Möbius Tank’s Twisty Treads Became Bendy

[James Bruton]’s unusual Möbius Tank has gotten a little more unusual with the ability to bend itself, which allows it to perform turns even though it is a single-track vehicle.

The turning radius isn’t great, but three-point turns are perfectly feasible.

The Möbius Tank was a wild idea that started as a “what if” question: what if a tank tread was a Möbius strip? We saw how [James] showed it could be done, and he demonstrated smart design and assembly techniques in the process.

He’s since modified the design to a single-track, and added a flex point in the center of the body. Two linear actuators work together to make the vehicle bend, and therefore give it the ability to steer and turn. A normal tread would be unable to bend in this way, but the twist in the Möbius tread accommodates this pivot point perfectly well.

It works, but it’s not exactly an ideal vehicle. With the tread doing a 90-degree twist on the bottom, there isn’t a lot of ground clearance. In addition, since the long vehicle has only a single tread, it is much taller than it is wide. Neither does it any real favors when it comes to stability over uneven terrain, but it’s sure neat to try.

Even if it’s not practical, Möbius Tank is wild to look at. Check it out in the video, embedded just under the page break.

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An RC Tank Chassis That’s Not Messing About

It’s not uncommon to see a tracked robot build on these pages, but it’s fair to say that many of them are somewhat on the small side. That was where [iforce2d] started, but the idea of making a more capable version just wouldn’t go away. Thus, he’s come back and made what looks to be a very promising, fully capable outdoor RC tank chassis, one that, within reason, we think should eventually be able to go anywhere.

For plenty of power, he’s using a pair of hoverboard motors with a chain reduction drive and in turn, a couple of shafts to the tracks. The chassis is a TIG-welded aluminium affair, while the tracks are an early incarnation with machined MDF drive wheels and a homemade tread. The suspension is a work of machined-aluminium art, though, and while there are teething troubles as he takes it for a spin, we can see plenty of potential as its deficiencies are ironed out.  Take a look at it in the video below the break.

If large-size R/C tanks are your thing, we have another for you to look at.

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Single-piece Tank Chassis Goes Robotic

[EXTREME3DPRINT] has a new version of their print-in-place tank chassis: the PiPBOT now accepts drop-in motors (in the form of 360° rotation servos), RC receiver, and battery pack to make a functional RC tank platform in no time flat. The design is entirely 3D printed with no supports needed.

This new version is a paid 3D model (and it includes STEP files, thankfully) but the original proof-of-concept print-in-place tank chassis is free and remains a highly clever piece of design that really shows off what is possible when one plays to a 3D printer’s strengths.

A better look at the design’s details can be found on the designer’s website, and a short video demonstrating assembly and operation is embedded below. We particularly like the attachment points on the top of the PiPBOT, which allows for securely mounting all kinds of customized payloads.

Interested in this style of printable RC platform, but want something a little more accessible? If race cars are more your thing, we’d like to also mention the Gamma 2.0 by [Under Engineered]. It’s a print-in-place RC car that needs minimal parts to get rolling and would make an excellent afternoon project.

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Computer Gear With — Um — Gears

Analog computers have been around in some form for a very long time. One very obvious place they were used was in military vehicles. While submarine fire computers and the Norden bombsight get all the press, [msylvain59] has a lesser-known example: an M13A1 ballistic computer from an M48 tank that he tears down for us in the video below.

The M48, known as a Patton, saw service from 1952 to 1987. Just looking at the mechanical linkage to the tank’s systems is impressive. But inside, it is clear this is a genuinely analog computer. The thing is built — quite literally — like a tank. What was the last computer you opened that needed a hammer? And inside, you’ll find gears, bearings, and a chain!

We don’t pretend to understand all the workings. These devices often used gears and synchros (or selsyns, if you prefer) to track the position of some external thing. But we are guessing there was a lot more to it than that. It’s probably an exciting process to see something like that designed from scratch.

We did think of the Norden when we saw this. Hard to imagine, but there were “general purpose” analog computers.

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Behold The Track-Twisting Möbius Tank

It started with someone asking [James Bruton] about using a Möbius strip as a tank tread. He wasn’t sure what the point would be, but he was willing to make one and see what happened. Turns out it works reasonably well!

The grey plates are responsible for tensioning the tracks. Designing them as separate pieces means rework for fine-tuning avoids having to re-print structural parts.

The main design challenge was creating a tread system that would allow for the required rotation. [James] designed in the ability for each link to rotate about 18 degrees, and ensured plenty of open space on the upper side of the drive train to accommodate a full 180 degree twist. It took a little fine-tuning and looks a bit trippy, but in the end works about as well as a regular tread system.

[James] shows off a good technique to keep in mind when constructing big assemblies like this tank. It takes a lot of time and material to print large pieces, and in such cases it’s especially important to minimize rework. [James] therefore designs smaller, separate pieces as interfaces to other parts. This way, if changes are needed down the line (for example, to adjust motor placement or change tension on parts), only a smaller interface piece needs to be redone instead of having to re-print a huge part.

The unit uses an Arduino Mega, two 24 V gearmotors to drive each tread independently, an RC radio receiver, and some beefy BTS7960 DC motor drivers to drive the motors.

[James]’ unit is pretty big, but we’ve also seen 3D printed tanks capable of carrying a human driver. It’s clear that build plate size doesn’t seem to limit tank designs. Watch the Möbius tank get built and drive around in the video, just below the page break.

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Tank Boots Are A Dangerous Way To Get Around Town

Rollerskates are all well and good, but they’re even more fun when they’re powered. Then again, why stick with wheels, when you can have the off-road benefits of tracked propulsion? That’s precisely what [Joel] was thinking when he built this impressive set of Tank Boots.

The build uses a set of tracks from a tracked snowblower, sourced for $50. The tracks are a simple design sans suspension, consisting of a pair of plastic wheels inside the tracks and run via a chain drive. Each snowblower track was given a metal frame with a ski boot and a motor, gearbox, and controller straight out of a power drill. Power was courtesy of a lithium-polymer battery pack.

Riding the boots isn’t easy, with falls and tumbles rather common. Regardless, they get around great offroad in a way that regular rollerblades never could. Bolted together, they make a great tank chair, too. We’ve actually looked at the benefits of tracks versus wheels before, too. Video after the break.

One-Piece Tank Chassis Pushes Print-in-Place To New Heights

What’s better than 3D printing a tank chassis with working tracks? How about 3D printing the entire thing, moving parts and all, as a single piece? That’s [3D Honza]’s PiPBOT-1, and it’s the culmination of a whole lot of design work.

The design prints flat, then folds up into its final form.

[3D Honza] has been sharing progress pictures and videos on his Twitter account, and just recently released the first version of his design. Version 1.0 is just the mechanics, but he’s already at work on version 2.0 which includes the ability to attach servos to drive the treads. At this writing, the design is currently downloadable directly from his site and includes CAD files, which is great to see.

One part of the design we’d like to draw your attention to is the chunky hinge that doubles as a kind of axial structure making up the body. This allows the tank to print in an unfolded state with the treads and wheels flat on the print bed. After printing, the tank gets folded up a bit like a taco to attain its final form. It’s a clever layout that allows the unit to be printed according to a filament-based 3D printer’s strengths, printing as a single piece that transforms into a small tank chassis, complete with working treads, in a few seconds.

When it comes to vehicles and bots, whether to choose wheels or tracks is a serious question our own Lewin Day has explained thoroughly. And for those of you who choose tracks, this design is great for small devices but don’t forget it’s always possible to go bigger when it comes to 3D-printed tanks.

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