Hybrid Autonomous Underwater Glider (HAUG) Obstacle Detection and Avoidance

Hybrid Autonomous Underwater Glider (HAUG) is a vehicle used for underwater missions such as monitoring and finding new underwater resources. HAUG has good endurance and maneuverability compared to conventional Autonomous Underwater Vehicle (AUV) and Autonomous Underwater Glider (AUG). It is because HAUG has two operational modes. They are AUV and AUG's operational mode. When HAUG is in some missions, it may be faced with an obstacle that can be a threat to the HUG's safety. Therefore, HAUG should have the ability to detect and avoid obstacles. Gemini 720 im Imaging Forward Looking Sonar (FLS) is used for obstacle detection in this work. The main issue of underwater obstacle detection is noisy data received by sonar. Therefore, by designing an obstacle detection, it will overcome those issues. Frost filter and local histogram entropy are used in the sonar data processing. The processed sonar data are provided in the local sonar frame then will be used by obstacle avoidance systems. BK-product fuzzy and reactive algorithms are used for obstacle avoidance. In this paper, we added some procedures to those obstacle avoidance algorithms to handle the huge or non-complex u-shaped obstacle. Both of the obstacle detection and avoidance simulations are in ROS (Robot Operating System). The obstacle detection simulation shows that the different sizes of obstacles can be detected with average errors of approximately 0.335 meters. The obstacle avoidance simulations are in AUV's mode with no ocean current applied. The obstacle avoidance simulated in this work is with two cases. Using simulated lidar as a sensor's output and using sonar's plugin provided by Gazebo. The obstacle avoidance using simulated lidar shows that the error's value is approximately 10.12 meters, 103.62 meters, and 354.4 meters respectively. The obstacle avoidance simulation with sonar's plugin shows that the error's value is 6.55 meters.