Controllability of a hovercraft model (and two general results)

Modelling and controllability studies of a hovercraft system are undertaken. The system studied is a little more complicated than some in the literature in that the inertial dynamics of the thrust fan are taken into account. The system is shown to be representative of a large class of systems that are controllable only on a set described by the zeros, of a nontrivial analytic function. Results for controllability using vector-valued quadratic forms are useful in arriving at the stated conclusions. As part of the development, two controllability results of independent interest are proved.