Spiral path planning for docking of underactuated vehicles with limited FOV

Abstract

This paper proposes a novel approach for constructing a docking path for underwater vehicles, using a new spiral resulting of combining the Fermat and logarithmic spirals. The proposed spiral path has two properties that will help solve some of the challenges of docking autonomous underactuated vehicles (AUVs). The first property is that the spiral path reaches the entrance of the docking station without curvature, allowing a smooth transition when entering the docking station. The second is that the AUV never exceeds a certain bearing angle with respect to docking station. This last feature allows AUVs equipped with navigation sensors which have a reduced field of view (FOV), such as cameras or acoustic positioning systems, to always preserve the docking station inside the FOV. Furthermore, the paper presents an interpolation of the spiral using waypoints that are connected with segments of logarithmic spirals. This makes it possible to apply existing guidance laws to follow the docking spiral. The proposed spiral docking path has been experimentally tested using an autonomous underwater vehicle.

Learning an AUV docking maneuver with a convolutional neural network

“…In [10] a spiral path was proposed for reaching a docking station and at the same time preserve the field of view (FOV) of the transmitter or landmark mounted on the docking station for navigation purposes. In this paper, we propose an alternative solution to avoid the path planning.…”

“…Note that if the polar coordinates were used instead, this guidance system would only allow the vehicle to enter the docking station trough the centerline. The images and data used in this paper were obtained during the tuning and calibration phases of the experimental results published in [10]. The required images were obtained in the Marine Cybernetics Laboratory (MC-lab) at NTNU, Trondheim, Norway [11], in a tank of dimensions L: 40 m, H: 1.5 m and W: 6.45 m. The camera used to obtain the images was attached to an underwater vehicle which received real-time measurements of the robot's position and orientation were obtained from an underwater motion capture system, Qualisys, installed in the basin [12].…”

Path Following, Obstacle Detection and Obstacle Avoidance for Thrusted Underwater Snake Robots

“…However, the use of an oscillatory gait pattern causes steady state oscillations about zero for the cross-track error and the orientation, which is expected since it is difficult to achieve a purely non-oscillating motion for the CM and the orientation of underwater swimming snake robots (Kelasidi et al, 2016a(Kelasidi et al, , 2017b. These oscillations can be restrictive for several applications in subsea environment, such as for instance docking (Sans-Muntadas et al, 2017).…”

“…A comparison of these approaches is presented in Kelasidi et al (2017b) and Kelasidi et al (2016a). In addition, a docking approach for thrusted USRs using the joint angles to control the direction of the robot has been presented in Sans-Muntadas et al (2017). This paper presents a path following control strategy that is able to make the thrusted USR follow the desired reference path.…”

The Underwater Swimming Manipulator—A Bioinspired Solution for Subsea Operations

“…We define the heading of the USM, ψ, to be the heading of the front link in the inertial frame, and we use a simple but effective joint control strategy first proposed in [6] and more recently used in the experiments in [51]. The joint reference angles are set according to D e y < 0…”