Linear control of Euler-Lagrange systems

In this Letter, we study linear control of Euler-Lagrange (EL) systems. We prove that there exists a linear proportional-integral-derivative control such that any state of the EL system can be stabilized for any compact set of initial conditions. Basically, we show that integral control is necessary to attain the control objective in the face of model uncertainties and nonlinearities. We discuss some implications of our results on the control of physical systems, e.g., control of human and animal motions.