[jackgavigan]

I wonder whether the extra weight of a third, retractable/foldable leg would negate the power savings that could accrue from being able to switch to 3-wheeled mode when appropriate (thereby allowing the gyro to be spun down).

[v9v]

By gyro do you mean flywheel? Is there one in this robot?

[Isamu]

There does not appear to be one in this robot, from what I am able to read about it. I think sometimes people assume there must be something like that to help balance.

This generalizes fixed 2-wheel dynamic balancers which mostly don’t have flywheels for stability either, the focus is on the dynamics of keeping the wheels under the center of gravity, or a bit offset when moving.

The novelty here is about switching between dynamic control policies while keeping them simple.