This model is not as symmetrical as RILYBOT 2, mainly due to the difficulty of fitting three motors into such a small space.
This model uses #12 cross axles as its three main legs. The cross axles are connected to each other at mutually orthogonal angles using Throwbot "hip/ankle" ball-joint connectors:
Connecting three axles at mutually orthogonal angles
(There are also three #4 cross-axles on the top that are just for decoration and to make it look a little more like RILYBOT 2. The other black thing sticking out the top is a wire.)
There wasn't enough room to fit three micromotors, so I used just one. The micromotor is supported this way:
Using the Throwbot leg pieces made it very easy to support the micromotor and align it precisely the way I needed it to be.
The micromotor drives two of the robot's axles like this:
Micromotor, crown gear and two axles.
Normal wheels need to pretty much be oriented in the same direction (i.e. mounted on parallel axes) to work efficiently. A linear wheel is a wheel that can be combined with any number of other wheels oriented in different directions. The primary difference is that a normal wheel cannot "roll sideways" while a linear wheel can. Typically linear wheels are powered along one axis and roll freely on the other axis; in order to get full control of movement in a vehicle you use at least two sets of linear wheels, oriented in different directions.
Markus also made a smaller Killough platform, that has a bumpy ride.
Finally, here is Phillippe Hurbain's RAMA, another fairly compact design.
LEGO® creations index
The graph paper in my newer photos is ruled at a specing of 1 LSS, which is about 7.99 mm.
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