Lagrangian modeling of the Underwater Wave Glider

Abstract

This paper introduces a control-oriented modeling approach for a hybrid autonomous underwater vehicle: the Underwater Wave Glider. Thanks to a non-conventional design, the vehicle can accomplish both surface and underwater tasks, by changing its shape. The vehicle can operate as a wave glider at the sea surface, where the potential energy of the waves and the solar radiation can be exploited to recharge the onboard batteries, while moving at low speeds. Moreover, the Underwater Wave Glider can switch to the typical torpedoshaped configuration in order to operate both as a Glider and as a self-propelled Autonomous Underwater Vehicle. The vehicle dynamics are modeled via a non-standard Lagrangian approach and some simulations are provided.

Switching control of an underwater glider with independently controllable wings

“…According to Caiti et al, 11 the equations governing the dynamics of the position and the velocity of the CoG are…”

“…For any generic vector v, we adopt the notation with superscript ''b'' to indicate the components of v expressed in the body-fixed frame ''attached'' to the vehicle, while we use the superscript ''n'' to indicate the navigation reference frame. According to Caiti et al, 11 the equations governing the dynamics of the position and the velocity of the CoG are…”

“…This latter characteristic is clearly not available if the glider is equipped with hydrodynamic wings that are fixed. This study is motivated by the recently introduced concept of the underwater wave glider, 11 capable of both wave-propelled surface navigation and buoyancydriven underwater motions. The mentioned vehicle is indeed a hybrid underwater vehicle, in the sense that it is both a surface vehicle and an underwater glider.…”

Dynamic modeling of wave driven unmanned surface vehicle in longitudinal profile based on D-H approach

“…QI et al [7] built a three-degree dynamic model of wave glider in longitudinal profile based on Kane's equation, but lacking the computing of the wave force and further comparative analysis of the results under different wave inputs. CAITI et al [8] tried to present a UWG concept, and used the D-H approach to establish the dynamic model of UWG in longitudinal profile [8]. But UWG can change its shape to realize different operating modes while the float body and underwater glider body of WUSV are connected through the flexible cable.…”

Lagrangian dynamic modeling of wave-driven unmanned surface vehicle in three dimensions based on the D-H approach

“…Zhanfeng Qi et al from National ocean technology center build three degree dynamic model of wave glider in longitudinal profile based on the Kane's equation, but lacking the computing of the wave force [5]. Andrea Caiti et al from University of Pisa, tried to present a UWG concept, combining WUSV and underwater glider, and use D-H approach to establish the dynamic model of UWG in longitudinal profile [6], but the UWG structure is very different from WUSV and its model cannot be applied directly in the WUSV dynamic analysis. This paper uses D-H approach applied in manipulator to describe the relative motion relationship of various moving parts in WUSV, and then establishs its dynamic model in three dimension by Lagrangian mechanics.…”