(a) The red line corresponds to the dynamic friction coefficient, describing the friction law; The dashed black line corresponds to the experimental friction law defined by Derler and Rotaru [10]; the gray line is the linearized friction law at a slipping equilibrium point symbolized by the gray cross; the white background corresponds to the zoom on the friction curve for (b). (b) represents the friction curve. The black line named Δ corresponds to the linear function that allows the calculation of the time-domain simulation (see Eq. (10)) for the instant A; the seven instants (A–F) describe the stick-slip cycle (refer to the Figs. 5a, 4c and 4d for illustration of these instants). The different steps of the stick-slip cycle are indicated by the different colors (red, cyan, blue and black); the gray line refers to the unused part of the friction law. The arrows show the direction of the cycle, each branch is taken twice during one cycle: the first passage is shown by solid arrows, the second passage by dashed arrows; (c) and (d) correspond respectively to relative velocity and friction force as a function of time; the red and black lines refer to the slipping phase, when the resonator is respectively slower and faster than the finger. The cyan color (for (b)–(c)–(d)) represents the passage between these two parts of the curve. The blue color represents the sticking state.