The Gyro Monorail: How To Make Trains Better With A Gyroscope

The gyroscopic system for gyro monorail trains that Brennan developed. (Credit: Primal Space)

Everyone who has ever handled a spinning gyroscope found themselves likely mesmerized by the way it absolutely maintains its orientation even when disturbed. Much of modern technology would be impossible without them, whether space telescopes or avionics. Yet during the early 20th century a much more radical idea was proposed for gyroscopes, one that would essentially have turned entire trains into gyroscopes. This was the concept of the Gyro Monorail, with Louis Brennan being among those who built a full-sized, working prototype in 1910, with its history and fate covered in detail by [Primal Space], along with an accompanying video.

At first glance it may seem rather daft to have an entire train balancing on a single rail track, using nothing but gyroscopic forces to keep the entire contraption level and balanced even when you feel the thing should just tip over. Yet the gyroscopic system that Brennan created and patented in 1903 turned out to function really well, and reliably kept the train on its single track. Key to this was the use of two gyroscopic wheels, each spinning in an opposite direction, with a pneumatic system linked to a gear system between the two wheels that used the gyroscope’s precession in corners to quickly establish a new balance.

Despite this success, investors were unconvinced, and regular trains were already firmly established, and the system would also require that each car had its own gyro system. Even so, the idea of the gyro monorail never truly died, as evidenced by the recently created German MonoCab-OWL project. This targets converting single-rail sections into dual-rail, bi-directional service with no infrastructure investment required.

Thanks to [Stephen Walters] for the tip.

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Teardown Of Two Russian Missile Sensors

Recently [Michel] received two packages from Ukraine containing some salvaged Russian electronics that once belonged to (presumably) a 9K38 Igla, Vympel R-27 or similar infrared homing missile, as well as a Fiber Optic Gyroscope (FOG) from an unknown missile, though possibly from the Tornado family of MRLSes. The latter uses the Sagnac effect to detect the phase shift between two laser beams being injected into the same fiber when the fiber, and thus the device, are rotating. The advantage of such a gyroscope is that it is effectively solid-state, requiring only some optical components, amplifier stage and as shown here an Altera Cyclone II FPGA to integrate the results.

The 16-channel linear infrared array sensor is more basic, with a matching amplification channel for each optical receiver element, which are fed into a multiplexer IC in a rather remarkable looking ceramic-gold packaged DIP format, with what looks like a 2004 date code (‘0424’). Although both are rather damaged, [Michel] figures that he might be able to restore the FOG to working condition, assuming no crucial and irreplaceable parts are missing. As useful as FOGs are in missiles, they also have countless uses outside of military applications.

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Fancy Gyroscopes Are Key To Radio-Free Navigation

Back in the old days, finding out your location on Earth was a pretty involved endeavor. You had to look at stars, use fancy gimballed equipment to track your motion, or simply be able to track your steps really really well. Eventually, GPS would come along and make all that a bit redundant for a lot of use cases. That was all well and good, until it started getting jammed all over the place to frustrate militaries using super-accurate satellite-guided weapons.

Today, there’s a great desire for more accurate navigational methods that don’t require outside communications that can easily be jammed. High-tech gyroscopes have long been a big part of that effort, allowing the construction of inertial navigation systems with greater accuracy than ever before.

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Gyroscope Walks The Tightrope

Gyroscopes are one of those physics phenomena that are a means to many ends, but can also enjoyed as a fascinating object in their own right. Case and point being [Hyperspace Pirate]’s tightrope-balancing crawler in the video after the break.

Inside the PLA and aluminum shell is a 3D-printed wheel with steel bolts around the edge for added moment of inertia. It is powered by a low-KV¬†brushless motor with a 3:1 GT2 belt-drive and controlled by a simple servo tester, running on a 4 cell LiPo battery. The 3D-printed drive wheel is powered by a geared DC motor hooked directly to the battery. [Hyperspace Pirate] goes over the math of the design, showing that path to stability is a high speed and high moment of inertia flywheel, while staying well within the strength limits of the wheel’s material.

It’s balancing act was first demonstrated on a length of PVC conduit and then on a section of rope, with the characteristic circular wobbling of a gyroscope, known as gyroscopic precession. Without active correction, this the angle of procession will steadily increase until the machine falls over. Even so, it’s still great to watch a small scale version, like the one that inspired this build, would make a pretty cool desk toy.

Gyroscopes are commonly used in attitude indicators and and heading indicators in aircraft, and we’ve also seen them get used for balancing robots. Any ideas for practical uses for a mono-wheel rail/rope walker? Drop them in the comments below.

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Prototype Robot For Omniwheel Bicycle

For all its ability to advance modern society in basically every appreciable way, science still has yet to explain some seemingly basic concepts. One thing that still has a few holes in our understanding is the method by which a bicycle works. Surely, we know enough to build functional bicycles, but like gravity’s inclusion into the standard model we have yet to figure out a set of equations that govern all bicycles in the universe. To push our understanding of bicycles further, however, some are performing experiments like this self-balancing omniwheel bicycle robot.

Functional steering is important to get the bicycle going in the right direction, but it’s also critical for keeping the bike upright. This is where [James Bruton] is putting the omniwheel to the test. By placing it at the front of the bike, oriented perpendicularly to the direction of travel, he can both steer the bicycle robot and keep it balanced. This does take the computational efforts of an Arduino Mega paired with an inertial measurement unit but at the end [James] has a functional bicycle robot that he can use to experiment with the effects of different steering methods on bicycles.

While he doesn’t have a working omniwheel bicycle for a human yet, we at least hope that the build is an important step on the way to [James] or anyone else building a real bike with an omniwheel at the front. Hopefully this becomes a reality soon, but in the meantime we’ll have to be content with bicycles with normal wheels that can balance and drive themselves.

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What do we want? Monowheel!

Monowheel Mayhem: When Good Gyroscopic Precession Goes Bad

Since the dawn of the age of the automobile, motorheads have been obsessed with using as few wheels as possible. Not satisfied with the prospect of being incompletely maimed by a motorcycle, the monocycle was born. Gracing the covers of Popular magazines and other periodicals, these futuristic wheels of doom have transfixed hackers of all kinds. [James Bruton] is one such hacker, and in the video below the break you can see his second iteration of a 3d printed monowheel.

[James]’ wonderful monowheel is beautifully engineered. Bearing surfaces, gears, idlers, motors, and yes, twin gyroscopes are all contained within the circumference of the tire. The gyroscopes are actuated by a rather large servo, and are tied together by a gear that keeps their positions in sync. Their job is to keep the monowheel balanced at all times.

But as [James] discovered, the chief difficulty of only having one wheel isn’t lateral balancing. Ask any monocyclist and they’ll assure you that it’s possible. The real trick is balancing the machine fore and aft. Unlike a two wheeled velocipede, the monowheel has nothing to exert torque against save for a bit of gravity.

As [James] found out the hard way, it was within this fore-aft balancing act that the gyroscopic precession reared its ugly head. The concept is explained well in the video. We won’t spoil the surprise ending because the explanation and conclusion are quite good so make sure to watch to the end!

If you’d like to look at [James]’ first version, we covered it here. And if you’re the daredevil type, perhaps we can interest in you in a two stroke human sized monowheel that will probably end in an ER visit. At least they wore a helmet. Thanks to [Baldpower] for the tip!

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1949 Gyroscope Spins Up Again

[Curious Marc] has an Apollo-era gyroscope but isn’t quite ready to put it through this paces without some practice. So he borrowed a 1949 vintage Sperry C5 gyro and did some experiments with it using a 3-phase power supply he plans to use on the other gyro.

There is a little bit of troubleshooting and a lot of gorgeous close up shots of these electromechanical marvels. They sure are noisy, though.

[Marc] wanted a gyro testing table that can control the orientation of a gyro under test. He went the auction route to get a pretty expensive piece of gear for a relatively low price but without the expensive software. In a stroke of luck, he managed to score the required software from the vendor who was intrigued by his project. It looked to us like a table like this wouldn’t be that hard to build from scratch, either.

We are interested in what [Marc] will do with his gyros next. It is hard to imagine that gyros have come from this sort of device to a tiny IC inertial measurement unit that can fit in a phone. Imagine packing the Sperry unit on your next walking robot or self-balancing unicycle.

Need a refresher on how gyro’s work? We got that, too. It even covers the modern kind.

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