Electronic charts and marine radars are indispensable equipment in ship navigation systems, and the fusion display of these two parts ensures that the vessel can display dangerous moving targets and various obstacles on the sea. To reduce the noise interference caused by external factors and hardware, a novel radar image denoising algorithm using the concept of Generative Adversarial Network (GAN) using Wasserstein distance is proposed. GAN focuses on transferring the image noise distribution between strong and weak noise, while the perceptual loss approach is to suppress the noise by comparing the perceptual characteristics of the output after denoising. Afterwards, an image registration method based on image transformation is proposed to eliminate the imaging difference between the radar image and chart image, in which the visual attribute transfer approach is used to transform images. Finally, the sparse theory is used to process the high frequency and low frequency subband coefficients of the detection image obtained by the fast Fourier transform in parallel to realizing the image fusion. The results show that the fused contour has a high consistency, fast training speed and short registration time.

To address the sideslip phenomenon caused by the lack of lateral constraints in path following of underactuated hovercraft, this paper proposes a path following control algorithm. The algorithm adopts a method of controlling two control points on the underactuated hovercraft, in which the first control point ensures position tracking accuracy while the second point decreases the sideslip angle. To further decrease the sideslip effects during turning maneuvers, a speed regulator based on path curvature radius is designed to adjust the desired speed by balancing centrifugal force and lateral dynamic constraints. Simulation results show that the sideslip angle can be reduced while the position error exponentially converges to zero.

This article addresses the problem of singularity-free fixed-time tracking control for multiple unmanned surface vehicles (USVs) with model uncertainties. To compensate for the uncertain nonlinearities in the multi-USV systems, fuzzy logic approximators are employed to estimate unknown hydrodynamic parameters. By integrating adaptive fixed-time control theory with backstepping methodology, a novel singularity-free fixed-time consensus control scheme is developed, incorporating a error switching mechanism to prevent singularities arising from the differentiation of speed control laws. Through rigorous analysis via fixed-time stability theory, the proposed control scheme guarantees that consensus tracking errors reach a small region around zero within fixed-time. Numerical simulations demonstrate the efficacy of the presented method.

This paper proposes a finite-time fault-tolerant tracking controller for an air cushion vehicle (ACV) based on the backstepping method. A four-degree-of-freedom ACV with model uncertainties is considered, where the unknown nonlinearities can be approximated by radial basis function neural networks. By combining the command filter with the backstepping method, the calculation of virtual control derivatives is avoided. The proposed adaptive finite-time fault-tolerant controller can estimate the unknown boundaries of actuator fault parameters so that an unbounded number of actuator faults can be processed. The proposed theory ensures that the stability of the system and its tracking performance can be guaranteed in a finite time. This paper focuses on simulation-based work. Simulation results confirm the capability of the proposed trajectory tracking control scheme.

Effectively addressing the formation control of ABS-assisted hovercraft systems with heterogeneities, unavailable leaders’ convex combination states, nonlinearities, and mixed disturbances poses significant challenges. This paper proposes a distributed neuroadaptive formation tracking strategy of ABS-assisted hovercraft systems for the first time, where aerial base stations (ABSs) are composed of unmanned aerial vehicles (UAVs) for data distribution and computation offloading. Firstly, UAVs are designed to track the virtual-leader while shaping a fixed formation, and the observer is devised for each follower hovercraft to estimate the convex combination states of UAVs. Then, output regulation equations are employed to transform heterogeneous systems into a compact form via the Kronecker product, while neural networks (NNs) are introduced to compensate for model nonlinearities. Furthermore, based on random differential equations (RDEs) combined with Lyapunov theory, the noise-to-state practical stability in probability (NSPS-P) property of the error dynamics under mixed disturbances can be obtained. Finally, simulation examples demonstrate that the outputs of follower hovercrafts rapidly achieve a time-varying formation and rotate around convex combination states of leader UAVs simultaneously.

This article investigates the problem of adaptive fault-tolerant trajectory tracking control for a differential-driven unmanned surface vehicle (USV) with propeller faults. A new USV control system considering a propeller servo loop is established, which is composed of kinematics, kinetics including unhealthy surge force and yaw moment, and propeller motor shaft speed dynamics. Firstly, the control design of the kinematic level derives the virtual surge speed and yaw rate, which can accurately guide the tracking design of the kinetic level. Secondly, by estimating the bound of the unknown propeller fault parameters, the virtual fault-tolerant control laws are constructed in the kinetic level, which can generate the desired motor angular shaft speeds with an active compensation feature. Thirdly, in the control design of the propeller servo loop, the command duty cycles are designed to force the actual motor shaft speeds to track the desired signals produced from the kinetic level. It can be proven that tracking errors are semiglobally ultimately uniformly bounded based on Lyapunov stability theory. Finally, simulations considering single propeller and twin propeller faults prove the validity of the developed method.