Duarte, Fernando B. M.Tenreiro Machado, J. A.2019-04-042019-04-042008-06http://hdl.handle.net/10400.22/13381This paper studies the describing function (DF) of systems constituted by a mass subjected to nonlinear friction. The friction force is decomposed in two components namely, the viscous and the Coulomb friction. The system dynamics is analyzed in the DF perspective revealing a fractional-order behaviour. The reliability of the DF method is evaluated through the signal harmonic contents.engDescribing FunctionFrictionControlModellingDescribing function of a simple mechanical system with non-linear frictionconference object