ME Seminar by Dr. Firat Eren -Pose detection and control of Unmanned Underwater Vehicles (UUVs) utilizing an Optical Detector Array and Airborne Lidar Bathymetry (ALB) systems-27th May-Wednesday-at 13:40 in FENS L063
Part 1: Pose detection and control of Unmanned Underwater Vehicles (UUVs) utilizing an Optical Detector Array
As part of the research for development of a leader-follower formation between unmanned underwater vehicles (UUVs), this study presents an optical feedback system for UUV navigation via an optical detector array. Capabilities of pose detection (translational offsets in x, y, z-axes and also yaw rotation) and control in a static-dynamic system (e.g. UUV navigation into a docking station) and a dynamic-dynamic system (e.g. UUV to UUV leader-follower system) are investigated. In both systems, a single light source is utilized as a guiding beacon for a tracker/follower UUV. The UUV uses an optical array consisting of photodiodes to receive the light field emitted from the light source and convert it into positional feedback. Experimental results demonstrate that x, y and z-axes position estimations are accurate to within 0.5 m, 0.2 m and 0.2 m, respectively.
Part 2: Airborne Lidar Bathymetry (ALB) systems
Airborne lidar bathymetry (ALB) is a remote sensing technique to measure the depths of moderately clear coastal waters and lakes. ALB systems utilize aircrafts that transmit scanning, pulsed laser beams, usually a green (532 nm) pulsed laser beam to measure the nearshore topography and bathymetry. The main path of the ALB beam occurs once the beam interacts with the water surface (surface return). A small amount of energy returns to the ALB detector system and the remaining energy is refracted into the water column, where it undergoes scattering and absorption. As the light beam travels in the water column, the magnitude of the laser beam energy decreases exponentially in the water column based on the diffuse attenuation coefficient of the water. The final interaction is with the bottom where the laser beam reflects from the bottom and gets collected by the ALB detector system (bottom return). The range of the laser beam is calculated based on the time difference between the surface return and the bottom return.
Firat Eren received the B.S. degree in Mechatronics Engineering from Sabanci University, Istanbul, Turkey, in 2008, the M.S. degree in Mechanical Engineering from the University of New Hampshire, Durham, NH, USA, in 2011, and the Ph.D. degree in Mechanical Engineering at the University of New Hampshire, Durham, NH, USA, in 2015. His research interests include system dynamics and control, navigation, detection and control of underwater vehicles, optical systems, and communication. Currently, his research interests are in the field of airborne lidar bathymetry (ALB) systems with a focus on characterizing the measurement uncertainties due to the environmental effects such as variations in water column and seafloor characteristics.