Reachable set of bilinear control systems with time varying drift

In this article, we give a complete characterization of the reachable set at all times for a class of bilinear control systems with time varying drift and unbounded control amplitude. These results are of fundamental interest in geometric control theory and have important applications to control of coupled spins in solid state NMR spectroscopy. (c) 2005 Elsevier B.V. All rights reserved.