Preliminary performance experiments in sea of a multi-legged ROV Crabster for Survey of Underwater Cultural Heritages

Abstract

Marine Robotics Laboratory of Korea Research Institute of Ships & Ocean Engineering has been developing a novel ROV(Remotely Operated Vehicle) who uses six artificial legs to move and control its motion. Its name is Crabster. Using precise control of these articulated joints of the legs, the robot is able to accomplish subtle and fine motion and attitude change for imaging sonars and optical cameras. In addition, the ROV walks on sea floor minimizing sediment blowing and can keep its underwater position better against currents and flow.

As these advantages are considered to be suitable for marine archaeology investigation, we conducted preliminary tests to evaluate the mission capabilities for search and recovery of underwater artifacts near the find-spots of Mado shipwrecks in the west coast of the Korean peninsula from April to May in 2015.

The Crabster is equipped with a scanning sonar, an acoustic camera, several optic cameras, LED lights, an ADCP(Acoustic Doppler Current Profiler), an altimeter, a CTD(Conductivity, Temperature, Depth) sensor in default. A magnetic sensor also can be added if necessary. Two manipulators are installed on the front two legs. Maximum operating depth is 200m.

The Crabster could do forward and backward walking, rotating and side-stepping. And circular acoustic images and high-resolution acoustic images were acquired using the scanning sonar and the acoustic camera, respe