Electromagnetic Launch System Research Articles

Characteristic Analysis and Modeling of Network Traffic for the Electromagnetic Launch System

The electromagnetic launch system (EMLS) is a kind of large-scale complex system with strong mechanical, electrical, and hydraulic coupling. The effective operation of the system requires the support of advanced and reliable health management system, and the function of the health management system relies on the network traffic to complete data transmission and interaction. Through protocol filtering and time-frequency characteristic analysis of network traffic, it is found that the system mainly includes CIP and TCP; traffic of CIP shows continuity and stability, while traffic of TCP shows sparsity and impact. Based on the analysis of traffic characteristics, an SVR-ARMA network traffic model is established, which improves the prediction accuracy and performance of network traffic and provides a reliable technical guarantee for the fault diagnosis and health management of the EMLS.

Improved study on position measurement system for linear motor applied in electromagnetic launch system

The linear motor applied in electromagnetic emission system uses a closed loop position control strategy, which needs a set of position measurement system with high reliability, high resolution and integration to achieve real-time acquisition and analysis of position signals. The existing position controller is based on the simple logic chip design without memory function, and does not have the storage analysis and preprocessing function to position signals. Therefore, the system has insufficient scalability, low integration and reliability. Aiming at the improvement of the existing position measurement system, an intelligent position measurement system integrating the functions of position signals acquisition, processing and uploading, data storage and analysis is proposed in this paper, and its working principle and system composition are discussed in detail. The position, speed and acceleration obtained on the electromagnetic emission platform are in good agreement with the expected value of the system. As results, the feasibility and accuracy of the improved integrated intelligent position measurement system are verified, and the control performance of the system is also satisfied well, which can be good guidance and reference for subsequent engineering practice.

Simulations on Saddle Armature With Concave Arc Surface in Small Caliber Railgun

Keeping good electrical contact between armature and rails is an important issue in the electromagnetic launch process. At the start of railgun launching with driving current ramp-up, the appearance of aluminum coating tends to be concentrated on the outsides of rails, which indicates current concentration on the edge of armature resulting in the armature edge erosion. The current distribution in the railgun determines its efficiency and contact performance of armature/rail sliding. To improve the electromechanical performance, one type of armature with concave arc surface and saddle structure is designed by removing arch forms from the conventional flat armature and adopts saddle structure. Using a finite-element software to establish a 3-D perfect electric contact simulation models on static condition, the current density distribution of armature, inductance gradient of railgun, and erosion area of armature with various central angles $\varphi $ was numerically simulated. The results show that: 1) in the nonaugmented railgun system, the increase in the central angle $\varphi $ is beneficial to reduce the maximum current density value of contact interface and the erosion area of armature, but it is not conducive to the improvement on the electromagnetic launch system’s inductance gradient and 2) in the augmented railgun system, the change of the central angle $\varphi $ has little effect on the maximum current density value of contact interface and the electromagnetic emission system’s inductance gradient, but the influence on the erosion area is obvious. Based on the above-mentioned work, the improved armature structures are proposed.

An Initial Survey of the Life of Rail for Electromagnetic Launch

The rail life is an important factor that influences the rail-type electromagnetic launch (EML) engineering. This paper gives an introduction about the structure of the rail-type EML system, makes an analysis of some indirect or direct factors that affect the rail life, and points out the sectional characteristics of the rail life. By optimizing the armature-rail structural design and material matching and taking measures to control the discharge waveform of pulse current, it is possible to prevent the rail surface from being damaged. However, the mechanical fatigue caused by multiple launches and the plastic deformation under thermal stress will result in a decrease in performance of the rail.

Analysis of GFRP insulator characteristics under multiphysical fields in electromagnetic rail launchers

The glass fiber-reinforced polymer (GFRP) insulators in electromagnetic rail launchers (EMRLs) work in a complex environment coupling electromagnetic, thermal and structural fields. Ablation, metal deposition, fracture and other destructive forms easily appear in GFRP insulators, which will affect the efficiency and service life of the electromagnetic launcher system. To explore the factors causing insulator performance degradation, a coupling model of multiphysical fields, including electromagnetism, temperature and structure, was established to analyze the physical load on the GFRP insulators in EMRLs. And based on the results of the coupling numerical analysis, delamination or fracture may occur in the middle of insulators. An insulator sample was experimentally analyzed after electromagnetic launch tests to verify the simulation conclusions and to obtain the failure mechanism of GFRP insulators under extreme environments of multiphysical fields. During electromagnetic launching, the rails repeatedly compress the GFRP insulators and cause cracking of the GFRP insulators. High temperature causes carbonization and metal contamination on the surface of the GFRP insulators, which results in a decrease in surface resistivity. In addition, there were pits on the surface of the GFRP insulators, possibly due to the armature planing against the GFRP insulators during electromagnetic launching.

Conceptual Models of HTS Levitation and Linear Propulsion System

High-temperature superconductor (HTS) materials, including HTS wires and bulks, become available to apply in transportation applications such as various hybrid levitation and linear propulsion systems. In this paper, for the evacuated tube transportation and electromagnetic aircraft launch system applications, two different types of hybrid HTS levitation and linear propulsion systems have been designed and modeled, respectively. The levitation force and electromagnetic thrust performance of the systems have been studied by a numerical and finite element method. With the principal parameters' verification, this work forms a basis for the structural and electromagnetic design of a hybrid HTS levitation and linear propulsion systems for practical hyper flight applications.

Performance Analysis of Electromagnetic Railgun Launch System Based on Multiple Experimental Data

As an emerging kinetic damage weapon system, railgun has attracted much attention due to its remarkable advantages such as high initial speed, high kinetic energy, high shooting speed, high emission density, low cost, and antijamming. However, there are currently degradations of electromagnetic railgun launch performance and reliability, the limited service life as well, resulting from rail damage such as the transition erosion and grooving damage. Based on 24 consecutive shots, this paper presents the statistical analysis of B-dot probe data, aiming to show the working stability and reliability of the electromagnetic rail launch system when consecutive firing. On the basis of current data and B-dot probe data, the speed-displacement curve was obtained by simulation, through which it is easy to get the movement state of the armature in the launch track. Finally, by checking the disassembly of the launch rail, this paper analyses the damage states of launching rail after the 24 consecutive launch experiments. Through the above three aspects of research and analysis, this paper could be the reference for the further research and analysis on the performance and lifetime of railgun.

Analysis of a Measurement Method for the Railgun Current and the Armature’s Speed and Initial Position

This paper introduces a measurement method for the railgun current and the armature’s speed and initial position for electromagnetic launch systems. The measurement device consists of several parts: a current B-dot probe, several speed B-dot probes, the data acquisition system, and a computer. A calibration experiment was done by comparing with another commercial Rogowski coil. The measured instantaneous continuous speed curve of the armature has a characteristic of extrapolation and shows clear physical meaning. At the same time, the method can also give us the main transient railgun current and the armature’s initial position data. The results show that the method can get the railgun transient main current waveform, the armature’s instantaneous continuous speed waveform, and the initial position data simultaneously. It would benefit the electromagnetic launch system design.

Electromagnetic launch system based on a Halbach array configuration

Electromagnetic launch system based on a Halbach array configuration

Electromagnetic launching technology and boron at Moon for Space

Gelecek yıllarda, ay yerinde keşfedildiğinde, aydan uzaya malzeme nakliyesi yeteneklerinin geliştirilmesi planlanmaktadır. Uzay araçlarının yakıt ikmali için gerekli oksijen gibi ay malların yörüngedeki depolara taşınaması sağlanacaktır. Genel olarak aydan malzeme nakliyesi söz konusu olduğunda EMFS (Elektromanyetik Fırlatma Sistemi) teknolojisinin, yakın gelecekteki üstünlükleri çok iyi açıklanabilir. EMFS’nin kimyasal fırlatma sistemine göre, yüksek kapasiteli taşıma, yüksek güvenlik ve çevresel sürdürülebilirlik ile düşük bakım maliyetleri ve yüksek verimlilik gibi çeşitli avantajları bulunmaktadır. Sunulan ön konseptin geliştirilmesi ve bu tür bir sistemle dağıtımının fizibilite ve net faydası ile ilgili, yüksek yük taşıma kapasitesine sahip oluşu EMFS’yi desteklemektedir. EMFS halen sürdürülen bir çalışmadır ve özellikle donanım geliştirme aşamasında dikkate alınması gereken birçok zorlukları bulunmaktadır. Bu çalışmada Yüksek Sıcaklık Süperiletken (HTSC) MgB2 gibi malzemeler, ana güç üretimi, veriyolu çalışması, endüktif enerji depolama, devre açma anahtarları, başlatıcı bobinler ve yükler dahil, birçok EMFS bileşenleri için yaygın olarak kullanılan uygulamalardır.

A High-Temperature Superconducting Pulsed-Power Supply Circuit With ICCOS

Recently, inductive energy storage systems have attracted interests due to high energy densities. The high-temperature superconducting pulsed-power supply (HTSPPS) is one inductive PS topology for electromagnetic launching system. The topology can achieve a high amplitude load current and cut down the electrical losses due to the zero resistance characteristic of superconducting inductors. However, in this topology, the integrated gated commuted thyristor is used as a switch and cannot withstand high current, which limits the expansion of the system. Besides, it has significant current amplification ability as a single unit, but one module cannot provide sufficient amplitude and appropriate pulsewidth for the load current of the electromagnetic launching. In this paper, by applying the principle of inverse current commutation with semiconductor devices (ICCOS) in the HTSPPS, a novel circuit topology called HTSPPS with ICCOS is presented. This topology is analyzed and the multiple modules system is established. Simulation results show that the HTSPPS with ICCOS exceeds the current limitations of the original one and ensures the reliable cutting off of the main switch. It has potential applications in the future of high-energy systems while reducing the cost greatly. By asynchronous cooperative triggered discharge of the multiple HTSPPS with ICCOS modules in parallel, the appropriate amplitude and flat shape current of the load can be achieved through the careful design of the trigger time.

Feasibility Study on SSTO Rocket with an Initial Velocity Given by EML

This paper studies the feasibility of the single-stage-to-orbit (SSTO) rocket with an initial nonzero velocity given by the auxiliary electromagnetic launch (EML) system. First, the development history of the SSTO rocket is sketched. Then, on the basis of Ziolkovsky formula, the preliminary feasibility analysis of SSTO rockets is proposed, which is very helpful to draw the boundary of feasible SSTO rockets’ payload ratios, and shows the difficulty of SSTO without the initial velocity. Furthermore, deriving from the rocket’s dynamic model in the longitudinal plane, a theoretical relationship function between the initial velocity and the maximum payload ratio of SSTO rockets is emphatically researched. Then, taking some typical SSTO rockets’ prototypes or demonstrators as example, based on the corresponding trajectory simulations of their nonlinear dynamic models, the initial velocities for the feasible SSTO scheme are achieved under different maximum payload ratios. Finally, the conclusion is presented by analyzing the simulation results of the aforementioned study, and the application scope of SSTO rockets with EML technology is introduced in the terms of the mission feasibility and economics.

Quantitative Comparison of Linear Flux-Switching Permanent Magnet Motor With Linear Induction Motor for Electromagnetic Launch System

To incorporate the merits of simple and robust movers of induction linear motors and higher power factor and high efficiency of permanent magnet linear motors, a new long primary double-sided linear flux-switching permanent magnet (DSLFSPM) motor is proposed, investigated, and quantitatively compared with linear induction motors (LIM) for the electromagnetic launch system. First, the topology, operation principle, and electromagnetic performance of the DSLFSPM motor have been investigated. Then, in order to analyze the LIMs comprehensively, three LIMs have been designed based on the same overall dimensions and other key parameters. Finally, the electromagnetic performance of DSLFSPM motor and LIMs have been compared and summarized. The results show that the DSLFSPM motor has some merits such as higher efficiency, higher power factor, more robust mover, larger thrust force, and smaller force ripple than LIM motors. In order to validate the simulation results, a small-scale prototype of DSLFSPM motor has been built and measured.

Research on TBCC-RR Reusable Vehicle Launch System Based on Electromagnetic Propulsion

The traditional non-reusable launch vehicle is the main approach to complete space launch mission. But the traditional rocket is inefficient and uneconomical, the more economical space launch approach has been studied in recent years. Two-Stage-To-Orbit(TSTO) reusable launch configuration which is combined Turbine Based Combined Cycle (TBCC) with reusable rocket (RR) is one of the main trends of current research. Based on TBCC-RR approach, a new design was proposed to improve the carrying capacity. In this design, the electromagnetic propulsion system (EMPS) was applied to increase the initial speed as the first stage engine, leaving the TBCC-RR to take care of the rest launch job. The overall concept of To-Orbit system was constructed and the electromagnetic launch system model was established. Then the mathematic model of EMPS-TBCC-RR-To-Orbit system is simulated and calculated. The result shows that EMPS is capable of accelerating the vehicle, which weighs hundreds of tons, up to one hundred meters per second, using EMPS can reduce the takeoff weight of the spacecraft and significantly enhance the carrying capacity of the spacecraft. Therefore, it is foreseeable that EMPS has a certain potential in the future space launch mission.

Moon-based planetary defense campaign

The Moon is an ideal location to launch intercepting missions to life-threatening and catastrophic asteroids. The effectiveness of the interception greatly depends on the weight of the spacecraft. Unfortunately, interceptors launched from the Earth lose more than 98% of their weight by burning the majority of their onboard fuel and by jettisoning their lower stage structures before entering a heliocentric orbit. However, if interceptors are launched from the Moon by a lunar surface accelerator, they can enter a heliocentric orbit without consuming any onboard fuel or jettisoning any part of the spacecraft. A 5-ton construction package, which consists of robots and industrial production equipment, would enable mining on the moon and construction of a 3.5 km-long, 5,000-ton accelerator.Large asteroid impacts have and will inevitably occur, and it is important to be prepared to avoid catastrophes, but they may not happen immediately or even within the next fifty years. The future planetary defense system must be a dual-use system, which continuously provides a secondary benefit to justify its operation and maintenance costs. When it is not defending the planet, the Lunar Electromagnetic Interceptor Launch System (LEILAS) can send over a thousand tons of construction material and fuel annually to the Low Earth Orbit (LEO) or Earth-Moon Lagrange Point Two (EML-2) to build space stations and to construct large spacecraft for deep space missions.

Analysis and optimization of a new double- sided permanent magnet linear synchronous motor for electromagnetic launching

Double-sided-moving-magnet ring-winding permanent magnet linear synchronous motors (DSMM-R-PMLSMs) offer high thrust density and power factor, light mover quality, strong structure, segmented control, and powering convenience making them the favored choice for use as electromagnetic launch systems. In this paper, we analyze the mover magnetic field and propose a DSMM-R-PMLSM with a new mover structure with the aim of achieving a large thrust and high acceleration in the linear motor. The dynamic characteristics are obtained by setting up a mathematical model of this motor type, and the thrust performances of movers with different structures under normal and eccentric operation are compared and then rationalized by field-circuit combined analysis and separate prototype tests. The results show that the new mover structure lends the linear motor the merits of higher electromagnetic thrust, lighter mover quality and better acceleration, thereby providing a reference for future research on linear motors for electromagnetic launch systems.

Inductance gradient and current density distribution for T-shaped convex and concave rail cross-sections

Rectangular rail was the most widely used cross section shape for the rail gun electromagnetic launching (EML) system. Based on sector assimilation, the rail gun key parameter especially current density (J) and inductance gradient (L’) greatly affected. J decides the efficiency of EML and L’ decides the force acting on the projectile of EML. So, it is mandatory to look upon the sector assimilation of rails. In this paper T shape convex and concave shape rail cross section is proposed and rail gun key design parameters are calculated by varying its dimensions using Ansoft Maxwell 2-D eddy current solver which uses finite element analysis technique to calculate these parameters. The performance of rail gun discussed using the obtained values and it has been observed and that the compared with other considered rail geometries, the T-shaped concave model shows more impact on inductance value which causes uniform current density distribution over the rails.

High Rate Pulse Discharge of Lithium Battery in Electromagnetic Launch System

AbstractAimed at the miniaturization of the power-supply system for electromagnetic launch (EML) system, this paper deals with the problem of high rate pulse discharge of lithium batteries in the EML system. In order to reduce the number of batteries on series-parallel to increase the energy density, the factors such as safety, exotherm and life cycle must be taken into consideration, and there is need for optimization in terms of selection and design as well as discharge control of the battery. According to the power requirements of the EML system, the battery safety and discharge ability are important indexes in the aspect of selection and design, which refer to the design principle for selected batteries and the design scheme for raising their discharge ability under the precondition of discharge, and in the aspect of discharge control, the balancing-discharge control strategy is adopted to reduce the duration of high-rate discharge and the heat generation and extend the service life of batteries according to the EML operating conditions. Finally a test platform is established for verification.

Analysis of superconducting linear synchronous motor for electromagnetic propulsion

There is a high demand for electromagnetic launchers in applications such as electromagnetic catapults and launch-assist systems for spacecraft, owing to their advantages in terms of controllability and reusability. This work proposes a double-sided superconducting-magnet linear synchronous motor capable of large thrust densities that can satisfy the demands of high-load launcher systems. Ring windings and narrow-toothed structures were applied to increase the density of the armature winding and reduce cogging-torque-induced fluctuations, and superconducting magnet with iron-core was first proposed to produce a strong air gap magnetic field. Numerical simulations are used to construct a simulation model of the motor, which is then used to study the relationships between the thrust characteristics of the motor and the dimensions of its armature and air-gap length. The results of this analysis provide information on the optimal thrust characteristics of linear motors in electromagnetic launcher systems.

Modeling and Simulation of Railgun System Driven by Multiple HTSPPT Modules

In the rail-type electromagnetic launching system, the equivalent load of pulsed-power supplies (PSs) varies with the launching process, while it has a certain influence on the discharge of pulsed PS. However, in the analysis and design of pulsed PS, researchers usually use the fixed resistance and inductance to simulate the load, which is impossible to accurately study the characteristics of the pulsed PS. The electromagnetic launching needs high-amplitude current pulse. Therefore, in this paper, a mathematical model of electromagnetic launching system driven by multiple superconducting inductive pulsed PS modules is established. In this model, the fixed resistance and inductance load are replaced by the dynamic load model of the railgun; the effects of dynamic load and fixed load on the discharge characteristics are analyzed; the parallel discharge characteristics of multiple high-temperature superconducting pulsed-power transformer (HTSPPT) modules are studied; and the characteristics of the simple rail-type electromagnetic launching driven by multiple HTSPPT modules are analyzed. The simulation results show that a high amplitude of current pulse can be produced using synchronous parallel discharge of multiple HTSPPT modules. The simulation results show that when the resistance and inductance of load are fixed at 2 $\text{m}\Omega$ and 0.5 $\mu \text{H}$ , respectively, the current amplification factor is 15.666, and the maximum voltage of the auxiliary capacitor is 1079 V. In the dynamic load model, the current amplification factor is 17.174, and the error is 9.6%. The maximum voltage of the auxiliary capacitor is 983 V, and the error is 8.9%. Therefore, the discharge characteristics of pulsed PS can be more accurately studied using dynamic models.