where c is the viscous damping coefficient, NL and NR
are the normal pressures on the left and right wheels,
is the friction coefficient, _
dL and _
dR are the rates of the
corresponding left and right displacements for the suspension
mounted on each wheel.
Substituting the system kinetic, potential, and dissipated
energies in equation (9), the dynamic model can
be obtained in the state space as