Nonlinear path following for Water-jet-based Spherical Underwater Vehicles

A command filtered back-stepping path following control is exploited to design a dynamic state-feedback controller for a Water-jet-based Spherical Underwater Vehicles, which obviates the computation of analytic derivatives in the traditional back-stepping design. The ISS-modular approach provides a simple and effective way for controlling non-linear Underwater Vehicle satisfying the strict-feedback form, simultaneously solving the problem of “explosion of complexity” in conventional back-stepping approach by combining command filtered back-stepping, sliding-mode-based integral filters and Input-to-State Stability (ISS) analysis. The stability analysis of the closed-loop system is verified based on the small-gain theorem. Numerical simulations illustrate the performance of the proposed nonlinear control method.