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In this paper, a novel nonsingular finite-time backstepping controller is constructed for trajectory tracking of marine vessel subject to unknown external disturbances. Firstly, in the presence of disturbances, a disturbance observer (DO) is proposed to estimate and compensate the disturbances exactly in finite time. Secondly, a finite-time tracking controller is designed in the classical backstepping procedure, however, the inevitable singularity appears in calculating the derivative of virtual control. Furthermore, for overcoming this singularity, a nonsingular finite-time backstepping controller is designed by adopting a finite-time command filter to estimate the derivative, instead of calculating it directly. Theoretical analysis demonstrates the closed-loop system is finite-time stable. Finally, simulation results and comparisons illustrate the effectiveness of the proposed method.

In view of the flight characteristics of cruise missiles, a new path planning area map, slant distance map, is proposed on the premise that cruise missiles move at constant speed at a certain altitude. The path planning diagram is compared with the one without improvement. Particle swarm optimization (pso) is used to build a mathematical model for intelligent path planning and simulation of multiple cruise missiles. The results show that slant distance graph and particle swarm optimization can solve the path planning problem of multiple cruise missiles.

The aim of this work is to design and build a hardware-in-the-loop simulation (HILS) system for a guided bomb. This paper presents a design scheme, based on the guidance and control system of the guided bomb, and the corresponding test flow of a guided bomb control system to provide a support platform to verify its performance. The design HILS test based on actual conditions is also described. Based on the similarity theory, we provide three examples of simulation experiments. The simulation results confirm the effectiveness of the HILS system of the guided bomb.

A novel time synchronization scheme using superimposed training symbols is proposed for the generalized frequency division multiplexing (GFDM) systems. The training symbols of the GFDM symbols are firstly generated with the same amount of out of band emission (OOBE) as that of a GFDM symbol, and then are superimposed on the GFDM signal in the time domain without sacrificing bandwidth efficiency, to meet the requirement of the future wireless communication systems. The OOBE property and the performance of the proposed superimposed training for time synchronization over the Rayleigh multipath channel are verified with simulations. The simulation results validated the correctness and efficiency of the proposed synchronization scheme.

In this paper, a thin-disk laser with the output power of kW level is demonstrated. The laser used is Nd:YAG laser medium for easiness to reach the threshold power densities of the pump and less heat to dissipate from the crystal. The thin disk of 1 mm thickness with 1.5-at. % Nd doped and a simple 4-pass pump coupling system is designed to fulfill the total absorption of the pump light. 2D-stacks diode array works as the pump source and a conventional optics is used for efficient and uniform pumping.