ABSTRACT
Consider a nonlinear system q f q u= ( , ) with f q( , )0 0 0= and f continuously differentiable in a neighborhood of ( , )q0 0 . Necessary conditions for the existence of a continuously differentiable control law for asymptotically stabilizing ( , )q0 0 are as follows:
1. The linearized system has no uncontrollable modes associated with eigenvalues with positive real part.
