Concise behavior arbitration mechanism for the ISiMI100 AUV

This paper presents a concise behavior arbitration mechanism for the ISiMI100 Autonomous Underwater Vehicle (AUV) which was developed by MOERI-KORDI. The control architecture of the ISiMI100 AUV is a hybrid architecture consisting of the mission layer, the behavior layer, the logical sensor layer, and the library layer. This paper focuses on the behavior layer supported by the Tiny Mission Language on the mission layer. The Tiny Mission Language can describe an AUV mission with the composition of behaviors. After input process of sensors, the mission layer activates or inactivates behaviors by given mission and the behavior arbiter selects and performs active behaviors according to defined rule. The arbitration rule is very simple. One rule is that active behaviors having unique priority are executed sequentially from high priority to low priority. Another is that running behavior can activate or inactivate other behaviors having lower priority than current priority. This arbitration mechanism based on priority is deterministic and robust. The execution of active behaviors repeats periodically and the execution time of a cycle is less than 10ms to keep control frequency as 10Hz. The arbitration mechanism was verified by 3 sea trials in the sea near south of Korea, and the experimental results show valid and robust execution on the behavior layer.