Global output tracking control of a class of Euler-Lagrange systems

We address the problem of output feedback tracking control of a class of Euler-Lagrange systems subject to nonlinear dissipative loads. By imposing a monotone damping condition on the nonlinearities of the unmeasured states, the common restriction that the nonlinearities be globally Lipschitz is removed. The proposed observer-controller scheme renders the origin of the error dynamics uniformly globally asymptotically stable.