BOUNDED OUTPUT-FEEDBACK TRACKING CONTROL OF FULLY ACTUATED EULER-LAGRANGE SYSTEMS

In this short note we deal with the problem of trajectory tracking con trol of fully actuated Euler-Lagrange systems with unmeasurable veloci ties and bounded control inputs. In order to avoid the use of velocity measurements we introduce a nonlinear dynamic extension for the plant which renders the closed-loop system semi-globally asymptotically sta ble, hence, we prove that by increasing some of the dynamic extension parameters it is possible to enlarge the domain of attraction and to m aintain the control inputs bounded. (C) 1998 Elsevier Science B.V. All rights reserved.