Position feedback global tracking control of EL systems: a state transformation approach

The contribution of this paper is a dynamic position feedback global tracking controller for fully actuated Euler-Lagrange (EL) systems. The properties we show for the closed loop system are uniform stability and exponential convergence, global in the initial tracking errors and semiglobal in the initial estimation errors. The novelty of our approach is that our observer and control design are based on a new model for EL systems which is linear in the immeasurable velocities. This model is shown to fit robot manipulators. We also provide some simulation results