Robotics and Autonomous Systems 53 (2005) 214–229 Proximal object and hazard detection for autonomous underwater vehicle with optical fibre sensors Daniel J.F. Toal ∗ , Colin Flanagan, William B. Lyons, Sean Nolan, Elfed Lewis Department of Electronics and Computer Engineering, University of Limerick, Limerick, Ireland Received 28 November 2003; received in revised form 28 August 2005; accepted 13 September 2005 Available online 27 October 2005 Abstract This paper describes short range and tactile optical fibre sensors for marine applications. The sensors are designed for obstacle avoidance on unmanned underwater vehicles (UUVs) operating in confined spaces, but have other possible applications. The fibre sensors augment the sensory abilities derived from ultrasonic and other sensors employed for marine proximity measurement. Of particular interest is proximity detection in the “near” (less than 1 m) and tactile areas. The paper describes the basic principle of operation and alternative sensor configurations. Results are given based on laboratory tests and deployment on a mini autonomous submersible in a test pool. © 2005 Elsevier B.V. All rights reserved. Keywords: Autonomous underwater vehicles; Optical fibre sensor; Obstacle avoidance; Behaviour-based control 1. Introduction In the realm of submersible technology, the autonomous underwater vehicle (AUV) is coming to maturity. Up till now the workhorse for offshore oil and gas operations and marine survey has been the remotely operated vehicle (ROV). In the case of both ROVs and manned submersibles, a human pilot con- trols the vehicle based on visual information (video and sonar images relayed to surface) and sonar sen- sor data. A major disadvantage with this technology is ∗ Corresponding author. Tel.: +353 61 202264; fax: +353 61 338176. E-mail address: daniel.toal@ul.ie (D.J.F. Toal). cost-of-use due to the requirement for a surface sup- port vessel and human pilot for every mission. Still, ROV technology is used extensively by the offshore oil and gas industry in the inspection and mainte- nance of sub-sea oil and gas plant such as pipelines and risers. For an AUV an onboard controller inter- prets sensor input and delivers commands to robot actuators to implement mission objectives. Key to the success and effectiveness of the navigation and control scheme employed by the onboard controller are vehi- cle sensors. Advances in navigation, guidance, obsta- cle classification/avoidance, and control of AUVs are necessary before AUVs overtake the ROV as the off- shore oil and gas industry’s work-vehicle of choice. However, over the last number of years the number 0921-8890/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.robot.2005.09.007