|Fractional Sliding Mode Control of Underwater ROVs subject to Non-differentiable Disturbances
Aldo-Jonathan Muñoz-Vázquez*, Heriberto Ramírez-Rodríguez, Vicente Parra-Vega, and Anand Sánchez-Orta
International Journal of Control, Automation, and Systems, vol. 15, no. 3, pp.1314-1321, 2017
Abstract : "Some hydrodynamic phenomena of an underwater Remotely Operated Vehicle (ROV), such as turbulence,
cavitation, and multi-phase fluidic regimes, are associated to continuous but nowhere differentiable functions.
These disturbances stand as complex forces potentially influencing the ROVs during typical navigation tasks. In this
paper, the tracking control of a ROV subject to nonsmooth Hölder disturbances is proposed based on a fractionalorder
robust controller that ensures exponential tracking. Notably, the controller gives rise to a closed-loop system
with the following characteristics: a) continuous control signal that alleviates chattering effects; b) the fractional
sliding motion is substantiated on a proposed resetting memory principle; c) the control is robust to model uncertainties;
and d) exact rejection of Hölder disturbances in finite-time. A representative simulation study reveals the
feasibility of the proposed scheme."
Fractional-order control, fractional sliding modes, Hölder functions, remotely operated vehicle.