The time-sampling control strategy has communication discontinuities in the control of multiple AUVs (autonomous underwater vehicles). To overcome this problem, a distributed event-triggered communication mechanism is proposed to make each AUV communicate only when its own state is updated, which reduces the frequency of communication and improves the stability. This mechanism has better adaptability for formation control between heterogeneous AUV groups. At the same time, two consistency control algorithms based on event-triggered for homogeneous and heterogeneous AUV groups are studied, respectively. The known consistency algorithms are applied to the control of heterogeneous AUV groups for comparative analysis. The simulation results demonstrate that the number of communication among AUVs under the event-triggered control strategy can be significantly reduced. Therefore, the stability of the system is improved. Compared with the traditional consensus algorithm, the algorithm proposed in this paper has advantages in the control of heterogeneous AUV groups.

In this letter, a novel high-power microwave (HPM) phase shifter (PS) is proposed. The PS is based on the principle of tunable electrical length and can shift phase by turning a rotary choke piston in a toroidal-shaped phase-shifting segment. The simulation results show that the PS can shift phase linearly over 360 $^{\circ}$ in the frequency range of 2.7–2.9 GHz, the power handling capacity of this PS exceeds 450 MW, and the phase-shifting precision reaches 3.29 $^{\circ}$ / $^{\circ}$ at the central frequency. The cold test showed that the measured phase-shifting performance of the PS is in good agreement with the simulation results, furthermore, the PS can shift phase within 360 $^{\circ}$ in 30 ms, the return loss is higher than 12 dB, and the insertion loss is less than 0.4 dB.

An improved multi-objective particle swarm optimization algorithm is combined with a machine learning classifier to meet the needs of underwater manned/unmanned cooperative warfare architecture evaluation. Firstly, based on the traditional Cauchy variation method, the particles in the population are disturbed in a dynamic way so that the particles trapped in the local optimal can jump out of the local optimal, and the convergence performance of the particle swarm optimization is improved. Secondly, the accuracy of the index set is analyzed based on the CART decision tree algorithm and the IWRF algorithm. A screening method of key indexes with fewer evaluation indexes and high evaluation accuracy is developed to solve the problem of a large number of evaluation indexes and unclear correlation of the underwater combat system. Through simulation, the extraction results of key indicators were verified, and the reliability coefficient of the final simulation experiment was 0.93, which can be considered as high reliability and effectiveness of the key indicators extracted in this study. By combining multi-objective optimization with machine learning and weighing evaluation efficiency and accuracy, a high-precision and rapid evaluation of a few indicators is achieved, which provides support for establishing an evaluation model of SoS architecture for underwater manned/unmanned cooperative operations. This research result can provide inspiration for the evaluation and evaluation of the system in order to analyze the accuracy of indicators and the evaluation effect and carry out research by simulating the actual system with tools with a high simulation degree.

The cathode emission surface (CSD) defect is one of the main reasons for the performance difference in relativistic magnetron multiple pulses operation, but its impact mechanism is unclear. In this work, the kinetics model and the particle in a cell method were used to explain the influence of the emission defect effect. The results indicate that the CSD effect causes deformation of the electron sheath and reduces the current. The emission defects in the azimuthal direction −π/2<nφ*<π/2 region favor the electron bunching. Moreover, the emission defects on the cathode side near the accelerator in the axial direction weaken the axial drift issues. Our work will provide a basis for the large-area cathode design and facilitate the relativistic magnetron experimental analysis.

An efficient Cherenkov oscillator with gigawatt phase-controlled super-radiance (SR) pulses is studied for the application of coherent summation systems. To obtain phase-controlled SR pulses, an ultra-short seed pulse is required to be injected into the interaction space from the direction of the collector, which substitutes the impact of the spontaneous emission from the front edge of the electron beam. It means that, for a conventional Cherenkov oscillator, the injection seed pulse and output gigawatt SR pulse need to share the same channel. Therefore, an additional quasi-optical reflection system is needed to separate these two signals. To optimize such a scheme, we introduce a front extractor near the reflector and an injection channel at the side of the collector, allowing the output and injection channels to be independent of each other. Particle-in-cell simulations reveal that as the diode voltage is 260 kV, the beam current is 3.5 kA, and the magnetic field is 0.42 T, a short SR pulse with peak power of 1.93 GW is obtained. The corresponding conversion factor (ratio of average output power and input DC power) is up to 2.12. When the seed pulse has a rise time of 0.3 ns and a width of 0.2 ns injection, the phase of the seed pulse and the initiated SR pulse are closely correlated with the accuracy of 0.17 rad as the power ratio is down to −25 dB. The advantages of high efficiency and phase control make the oscillator a promising device used for the miniaturization and practicability of coherent summation systems.