[William Tell]

I get an eerie feeling that this is one of those once or twice per century developments. I wonder how efficient they are?

In the last year or so I have been playing with Texas Instruments controllers and more recently with the Beaglebone Black computer board.

I have been reluctant to try some mechanical projects with them because of the cost, weight, and power requirements of conventional motors and mechanical linkages. I will have to see if I can make some of these things myself.

I am vaguely recalling a resistive rubber string or filament which changes resistance with stretching. Using this for feedback, I can picture a pretty compact one dimensional "motor".

Add in some readily manufactured plastic parts using 3-d printing and the possibilities seem pretty exciting.

... As if I don't have enough hobbies already.

[HiTech RedNeck]

It was basically done by mimicking nature.

It might not be all that wonderfully energy efficient (a vehicle based on this might not win any fuel efficiency prizes), but it sure seems to have the virtue of flexible application. It’s lower-tech, and it is easier to do heat than it is to do electromagnetics.