Here’s a robot I’ve been working on recently. I used the Lynxmotion 3" tracks (3 sets) with their idlers and sprockets. Side plates for the tracks were drawn up in Bobcad and cut on a Tormach cnc center out of Mic-6 aluminum for the inner plates and 5052 for the outers. I made the rollers which support the track between the sprockets from .750 solid round pvc material. Each roller was machined to accept two ball bearings pressed onto a .250 standoff 2.5 inches long (hard to find stand offs 2.5" long. Hint hint Lynmotion… 
) The base is machined out of Mic-6 aluminum plates .5 thick and hollowed out to make things lighter. The upper section of the base is 5052 aluminum panels which are easily removeable to gain access to the electronics.
The motors are IG42 24vdc planetary units, motor torque is 18 kgf-cm which seems to be plenty to speed the robot along. I used two 12vdc Nimh batteries rated at 4500mah for the motors through a Sabertooth 2/12 controller. The motors pull less than 3 amps each so the combination works great!
The head houses a hi-res camera and 500 mw video transmitter on one side and the other side holds the battery for the video needs. The head sits on a 1/4 scale servo for tilt and the base is driven by a small gearmotor for pan.
Behind the front drive motors is a small rotary disk which is mechanically tied to another 1/4 scale servo. This will be for a future use.
Right now, I’m using a Futaba 6 channel radio to drive the robot around. The kids have nicnamed him Wall-e and said I need to add some arms. I guess that will be the next project. :mrgreen:[attachment=2]1.JPG[/attachment]
Looks really nice.
It would be great to see a side view showing the tracks.
Kurt
WOW! A bit of a monster, well designed and very nicely executed. I would really like to see some video of this in action. Do you have some specific purposes or goals for it, or do you plan to let it develop wherever it may lead you as you go along? Are your kids of ages where it could become a playmate for them? I can think of all sorts of performance questions which I believe would interest us all such as speed, payload, tractive effort, climbing ability, surface adaptability, and on and on.
For now, VERY WELL DONE! 
It just seems much too formidible to be blocked and halted by a technologically inferior soda can. 
Thank you for the compliments!
I loved the one about the technologically inferior soda can. 
Here’s a couple more pictures. The first picture shows some of the components used in building the tracks.
The plate comes from a CAD/CAM file so I can make as many as I need. This was the first prototype side plate, note the oversized hole for the rear idler. The motor mount had to be turned on a lathe for now. As soon as time permits, I’ll draw it up and have a CAM file so I can cut them as needed. I’ll try to shoot some video today or tomorrow.
Thanks again for the support!
Well, your photo is suggestively reminiscent of that famous picture from Tianamin Square. However, in your case, we are not cheering for the soda can.
Nice machine work!
I can see why your kids call it a Wall-E. Just a little more engineering to make the arms…
Mic-6 or T909 (?) plate?
the Tormach cnc center is a nice machine! How’d you get so lucky?
Alan KM6VV
Alan KM6VV
Again, thanks for the positive support. The tracks are made up of an inner and an outer plate. The inner plate is Mic-6 aluminum which is .250 and the outer is T6061 which is .125. Think I said it was 5052H earlier… oops! I’m thinking I’d like to design another set with three sprockets, something closer in appearance to the Tri Track set up sold in the online store.
As for the Tormach, it’s a recent buy that required a lot of soul searching, the machine is expensive but add the options… oh my my! Anyone need some machine work, just PM me.
Can anyone give me some advise on the servo I used for the head. The head bounces around way too much when the robot is out driving through the yard. I’d really like to find a very small mechanical actuator and do away with the servo completely. Any ideas?
I’m working up my own ripoff of Wall-E, using a Tri-Track chassis. Your all-metal bodywork looks superb, I’m only working in ABS sheets and some sheet metal.
The problem with the head wiggles, a lot of that may be due to the neck. I plan on pretty much bypassing a neck, and putting an old Traxxster head (with tilt built in) mounted directly to a Base Rotate kit. The mounting on the head is the bottom strap which is as long as the Base is wide. The Base rotate gets mounted on the top of my plastic boxy body. (Not done yet!) I’m hoping this rather stubby neck will keep vibration and the ‘wobbles’ to a minimum.
Another possible way to dampen the wobbles is to use springs or rubber bands, like on the larger arms here. Or RC shocks, whichever looks cooler. (See some photos of Arm assembly for mounting details.)