Design of excitation signals for the closed loop identification of industrial robots

Abstract

This paper focuses on closed loop experiment designs for the estimation of frequency response functions of industrial manipulators. It addresses the difficult choice of excitation signals w.r.t. a minimization of the disturbing impact of nonlinearities like Coulomb friction. The basis for the treatise are two widespread types of excitations, multisine and chirp signals. By superimposing the actual excitation with additional signals and by introducing a frequency dependent amplitude of the excitation signal, the disturbances due to the nonlinearities are purposefully detected and/or eliminated. Simulations of a simple academical example and experiments performed in a hardware testbed allow for a comparison of the proposed approaches and show their effectiveness and synergies.