Here is a vid of a project that I am colaberating on…
Bigger that 1/4 scale…hex
Are those custom made worm gears and drives, or are they off the shelf components?
YAY!! About time someone started using worm gears! I want to see the full robot in action when its done! 
Now, why was that posted here? 
(you need your own project thread where we can fawn 
)
Someone want to tell me how he’s controlling drill motors as servos!!! 
If you have an absolute encoder or some other way to measure shaft rotation, it’s pretty easy to do it in software. This is really all that the “regular” servos do (they use pots to determine the shaft position for the most part)
If I were going to go this route, I would want to deal with somebody locally. So far, I only person here I know is local to me is Tyberius. I get the job done, but it just takes me a lot longer than it would take most others. I am also very picky about how things are done, so it’s usually just best that I do it myself.
8-Dale
sighs
I hate waiting for parts to come in… the laser cut panels for the tread boxes still haven’t come in. 
And then… I also haven’t ordered anything from mcmaster yet either, nor have I ordered anything from digikey yet…
Hmm… I wonder if this project is on the back burner for a little bit?
Of course, what I did order was a lot of SES from LM, some stuff from DE, and my first four ‘real’ servos So, for right now, my path forward is as follows:
- Build a 4 servo walker.
- Buy two more servos and maybe a few more SES stuff, and build a Brat.
- Buy three more servos, and build a 3DOF tripod.
- Buy a couple more servos and build a Scout maybe?
- Even more servos…
- Finally have enough servos to build my Phoenix kit!
Oh, and somewhere along there buy sprockets and chain and stuff for the tank…
So, maybe I will have some progress by… Christmas…
(I need to limit how many expensive hobbies I have!! this is ridiculous )
Oh, I should have mentioned, I trying Hobbico servos… Hopefully they work out for robotics. We will see after these first four come in (CS-160s, and I will be getting CS-150s for some joints as well)
Starting out with smaller projects is a great way to get to play with stuff.
You might take a look at “Loki”, the 4-servo biped that I posted on. Cut the feet parts out of PCB material, and bend up two simple brackets (maybe LM will decide to offer them).
lynxmotion.net/viewtopic.php?t=3184&highlight=
http://www.marconettengineering.com/LokiLegs18b.jpg
or maybe this one?
http://www.marconettengineering.com/joueur.jpg
A tripod? Really? That would be a really neat 'bot! Getting the Gait right might be tough. But if it could be done…
drzeus.best.vwh.net/wotw/other/gait/
Yeah, one always needs more servos.
Alan KM6VV
Below is another simple bot that you could get the needed stuff (thin plywood, bolts/nuts, coping saw, etc) from Lows/Home Depot this afternoon. Hot glue could save some time in certain places. You might even be able to duplicate the “Loki” using the thin plywood.
Not bad! Even 'tho I’m not into wood.
Guess what? The original Loki by David Buckley, I found out, WAS thin plywood!
I have drawings of the feet and parts I made. One should be able to make the parts in 1/16" aircraft plywood as well as the PCB material I used. Contact me off list if interested, or I might even post JPG drawings of the parts on the Loki thread.
You’ll have to select your own processor board (ABB?) and probably program it. I’m using C and a PIC on a PICbook PCB. It will be a while before the program would be available.
Alan KM6VV
My back burner has quite a lot on it right now, and I keep stacking more on it. 
There are so many things I want to build and experiment with. I am just focusing on MsBRAT and W.A.L.T.E.R. right now.
8-Dale
Yep, I already have a design in mind, and SES parts to do it, on order. It will be a lot like the other SES based 4 servo walkers. (not exactly of course, or that wouldn’t be fun )
As for the tripod, its going to look a lot like a normal round hex… only minus three legs. So, no legs under it like the link.
And I forgot completely about the three servo walkers! I used to make those out of LEGO :look
[Tripod] Round would be OK, but I think the legs need to be under the 'bot, as lifting one otherwise would be catastrophic. How much have you thought about it? Do you have a (game) plan?
With the legs under, I think it might be possible to shift the weight off of one leg just before quickly moving it (shuffle) forward.
Alan KM6VV
(Re, my planned tripod)
There are two camps I think in robotics:
-
Robots always have to have a ‘stable’ position.
-
Stable? Whats that!? Real life jumps!!
I am one of the people in the 2nd camp. I fully expect the bot to ‘fall’ in the direction of the lifted leg. Thats why for certain servos, I am using high speed versions, not our normal high torque versions.
I have thought about it, and I think it will be a great project while I wait for paychecks to build my bigger bots.
It certainly might fail, but there is no fun to me repeating everyone else’s success!
–
And Dale, when did it become “MsBRAT”?
She’s has pretty much always been MsBRAT. She likes to wiggle her buns and jitterbug. I am considering a proper name for her now.
8-Dale
It couldn’t be any more difficult than getting a biped to walk. Two legs down, one leg up, balanced like a biped.
8-Dale
Nah,
I wouldn’t want it to do funny balancing games like on the Brat (or Loki!). I’d want it to walk very closely to that in the GIF animation I posted. Just a little jump, perhaps.
Gotta look like the 'bots in the movie “War of the Worlds” (it was on again today).
Alan KM6VV
Yep… I was right. (I was right that I would be wrong, that is )
http://www.siennahanon.com/Robotics/bb_failed_tread_1.jpg
It seems I overestimated the length of the track by just shy of 2 track segments… Drat!
And, somehow I got the ends rounded at the exact radius of the flange on the 9 tooth sprockets. Don’t ask how that happened, it certainly wasn’t my intent!
that must be frustrating!
I’m writing some software to solve for the location of the sprockets relative to one another for a given length of track and tread configuration. Nothing special, just something quick and dirty so I can see different configurations without having to recrunch the numbers each time. If it ends up working like it should, I’ll post it
Since one doesn’t have fine control over the tracks, get the tracks and then tweek the frame to fit them.