Dynamics of Two Active Autonomous Dock Mechanisms for Auv Recovery

Abstract

Autonomous Underwater Vehicles (AUVs) are presenting an ever expanding range of applications that enhance human capabilities and mitigate human risk. Development of a successful subsurface autonomous launch and recovery system would expand the functional use of AUVs in many fields, e.g., year-round Canadian Arctic exploration and sovereignty missions. This paper provides an overview of the design and dynamic modelling of two concept mechanisms being developed to recover AUVs to a slowly moving submerged submarine. Both have a serial R⊥R⊥P architecture; one is mechanically actuated while the second uses an actively pitched wing to indirectly provide motive force for the passive revolute joint. Dynamic models of both manipulators are developed. Although similar in architecture, several extensions are required to accurately predict the non-linear dynamics provided by the wing. High speed actuation of the devices is required to compensate for relative trajectory errors between the submarine and AUV during significant sea states in littoral waters. Alterations to the recursive Newton-Euler method to include hydrodynamic and additional inertial forces present in water are explained. Results of some initial modelling are presented.

The ARTEMIS under‐ice AUV docking system

“…and McFarland et al . In a subsurface approach, Currie et al . present active grappling arm techniques for docking an AUV to a slow‐moving submarine.…”

“…Broadly considered, this group also includes open-water recovery techniques in which personnel at the surface manually connect recovery lines and/or lifting mechanisms to the vehicle. Open-water recovery is used routinely in the open ocean, but has also been used for under-ice work as by Bellingham et al, 16 McPhail et al, 17 Williams et al 18 and McFarland et al 19 In a subsurface approach, Currie et al 20 present active grappling arm techniques for docking an AUV to a slow-moving submarine.…”

A simplified concept for recovering a UUV to a submarine

“…The operation of UUVs from manned submarines reduces the risk to the submarine and potentially enables tasks to be undertaken that would not be possible with a standard submarine, either conventional or nuclear powered (e.g. Currie et al, 2014;Hardy and Barlow, 2008;Purton and Andrews, 2014).…”

“…Some of these are discussed in Currie et al (2014), Hardy and Barlow (2008), Irani et al (2014) and Watt et al (2011). The solutions broadly fall into three different categories: a) recovering the UUV on a slowly moving submarine through the torpedo tube; b) recovering the UUV on a slowly moving submarine into a specially designed location; and c) recovering the UUV to a stationary bottomed submarine.…”

“…Solutions where the UUV overtakes the submarine to enable it to dock into a specially designed arm, such as described by Currie et al (2014) and Irani et al (2014), require the UUV to be able to travel faster than the submarine which is receiving it. This can pose serious problems, as it is difficult to operate a submarine safely at low speeds, and even the top speed of a UUV is slow by comparison to that of a submarine.…”