Design of Finite – time Proportional- Derivative (AFPD) Controller for Stabilization of Six DOF Autonomous Underwater Vehicle (AUV) with Input Dead- zone NonLinearity, uncertainty and Noise

One of the important factors for stabilization of autonomous underwater vehicles (AUV) is considering high nonlinearity of underwater environments. In this paper, firstly global finite-time stability of six DOF autonomous underwater vehicles without input dead-zone non-linearity based on adaptive finite- time proportional-derivative (AFPD) controller is proposed. The proposed controller doesn’t refer to the modeling parameter and is much simpler; thus it is readily implemented. Stability of the system is guaranteed by the Lyapunov’s direct method, LaSalle’ s invariance principle and geometric homogeneity techniques. Then global finite- time stability of the system with considering input dead-zone non-linearity, uncertainty and noise based on Lyapunov’ s direct method and a finite-time stability lemma is proven. Theoretical analysis also shows the finite–time stability of the AUV’ s states. Analysis results are confirmed via computer simulations.