**Table 6.**

*Average of twenty (20) experiments trapezoidal tracking motion for three controllers (increased mass).*

*Enhanced Nonlinear PID Controller for Positioning Control of Maglev System DOI: http://dx.doi.org/10.5772/intechopen.96769*

**Figure 20.** *Sensitivity response of the FF PI-PD +* K*<sup>z</sup> and the FSP controllers.*

control scheme. On the other hand, the FF PI-PD + *K*<sup>z</sup> achieves approximately three (3) times shorter settling time than the FSF controller when the mass increased. In short, the FF PI-PD + *K*<sup>z</sup> controller demonstrates the best positioning performance among the compared controllers regardless of the mass variation.

As referred to the **Figure 20**, the FF PI-PD + *K*<sup>z</sup> controller performs smaller sensitivity function magnitude than the FF PI-PD controller. Hence, it is less sensitive to parameter variation. In short, despite the variation of mass and amplitude, the FF PI-PD + *K*<sup>z</sup> controller demonstrates a superior tracking performance than the FF PI-PD and FSF controllers, where it tracks the trapezoidal command accurately and precisely via illustrating the lowest *Emax* and *Erms* values.
