An input error method for parameter identification of a class of Euler-Lagrange systems

In this paper, an input error identification algorithm for a class of Euler-Lagrange systems is proposed. The algorithm has a state-observer structure which uses the input error between the real system and an estimated model instead of the output error. Both systems are controlled by two Proportional-Derivative (PD) controllers with the same gain values. An excitation signal is added to the PD controllers to guarantee parameter estimates convergence. Stability of the complete identification method and parameter estimates convergence are assessed via Lyapunov stability theory. Simulation studies are carried out to verify the approach.