Globally Stable I/O Robust Control Of Flexible Joint Robots

This paper presents the first input-output robust control design for the trajectory following problem of a flexible-joint robot manipulator. The proposed design provides a class of controllers which only require position and velocity feedback and ensure global stability. The resulting stability is that the tracking error can be made to be smaller than a design parameter arbitrarily chosen by the designer. The proposed control is robust since it guarantees tracking performance in the presence of high-order nonlinear uncertainties including unknown joint elasticity, unknown parameters, load variation, disturbances. It is practically more important that no measurement on acceleration, jerk, or position and velocity deformation is required