“Well sir, there’s nothing on earth
like a genuine
bona fide
– Lyle Lanley

In keeping with the gyroscope theme from my last post, I wanted to highlight an interesting application space for inertial tilt sensors: monorails! If you’re like me, all of your mental associations with that word revolve around The Simpsons but there is actually some cool history around this idea, as well as some excellent contemporary mechatronics projects.

A gyroscopic monorail is essentially a train that runs on a single rail and uses the gyroscopic properties of spinning wheels to balance. Theoretical advantages of a monorail as compared to traditional bi-rail trains include sharper turns (because the cars will automatically bank during bends, which also eliminates lateral centrifugal acceleration) and the suppression of hunting oscillation (basically swaying of the rail cars arising from the interaction of inertial and adhesion forces). Furthermore, track gauge mismatch issues can be avoided. However, the downside is that all the cars require a powered gyroscopic system to stay balanced.

In practice, full size gyroscopic monorails never progressed beyond prototypes, although several people worked on the idea in the early 20th century. However, there are several contemporary projects working on small-scale systems that are pretty cool. In particular, Youtube user AkubiLR has posted a number of interesting videos documenting a series of prototypes and experiments; including these two of his prototype #11 both balancing statically and running at speed.

The monorail didn’t work out for Springfield on TV but continual improvement of inertial sensor performance and decreases in price mean that maybe someone will revisit this space a little sooner than we think. All aboard!

Be Sociable, Share!