... proof of global asymptotic stability of the origin of the closed-loop system, was first solved for one-degree -of- freedom robots (including a term that is quadratic in the velocities) in • Lor´ A., ... and La Salle’s Theorem 2.7 This controller was proposed and analyzed in Kelly R., Ortega R., Ailon A., Loria A., 1994, “Global regulation of flexible joint robots using approximate differentiation”, ... considered as part of the last link) is of uncertain mass and/ or inertia The consequence in this situation cannot be overestimated; due to the uncertainty in some of the parameters of the robot model...