Improved robust control for multi-link flexible manipulator with mismatched uncertainties

We consider a class of flexible joint manipulator system which is nonlinear and contains uncertainty. The inertial matrix can be used to construct Lyapunov function, even though some of the joints are prismatic. We construct subsystems via backstepping method and suggest a state transformation under which implanted control is used. From this state transformation, a robust controller, which is only based on the possible bound of uncertainty and the uniform positive definiteness of the inertial matrix, is designed to guarantee the practical stability of the system. A numerical example illustrates our conclusions.