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A project log for Autonomous tracked robotic platform UGV

One of my most advanced projects to date. A tracked robotic development platform that [hopefully] raises the bar for hobby robotics.

Maximiliano PalayMaximiliano Palay 10/08/2021 at 02:190 Comments

Continuing from the last log, I printed the 3 remaining wheels, now it's time for the axles.

Axles

For these, I repurposed parts of old 3d printers that were scrapped. These usually have a couple of steel axles, as pictured below.

Scrap printer axles and some post-processed in the center.
Scrap printer axles and some post-processed in the center.

I stripped the rubber these had, and searched for 8mm axles specifically. As I'd be using 608zz bearings, this size would fit nicely. I then cut these to proper length, and filed one end off.

Filing the axles flat on one end.
Filing the axles flat on one end.

These were then hammered into hexagonal adapters that would interface with the wheel.

Finished axle with adapter
Finished axle with adapter (view 1)
Finished axle with adapter
Finished axle with adapter (view 2)
Wheel and axle set
Wheel and axle set

We're still missing some body parts

The lateral compartments, fenders and robot handle had the same treatment as the chassis. Some sanding, primer, paint, and ready to go. Actually, the fenders had to be pasted together too.

A joined and sanded fender, and a freshly come out the printer fender in two pieces.
A joined and sanded fender, and a freshly come out the printer fender in two pieces.
Two finished fenders
Two finished fenders

The recess that can be seen is for accommodating the LED lights that will go on top.

Side compartments and handle ready to be painted
Side compartments and handle ready to be painted.
All the things.
All the things I have been doing are combined into one picture.

In this one, you can see the outermost parts are for securing the LED sidelights on top of the fenders. These were left as-is. Just as a reminder that this is all 3d printed. Some motors and pulleys are showing up too!

Top cover / the lid

This top cover, will not only serve as a means to enclose the robotic platform, but will double as an accessory or payload bay. The idea is to make something see through, with acrylic so internals can be seen. If you wouldn't like this, it can be made entirely from printed plastic as well.

Mark 1

This version of the lid was intended to be printed in two parts, with a canal that would hold the 2mm acrylic. When joining these parts with glue and threaded rods, the acrylic couldn't be removed. This proved to be a pretty bad design choice. I'm leaving a couple of pictures, just for the record.

The top cover with threaded rods partially inserted, and acrylic in place.
The top cover with threaded rods partially inserted, and acrylic in place.
Top cover canal that holds the acrylic.
Top cover canal that holds the acrylic.

Mark 2

For mark 2, I decided to make the acrylic removable. So instead of enclosing it forever when assembling the cover, it is held in place sandwiched between a lip in the cover and screws from below. Not a super elegant solution, but it proved to be enough.

Bottom view of the ready to be painted cover.
Bottom view of the ready to be painted cover. The aforementioned screws can be seen.
Top view of almost finished cover.
Top view of almost finished cover.

Stay tuned for assembly.

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