Station-keeping strategy for wave gliders considering obstacle area

An obstacle mode station-keeping strategy that considers obstacles in the station-keeping center area is proposed for wave gliders (WGs) to cope with special applications such as oil spill monitoring on drilling platforms and observation around the island. Different from the traditional station-keeping strategy which requires closing in the preset position as much as possible, this strategy uses the adaptive integral line of sight (AILOS) algorithm to make the WG sail around the preset obstacle area. A partitioning control strategy based on distance error is introduced to divide three areas according to the risk level: warning area, escape area and obstacle area. A tan-type barrier Lyapunov function (BLF) is introduced into the warning area control method to determine the boundary. To avoid the potential risk of collision, the escape area control strategy is to make the WG move away from the obstacle area as quickly as possible. Simulation and sea trial results verified the capability of the proposed station-keeping strategy in a stable ocean environment and the station-keeping safety of the WG using this strategy under extreme situations.