hex. I was using one on which I installed a camera on a pan/tilt mechanism on the back. I also mounted a custom gripper on the front. While the tripod gate was incredibly fast on the straight, the ripple gate was by far the smoothest gate for remote driving using the wifi camera which was mounted on its back.

I was able to drive the hex into another room where I could pick up objects in the gripper and return with them to my desk pretty easily.

I found Nuke easy to use.

Getting the arbotix set up on the computer requires carefully following the directions step by step on the getting started page. Be really careful with this. I have done it several times on several different computers, and I don't think I have gotten it 100 % right the first go round yet. The good news is that I'm pretty sure it is damn near impossible to brick the arbotix so in that sense you should be ok.

Good luck with your knew purchase,

DB

[tician]

If you have an AVR-ISP compatible dongle and the port has been broken out, it is nearly impossible to brick any AVR. If you happen to mess up any of the fuses (disable the RESET pin or change to the wrong clock source), then there is still the "high voltage" programming which can override most everything to fix it.

[KurtEck]

Thanks guys, I think I received a shipping notification today So it should be here maybe Friday . Yep, I have 2 different AVR ISP's. I have the official Atmel version and one by Olimex... Thanks for the tip about being very careful on your setup. I have lots of experimenting to do! Kurt

[tom_chang79]

Crazy thing is, I saw the Phantom X bot in an older youtube video on Mechwarfare 2010... The AX-12+ actuators has always been intriguing and great powerplant for the cost...

[KurtEck]

Last I checked, the package should arrive Friday In the mean time, I have downloaded and installed all of the software. I also did download the SVN trunk to see the current stuff as I would like to get this to run on Arduino 1.0. Did not look like converting pypose and Nuke should be too difficult, so I will try to hack up a version. Will wait until I have hardware to test it with. Still learning, which is one of the main points of this. I finally realized that you don't need to install libraries into the your actual install of Arduino, but can/should install them in your Sketchbook. Likewise for Hardware, which is great. Lots of things to play with. Will be fun trying downloads over XBee. If this appears to be too slow, may be fun to build a version of the boot-loader that talks to the XBees at a higher speed. I know that the Atmega running at 16mhz will not communicate well with an XBee at 57600 or 115200, but does work great at 62500, not sure if it would be simple as rebuilding the bootloader with different baud, and changing the boards.txt file... Tom - Yes I have been following the bioloids for a long time. Used to follow the RoboSavvy forum, before there were any US distributors of Robotis. Used to be up there when I was playing with my RoboNova, which is still around here someplace collecting dust. Kurt

[KurtEck]

Quick question on directory to use to install Arbotix libraries... (Hardware is coming today ) I downloaded build-0023 of Arduino, downloaded the Arbotix stuff, put the libraries into (sketch book)\libraries. Now when I try to compile some of my own programs for Arduino 1.0, they no longer compile as the wire.h file is being used from these directories instead of the Arduino version. Can the Arbotix libraries be placed in a hardware specific location? Like (sketch book)\hardware\Arbotix\Libraries ? Will try, but would be nice to know. Thanks Kurt