On the Stability of Digital Position Control with Viscous Damping and Coulomb Friction

  • Csaba Budai Department of Mechatronics, Optics and Mechanical Engineering Informatics, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, Hungary
  • László L. Kovács Department of Mechanical Engineering and Centre for Intelligent Machines, McGill University, Canada


In this paper, we investigate the combined effect of viscous damping and Coulomb friction on sampled-data mechanical systems. In these systems, instability can occur due the sampling of the applied discrete-time controller which is compensated by the two different physical dissipation effects. In order to investigate the interplay between these, we focus on how the stable domain of operation is extended by the dry friction compared to viscous damping. We also show that dry friction causes concave envelope vibrations in this extended region. The analytical results, presented in the form of stability charts, are verified by a detailed set of simulations at different representative control parameter values.

Keywords: position control, sampled-data system, friction effects, concave vibration envelope, stability
Published online
How to Cite
Budai, C. and Kovács, L. (2017) “On the Stability of Digital Position Control with Viscous Damping and Coulomb Friction”, Periodica Polytechnica Mechanical Engineering, 61(4), pp. 266-271. https://doi.org/10.3311/PPme.10537.