Three-dimensional optimal path planning for waypoint guidance of an autonomous underwater vehicle

• An optimal 3D path is generated offline for waypoint guidance of an AUV.
• Four objective functions are selected and Pareto-front is found using the NSGA-II.
• A 3D guidance system is used for guidance of the AUV through the optimal paths.
• The dynamic modeling of a novel miniature AUV is derived.
• Heading autopilot and depth controller are designed for the miniature AUV.

In this paper, optimal three-dimensional paths are generated offline for waypoint guidance of a miniature Autonomous Underwater Vehicle (AUV). Having the starting point, the destination point, and the position and dimension of the obstacles, the AUV is intended to systematically plan an optimal path toward the target. The path is defined as a set of waypoints to be passed by the vehicle. Four criteria are considered for evaluation of an optimal path; they are “total length of path”, “margin of safety”, “smoothness of the planar motion” and “gradient of diving”. A set of Pareto-optimal solutions is found where each solution represents an optimal feasible path that cannot be outrun by any other path considering all four criteria. Then, a proposed three-dimensional guidance system is used for guidance of the AUV through selected optimal paths. This system is inspired from the Line-of-Sight (LOS) guidance strategy; the idea is to select the desired depth, presumed proportional to the horizontal distance of the AUV and the target. To develop this guidance strategy, the dynamic modeling of this novel miniature AUV is also derived. The simulation results show that this guidance system efficiently guides the AUV through the optimal paths.