Underwater robots for cable following

A sensor fusion technique is proposed for autonomous underwater vehicles (AUVs) to track underwater cables. The focus of this paper is to solve the two practical problems encountered in optical vision based systems in underwater environments: (1) navigation of AUV when cable is invisible in the image; and (2) selection of the correct cable when there are many similar features appearing in the image. The proposed sensor fusion scheme uses the dead reckoning position uncertainty with a 2D position model of the cable to predict the region of interest in the image. This reduces the processing data, increases the processing speed and avoids tracking other similar features appearing in the optical image. The proposed method uses a priori map of the cable for AUV navigation when the cable features are invisible in the predicted region in the image. An experiment was conducted to test the performance of the proposed algorithm using the AUV "Twin-Burger 2". The experimental results obtained show how the proposed method handles the above-mentioned practical problems.