The nonlinear dynamics of the lateral micro-resonator including the air damping effect is researched. The air damping force is varied periodically during the resonator oscillating, and the air damp coefficient can not...The nonlinear dynamics of the lateral micro-resonator including the air damping effect is researched. The air damping force is varied periodically during the resonator oscillating, and the air damp coefficient can not be fixed as a constant. Therefore the linear dynamic analysis which used the constant air damping coefficient can not describe the actual dynamic characteristics of the mi-cro-resonator. The nonlinear dynamic model including the air damping force is established. On the base of Navier-Stokes equation and nonlinear dynamical equation, a coupled fluid-solid numerical simulation method is developed and demonstrates that damping force is a vital factor in micro-comb structures. Compared with existing experimental result, the nonlinear numerical value has quite good agreement with it. The differences of the amplitudes （peak） between the experimental data and the results by the linear model and the nonlinear model are 74.5% and 6% respectively. Nonlinear nu-merical value is more exact than linear value and the method can be applied in other mi-cro-electro-mechanical systeme （MEMS） structures to simulate the dynamic performance.展开更多
This paper investigates the problem of formation tracking control for multiple flight vehicle(MFV) system considering actuator saturation constraints. First, the formation tracking control model is established. Then, ...This paper investigates the problem of formation tracking control for multiple flight vehicle(MFV) system considering actuator saturation constraints. First, the formation tracking control model is established. Then, the problem of formation control of the MFV system is converted to the convergence of a dynamical system, which is obtained by using the differential geometry theory.A class of saturation functions is introduced, and on this basis a second-order finite-time formation control protocol is developed.With the help of the homogeneous theory and Lasalle's invariance principle, it is theoretically proved that the designed formation protocol could complete the formation task in finite time, and the control inputs are shown to remain within their available actuating limits. Finally, simulations are performed to verify the effectiveness of the scheme.展开更多
This paper introduces a launch vehicle scheme for the new generation of cryogenic and quick-launch launch vehicle(LM-6). The main technical innovations of LM-6 launch vehicle include the capability of twenty satellite...This paper introduces a launch vehicle scheme for the new generation of cryogenic and quick-launch launch vehicle(LM-6). The main technical innovations of LM-6 launch vehicle include the capability of twenty satellites launched by one vehicle, high-pressure staged combustion cycle engine and oxygen tank self-pressurization, sandwich bulkhead tank with 200 K temperature difference, and 7-day quick-launch using the "three horizontals" test and launch mode with integral transportation and erection. The future development of the quick-launch launch vehicle is predicted based upon the need for vehicle mission coverage improvement, better response speed, and stronger market competiveness.展开更多
An overall bi-directional panoramic solar system exploration activity,not just looking at the solar system at a macro level and helping to build a simulation model for the solar system,but the probe will also be able ...An overall bi-directional panoramic solar system exploration activity,not just looking at the solar system at a macro level and helping to build a simulation model for the solar system,but the probe will also be able to explore the Milky Way and the vast universe from a much wider perspective.By observing the characteristics of the solar system,solar wind,ionization envelope and other parameters from a bi-directional panorama on both sides of the solar ecliptic plane,it will assist the scientific community and human kind to understand the solar system in a more extensive,deeper and systematic way than before.The exploration can be done in two steps.The first step is to launch a solar polar probe.Secondly to launch a bi-directional probe orbiting the galaxy in sync with the sun.展开更多
The key parameters of vertical AlN Schottky barrier diodes(SBDs) with variable drift layer thickness(DLT) and drift layer concentration(DLC) are investigated. The specific on-resistance(R_(on,sp)) decreased to 0.5 mΩ...The key parameters of vertical AlN Schottky barrier diodes(SBDs) with variable drift layer thickness(DLT) and drift layer concentration(DLC) are investigated. The specific on-resistance(R_(on,sp)) decreased to 0.5 mΩ · cm^(2) and the breakdown voltage(V_(BR)) decreased from 3.4 kV to 1.1 kV by changing the DLC from 10^(15) cm^(-3) to 3×10^(16) cm^(-3). The VBRincreases from 1.5 kV to 3.4 kV and the Ron,sp also increases to 12.64 mΩ · cm^(2) by increasing DLT from 4-μm to 11-μm. The VBRenhancement results from the increase of depletion region extension. The Baliga's figure of merit(BFOM) of3.8 GW/cm^(2) was obtained in the structure of 11-μm DLT and 10^(16) cm^(-3) DLC without FP. When DLT or DLC is variable,the consideration of the value of BFOM is essential. In this paper, we also present the vertical AlN SBD with a field plate(FP), which decreases the crowding of electric field in electrode edge. All the key parameters were optimized by simulating based on Silvaco-ATLAS.展开更多
A scheme is proposed to generate genuine tripartite Einstein-Podolsky-Rosen(EPR)steering in cascaded nonlinear process of the fourth-harmonic generation.The second-harmonic is generated by the first double-frequency p...A scheme is proposed to generate genuine tripartite Einstein-Podolsky-Rosen(EPR)steering in cascaded nonlinear process of the fourth-harmonic generation.The second-harmonic is generated by the first double-frequency process in an optical superlattice.Then,the fourth-harmonic is produced by the second cascaded double-frequency process through quasi-phase-matching technique in the same optical superlattice.The genuine tripartite EPR steering among the pump,the second-harmonic,and the fourth-harmonic beams can be obtained by this cascaded nonlinear process according to a criterion for genuine multipartite quantum steering.The quantum steering properties are discussed by adjusting the parameters related to the cascaded nonlinear system.The present research provides a reference scheme and data for obtaining good multipartite EPR steering in experiment and can advance the applications of quantum steering in the quantum information processing.展开更多
To address the eccentric error of circular marks in camera calibration,a circle location method based on the invariance of collinear points and pole–polar constraint is proposed in this paper.Firstly,the centers of t...To address the eccentric error of circular marks in camera calibration,a circle location method based on the invariance of collinear points and pole–polar constraint is proposed in this paper.Firstly,the centers of the ellipses are extracted,and the real concentric circle center projection equation is established by exploiting the cross ratio invariance of the collinear points.Subsequently,since the infinite lines passing through the centers of the marks are parallel,the other center projection coordinates are expressed as the solution problem of linear equations.The problem of projection deviation caused by using the center of the ellipse as the real circle center projection is addressed,and the results are utilized as the true image points to achieve the high precision camera calibration.As demonstrated by the simulations and practical experiments,the proposed method performs a better location and calibration performance by achieving the actual center projection of circular marks.The relevant results confirm the precision and robustness of the proposed approach.展开更多
In order to explore the bonding failure mechanism of high modulus carbon fiber composite materials,the tensile experiment and finite element numerical simulation for single-lap and bevel-lap joints of unidirectional l...In order to explore the bonding failure mechanism of high modulus carbon fiber composite materials,the tensile experiment and finite element numerical simulation for single-lap and bevel-lap joints of unidirectional laminates are carried out,and the stress distributions,the failure modes,and the damage contours are analyzed. The analysis shows that the main reason for the failure of the single-lap joint is that the stress concentration of the ply adjacent to the adhesive layer is serious owing to the modulus difference,and the stress cannot be effectively transmitted along the thickness direction of the laminate. When the tensile stress of the ply exceeds its ultimate strength in the loading process,the surface fiber will fail. Compared with the single-lap joint,the bevel-lap joint optimizes the stress transfer path along the thickness direction,allows each layer of the laminate to share the load,avoids the stress concentration of the surface layer,and improves the bearing capacity of the bevel-lap joint. The improved bearing capacity of the bevellap joint is twice as much as that of the single-lap joint. The research in this paper provides a new idea for the subsequent study of mechanical properties of adhesively bonded composite materials.展开更多
The spinning technique has been widely used in the manufacture of aerospace thin-walled axisymmetric components because of its excellent formability. Damage and fracture,as the important defects that often occur and m...The spinning technique has been widely used in the manufacture of aerospace thin-walled axisymmetric components because of its excellent formability. Damage and fracture,as the important defects that often occur and must be avoided in the forming and service stages of components,have attracted much attention of researchers. In this paper,the fracture behavior and laws of spinning components such as conical parts,tubular parts,and components with inner ribs are summarized,the typical coupled and uncoupled ductile fracture models are introduced,and their applications in spinning are analyzed. Meanwhile,the recent developments on the modified ductile fracture model in analyzing damage and fracture mechanisms of spinning are emphatically introduced. The results could provide guidance for the selection and establishment of appropriate ductile fracture models in the finite element simulation for the accurate prediction and analysis of fracture moment,location,form,damage mechanism,and evolution law,and help the development of precision spinning techniques for high-performance thin-walled complex components.展开更多
As a new support platform of information technology for social development, virtual reality technology(VRT) has been widely used in many fields. Here, the concept and important features of VRT are summarized first. Th...As a new support platform of information technology for social development, virtual reality technology(VRT) has been widely used in many fields. Here, the concept and important features of VRT are summarized first. Then, the analysis requirement for VRT in design, display, operation and maintenance training, and state monitoring for aerospace products is elaborated. This is followed with a review of foreign and domestic policy planning of VRT, and their application in aerospace. Last, future development of VRT is discussed.展开更多
Optimal design of the tank has a significant effect on reducing the weight of a launch vehicle’s structure.In this paper,the key characteristics of a stiffened shell are identified from the design requirements,focusi...Optimal design of the tank has a significant effect on reducing the weight of a launch vehicle’s structure.In this paper,the key characteristics of a stiffened shell are identified from the design requirements,focusing on the influence of the internal pressure on the axial compression load-bearing capacity.The computing method of the ultimate load of the stiffened shell,the parametric modeling method and the surrogate modeling technique for optimal design are reviewed.An optimization process applicable to the stiffened shell was developed and applied in the optimization work for the tanks of solid-liquid bundled launch vehicle,so a better weight reduction effect could be achieved.展开更多
Why has the sun burnt for billions of years? What is the mechanism of combustion? What will happen to the trend of solar combustion? Modern humans have only just begun their close-up exploration of the sun. By studyin...Why has the sun burnt for billions of years? What is the mechanism of combustion? What will happen to the trend of solar combustion? Modern humans have only just begun their close-up exploration of the sun. By studying the sun, we can learn more about other stars. The more we understand other stars, the more we will know about the universe in the end. The exploration of the origin of solar energy will help people to deepen their understanding of the origin of the universe as well as the development of the universe. Solar probes will help us further understand the characteristics of the sun, validate relevant theories and make new discoveries.展开更多
In this paper,based upon the characteristics of elastic modal combination of large solid bundled launch vehicles,the finite element theory is used to describe the complex elastic vibration of a solid bundled launch ve...In this paper,based upon the characteristics of elastic modal combination of large solid bundled launch vehicles,the finite element theory is used to describe the complex elastic vibration of a solid bundled launch vehicle,and a new three-channel unified elastic vibration equation was established.The elastic vibration equation can reflect the coupling between channels and between boosters and core stage.Some issues need consideration in the theoretical derivation,an engineering application was proposed,and the elastic vibration model was verified.The results of the theoretical derivation and simulation show that the elastic vibration equation of a solid bundled launch vehicle established in the paper is correct and can meet the needs for the engineering application.展开更多
For the final stage of a launch vehicle which cannot start multiple times,the main constraint of a highly eccentric orbit launch mission is the argument of perigee,which is conditioned by the range.This paper studies ...For the final stage of a launch vehicle which cannot start multiple times,the main constraint of a highly eccentric orbit launch mission is the argument of perigee,which is conditioned by the range.This paper studies the payload capacity at different launch sites for a highly eccentric orbit(e.g.GTO)and gives a method to improve the payload capacity with an argument of perigee constraint by increasing the sliding time before the final ignition and simultaneously adjusting the launch azimuth and yaw at the final stage.An example of launching to GTO orbit on a rocket from Hainan is given,which proves that the method has strong engineering value.展开更多
New program was proposed in LM-6 rolling control technology that using high-pressure staged combustion gas. Launch vehicle rolling control by just one engine was realized. Under the limit of the rolling control moment...New program was proposed in LM-6 rolling control technology that using high-pressure staged combustion gas. Launch vehicle rolling control by just one engine was realized. Under the limit of the rolling control moment of the launch vehicle, a new attitude dynamic model is established. Interference source and how to reduce the effect was analyzed, and method of designing a pre-compensated robust controller was proposed. Simulation and flight resuits showed that the attitude dynamic model established and the pre-compensation robust controller proposed in this paper could solve the key problems with a strong coupling attitude controller, and realize high quality and high reliability control in wind areas, and improve the capability of the launch vehicle.展开更多
The three-axis servo system with the core of gyro stabilization is the foundation to realize its function, and a key technology of the seeker devolopment. In order to reduce the costs, improve the efficiency of resear...The three-axis servo system with the core of gyro stabilization is the foundation to realize its function, and a key technology of the seeker devolopment. In order to reduce the costs, improve the efficiency of research and devolopment, a new method that instead of physical prototype by virtual prototype was proposed. Adams and MATLAB/simulink are used to establish the mechanical dynamics model and controller model of the three-axis servo system. The simulation data which was processed and analyzed is compared with test data, to determine the control parameters of the virtual prototype and improve the accuracy of the model, and test the multiple condition simulation,which can provide a reference for practical production.The simulation results verify the feasibility of the models.展开更多
Compared with using liquid rocket engines,there are a lot of high-temperature solid particles in the solid-liquid bundled rocket,which make the rocket base thermal environment worse.In order to study the influence of ...Compared with using liquid rocket engines,there are a lot of high-temperature solid particles in the solid-liquid bundled rocket,which make the rocket base thermal environment worse.In order to study the influence of high-temperature solid particles on the base thermal environment,firstly,the effect of particle diameter on the jet distribution and the thermal environment in a single solid motor jet was analyzed using a numerical simulation method,and the results were compared with those of a ground test.Further,the effects of high-temperature solid particles on the jet and the thermal environment of the solid-liquid bundled rocket were analyzed and compared with flight data.The results show that high-temperature solid particles can increase the jet temperature and reduce the jet velocity.The larger the particle diameter,the greater the impact on the jet core temperature.The role of high-temperature solid particles cannot be ignored in the study of the base thermal environment.展开更多
On March 29,2022,the Long March 6A launch vehicle developed by the Shanghai Academy of Space-flight Technology successfully made its maiden flight at the Taiyuan Satellite Launch Center.The Long March 6A launch vehicl...On March 29,2022,the Long March 6A launch vehicle developed by the Shanghai Academy of Space-flight Technology successfully made its maiden flight at the Taiyuan Satellite Launch Center.The Long March 6A launch vehicle was China’s first solid bundled rocket.It uses non-toxic and non-polluting propellants,and has a 700 km sun-synchronous orbit carrying capacity of no less than 4.5 t,which is more than 50%higher than that of a LM-4C launch vehicle.During the development of the LM-6A launch vehicle,the matching relationship between systems and the overall performance of the entire rocket improved significantly through continuous overall optimization work.This paper introduces the typical overall optimization work during the development of the LM-6A launch vehicle.展开更多
Based on the concept of DIY, this paper demonstrates the essential potential of DIY manufacturing technology in the application of space equipment. According to the future space technology development trends, the futu...Based on the concept of DIY, this paper demonstrates the essential potential of DIY manufacturing technology in the application of space equipment. According to the future space technology development trends, the future spacecraft DIY idea and system standard are proposed. The standardized, modularized and serialized micro/nano-satellite DIY products are introduced. Finally, a commercial remote sensing satellite system based on spacecraft DIY is designed and its application prospect is analyzed.展开更多
China’s space technology has gradually improved from the early stages’ introduction, absorption and re-innovation based on backward design to independent innovation based on forward design. It is necessary to develo...China’s space technology has gradually improved from the early stages’ introduction, absorption and re-innovation based on backward design to independent innovation based on forward design. It is necessary to develop a new approach of systems engineering to improve the quality and efficiency of space systems design considering the large number of original design problems expected in the future. Adopting Model-Based Systems Engineering(MBSE) and Digital Twin method are important development initiatives in the field of modern engineering design. In the initial phase of system design, it is necessary to generate firm system architecture models based on the needs of stakeholders. The quality of the system design in this phase has a great impact on the detailed design and implementation for the subsequent system, and also plays an important role in the performance, development progress and cost of the whole system. Through the collaboration of cross-professional teams, modeling and model execution, comparing the model execution with expected results, MBSE has enabled digital model-level verification and validation before test verification and validation based on physical products, thus improving the design exactness, completeness and greatly reducing design errors or defects. This paper explores the logical ideas behind modeling of system architectures in order to promote the adoption of MBSE in the field of space systems.展开更多
基金This project is supported by Shanghai Municipal Science and Technique Committee Foundation, China (No. 03QF14019, No. 0452nm023, No. AM0420).
文摘The nonlinear dynamics of the lateral micro-resonator including the air damping effect is researched. The air damping force is varied periodically during the resonator oscillating, and the air damp coefficient can not be fixed as a constant. Therefore the linear dynamic analysis which used the constant air damping coefficient can not describe the actual dynamic characteristics of the mi-cro-resonator. The nonlinear dynamic model including the air damping force is established. On the base of Navier-Stokes equation and nonlinear dynamical equation, a coupled fluid-solid numerical simulation method is developed and demonstrates that damping force is a vital factor in micro-comb structures. Compared with existing experimental result, the nonlinear numerical value has quite good agreement with it. The differences of the amplitudes （peak） between the experimental data and the results by the linear model and the nonlinear model are 74.5% and 6% respectively. Nonlinear nu-merical value is more exact than linear value and the method can be applied in other mi-cro-electro-mechanical systeme （MEMS） structures to simulate the dynamic performance.
基金supported by the National Natural Science Foundation of China (61903099)the Natural Science Foundation of Heilongjiang Province (LH2020F025)the Fundamental Research Funds for the Central Universities (3072020CF0406)。
文摘This paper investigates the problem of formation tracking control for multiple flight vehicle(MFV) system considering actuator saturation constraints. First, the formation tracking control model is established. Then, the problem of formation control of the MFV system is converted to the convergence of a dynamical system, which is obtained by using the differential geometry theory.A class of saturation functions is introduced, and on this basis a second-order finite-time formation control protocol is developed.With the help of the homogeneous theory and Lasalle's invariance principle, it is theoretically proved that the designed formation protocol could complete the formation task in finite time, and the control inputs are shown to remain within their available actuating limits. Finally, simulations are performed to verify the effectiveness of the scheme.
文摘This paper introduces a launch vehicle scheme for the new generation of cryogenic and quick-launch launch vehicle(LM-6). The main technical innovations of LM-6 launch vehicle include the capability of twenty satellites launched by one vehicle, high-pressure staged combustion cycle engine and oxygen tank self-pressurization, sandwich bulkhead tank with 200 K temperature difference, and 7-day quick-launch using the "three horizontals" test and launch mode with integral transportation and erection. The future development of the quick-launch launch vehicle is predicted based upon the need for vehicle mission coverage improvement, better response speed, and stronger market competiveness.
文摘An overall bi-directional panoramic solar system exploration activity,not just looking at the solar system at a macro level and helping to build a simulation model for the solar system,but the probe will also be able to explore the Milky Way and the vast universe from a much wider perspective.By observing the characteristics of the solar system,solar wind,ionization envelope and other parameters from a bi-directional panorama on both sides of the solar ecliptic plane,it will assist the scientific community and human kind to understand the solar system in a more extensive,deeper and systematic way than before.The exploration can be done in two steps.The first step is to launch a solar polar probe.Secondly to launch a bi-directional probe orbiting the galaxy in sync with the sun.
基金supported by Key-Area Research and Development Program of Guangdong Province,China (Grant Nos. 2020B010174001 and 2020B010171002)Ningbo Science and Technology Innovation 2025 (Grant No. 2019B10123)。
文摘The key parameters of vertical AlN Schottky barrier diodes(SBDs) with variable drift layer thickness(DLT) and drift layer concentration(DLC) are investigated. The specific on-resistance(R_(on,sp)) decreased to 0.5 mΩ · cm^(2) and the breakdown voltage(V_(BR)) decreased from 3.4 kV to 1.1 kV by changing the DLC from 10^(15) cm^(-3) to 3×10^(16) cm^(-3). The VBRincreases from 1.5 kV to 3.4 kV and the Ron,sp also increases to 12.64 mΩ · cm^(2) by increasing DLT from 4-μm to 11-μm. The VBRenhancement results from the increase of depletion region extension. The Baliga's figure of merit(BFOM) of3.8 GW/cm^(2) was obtained in the structure of 11-μm DLT and 10^(16) cm^(-3) DLC without FP. When DLT or DLC is variable,the consideration of the value of BFOM is essential. In this paper, we also present the vertical AlN SBD with a field plate(FP), which decreases the crowding of electric field in electrode edge. All the key parameters were optimized by simulating based on Silvaco-ATLAS.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61975184,91636108,and 61775043)the Natural Science Foundation of Zhejiang Province,China(Grant No.LY18A040007)+1 种基金the Science Foundation of Zhejiang Sci-Tech University(Grant Nos.19062151-Y and 18062145-Y)the Open Foundation of the Key Laboratory of Optical Field Manipulation of Zhejiang Province,China(Grant No.ZJOFM-2019-002).
文摘A scheme is proposed to generate genuine tripartite Einstein-Podolsky-Rosen(EPR)steering in cascaded nonlinear process of the fourth-harmonic generation.The second-harmonic is generated by the first double-frequency process in an optical superlattice.Then,the fourth-harmonic is produced by the second cascaded double-frequency process through quasi-phase-matching technique in the same optical superlattice.The genuine tripartite EPR steering among the pump,the second-harmonic,and the fourth-harmonic beams can be obtained by this cascaded nonlinear process according to a criterion for genuine multipartite quantum steering.The quantum steering properties are discussed by adjusting the parameters related to the cascaded nonlinear system.The present research provides a reference scheme and data for obtaining good multipartite EPR steering in experiment and can advance the applications of quantum steering in the quantum information processing.
基金supported by the Aerospace Science and Technology Joint Fund(6141B061505)the National Natural Science Foundation of China(61473100).
文摘To address the eccentric error of circular marks in camera calibration,a circle location method based on the invariance of collinear points and pole–polar constraint is proposed in this paper.Firstly,the centers of the ellipses are extracted,and the real concentric circle center projection equation is established by exploiting the cross ratio invariance of the collinear points.Subsequently,since the infinite lines passing through the centers of the marks are parallel,the other center projection coordinates are expressed as the solution problem of linear equations.The problem of projection deviation caused by using the center of the ellipse as the real circle center projection is addressed,and the results are utilized as the true image points to achieve the high precision camera calibration.As demonstrated by the simulations and practical experiments,the proposed method performs a better location and calibration performance by achieving the actual center projection of circular marks.The relevant results confirm the precision and robustness of the proposed approach.
文摘In order to explore the bonding failure mechanism of high modulus carbon fiber composite materials,the tensile experiment and finite element numerical simulation for single-lap and bevel-lap joints of unidirectional laminates are carried out,and the stress distributions,the failure modes,and the damage contours are analyzed. The analysis shows that the main reason for the failure of the single-lap joint is that the stress concentration of the ply adjacent to the adhesive layer is serious owing to the modulus difference,and the stress cannot be effectively transmitted along the thickness direction of the laminate. When the tensile stress of the ply exceeds its ultimate strength in the loading process,the surface fiber will fail. Compared with the single-lap joint,the bevel-lap joint optimizes the stress transfer path along the thickness direction,allows each layer of the laminate to share the load,avoids the stress concentration of the surface layer,and improves the bearing capacity of the bevel-lap joint. The improved bearing capacity of the bevellap joint is twice as much as that of the single-lap joint. The research in this paper provides a new idea for the subsequent study of mechanical properties of adhesively bonded composite materials.
基金National Science and Technology Major Project(J2019-VII-0014-0154)the Key Project of National Natural Science Foundation of China(No.52130507)+1 种基金National Natural Science Foundation of China(No.51790175)National Key R&D Program of China(Nos.2020YFA0711100 and 2021YFB3400900)。
文摘The spinning technique has been widely used in the manufacture of aerospace thin-walled axisymmetric components because of its excellent formability. Damage and fracture,as the important defects that often occur and must be avoided in the forming and service stages of components,have attracted much attention of researchers. In this paper,the fracture behavior and laws of spinning components such as conical parts,tubular parts,and components with inner ribs are summarized,the typical coupled and uncoupled ductile fracture models are introduced,and their applications in spinning are analyzed. Meanwhile,the recent developments on the modified ductile fracture model in analyzing damage and fracture mechanisms of spinning are emphatically introduced. The results could provide guidance for the selection and establishment of appropriate ductile fracture models in the finite element simulation for the accurate prediction and analysis of fracture moment,location,form,damage mechanism,and evolution law,and help the development of precision spinning techniques for high-performance thin-walled complex components.
文摘As a new support platform of information technology for social development, virtual reality technology(VRT) has been widely used in many fields. Here, the concept and important features of VRT are summarized first. Then, the analysis requirement for VRT in design, display, operation and maintenance training, and state monitoring for aerospace products is elaborated. This is followed with a review of foreign and domestic policy planning of VRT, and their application in aerospace. Last, future development of VRT is discussed.
文摘Optimal design of the tank has a significant effect on reducing the weight of a launch vehicle’s structure.In this paper,the key characteristics of a stiffened shell are identified from the design requirements,focusing on the influence of the internal pressure on the axial compression load-bearing capacity.The computing method of the ultimate load of the stiffened shell,the parametric modeling method and the surrogate modeling technique for optimal design are reviewed.An optimization process applicable to the stiffened shell was developed and applied in the optimization work for the tanks of solid-liquid bundled launch vehicle,so a better weight reduction effect could be achieved.
文摘Why has the sun burnt for billions of years? What is the mechanism of combustion? What will happen to the trend of solar combustion? Modern humans have only just begun their close-up exploration of the sun. By studying the sun, we can learn more about other stars. The more we understand other stars, the more we will know about the universe in the end. The exploration of the origin of solar energy will help people to deepen their understanding of the origin of the universe as well as the development of the universe. Solar probes will help us further understand the characteristics of the sun, validate relevant theories and make new discoveries.
文摘In this paper,based upon the characteristics of elastic modal combination of large solid bundled launch vehicles,the finite element theory is used to describe the complex elastic vibration of a solid bundled launch vehicle,and a new three-channel unified elastic vibration equation was established.The elastic vibration equation can reflect the coupling between channels and between boosters and core stage.Some issues need consideration in the theoretical derivation,an engineering application was proposed,and the elastic vibration model was verified.The results of the theoretical derivation and simulation show that the elastic vibration equation of a solid bundled launch vehicle established in the paper is correct and can meet the needs for the engineering application.
文摘For the final stage of a launch vehicle which cannot start multiple times,the main constraint of a highly eccentric orbit launch mission is the argument of perigee,which is conditioned by the range.This paper studies the payload capacity at different launch sites for a highly eccentric orbit(e.g.GTO)and gives a method to improve the payload capacity with an argument of perigee constraint by increasing the sliding time before the final ignition and simultaneously adjusting the launch azimuth and yaw at the final stage.An example of launching to GTO orbit on a rocket from Hainan is given,which proves that the method has strong engineering value.
文摘New program was proposed in LM-6 rolling control technology that using high-pressure staged combustion gas. Launch vehicle rolling control by just one engine was realized. Under the limit of the rolling control moment of the launch vehicle, a new attitude dynamic model is established. Interference source and how to reduce the effect was analyzed, and method of designing a pre-compensated robust controller was proposed. Simulation and flight resuits showed that the attitude dynamic model established and the pre-compensation robust controller proposed in this paper could solve the key problems with a strong coupling attitude controller, and realize high quality and high reliability control in wind areas, and improve the capability of the launch vehicle.
文摘The three-axis servo system with the core of gyro stabilization is the foundation to realize its function, and a key technology of the seeker devolopment. In order to reduce the costs, improve the efficiency of research and devolopment, a new method that instead of physical prototype by virtual prototype was proposed. Adams and MATLAB/simulink are used to establish the mechanical dynamics model and controller model of the three-axis servo system. The simulation data which was processed and analyzed is compared with test data, to determine the control parameters of the virtual prototype and improve the accuracy of the model, and test the multiple condition simulation,which can provide a reference for practical production.The simulation results verify the feasibility of the models.
文摘Compared with using liquid rocket engines,there are a lot of high-temperature solid particles in the solid-liquid bundled rocket,which make the rocket base thermal environment worse.In order to study the influence of high-temperature solid particles on the base thermal environment,firstly,the effect of particle diameter on the jet distribution and the thermal environment in a single solid motor jet was analyzed using a numerical simulation method,and the results were compared with those of a ground test.Further,the effects of high-temperature solid particles on the jet and the thermal environment of the solid-liquid bundled rocket were analyzed and compared with flight data.The results show that high-temperature solid particles can increase the jet temperature and reduce the jet velocity.The larger the particle diameter,the greater the impact on the jet core temperature.The role of high-temperature solid particles cannot be ignored in the study of the base thermal environment.
文摘On March 29,2022,the Long March 6A launch vehicle developed by the Shanghai Academy of Space-flight Technology successfully made its maiden flight at the Taiyuan Satellite Launch Center.The Long March 6A launch vehicle was China’s first solid bundled rocket.It uses non-toxic and non-polluting propellants,and has a 700 km sun-synchronous orbit carrying capacity of no less than 4.5 t,which is more than 50%higher than that of a LM-4C launch vehicle.During the development of the LM-6A launch vehicle,the matching relationship between systems and the overall performance of the entire rocket improved significantly through continuous overall optimization work.This paper introduces the typical overall optimization work during the development of the LM-6A launch vehicle.
文摘Based on the concept of DIY, this paper demonstrates the essential potential of DIY manufacturing technology in the application of space equipment. According to the future space technology development trends, the future spacecraft DIY idea and system standard are proposed. The standardized, modularized and serialized micro/nano-satellite DIY products are introduced. Finally, a commercial remote sensing satellite system based on spacecraft DIY is designed and its application prospect is analyzed.
文摘China’s space technology has gradually improved from the early stages’ introduction, absorption and re-innovation based on backward design to independent innovation based on forward design. It is necessary to develop a new approach of systems engineering to improve the quality and efficiency of space systems design considering the large number of original design problems expected in the future. Adopting Model-Based Systems Engineering(MBSE) and Digital Twin method are important development initiatives in the field of modern engineering design. In the initial phase of system design, it is necessary to generate firm system architecture models based on the needs of stakeholders. The quality of the system design in this phase has a great impact on the detailed design and implementation for the subsequent system, and also plays an important role in the performance, development progress and cost of the whole system. Through the collaboration of cross-professional teams, modeling and model execution, comparing the model execution with expected results, MBSE has enabled digital model-level verification and validation before test verification and validation based on physical products, thus improving the design exactness, completeness and greatly reducing design errors or defects. This paper explores the logical ideas behind modeling of system architectures in order to promote the adoption of MBSE in the field of space systems.
