A 2-D visual servoing for underwater vehicle station keeping

This paper introduces a 2-D visual servoing technique for the station keeping of an unmanned underwater vehicle (UUV) with respect to planar targets on the sea bed. The underwater vehicle is subject to sea current disturbances which make it drift from its desired position. Feature points from unmarked objects are extracted and tracked with a sparse feature tracker developed in-house [1]. The scene depth is estimated from a planar homography. To validate our approach, we emulate the dynamics of the surge and the sway degrees-of-freedom (d.o.f.) of an UUV model with a planar Cartesian robot in our water test tank. Successful station keeping experiments obtained with a range of sea current disturbances are presented.