Friction Effects on Stability of a Digitally Controlled Pendulum

Abstract

This paper investigates the stability of a digitally controlled pendulum with Coulomb friction as primary source of dissipation. We focus on the stabilizing effect of friction against vibrations due to the otherwise unstable parameter settings, and we show how the stable domain of operation is expanded compared to the undamped case. Continuous time and discrete switched models are simulated to get information about the stabilization effect of friction. A special concave vibration envelope is identified, validated by experiments and shown as a characteristic form of vibrations for digitally controlled systems with dry friction.