Jim and Jaap, et al.

Attached are the nonlinear equations of motion, the characteristic
equation coefficients, and the stability criteria for the monocycle from
Carvallo placed side-by-side with mine for comparison.  I converted all of
Carvallo's equations and results into my notation which is at the front of
the attachment. The equations are laid out with the same ordering of
kinematic quantities.

There are boxes around terms where we have disagreement and circles around
the offending term within each box. Some differences appear to be due to
Carvallo neglecting the mass and/or inertia of the wheel in certain
instances, as you pointed out to me - but other differences don't seem to
be due to that.

The discrepancies in the nonlinear equations end up being insignificant
for the most part because they go away mostly in the linearization.
Still, the charac. eqn. coeff.'s are slightly different. The discrepancies
only lead to one difference in the stability criterion - the critical
speed for stability.

Mike Coleman,  Burlington VT, Jan 9, 2008