Robotic Wheels
Saturday, April 12th, 2008It’s hard to imagine building a robot that who’s sole purpose is to fall over on itself. However those researching robotic wheels have done just that. In fact their main purpose was to demonstrate a new method of robot locomotion that doesn’t require electric motors or gasoline engines. These “robowheels” are run by flexing the outside rim into different shapes allowing the start falling in a certain direction until it’s in a constant state of motion. The spokes are made of a smart material known as a shape memory alloy, or “memory metal”. Shape memory alloy is a very flexible metal, but is very unique in that when heated, or electrified, it will return to a rigid state. In order for these robot wheels to propel, they just make certain spokes rigid and certain spokes soft. The only downfall is that they are slow to start and stop, but they can travel over extremely rough terrain. These robot wheels can even jump in the air after first squishing flat to their lowest position and then quickly deforming to their tallest thinest shape. Using this design, it is even possible to make a full rolling ball that could never fall over! But of course it will indefinitely be trying to fall over. 
If you are interested in playing with shape memory alloy, you can buy it online. Making your own robot wheel with the Parallax Propeller chip would be a fun project.