To ensure the safety of astronauts and equipment during landing,the airbag landing system is commonly utilized to attenuate the impact response of the spacecraft.However,the complex impact dynamics and multi-disciplin...To ensure the safety of astronauts and equipment during landing,the airbag landing system is commonly utilized to attenuate the impact response of the spacecraft.However,the complex impact dynamics and multi-disciplinary coupling pose significant challenges to mission design.This paper first investigates the typical design scheme of the airbag landing system for manned spacecrafts to obtain basic insight.A comprehensive review of the past research works on the airbag landing system is then carried out from three aspects:dynamic modeling,performance optimization,and experimental study.The airbag landing system for spacecraft is a rigid-flexible-gas coupling system,which can be modeled through multi-body dynamics or finite element method.Different venting structures and optimization methods are introduced to improve the cushioning performance.Experimental setups for drop test and airbag test are developed to verify the design feasibility.Finally,this paper proposes key issues in the dynamics analysis and design optimization of the airbag landing system for future study.展开更多
Some ideas in the development of fault diagnosis system for spacecraft are introduced. Firstly, the architecture of spacecraft fault diagnosis is proposed hierarchically with four diagnosis frames, i.e., system level,...Some ideas in the development of fault diagnosis system for spacecraft are introduced. Firstly, the architecture of spacecraft fault diagnosis is proposed hierarchically with four diagnosis frames, i.e., system level, subsystem level, component level and element level. Secondly, a hierarchical diagnosis model is expressed with four layers, i.e., sensors layer, function layer, behavior layer and structure layer. These layers are used to work together to accomplish the fault alarm, diagnosis and localization. Thirdly, a fault-tree-oriented hybrid knowledge representation based on frame and generalized rule and its relevant reasoning strategy is put forward. Finally, a diagnosis case for spacecraft power system is exemplified combining the above with a powerful expert system development tool G2.展开更多
This paper studies the leader-following attitude coordination problems of multiple spacecraft in the presence of inertia parameter uncertainties. To achieve attitude coordination in the situation that even the leader&...This paper studies the leader-following attitude coordination problems of multiple spacecraft in the presence of inertia parameter uncertainties. To achieve attitude coordination in the situation that even the leader's attitude is only applicable to a part of the following spacecraft, a nonlinear attitude observer is proposed to obtain an accurate estimation of the leader's attitude and angular velocity for all the followers. In addition, a distributed control scheme based on noncertainty equivalence principle is presented for multiple spacecraft' attitude synchronization. With a dynamic scaling, attitude consensus can be achieved asymptotically without any information of the bounds of the uncertain inertia parameters. Furthermore, once the estimations of inertia parameters reach their ideal values, the estimation process will stop and the ideal value of inertia parameter will be held. This is a special advantage of parameter estimation method based on non-certainty equivalence. Numerical simulations are presented to demonstrate that the proposed non-certainty equivalence-based method requires smaller control toque and converges faster compared with the certainty equivalence-based method.展开更多
To comprehensively assess fi＇actionated spacecraft, an assessment tool is developed based on lifecycle simulation under uncertainty driven by modular evolutionary stochastic models. First, fractionated spacecraft nom...To comprehensively assess fi＇actionated spacecraft, an assessment tool is developed based on lifecycle simulation under uncertainty driven by modular evolutionary stochastic models. First, fractionated spacecraft nomenclature and architecture are clarified, and assessment criteria are analyzed. The mean and standard deviation of risk adjusted lifecycle cost and net present value （NPV） are defined as assessment metrics. Second, fractionated spacecraft sizing models are briefly described, followed by detailed discussion on risk adjusted lifecycle cost and NPV models. Third, uncertainty sources over fractionated spacecraft life- cycle are analyzed and modeled with probability theory. Then the chronological lifecycle simulation process is expounded, and simulation modules are developed with object oriented methodology to build up the assessment tool. The preceding uncertainty models are integrated in these simulation modules, hence the random object status can be simulated and evolve with lifecycle timeline. A case study to investigate the fractionated spacecraft for a hypothetical earth observation mission is carried out with the proposed assessment tool, and the results show that fractionation degree and launch manifest have great influence on cost and NPV, and generally fractionated spacecraft is more advanced than its monolithic counterpart under uncertainty effect. Finally, some conclusions are given and future research topics are highlighted.展开更多
This paper presents a new device integrating a nonlinear vibration absorber with a levitation magnetoelectric energy harvester for whole-spacecraft systems. This device effectively reduces vibration and has a stronger...This paper presents a new device integrating a nonlinear vibration absorber with a levitation magnetoelectric energy harvester for whole-spacecraft systems. This device effectively reduces vibration and has a stronger energy harvesting capability than the existing systems. It harvests energy from a wide frequency range and has a high output voltage. The harvested energy is determined by magnetic field strength, excitation frequency, and resistive load. The change in the magnetic field strength has the least impact on the output voltage. The vibration reduction effects and harvested energy of the system are analyzed with an approximate analytical method that combines the harmonic balance approach and the pseudo-arclength continuation algorithm. The results of the Runge-Kutta method are nearly consistent with those of the approximate analytical method. Moreover, the effects of the excitation frequency, resistive load, and parameters of the nonlinear energy sink on the system vibration response and energy harvesting are analyzed.展开更多
This paper considers a fault-tolerant control and vibration suppression problem of flexible spacecraft.The attitude dynamics is modeled by an interconnected system,in which the rigid part and the flexible part are cou...This paper considers a fault-tolerant control and vibration suppression problem of flexible spacecraft.The attitude dynamics is modeled by an interconnected system,in which the rigid part and the flexible part are coupled with each other.Such a model allows us to use the interconnected system approach to analyze the flexible spacecraft.Both distributed and decentralized observer-based fault-tolerant control schemes are developed,under which the closed-loop stability of flexible spacecraft can be ensured by using the cycle-small-gain theorem.Compared with the traditional method,this paper considers the faults occurred not only in the rigid parts,but also in the flexible parts.In addition,the application of the interconnected system approach simplifies the system model of flexible spacecraft,thereby the difficulty of theoretical analysis and engineering practice of fault-tolerant control of flexible spacecraft are greatly reduced.Simulation results show the effectiveness of the proposed methods and the comparison of different fault-tolerant control approach.展开更多
An integrated simulation system for solar sail spacecraft with individually controllable elements(SSICE)is investigated in this paper,including the modelling of power management,thermal control,attitude control,umbra ...An integrated simulation system for solar sail spacecraft with individually controllable elements(SSICE)is investigated in this paper,including the modelling of power management,thermal control,attitude control,umbra prediction,and orbit prediction subsystems.Considering the self-control and reactivity subsystems,an agent based method is applied to develop the subsystem models.Each subsystem is an individual agent component,which manages itself autonomously and reacts to the requirements from other agents.To reduce computing burden on a specified computer and improve the suitability and flexibility of the integrated simulation system,a distributed framework is employed in the system by deploying agent components on different computers.The data transmission among agents is based on the transmission control protocol/Internet protocol(TCP/IP).A practical example of sun pointing is used to test the operating effect of the integrated system and the working condition of subsystems.The simulation results verify that the integrated system has higher sun pointing accuracy,quicker dynamical response to variations of the lighting,attitude and temperature and fewer computing resources with effective and accurate subsystems.The integrated system proposed in this paper can be applied to solar sail design,operation,and mission planning.展开更多
A control strategy combining feedforward control and feedback control is presented for the optimal deployment of a spacecraft solar array system with the initial state uncertainty. A dynamic equation of the spacecraft...A control strategy combining feedforward control and feedback control is presented for the optimal deployment of a spacecraft solar array system with the initial state uncertainty. A dynamic equation of the spacecraft solar array system is established under the assumption that the initial linear momentum and angular momentum of the system are zero. In the design of feedforward control, the dissipation energy of each revolute joint is selected as the performance index of the system. A Legendre pseudospectral method(LPM) is used to transform the optimal control problem into a nonlinear programming problem. Then, a sequential quadratic programming algorithm is used to solve the nonlinear programming problem and offline generate the optimal reference trajectory of the system. In the design of feedback control, the dynamic equation is linearized along the reference trajectory in the presence of initial state errors. A trajectory tracking problem is converted to a two-point boundary value problem based on Pontryagin’s minimum principle. The LPM is used to discretize the two-point boundary value problem and transform it into a set of linear algebraic equations which can be easily calculated. Then, the closed-loop state feedback control law is designed based on the resulting optimal feedback control and achieves good performance in real time. Numerical simulations demonstrate the feasibility and effectiveness of the proposed control strategy.展开更多
FSC （Fractionated Spacecraft Cluster） is a kind of loosely distributed space system which is comprised of multiple physically independent spacecrafts orbiting closely and interactively communicating via wireless net...FSC （Fractionated Spacecraft Cluster） is a kind of loosely distributed space system which is comprised of multiple physically independent spacecrafts orbiting closely and interactively communicating via wireless network. Spaceborne ad-hoc network, as the physical infrastructure for information exchanging, is one of the enabling technologies of FSC. The demonstration of FSC flying supported by ad-hoc network is worth for the sake of proving the rationality of FSC and seeking technological improvements. Considering this, a NNP （Network Node Prototype） for spaceborne ad-hoc network is developed in this paper, which transmits the information required by the FSC cooperation. Four NNPs are then built up and collaborated into a hardware-in-loop simulation system, in which a typical loose satellite cluster flying mission was performed. The simulation results showed that the NNPs can support the inter-satellite communication for satellite cluster flying.展开更多
This paper presents a discrete-time attitude control strategy with equi-global practical stabilizability for aligning the attitude of multiple spacecraft to a predesigned configuration according to a time-variant refe...This paper presents a discrete-time attitude control strategy with equi-global practical stabilizability for aligning the attitude of multiple spacecraft to a predesigned configuration according to a time-variant reference.By utilizing the interference of the wireless channel,the communication scheme designed in this paper can save communication resources,amount of computation,and energy proportionally to the number of spacecraft.The exact discrete-time model and approximate discrete-time model of the consensus-based spacecraft tracking system are given.Then the framework for the design of an event-triggered control scheme for the exact discrete-time system via its approximate models is developed,which avoids the periodic actuation,and Zeno behavior is proved to be excluded.Furthermore,the control scheme can handle the presence of the unknown fading channel.Finally,simulation results are presented to demonstrate the effectiveness of the control strategy.展开更多
The problem of robust global stabilization of a spacecraft circular orbit rendezvous system with input saturation and inputadditive uncertainties is studied in this paper. The relative models with saturation nonlinear...The problem of robust global stabilization of a spacecraft circular orbit rendezvous system with input saturation and inputadditive uncertainties is studied in this paper. The relative models with saturation nonlinearity are established based on ClohesseyWiltshire equation. Considering the advantages of the recently developed parametric Lyapunov equation-based low gain feedback design method and an existing high gain scheduling technique, a new robust gain scheduling controller is proposed to solve the robust global stabilization problem. To apply the proposed gain scheduling approaches, only a scalar nonlinear equation is required to be solved.Different from the controller design, simulations have been carried out directly on the nonlinear model of the spacecraft rendezvous operation instead of a linearized one. The effectiveness of the proposed approach is shown.展开更多
The fuel slosh in the storage tanks affects the attitude dynamics of the liquid-filled spacecraft during orbit transferring. To describe the interactions between the fuel slosh dynamics and the spacecraft attitude dyn...The fuel slosh in the storage tanks affects the attitude dynamics of the liquid-filled spacecraft during orbit transferring. To describe the interactions between the fuel slosh dynamics and the spacecraft attitude dynamics, a novel nonlinear dynamic model for three-axis liquid-filled spacecraft is presented, and in this paper, the multi-body dynamics method is utilized. In this model, the fuel slosh is represented by the motions of an equivalent sphere pendulum, and the fuel slosh is underactuated. The proposed dynamics model meets the demand of attitude controller design of liquid-filled spacecraft. Then, a nonlinear proportional-plus-derivative (PD) type controller is designed for the proposed model based on the Lyapunov direct approach. This controller can suppress the fuel slosh and stabilize the attitude of the liquid-filled spacecraft. Numerical simulations are presented to verify the effectiveness of the proposed nonlinear dynamic model and the designed underactuated controller when compared with the conventional control scheme.展开更多
The 200mm class ion propulsion system(LIPS-200)developed by CAST subsidiary Lanzhou Institute of Vacuum Physics(LIP)has passed its 6000-hour accumulative ground test recently with 3000 times on-off switching throughou...The 200mm class ion propulsion system(LIPS-200)developed by CAST subsidiary Lanzhou Institute of Vacuum Physics(LIP)has passed its 6000-hour accumulative ground test recently with 3000 times on-off switching throughout the test.It is capable of ensuring reliable in-orbit operation of a satellite for 15 years.China’s indigenous state-of-the-art electric propulsion system is ready to apply on spacecraft meeting the requirement for the展开更多
In the history of human space exploration, many failures of launch vehicles and spacecraft tare caused by vibration. At first, the periods in which the space products are in a vibration environment are discussed and t...In the history of human space exploration, many failures of launch vehicles and spacecraft tare caused by vibration. At first, the periods in which the space products are in a vibration environment are discussed and the need for vibration testing is then introduced. As the main content of this paper, the current situation of shaker systems is elaborated in detail. In this part, electrodynamic shakers, as the most widely used vibration generators, are illustrated in detail including structures, principles and performances. Special inventions worldwide in the development of electrodynamic shakers such as induction ring shakers, high force shakers, multi-axial vibration testing systems and combined environmental testing systems are presented. At last, the recent progress and outlook of shaker systems are summarized.展开更多
1. Introduction Celestial navigation is a kind of navigation with a long history.With the increasing demand for intelligent autonomy and antielectromagnetic interference in spacecraft, celestial navigation has become ...1. Introduction Celestial navigation is a kind of navigation with a long history.With the increasing demand for intelligent autonomy and antielectromagnetic interference in spacecraft, celestial navigation has become one of the current research hotspots in spacecraft autonomous navigation. Spacecraft face complex electromagnetic interference in orbit. The time-varying, non-Gaussian interference from internal devices and external environment can lead to measurement distortion.展开更多
In response to the need for a supportive on-orbit platform for future Mars exploration missions,this paper proposes the design and implementation of an autonomous spacecraft formation flying system near the Martian sy...In response to the need for a supportive on-orbit platform for future Mars exploration missions,this paper proposes the design and implementation of an autonomous spacecraft formation flying system near the Martian synchronous orbit using fuzzy learning-based intelligent control.A detailed analysis of spacecraft relative motion in the Mars environment is conducted,deducing the necessary conditions to reach the Martian synchronous orbit constraints.The modified Clohessy-Wiltshire(C-W)equation with Martian J_(2)(Oblateness index)perturbation is used as a reference to design a fuzzy learning-based intelligent and robust nonlinear control approach,which helps to autonomously track the desired formation configuration and stabilizes it.An introduction to spacecraft propulsion mechanisms is provided to analyze the feasibility of using electrical thrusters for spacecraft formation configuration tracking and stabilization in Martian synchronous orbits.The simulations show the effectiveness of the proposed control system for long-term on-orbit operations and reveal its reliability for designing intelligent deep-space formation flying configurations,such as an autonomous Mars observatory,a Martian telescope,or an interferometer.展开更多
The oscillation of large space structure(LSS)can be easily induced because of its low vibration frequency.The coupling effect between LSS vibration control and attitude control can significantly reduce the overall per...The oscillation of large space structure(LSS)can be easily induced because of its low vibration frequency.The coupling effect between LSS vibration control and attitude control can significantly reduce the overall performance of the control system,especially when the scale of flexible structure increases.This paper proposes an optimal placement method of piezoelectric stack actuators(PSAs)network which reduces the coupling effect between attitude and vibration control system.First,a spacecraft with a honeycomb-shaped telescope is designed for a resolution-critical imaging scenario.The coupling dynamics of the spacecraft is established using finite element method(FEM)and floating frame of reference formulation(FFRF).Second,a coupling-effect-reducing optimal placement criterion for PSAs based on coupling-matrix enhanced Gramian is designed to reduce the coupling effect excitation while balancing controllability.Additionally,a laddered multi-layered optimizing scheme is established to increase the speed and accuracy when solving the gigantic discrete optimization problem.Finally,the effectiveness of the proposed method is illustrated through numerical simulation.展开更多
Pose estimation of spacecraft targets is a key technology for achieving space operation tasks,such as the cleaning of failed satellites and the detection and scanning of non-cooperative targets.This paper reviews the ...Pose estimation of spacecraft targets is a key technology for achieving space operation tasks,such as the cleaning of failed satellites and the detection and scanning of non-cooperative targets.This paper reviews the target pose estimation methods based on image feature extraction and PnP,the target estimation methods based on registration,and the spacecraft target pose estimation methods based on deep learning,and introduces the corresponding research methods.展开更多
It is widely known that the hypervelocity impact of orbital debris can cause serious damage to spacecraft,and enhancing the impact resistance is the great concern of spacecraft shield design.This paper provides a comp...It is widely known that the hypervelocity impact of orbital debris can cause serious damage to spacecraft,and enhancing the impact resistance is the great concern of spacecraft shield design.This paper provides a comprehensive overview of advances in the development of bumper materials for spacecraft shield applications.In particular,the protective mechanism and process of the bumper using different materials against hypervelocity impact are reviewed and discussed.The advantages and disadvantages of each material used in shield were discussed,and the performance under hypervelocity impact was given according to the specific configuration.This review provides the useful reference and basis for researchers and engineers to create bumper materials for spacecraft shield applications,and the contemporary challenges and future directions for bumper materials for spacecraft shield were presented.展开更多
The modular design pattern revolutionizes the monolithic morphology of traditional spacecraft into the reconfigurable combination of modular units.However,due to the morphological changes,the effective takeover contro...The modular design pattern revolutionizes the monolithic morphology of traditional spacecraft into the reconfigurable combination of modular units.However,due to the morphological changes,the effective takeover control of the combination through multiple independent modules,including the controller and actuator modules,remains a challenge.In this paper,a robust takeover control scheme with high allocation accuracy,independent of precise inertia,is proposed for the reconfigurable combination in the presence of the inertia uncertainty,model parameters uncertainty,communication delay,and external disturbance.By reregulating the conditions for performance synthesis into a symmetric form with similar structure,a hybrid non-fragile H_(2)/H_(∞)controller is designed for handling two types of controller gain perturbations,achieving superior performance with less energy consumption through simultaneous perturbation suppression.Moreover,through temporarily storing the allocation signals in the initial stage to cover the upper bound of the communication delay,the proposed distributed dynamic allocation scheme enables the actuator modules to implement the control signals jointly to stabilize the combination.Distinguished from general allocators,the proposed high-precision allocation scheme under communication delay can not only ensure full exploitation of controller performance,but also dynamically adjust allocation coefficients based on energy consumption index of controller modules to prevent actuator saturation.Numerical simulations demonstrate the superiority of the proposed hybrid non-fragile controller and the allocation scheme.展开更多
基金co-supported by the National Natural Science Foundation of China(Nos.11932001,12272003,U224126)。
文摘To ensure the safety of astronauts and equipment during landing,the airbag landing system is commonly utilized to attenuate the impact response of the spacecraft.However,the complex impact dynamics and multi-disciplinary coupling pose significant challenges to mission design.This paper first investigates the typical design scheme of the airbag landing system for manned spacecrafts to obtain basic insight.A comprehensive review of the past research works on the airbag landing system is then carried out from three aspects:dynamic modeling,performance optimization,and experimental study.The airbag landing system for spacecraft is a rigid-flexible-gas coupling system,which can be modeled through multi-body dynamics or finite element method.Different venting structures and optimization methods are introduced to improve the cushioning performance.Experimental setups for drop test and airbag test are developed to verify the design feasibility.Finally,this paper proposes key issues in the dynamics analysis and design optimization of the airbag landing system for future study.
文摘Some ideas in the development of fault diagnosis system for spacecraft are introduced. Firstly, the architecture of spacecraft fault diagnosis is proposed hierarchically with four diagnosis frames, i.e., system level, subsystem level, component level and element level. Secondly, a hierarchical diagnosis model is expressed with four layers, i.e., sensors layer, function layer, behavior layer and structure layer. These layers are used to work together to accomplish the fault alarm, diagnosis and localization. Thirdly, a fault-tree-oriented hybrid knowledge representation based on frame and generalized rule and its relevant reasoning strategy is put forward. Finally, a diagnosis case for spacecraft power system is exemplified combining the above with a powerful expert system development tool G2.
基金supported by the National Natural Science Foundation of China(Nos.11402200,11502203)
文摘This paper studies the leader-following attitude coordination problems of multiple spacecraft in the presence of inertia parameter uncertainties. To achieve attitude coordination in the situation that even the leader's attitude is only applicable to a part of the following spacecraft, a nonlinear attitude observer is proposed to obtain an accurate estimation of the leader's attitude and angular velocity for all the followers. In addition, a distributed control scheme based on noncertainty equivalence principle is presented for multiple spacecraft' attitude synchronization. With a dynamic scaling, attitude consensus can be achieved asymptotically without any information of the bounds of the uncertain inertia parameters. Furthermore, once the estimations of inertia parameters reach their ideal values, the estimation process will stop and the ideal value of inertia parameter will be held. This is a special advantage of parameter estimation method based on non-certainty equivalence. Numerical simulations are presented to demonstrate that the proposed non-certainty equivalence-based method requires smaller control toque and converges faster compared with the certainty equivalence-based method.
基金Foundation items： National Natural Science Foundation of China （50975280, 61004094） Program for New Century Excellent Talents in University （NCET-08-0149）+1 种基金 Fund of Innovation by Graduate School of National University of Defense Technology （B090102） Hunan Provincial Innovation Foundation for Postgraduate, China.
文摘To comprehensively assess fi＇actionated spacecraft, an assessment tool is developed based on lifecycle simulation under uncertainty driven by modular evolutionary stochastic models. First, fractionated spacecraft nomenclature and architecture are clarified, and assessment criteria are analyzed. The mean and standard deviation of risk adjusted lifecycle cost and net present value （NPV） are defined as assessment metrics. Second, fractionated spacecraft sizing models are briefly described, followed by detailed discussion on risk adjusted lifecycle cost and NPV models. Third, uncertainty sources over fractionated spacecraft life- cycle are analyzed and modeled with probability theory. Then the chronological lifecycle simulation process is expounded, and simulation modules are developed with object oriented methodology to build up the assessment tool. The preceding uncertainty models are integrated in these simulation modules, hence the random object status can be simulated and evolve with lifecycle timeline. A case study to investigate the fractionated spacecraft for a hypothetical earth observation mission is carried out with the proposed assessment tool, and the results show that fractionation degree and launch manifest have great influence on cost and NPV, and generally fractionated spacecraft is more advanced than its monolithic counterpart under uncertainty effect. Finally, some conclusions are given and future research topics are highlighted.
基金the National Natural Science Foundation of China (Project No. 11772205)the Training Project of Liaoning Provincial Higher Education Institutions in Domestic and Overseas (Project No. 2018LNGXGJWPY-YB008)the Scientific Research Fund of Liaoning Provincial Education Department (Project No. L201703).
文摘This paper presents a new device integrating a nonlinear vibration absorber with a levitation magnetoelectric energy harvester for whole-spacecraft systems. This device effectively reduces vibration and has a stronger energy harvesting capability than the existing systems. It harvests energy from a wide frequency range and has a high output voltage. The harvested energy is determined by magnetic field strength, excitation frequency, and resistive load. The change in the magnetic field strength has the least impact on the output voltage. The vibration reduction effects and harvested energy of the system are analyzed with an approximate analytical method that combines the harmonic balance approach and the pseudo-arclength continuation algorithm. The results of the Runge-Kutta method are nearly consistent with those of the approximate analytical method. Moreover, the effects of the excitation frequency, resistive load, and parameters of the nonlinear energy sink on the system vibration response and energy harvesting are analyzed.
基金supported by National Natural Science Foundation of China(Nos.61622304,61773201)Natural Science Foundation of Jiangsu Province,China(No.BK20160035)Fundamental Research Funds for the Central Universities,China(No.NE2015002)。
文摘This paper considers a fault-tolerant control and vibration suppression problem of flexible spacecraft.The attitude dynamics is modeled by an interconnected system,in which the rigid part and the flexible part are coupled with each other.Such a model allows us to use the interconnected system approach to analyze the flexible spacecraft.Both distributed and decentralized observer-based fault-tolerant control schemes are developed,under which the closed-loop stability of flexible spacecraft can be ensured by using the cycle-small-gain theorem.Compared with the traditional method,this paper considers the faults occurred not only in the rigid parts,but also in the flexible parts.In addition,the application of the interconnected system approach simplifies the system model of flexible spacecraft,thereby the difficulty of theoretical analysis and engineering practice of fault-tolerant control of flexible spacecraft are greatly reduced.Simulation results show the effectiveness of the proposed methods and the comparison of different fault-tolerant control approach.
基金This work was supported by the National Natural Science Foundation of China(11772024).
文摘An integrated simulation system for solar sail spacecraft with individually controllable elements(SSICE)is investigated in this paper,including the modelling of power management,thermal control,attitude control,umbra prediction,and orbit prediction subsystems.Considering the self-control and reactivity subsystems,an agent based method is applied to develop the subsystem models.Each subsystem is an individual agent component,which manages itself autonomously and reacts to the requirements from other agents.To reduce computing burden on a specified computer and improve the suitability and flexibility of the integrated simulation system,a distributed framework is employed in the system by deploying agent components on different computers.The data transmission among agents is based on the transmission control protocol/Internet protocol(TCP/IP).A practical example of sun pointing is used to test the operating effect of the integrated system and the working condition of subsystems.The simulation results verify that the integrated system has higher sun pointing accuracy,quicker dynamical response to variations of the lighting,attitude and temperature and fewer computing resources with effective and accurate subsystems.The integrated system proposed in this paper can be applied to solar sail design,operation,and mission planning.
基金supported by the National Natural Science Foundation of China(Nos.11732005 and11472058)
文摘A control strategy combining feedforward control and feedback control is presented for the optimal deployment of a spacecraft solar array system with the initial state uncertainty. A dynamic equation of the spacecraft solar array system is established under the assumption that the initial linear momentum and angular momentum of the system are zero. In the design of feedforward control, the dissipation energy of each revolute joint is selected as the performance index of the system. A Legendre pseudospectral method(LPM) is used to transform the optimal control problem into a nonlinear programming problem. Then, a sequential quadratic programming algorithm is used to solve the nonlinear programming problem and offline generate the optimal reference trajectory of the system. In the design of feedback control, the dynamic equation is linearized along the reference trajectory in the presence of initial state errors. A trajectory tracking problem is converted to a two-point boundary value problem based on Pontryagin’s minimum principle. The LPM is used to discretize the two-point boundary value problem and transform it into a set of linear algebraic equations which can be easily calculated. Then, the closed-loop state feedback control law is designed based on the resulting optimal feedback control and achieves good performance in real time. Numerical simulations demonstrate the feasibility and effectiveness of the proposed control strategy.
文摘FSC （Fractionated Spacecraft Cluster） is a kind of loosely distributed space system which is comprised of multiple physically independent spacecrafts orbiting closely and interactively communicating via wireless network. Spaceborne ad-hoc network, as the physical infrastructure for information exchanging, is one of the enabling technologies of FSC. The demonstration of FSC flying supported by ad-hoc network is worth for the sake of proving the rationality of FSC and seeking technological improvements. Considering this, a NNP （Network Node Prototype） for spaceborne ad-hoc network is developed in this paper, which transmits the information required by the FSC cooperation. Four NNPs are then built up and collaborated into a hardware-in-loop simulation system, in which a typical loose satellite cluster flying mission was performed. The simulation results showed that the NNPs can support the inter-satellite communication for satellite cluster flying.
基金co-supported by the Equipment Advance Research Project,China(No.50912020401)the Chinese Government Scholarship(No.201906830037)。
文摘This paper presents a discrete-time attitude control strategy with equi-global practical stabilizability for aligning the attitude of multiple spacecraft to a predesigned configuration according to a time-variant reference.By utilizing the interference of the wireless channel,the communication scheme designed in this paper can save communication resources,amount of computation,and energy proportionally to the number of spacecraft.The exact discrete-time model and approximate discrete-time model of the consensus-based spacecraft tracking system are given.Then the framework for the design of an event-triggered control scheme for the exact discrete-time system via its approximate models is developed,which avoids the periodic actuation,and Zeno behavior is proved to be excluded.Furthermore,the control scheme can handle the presence of the unknown fading channel.Finally,simulation results are presented to demonstrate the effectiveness of the control strategy.
基金supported by the Innovative Team Program ofthe National Natural Science Foundation of China(No.61021002)National Basic Research Program of China(973 Program)(No.2012CB821205)
文摘The problem of robust global stabilization of a spacecraft circular orbit rendezvous system with input saturation and inputadditive uncertainties is studied in this paper. The relative models with saturation nonlinearity are established based on ClohesseyWiltshire equation. Considering the advantages of the recently developed parametric Lyapunov equation-based low gain feedback design method and an existing high gain scheduling technique, a new robust gain scheduling controller is proposed to solve the robust global stabilization problem. To apply the proposed gain scheduling approaches, only a scalar nonlinear equation is required to be solved.Different from the controller design, simulations have been carried out directly on the nonlinear model of the spacecraft rendezvous operation instead of a linearized one. The effectiveness of the proposed approach is shown.
基金Sponsored by the Innovative Team Program of the National Natural Science Foundation of China ( Grant No. 61021002)
文摘The fuel slosh in the storage tanks affects the attitude dynamics of the liquid-filled spacecraft during orbit transferring. To describe the interactions between the fuel slosh dynamics and the spacecraft attitude dynamics, a novel nonlinear dynamic model for three-axis liquid-filled spacecraft is presented, and in this paper, the multi-body dynamics method is utilized. In this model, the fuel slosh is represented by the motions of an equivalent sphere pendulum, and the fuel slosh is underactuated. The proposed dynamics model meets the demand of attitude controller design of liquid-filled spacecraft. Then, a nonlinear proportional-plus-derivative (PD) type controller is designed for the proposed model based on the Lyapunov direct approach. This controller can suppress the fuel slosh and stabilize the attitude of the liquid-filled spacecraft. Numerical simulations are presented to verify the effectiveness of the proposed nonlinear dynamic model and the designed underactuated controller when compared with the conventional control scheme.
文摘The 200mm class ion propulsion system(LIPS-200)developed by CAST subsidiary Lanzhou Institute of Vacuum Physics(LIP)has passed its 6000-hour accumulative ground test recently with 3000 times on-off switching throughout the test.It is capable of ensuring reliable in-orbit operation of a satellite for 15 years.China’s indigenous state-of-the-art electric propulsion system is ready to apply on spacecraft meeting the requirement for the
文摘In the history of human space exploration, many failures of launch vehicles and spacecraft tare caused by vibration. At first, the periods in which the space products are in a vibration environment are discussed and the need for vibration testing is then introduced. As the main content of this paper, the current situation of shaker systems is elaborated in detail. In this part, electrodynamic shakers, as the most widely used vibration generators, are illustrated in detail including structures, principles and performances. Special inventions worldwide in the development of electrodynamic shakers such as induction ring shakers, high force shakers, multi-axial vibration testing systems and combined environmental testing systems are presented. At last, the recent progress and outlook of shaker systems are summarized.
基金supported by the National Level Project of China (No. 2020-JCJQ-ZQ-059)。
文摘1. Introduction Celestial navigation is a kind of navigation with a long history.With the increasing demand for intelligent autonomy and antielectromagnetic interference in spacecraft, celestial navigation has become one of the current research hotspots in spacecraft autonomous navigation. Spacecraft face complex electromagnetic interference in orbit. The time-varying, non-Gaussian interference from internal devices and external environment can lead to measurement distortion.
基金supported by the National Laboratory of Space Intelligent Control(No.HTKJ2023KL502007)the Chinese Government Scholarship(CSC)。
文摘In response to the need for a supportive on-orbit platform for future Mars exploration missions,this paper proposes the design and implementation of an autonomous spacecraft formation flying system near the Martian synchronous orbit using fuzzy learning-based intelligent control.A detailed analysis of spacecraft relative motion in the Mars environment is conducted,deducing the necessary conditions to reach the Martian synchronous orbit constraints.The modified Clohessy-Wiltshire(C-W)equation with Martian J_(2)(Oblateness index)perturbation is used as a reference to design a fuzzy learning-based intelligent and robust nonlinear control approach,which helps to autonomously track the desired formation configuration and stabilizes it.An introduction to spacecraft propulsion mechanisms is provided to analyze the feasibility of using electrical thrusters for spacecraft formation configuration tracking and stabilization in Martian synchronous orbits.The simulations show the effectiveness of the proposed control system for long-term on-orbit operations and reveal its reliability for designing intelligent deep-space formation flying configurations,such as an autonomous Mars observatory,a Martian telescope,or an interferometer.
基金supported by National Natural Science Foundation of China(No.U23B6001).
文摘The oscillation of large space structure(LSS)can be easily induced because of its low vibration frequency.The coupling effect between LSS vibration control and attitude control can significantly reduce the overall performance of the control system,especially when the scale of flexible structure increases.This paper proposes an optimal placement method of piezoelectric stack actuators(PSAs)network which reduces the coupling effect between attitude and vibration control system.First,a spacecraft with a honeycomb-shaped telescope is designed for a resolution-critical imaging scenario.The coupling dynamics of the spacecraft is established using finite element method(FEM)and floating frame of reference formulation(FFRF).Second,a coupling-effect-reducing optimal placement criterion for PSAs based on coupling-matrix enhanced Gramian is designed to reduce the coupling effect excitation while balancing controllability.Additionally,a laddered multi-layered optimizing scheme is established to increase the speed and accuracy when solving the gigantic discrete optimization problem.Finally,the effectiveness of the proposed method is illustrated through numerical simulation.
文摘Pose estimation of spacecraft targets is a key technology for achieving space operation tasks,such as the cleaning of failed satellites and the detection and scanning of non-cooperative targets.This paper reviews the target pose estimation methods based on image feature extraction and PnP,the target estimation methods based on registration,and the spacecraft target pose estimation methods based on deep learning,and introduces the corresponding research methods.
基金supported by National Natural Science Foundation of China(Grant Nos.12202068,12202087)China National Space Administration Preliminary Research Project(Grant Nos.KJSP2023020201,KJSP2020010402).
文摘It is widely known that the hypervelocity impact of orbital debris can cause serious damage to spacecraft,and enhancing the impact resistance is the great concern of spacecraft shield design.This paper provides a comprehensive overview of advances in the development of bumper materials for spacecraft shield applications.In particular,the protective mechanism and process of the bumper using different materials against hypervelocity impact are reviewed and discussed.The advantages and disadvantages of each material used in shield were discussed,and the performance under hypervelocity impact was given according to the specific configuration.This review provides the useful reference and basis for researchers and engineers to create bumper materials for spacecraft shield applications,and the contemporary challenges and future directions for bumper materials for spacecraft shield were presented.
基金co-supported by the National Natural Science Foundation of China(No.12372048)the China Postdoctoral Science Foundation(No.2023M742835)+3 种基金the Guangdong Basic and Applied Basic Research Foundation,China(No.2023A1515011421)the Aeronautical Science Foundation of China(No.2022Z004053001)the Fundamental Research Funds for the Central Universities,China(No.D5000210833)the Young Talent Fund of Association for Science and Technology in Shaanxi,China(No.20220509)。
文摘The modular design pattern revolutionizes the monolithic morphology of traditional spacecraft into the reconfigurable combination of modular units.However,due to the morphological changes,the effective takeover control of the combination through multiple independent modules,including the controller and actuator modules,remains a challenge.In this paper,a robust takeover control scheme with high allocation accuracy,independent of precise inertia,is proposed for the reconfigurable combination in the presence of the inertia uncertainty,model parameters uncertainty,communication delay,and external disturbance.By reregulating the conditions for performance synthesis into a symmetric form with similar structure,a hybrid non-fragile H_(2)/H_(∞)controller is designed for handling two types of controller gain perturbations,achieving superior performance with less energy consumption through simultaneous perturbation suppression.Moreover,through temporarily storing the allocation signals in the initial stage to cover the upper bound of the communication delay,the proposed distributed dynamic allocation scheme enables the actuator modules to implement the control signals jointly to stabilize the combination.Distinguished from general allocators,the proposed high-precision allocation scheme under communication delay can not only ensure full exploitation of controller performance,but also dynamically adjust allocation coefficients based on energy consumption index of controller modules to prevent actuator saturation.Numerical simulations demonstrate the superiority of the proposed hybrid non-fragile controller and the allocation scheme.
