Fuzzy Control for PVTOL Stabilization Based on Nested Saturation Functions

In this paper, a new approach for stabilization of the PVTOL is presented, considering the Nested Saturation Controller (NSC) algorithm that has been designed based on the Lyapunov theory for stabilization problem of this mechanical system. This NSC can be complemented with a Fuzzy Logic Control technique to improve the PVTOL features as the time of error convergence and performance in the feedback control system. As the NSC is based on saturation functions connected in recursive way, having as input the feedback states error, then the level of the bound limits for these saturation functions can be modified during the execution using a Fuzzy Logic Controller (FLC), which in base of the error calculates a new bound for the saturation function. The FLC operates in terms of the Mamdani inference Machine. Then the fuzzy nested saturation (FNSC) strategy allows a fast convergence of the states. Implementing numerical simulation the result are obtained, allowing a comparison of the F-NSC with respect to the classical NSC applied to the PVTOL dynamical model. To reinforce the results, the features of the F-NSC are established in terms of performance index criteria.