Path following of underactuated autonomous underwater vehicles in the presence of ocean currents

Line-of-sight curved path following for underactuated USVs and AUVs in the horizontal plane under the influence of ocean currents

“…Given an underactuated surface vessel described by the dynamical system (5). If Assumptions 1-5 hold, the controllers given by (19) and (21), and the guidance laws given by (13) and (14), give a cross-track error dynamics for which the equilibrium point y e = 0 is uniformly globally asymptotically stable (UGAS) and uniformly semi-globally exponentially stable (USGES), and the control objectives (12) are achieved.…”

“…However, this control approach is susceptible to environmental disturbances such as ocean currents, waves and wind: path deviation and convergence problems will occur if the vessel is affected by environmental disturbances [11]. For straight line paths, LOS can be used with integral action [11]- [13] or adaptive estimation techniques [7] by allowing the USV to side-slip to compensate for the effect of the ocean current. In [12] the steady state of the marine vessel is used to estimate the ocean current magnitude and direction, and in [7] the estimates of the ocean current is used directly in the LOS guidance law.…”

Uniform Semiglobal Exponential Stability of Integral Line-of-Sight Guidance Laws∗∗This work was partly supported by the Research Council of Norway through the Centres of Excellence funding scheme, project no. 223254 - AMOS

“…The resulting integral line-of-sight (ILOS) guidance law was proved to be globally stable. This result was extended to global κ-exponential stability in Caharija et al (2012a), Caharija et al (2012b) and Caharija et al (2014).…”

Point Stabilization for an Underactuated AUV in the Presence of Ocean Currents

“…Control design in the general case where nondiagonal matrix elements are also taken into account is not as difficult in a fully actuated case, but is nonetheless an active and difficult topic of research in the underactuated case [19,34]. Though many motion control algorithms have been developed for dealing with underactuated systems of the AUV and other marine vehicles in [13,14,[16][17][18][19][20]29,30,[34][35][36], little research has considered fore/aft asymmetry of the AUV model, the exceptions being [17][18][19][34][35][36]. In [17][18][19][34][35][36], details concerning the control performance differences of AUVs when comparing the nonlinear control method based on the symmetric model and that based on the non-symmetric model are not presented.…”

“…In this paper, a frequently used simplification that assumes the ocean current is irrotational and constant in an inertial reference coordinate system is adopted, as in, for example, [16,34]. Though many research results focused on the motion control of the AUV and other marine vehicles are obtained in the presence of ocean currents [13,16,30,[34][35][36], a detailed description of the relationship between the direction of the ocean current and the desired yaw angle for point stabilization has to date not been clearly proposed.…”