A new test for stick-slip limit cycles in dry-friction oscillators with   small nonlinear friction characteristics
  We consider a dry friction oscillator on a moving belt with both the Coulomb friction and a small nonlinear addition which can model e.g. the Stribeck effect. By using the perturbation theory, we establish a new sufficient condition for the nonlinearity to ensure the occurrence of a stick-slip limit cycle. The test obtained is more accurate compared to what one gets by building upon the divergence test. 
O. Makarenkov
math.DS