Control of Euler-Lagrange systems subject to constraints: An Explicit Reference Governor approach

This paper develops an Explicit Reference Governor that provides constraint-handling capabilities to pre-stabilized Euler-Lagrange systems. Using passivity arguments, it is shown that the constraints on the state variables can be translated into constraints on the energy of the closed-loop system. These energy constraints can then be enforced in continuous-time by manipulating the velocity of the applied reference in a suitable manner. The effectiveness of the proposed theory is supported by numerical examples.