High-altitude rescue is dangerous and difficult.A new rescue method is proposed here based on electromagnetically launched tethered nets.Four electromagnetic launching units are attached to a revolving platform,from w...High-altitude rescue is dangerous and difficult.A new rescue method is proposed here based on electromagnetically launched tethered nets.Four electromagnetic launching units are attached to a revolving platform,from which four projectiles are launched.The four projectiles are connected to a tethered net,bringing it into motion.As the tethered net approaches and comes into contact with the object,the object will be trapped,and the rescue task will then be completed as long as the tethered net can be restored along with the trapped object.The structural design of the electromagnetic launching unit is presented with the established mathematical model.The motion characteristics of the launched projectiles are studied and their exit velocities are modeled and measured.Terminal velocities of these projectiles are characterized,and the final shape and position of the projected tethered net are obtained.This study validates the feasibility of using electromagnetically launched tethered nets to perform high-altitude rescues.展开更多
On June 9,2025,CIIS held a launch event for its research report“Promoting Modernization Across Countries Through the Global Development Initiative.”The event was attended by CIIS President Chen Bo,Ambassador of Barb...On June 9,2025,CIIS held a launch event for its research report“Promoting Modernization Across Countries Through the Global Development Initiative.”The event was attended by CIIS President Chen Bo,Ambassador of Barbados to China Hallam Henry,Ambassador of Grenada to China Ma Yan,Ambassador of Timor-Leste to China Loro Horta,Ambassador of Bolivia to China Hugo Siles,Ambassador of Venezuela to China Remigio Ceballos Ichaso,Ambassador of Nepal to China Krishna Prasad Oli,Vice Director of the China Foreign Languages Publishing Administration and President of the Institute of Contemporary China and the World Yu Yunquan,Director of the Institute of International Strategy at Party School of the Central Committee(National Academy of Governance)Wu Zhicheng,and Vice Chairman of the National Global Strategy Think Tank at Chinese Academy of Social Sciences Wang Lei,all of whom delivered remarks at the launch.展开更多
In the era of global space industry’s rapid expansion,reusable launch technology has the advantage of cost reduction,but makes launch frequency and flight reliability remain critical.This study proposes that Artifici...In the era of global space industry’s rapid expansion,reusable launch technology has the advantage of cost reduction,but makes launch frequency and flight reliability remain critical.This study proposes that Artificial Intelligence(AI)would be the potential disruptive technology to solve these challenges.AI enables transformative capabilities for launch vehicles which are pointed out in four domains:Agile launch operations enabling automate testing,fault diagnosis,and decision-making for targeting hour-level launch cycles and minute-level fault resolution;high-reliability flight enabling real-time autonomous fault diagnosis,mission replanning,and fault-tolerant control within seconds during anomalies,potentially improving reliability by 1–2 orders of magnitude;rapid maintenance enabling real-time health monitoring and lifespan prediction for swift relaunch decisions;efficient space traffic management enabling predict/resolve orbital conflicts amid growing congestion from satellites and debris.The key challenges for AI applications are analyzed as well,including multi-system coupling,uncertain failure modes and narrow flight corridors,limited sensor data,and massive heterogeneous data processing.Finally,the study also proposes that AI promises substantial efficiency gains in launch vehicle design,manufacturing,and testing through multidisciplinary optimization and reduced reliance on physical testing.展开更多
As the performance of the box-type multiple launch rocket system(BMLRS)improves,its mechanical structures,particularly the plane clearance design between the slider on the rocket and the guide inside the launch canist...As the performance of the box-type multiple launch rocket system(BMLRS)improves,its mechanical structures,particularly the plane clearance design between the slider on the rocket and the guide inside the launch canister,have grown increasingly complex.However,deficiencies still exist in the current launch modeling theory for BMLRS.In this study,a multi-rigid-flexible-body launch dynamics model coupling the launch platform and rocket was established using the multibody system transfer matrix method and the Newton-Euler formulation.Furthermore,considering the bending of the launch canister,a detection algorithm for slider-guide plane clearance contact was proposed.To quantify the contact force and friction effect between the slider and guide,the contact force model and modified Coulomb model were introduced.Both the modal and launch tests were conducted.Additionally,the modal convergence was verified.By comparing the modal experiments and simulation results,the maximum relative error of the eigenfrequency is 3.29%.thereby verifying the accuracy of the developed BMLRS dynamics model.Furthermore,the launch test validated the proposed plane clearance contact model.Moreover,the study investigated the influence of various model parameters on the dynamic characteristics of BMLRS,including launch canister bending stiffness,slider and guide material,slider-guide clearance,slider length and layout.This analysis of influencing factors provides a foundation for future optimization in BMLRS design.展开更多
Sea-based rocket launches encounter significant challenges stemming from dynamic marine environmental interactions.During the hot launch phase,characterized by low-velocity ascent,the departure of the rocket from the ...Sea-based rocket launches encounter significant challenges stemming from dynamic marine environmental interactions.During the hot launch phase,characterized by low-velocity ascent,the departure of the rocket from the oscillatory platform exhibits heightened sensitivity to external disturbances.In the development stage,assessing the launch dynamics and the clearance between the rocket and framed launcher are crucial for improving the reliability of sea-based rocket launches in rough sea conditions.This study presents a high-fidelity dynamic model of maritime hot launch system,demonstrating 3.21%prediction error through rigorous validation against experimental datasets from comprehensive modal analyses and the full-scale rocket flight test.To mitigate collision risks,we develop a computational method employing spatial vector analysis for dynamic measurement of rocket-launcher clearance during departure.Systematic investigations reveal that in rough sea conditions,optimal departure dynamics are achieved at θ_(thrust)=270°nozzle azimuth configuration,reducing failure probability compared to conventional orientations.The developed assessment framework not only resolves critical safety challenges in current sea launch systems but also establishes foundational principles for optimizing adapter axial configuration patterns in future designs.展开更多
The research on optimization methods for constellation launch deployment strategies focused on the consideration of mission interval time constraints at the launch site.Firstly,a dynamic modeling of the constellation ...The research on optimization methods for constellation launch deployment strategies focused on the consideration of mission interval time constraints at the launch site.Firstly,a dynamic modeling of the constellation deployment process was established,and the relationship between the deployment window and the phase difference of the orbit insertion point,as well as the cost of phase adjustment after orbit insertion,was derived.Then,the combination of the constellation deployment position sequence was treated as a parameter,together with the sequence of satellite deployment intervals,as optimization variables,simplifying a highdimensional search problem within a wide range of dates to a finite-dimensional integer programming problem.An improved genetic algorithm with local search on deployment dates was introduced to optimize the launch deployment strategy.With the new description of the optimization variables,the total number of elements in the solution space was reduced by N orders of magnitude.Numerical simulation confirms that the proposed optimization method accelerates the convergence speed from hours to minutes.展开更多
Underwater launch is a transient vibration process under the impact load.The hydrodynamic calculation is an important part of equipment research.In this paper,firstly,combining the theory of the Euler-Bernoulli beam a...Underwater launch is a transient vibration process under the impact load.The hydrodynamic calculation is an important part of equipment research.In this paper,firstly,combining the theory of the Euler-Bernoulli beam and the potential flow,the transfer equation of the Euler-Bernoulli beam considering the hydroelastic effect is derived,which expands the application scope of the transfer matrix.The correctness of the transfer matrix for the beam with hydroelastic behaviors is verified by comparison with the results of the finite element analysis.Then the dynamics model of the underwater launch system is established based on the multibody system transfer matrix method,and the beam with hydroelastic behaviors is employed as the external vehicle.Subsequently,the overall transfer and dynamic equation are derived,resulting in the solution of the wet natural frequency and the dynamic response under the impact load.The comparison with experimental data validates the dynamics model and simulation results and ensures its reliability in practical applications.The dynamic of the system demonstrates that the launching interval and adjacent tube effect will exert an influence on the subsequent emission.This research provides a fast and efficient method for the dynamic calculation of the underwater launch system.展开更多
On January 15,2025,the China Road and Bridge Corporation(CRBC)Kenya Office and Africa Star Railway Operation Company Limited(Afristar),in collaboration with the Dream Building Service Association(DBSA),held the launch...On January 15,2025,the China Road and Bridge Corporation(CRBC)Kenya Office and Africa Star Railway Operation Company Limited(Afristar),in collaboration with the Dream Building Service Association(DBSA),held the launching ceremony for the International Free Lunch Programme at a school in the Mathare slum community of Nairobi.展开更多
On August 20,the Xi Jinping Thought on Diplomacy Studies Center held a book launch event“Hand in Hand,Heart to Heart-Toward a Shared Future”for Stories of the SCO in the New Era in Beijing.China's Assistant Mini...On August 20,the Xi Jinping Thought on Diplomacy Studies Center held a book launch event“Hand in Hand,Heart to Heart-Toward a Shared Future”for Stories of the SCO in the New Era in Beijing.China's Assistant Minister of Foreign Affairs Liu Bin and Deputy Secretary-General of the Shanghai Cooperation Organization(SCO)Ahmad Saidmurodzoda delivered speeches at the event,which was also attended by Zhang Deguang,China's former Vice Foreign Minister and the SCO's inaugural Secretary-General.展开更多
On the afternoon of September 29,2025,as part of the Beijing-Tianjin-Hebei Outstanding Popular Science Book Catalog Release and Popular Science Creation&Publishing Exchange Conference,the launch event for the Engl...On the afternoon of September 29,2025,as part of the Beijing-Tianjin-Hebei Outstanding Popular Science Book Catalog Release and Popular Science Creation&Publishing Exchange Conference,the launch event for the English edition of Hi,I'm China was held at the Beijing Library.Xie Gang,vice president of China International Communications Group,and Nie Zhenning,head of the national reading committee at the Publishers Association of China,attended the event and officially unveiled the new book.Representatives of readers from multiple countries,along with experts and scholars from various fields,were invited to participate.展开更多
With the aid of multi-agent based modeling approach to complex systems, the hierarchy simulation models of carrier-based aircraft catapult launch are developed. Ocean, carrier, aircraft, and atmosphere are treated as ...With the aid of multi-agent based modeling approach to complex systems, the hierarchy simulation models of carrier-based aircraft catapult launch are developed. Ocean, carrier, aircraft, and atmosphere are treated as aggregation agents, the detailed components like catapult, landing gears, and disturbances are considered as meta-agents, which belong to their aggregation agent. Thus, the model with two layers is formed i.e. the aggregation agent layer and the meta-agent layer. The information communication among all agents is described. The meta-agents within one aggregation agent communicate with each other directly by information sharing, but the meta-agents, which belong to different aggregation agents exchange their information through the aggregation layer first, and then perceive it from the sharing environment, that is the aggregation agent. Thus, not only the hierarchy model is built, but also the environment perceived by each agent is specified. Meanwhile, the problem of balancing the independency of agent and the resource consumption brought by real-time communication within multi-agent system （MAS） is resolved. Each agent involved in carrier-based aircraft catapult launch is depicted, with considering the interaction within disturbed atmospheric environment and multiple motion bodies including carrier, aircraft, and landing gears. The models of reactive agents among them are derived based on tensors, and the perceived messages and inner frameworks of each agent are characterized. Finally, some results of a simulation instance are given. The simulation and modeling of dynamic system based on multi-agent system is of benefit to express physical concepts and logical hierarchy clearly and precisely. The system model can easily draw in kinds of other agents to achieve a precise simulation of more complex system. This modeling technique makes the complex integral dynamic equations of multibodies decompose into parallel operations of single agent, and it is convenient to expand, maintain, and reuse the program codes.展开更多
The feasibility of providing the tank a limited anti helicopter ability with gun launched missile is studied. A type of simulation model of gun launched missile against attack helicopters is established. The simula...The feasibility of providing the tank a limited anti helicopter ability with gun launched missile is studied. A type of simulation model of gun launched missile against attack helicopters is established. The simulation and the parameter optimization of missile control system under various circumstances are done. The gun launched missile can directly hit the helicopters in the typical tracks, all the missdistances are less than 1?m and the maximum overload is less than available overload. Gun launched missile is a feasible choice for tanks against attack helicopters.展开更多
Launch barge is an effective tool for transporting ship segments from one place to another in shipyards. During shifting of segments onto a barge, the slideway on the barge＇s deck must be adjusted to maintain the sam...Launch barge is an effective tool for transporting ship segments from one place to another in shipyards. During shifting of segments onto a barge, the slideway on the barge＇s deck must be adjusted to maintain the same level as the wharf and also the barge must be kept level by adjusting the water in the ballast tanks. When to open the adjusting valves is an important factor influencing the barge＇s trim during the water-adjustment process. Because these adjustments are complex a mathematical model was formulated,after analyzing the characteristics of the process of moving the segments onto the barges deck, and considering the effects of this movement＇s speed and variations in tidal levels during the move. Then the model was solved by the penalty function method, the grid method, and improved simulated annealing, respectively. The best optimization model and its corresponding solution were then determined. Finally, it was proven that the model and the method adopted are correct and suitable, by calculating and analysing an example.展开更多
The relative characteristics of motion of the fuel and shell upon launching is analyzed. By means of mechanical analysis and calculation, it is proposed that relative motion exists not only in the ranges between the f...The relative characteristics of motion of the fuel and shell upon launching is analyzed. By means of mechanical analysis and calculation, it is proposed that relative motion exists not only in the ranges between the fuel and shell of the warhead, but also in the fuel in different positions. The result of study indicates that the position of the fuel in the warhead has a marked influence on the relative motion, while the frictional coefficient between the fuel and shell has less influence upon it.展开更多
This paper begins with a discussion on the significance of multi-physical fields in the research of railgun launching mechanism, followed by an introduction of research work about dynamic measurements and numerical si...This paper begins with a discussion on the significance of multi-physical fields in the research of railgun launching mechanism, followed by an introduction of research work about dynamic measurements and numerical simulations. The application of some measurement methods including the atomic emission spectrum, fiber-optic strain, optical level, pulsed X-ray, and high-speed video in observing the launching process was introduced. The models about the electromechanical dynamic processes and multi-physical fields in a railgun were developed. The mechanisms of the grooving, arc transition, and gouging were analyzed. These work provided a deeper understanding of launching mechanism of electromagnetic railgun. Some issues about the tactical railgun, such as the fiber composite overwrapped barrel, recoil,loading modes and eddy current loss were also discussed. Taking a medium-caliber launcher as an example, the basic process of design and analysis was introduced.展开更多
Instead of the capillary plasma generator(CPG),a discharge rod plasma generator(DRPG)is used in the30 mm electrothermal-chemical(ETC)gun to improve the ignition uniformity of the solid propellant.An axisymmetric two-d...Instead of the capillary plasma generator(CPG),a discharge rod plasma generator(DRPG)is used in the30 mm electrothermal-chemical(ETC)gun to improve the ignition uniformity of the solid propellant.An axisymmetric two-dimensional interior ballistics model of the solid propellant ETC gun(2D-IB-SPETCG)is presented to describe the process of the ETC launch.Both calculated pressure and projectile muzzle velocity accord well with the experimental results.The feasibility of the 2D-IB-SPETCG model is proved.Depending on the experimental data and initial parameters,detailed distribution of the ballistics parameters can be simulated.With the distribution of pressure and temperature of the gas phase and the propellant,the influence of plasma during the ignition process can be analyzed.Because of the radial flowing plasma,the propellant in the area of the DRPG is ignited within 0.01 ms,while all propellant in the chamber is ignited within 0.09 ms.The radial ignition delay time is much less than the axial delay time.During the ignition process,the radial pressure difference is less than 5 MPa at the place 0.025 m away from the breech.The radial ignition uniformity is proved.The temperature of the gas increases from several thousand K(conventional ignition)to several ten thousand K(plasma ignition).Compare the distribution of the density and temperature of the gas,we know that low density and high temperature gas appears near the exits of the DRPG,while high density and low temperature gas appears at the wall near the breech.The simulation of the 2D-IB-SPETCG model is an effective way to investigate the interior ballistics process of the ETC launch.The 2D-IB-SPETC model can be used for prediction and improvement of experiments.展开更多
基金Zhejiang Provincial Natural Science Foundation of China(No.LY22E050013)China Postdoctoral Science Foundation(No.2021M690545)National Natural Science Foundation of China(No.51805124).
文摘High-altitude rescue is dangerous and difficult.A new rescue method is proposed here based on electromagnetically launched tethered nets.Four electromagnetic launching units are attached to a revolving platform,from which four projectiles are launched.The four projectiles are connected to a tethered net,bringing it into motion.As the tethered net approaches and comes into contact with the object,the object will be trapped,and the rescue task will then be completed as long as the tethered net can be restored along with the trapped object.The structural design of the electromagnetic launching unit is presented with the established mathematical model.The motion characteristics of the launched projectiles are studied and their exit velocities are modeled and measured.Terminal velocities of these projectiles are characterized,and the final shape and position of the projected tethered net are obtained.This study validates the feasibility of using electromagnetically launched tethered nets to perform high-altitude rescues.
文摘On June 9,2025,CIIS held a launch event for its research report“Promoting Modernization Across Countries Through the Global Development Initiative.”The event was attended by CIIS President Chen Bo,Ambassador of Barbados to China Hallam Henry,Ambassador of Grenada to China Ma Yan,Ambassador of Timor-Leste to China Loro Horta,Ambassador of Bolivia to China Hugo Siles,Ambassador of Venezuela to China Remigio Ceballos Ichaso,Ambassador of Nepal to China Krishna Prasad Oli,Vice Director of the China Foreign Languages Publishing Administration and President of the Institute of Contemporary China and the World Yu Yunquan,Director of the Institute of International Strategy at Party School of the Central Committee(National Academy of Governance)Wu Zhicheng,and Vice Chairman of the National Global Strategy Think Tank at Chinese Academy of Social Sciences Wang Lei,all of whom delivered remarks at the launch.
基金supported by the National Natural Science Foundation of China(Nos.52495000 and 52332012).
文摘In the era of global space industry’s rapid expansion,reusable launch technology has the advantage of cost reduction,but makes launch frequency and flight reliability remain critical.This study proposes that Artificial Intelligence(AI)would be the potential disruptive technology to solve these challenges.AI enables transformative capabilities for launch vehicles which are pointed out in four domains:Agile launch operations enabling automate testing,fault diagnosis,and decision-making for targeting hour-level launch cycles and minute-level fault resolution;high-reliability flight enabling real-time autonomous fault diagnosis,mission replanning,and fault-tolerant control within seconds during anomalies,potentially improving reliability by 1–2 orders of magnitude;rapid maintenance enabling real-time health monitoring and lifespan prediction for swift relaunch decisions;efficient space traffic management enabling predict/resolve orbital conflicts amid growing congestion from satellites and debris.The key challenges for AI applications are analyzed as well,including multi-system coupling,uncertain failure modes and narrow flight corridors,limited sensor data,and massive heterogeneous data processing.Finally,the study also proposes that AI promises substantial efficiency gains in launch vehicle design,manufacturing,and testing through multidisciplinary optimization and reduced reliance on physical testing.
基金supported by National Natural Science Foundation of China(Grant No.92266201).
文摘As the performance of the box-type multiple launch rocket system(BMLRS)improves,its mechanical structures,particularly the plane clearance design between the slider on the rocket and the guide inside the launch canister,have grown increasingly complex.However,deficiencies still exist in the current launch modeling theory for BMLRS.In this study,a multi-rigid-flexible-body launch dynamics model coupling the launch platform and rocket was established using the multibody system transfer matrix method and the Newton-Euler formulation.Furthermore,considering the bending of the launch canister,a detection algorithm for slider-guide plane clearance contact was proposed.To quantify the contact force and friction effect between the slider and guide,the contact force model and modified Coulomb model were introduced.Both the modal and launch tests were conducted.Additionally,the modal convergence was verified.By comparing the modal experiments and simulation results,the maximum relative error of the eigenfrequency is 3.29%.thereby verifying the accuracy of the developed BMLRS dynamics model.Furthermore,the launch test validated the proposed plane clearance contact model.Moreover,the study investigated the influence of various model parameters on the dynamic characteristics of BMLRS,including launch canister bending stiffness,slider and guide material,slider-guide clearance,slider length and layout.This analysis of influencing factors provides a foundation for future optimization in BMLRS design.
基金the experimental technology support provided by the China Academy of Launch Vehicle Technology
文摘Sea-based rocket launches encounter significant challenges stemming from dynamic marine environmental interactions.During the hot launch phase,characterized by low-velocity ascent,the departure of the rocket from the oscillatory platform exhibits heightened sensitivity to external disturbances.In the development stage,assessing the launch dynamics and the clearance between the rocket and framed launcher are crucial for improving the reliability of sea-based rocket launches in rough sea conditions.This study presents a high-fidelity dynamic model of maritime hot launch system,demonstrating 3.21%prediction error through rigorous validation against experimental datasets from comprehensive modal analyses and the full-scale rocket flight test.To mitigate collision risks,we develop a computational method employing spatial vector analysis for dynamic measurement of rocket-launcher clearance during departure.Systematic investigations reveal that in rough sea conditions,optimal departure dynamics are achieved at θ_(thrust)=270°nozzle azimuth configuration,reducing failure probability compared to conventional orientations.The developed assessment framework not only resolves critical safety challenges in current sea launch systems but also establishes foundational principles for optimizing adapter axial configuration patterns in future designs.
文摘The research on optimization methods for constellation launch deployment strategies focused on the consideration of mission interval time constraints at the launch site.Firstly,a dynamic modeling of the constellation deployment process was established,and the relationship between the deployment window and the phase difference of the orbit insertion point,as well as the cost of phase adjustment after orbit insertion,was derived.Then,the combination of the constellation deployment position sequence was treated as a parameter,together with the sequence of satellite deployment intervals,as optimization variables,simplifying a highdimensional search problem within a wide range of dates to a finite-dimensional integer programming problem.An improved genetic algorithm with local search on deployment dates was introduced to optimize the launch deployment strategy.With the new description of the optimization variables,the total number of elements in the solution space was reduced by N orders of magnitude.Numerical simulation confirms that the proposed optimization method accelerates the convergence speed from hours to minutes.
基金supported by the National Natural Science Foundation of China(Grant No.92266201).
文摘Underwater launch is a transient vibration process under the impact load.The hydrodynamic calculation is an important part of equipment research.In this paper,firstly,combining the theory of the Euler-Bernoulli beam and the potential flow,the transfer equation of the Euler-Bernoulli beam considering the hydroelastic effect is derived,which expands the application scope of the transfer matrix.The correctness of the transfer matrix for the beam with hydroelastic behaviors is verified by comparison with the results of the finite element analysis.Then the dynamics model of the underwater launch system is established based on the multibody system transfer matrix method,and the beam with hydroelastic behaviors is employed as the external vehicle.Subsequently,the overall transfer and dynamic equation are derived,resulting in the solution of the wet natural frequency and the dynamic response under the impact load.The comparison with experimental data validates the dynamics model and simulation results and ensures its reliability in practical applications.The dynamic of the system demonstrates that the launching interval and adjacent tube effect will exert an influence on the subsequent emission.This research provides a fast and efficient method for the dynamic calculation of the underwater launch system.
文摘On January 15,2025,the China Road and Bridge Corporation(CRBC)Kenya Office and Africa Star Railway Operation Company Limited(Afristar),in collaboration with the Dream Building Service Association(DBSA),held the launching ceremony for the International Free Lunch Programme at a school in the Mathare slum community of Nairobi.
文摘On August 20,the Xi Jinping Thought on Diplomacy Studies Center held a book launch event“Hand in Hand,Heart to Heart-Toward a Shared Future”for Stories of the SCO in the New Era in Beijing.China's Assistant Minister of Foreign Affairs Liu Bin and Deputy Secretary-General of the Shanghai Cooperation Organization(SCO)Ahmad Saidmurodzoda delivered speeches at the event,which was also attended by Zhang Deguang,China's former Vice Foreign Minister and the SCO's inaugural Secretary-General.
文摘On the afternoon of September 29,2025,as part of the Beijing-Tianjin-Hebei Outstanding Popular Science Book Catalog Release and Popular Science Creation&Publishing Exchange Conference,the launch event for the English edition of Hi,I'm China was held at the Beijing Library.Xie Gang,vice president of China International Communications Group,and Nie Zhenning,head of the national reading committee at the Publishers Association of China,attended the event and officially unveiled the new book.Representatives of readers from multiple countries,along with experts and scholars from various fields,were invited to participate.
基金Aeronautical Science Foundation of China (2006ZA51004)
文摘With the aid of multi-agent based modeling approach to complex systems, the hierarchy simulation models of carrier-based aircraft catapult launch are developed. Ocean, carrier, aircraft, and atmosphere are treated as aggregation agents, the detailed components like catapult, landing gears, and disturbances are considered as meta-agents, which belong to their aggregation agent. Thus, the model with two layers is formed i.e. the aggregation agent layer and the meta-agent layer. The information communication among all agents is described. The meta-agents within one aggregation agent communicate with each other directly by information sharing, but the meta-agents, which belong to different aggregation agents exchange their information through the aggregation layer first, and then perceive it from the sharing environment, that is the aggregation agent. Thus, not only the hierarchy model is built, but also the environment perceived by each agent is specified. Meanwhile, the problem of balancing the independency of agent and the resource consumption brought by real-time communication within multi-agent system （MAS） is resolved. Each agent involved in carrier-based aircraft catapult launch is depicted, with considering the interaction within disturbed atmospheric environment and multiple motion bodies including carrier, aircraft, and landing gears. The models of reactive agents among them are derived based on tensors, and the perceived messages and inner frameworks of each agent are characterized. Finally, some results of a simulation instance are given. The simulation and modeling of dynamic system based on multi-agent system is of benefit to express physical concepts and logical hierarchy clearly and precisely. The system model can easily draw in kinds of other agents to achieve a precise simulation of more complex system. This modeling technique makes the complex integral dynamic equations of multibodies decompose into parallel operations of single agent, and it is convenient to expand, maintain, and reuse the program codes.
文摘The feasibility of providing the tank a limited anti helicopter ability with gun launched missile is studied. A type of simulation model of gun launched missile against attack helicopters is established. The simulation and the parameter optimization of missile control system under various circumstances are done. The gun launched missile can directly hit the helicopters in the typical tracks, all the missdistances are less than 1?m and the maximum overload is less than available overload. Gun launched missile is a feasible choice for tanks against attack helicopters.
文摘Launch barge is an effective tool for transporting ship segments from one place to another in shipyards. During shifting of segments onto a barge, the slideway on the barge＇s deck must be adjusted to maintain the same level as the wharf and also the barge must be kept level by adjusting the water in the ballast tanks. When to open the adjusting valves is an important factor influencing the barge＇s trim during the water-adjustment process. Because these adjustments are complex a mathematical model was formulated,after analyzing the characteristics of the process of moving the segments onto the barges deck, and considering the effects of this movement＇s speed and variations in tidal levels during the move. Then the model was solved by the penalty function method, the grid method, and improved simulated annealing, respectively. The best optimization model and its corresponding solution were then determined. Finally, it was proven that the model and the method adopted are correct and suitable, by calculating and analysing an example.
文摘The relative characteristics of motion of the fuel and shell upon launching is analyzed. By means of mechanical analysis and calculation, it is proposed that relative motion exists not only in the ranges between the fuel and shell of the warhead, but also in the fuel in different positions. The result of study indicates that the position of the fuel in the warhead has a marked influence on the relative motion, while the frictional coefficient between the fuel and shell has less influence upon it.
文摘This paper begins with a discussion on the significance of multi-physical fields in the research of railgun launching mechanism, followed by an introduction of research work about dynamic measurements and numerical simulations. The application of some measurement methods including the atomic emission spectrum, fiber-optic strain, optical level, pulsed X-ray, and high-speed video in observing the launching process was introduced. The models about the electromechanical dynamic processes and multi-physical fields in a railgun were developed. The mechanisms of the grooving, arc transition, and gouging were analyzed. These work provided a deeper understanding of launching mechanism of electromagnetic railgun. Some issues about the tactical railgun, such as the fiber composite overwrapped barrel, recoil,loading modes and eddy current loss were also discussed. Taking a medium-caliber launcher as an example, the basic process of design and analysis was introduced.
文摘Instead of the capillary plasma generator(CPG),a discharge rod plasma generator(DRPG)is used in the30 mm electrothermal-chemical(ETC)gun to improve the ignition uniformity of the solid propellant.An axisymmetric two-dimensional interior ballistics model of the solid propellant ETC gun(2D-IB-SPETCG)is presented to describe the process of the ETC launch.Both calculated pressure and projectile muzzle velocity accord well with the experimental results.The feasibility of the 2D-IB-SPETCG model is proved.Depending on the experimental data and initial parameters,detailed distribution of the ballistics parameters can be simulated.With the distribution of pressure and temperature of the gas phase and the propellant,the influence of plasma during the ignition process can be analyzed.Because of the radial flowing plasma,the propellant in the area of the DRPG is ignited within 0.01 ms,while all propellant in the chamber is ignited within 0.09 ms.The radial ignition delay time is much less than the axial delay time.During the ignition process,the radial pressure difference is less than 5 MPa at the place 0.025 m away from the breech.The radial ignition uniformity is proved.The temperature of the gas increases from several thousand K(conventional ignition)to several ten thousand K(plasma ignition).Compare the distribution of the density and temperature of the gas,we know that low density and high temperature gas appears near the exits of the DRPG,while high density and low temperature gas appears at the wall near the breech.The simulation of the 2D-IB-SPETCG model is an effective way to investigate the interior ballistics process of the ETC launch.The 2D-IB-SPETC model can be used for prediction and improvement of experiments.
