*5.2. Results*

After the initialization phase (*Tini* = <sup>10</sup>), the detection phase operated during the detection of a second class. This detection was made for the iteration *k* = 11. The inputs parameters were *Minpts* = *n*/2 = 4 and = 0.12. Results of AOC-OPTICS method are represented in Figure 9. The cluster number 2 appeared at iteration 11 and was confirmed by the following iterations. Despite the variation of loads and speed the accuracy was 100%. The results of our methodology could detect a tiny variation in the state of the bearing. All these results could demonstrate the robustness of the used methodology.

**Figure 9.** Experimental validation (**a**) Iteration 10, (**b**) Iteration 11 and (**c**) Iteration 90.
