Order reduction of control and estimation problems for flexible joint manipulator

The integral manifold method is used in the paper for controller design for manipulators with flexible joints in the case of a small friction. For a class of nonlinear systems a nonlinear controller, that achieves asymptotic tracking of given trajectory, is designed. It shows the existence of a lower order control problems, which are equivalent to an original singularly perturbed problems with initial conditions restricted to a slow integral manifold.