Globally stable I/O robust control of flexible joints robots

The first input-output robust control design for the trajectory-following problem of a flexible-joint robot manipulator is presented. The proposed design provides a class of controllers which require only position and velocity feedback and assure global stability. The resulting stability is such 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, and disturbances. It is more important from a practical point of view that no measurement of acceleration, jerk, or position and velocity deformation is required