This paper is concerned with the fault reconstruction observer design problem with unknown nonlinearities, external disturbances and faults. First, a neural-network-based fault estimation approach is developed to generate the estimations of the actuator failures. In this design, the neural network strategy is utilized to approximate the totally unknown nonlinear functions. Then, an iterative adaptive observer is designed to offer the accurate estimations of the sensor faults, where the estimations in the previous iteration are applied in the current iteration to guarantee the convergence of sensor fault estimation errors. The developed neural network observer design approach can reconstruct the states, actuator and sensor faults for the unmanned surface vessel simultaneously. Finally, a practical example of the unmanned surface vessel is presented to illustrate the effectiveness and the potential of the proposed observer technique.

Aiming at the problems of blind search, low environmental adaptability, and long path that exist in the Informed RRT* algorithm for AUV underwater 3D path planning, this paper introduces an improved version of the Informed RRT* algorithm. This enhanced algorithm introduces an adaptive step size to enhance the applicability and reduce the iteration count. Additionally, a bidirectional extension strategy is employed in the initial phase to minimize the time required for searching the initial path, and an angle constraint is added to improve goal-point orientation and search efficiency. A goal-directed sampling strategy is incorporated to further increase the efficiency of tree growth toward the goal point. Furthermore, a pruning strategy is used to optimize the found path by shortening the path length and reducing the number of path nodes, thus enhancing the smoothness of the path found by the algorithm. In this study, the underwater 3D environment modeling considers both the seabed topography and ocean currents, with ocean current information extracted and interpolated. The path length and the influence of ocean currents are taken as indicators to evaluate the path in the objective function. Simulation results demonstrate that the improved Informed RRT* algorithm provides a more effective solution for AUV underwater 3D path planning.

In this paper, a novel distributed tracking method is proposed for the problem of manoeuvring target tracking in sensor networks. Firstly, an adaptive adjustment tracking model is established by extended state observer (ESO) theory. Then, the consensus-based square-root cubature Kalman filter (SCKF) algorithm is proposed in order to improve the global accuracy and stability. In addition, the integrated model could reduce the influence of measurement noise. Finally, simulation is performed to verify the effectiveness of the scheme, whereby comparison results show that the estimation accuracy of the method proposed is higher than that of the traditional ESO and SCKF.

This paper presents a fixed-time cooperative guidance method with impact angle constraints for multiple flight vehicles (MFV) to address the challenges of intercepting large maneuvering targets with difficulty and low precision. A cooperative guidance model is proposed, transforming the cooperative interception problem into a consensus problem based on the remaining flight time of the flight vehicles. First, the impact angle constraint is converted into the line of sight (LOS) angle constraint, and a new fixed-time convergent non-singular terminal sliding surface is introduced, which resolves the singularity issue of the traditional sliding surfaces. With this approach, LOS angle rate and normal overloads can converge in fixed time, ensuring that the upper bound of the system convergence time is not affected by the initial value of the system. Furthermore, the maneuvering movement of the target is considered as a system disturbance, and an extended state observer is employed to estimate and compensate for it in the guidance law. Lastly, by applying consensus theory and distributed communication topology, the remaining flight time of each flight vehicle is synchronized to ensure that they intercept the target simultaneously with different impact angles. Simulation experiments are conducted to validate the effectiveness of the proposed cooperative interception and guidance method.