With the development of space technology,it is possible to build a space station in Earth-Moon space as a transit for Earth-Moon round-trip and entering in the deep space.Rendezvous and docking is one of the key techn...With the development of space technology,it is possible to build a space station in Earth-Moon space as a transit for Earth-Moon round-trip and entering in the deep space.Rendezvous and docking is one of the key technologies for building an Earth-Moon space station.A guidance strategy for rendezvous and docking from the Earth orbit to the space station in the Earth-Moon NRHO orbit is proposed in this paper,which is suitable for engineering applications.Firstly,the rendezvous and docking process is divided into three sections,i.e.,the large-range orbit transfer section,far-range guidance section,and close-range approaching section.The suitable terminal of large-range orbit transfer is selected according to the eigenvalue of NRHO orbit state transition matrix.The two-impulse guidance method based on the relative motion equation in the three-body problem is adopted for the far-range guidance section.The impulse time and amplitude are solved with the optimization algorithm.The linear constant three-body relative motion equation is proposed for the close-range approaching section,and the rendezvous and docking is completed by a two-stage linear approximation.Finally,a simulation analysis is carried out,and the simulation results show that the adopted dynamics equations and the designed guidance law are effective,and the three flight phases are naturally connected to accomplish the rendezvous and docking mission from the Earth orbit to the space station on the Earth-Moon NRHO.展开更多
At 1:36 am on November 3,China's Shenzhou 8 unmanned spaceship and Tiangong 1 space lab spacecraft accomplished the country's first space docking procedure and coupling in space at more than 343km above Earth&...At 1:36 am on November 3,China's Shenzhou 8 unmanned spaceship and Tiangong 1 space lab spacecraft accomplished the country's first space docking procedure and coupling in space at more than 343km above Earth's surface,marking a great leap in China's space program.展开更多
Teleoperation rendezvous and docking can be used as a backup for autonomous rendezvous and docking (RVD) for an unmanned spacecraft or for guiding the chaser docking with an uncooperative target.The inherent teleopera...Teleoperation rendezvous and docking can be used as a backup for autonomous rendezvous and docking (RVD) for an unmanned spacecraft or for guiding the chaser docking with an uncooperative target.The inherent teleoperation time delay is a rigorous problem,especially when the chaser is teleoperated on the ground.To eliminate the effect of time delay,a new approach for teleoperation RVD is studied.The characteristics of teleoperation RVD are analyzed by comparisons with the teleoperation robot and with manually controlled RVD;the relative motion of the chaser is predicted based on the C-W equation;and the processed measure information with time delay through the Kalman filter is utilized to correct the current prediction.Experimental results verify that the approach produces an 18% enhanced success rate of teleoperation RVD compared with direct visual feedback,and consumes less time and fuel.The developed approach also solves the time delay problem effectively.Teleoperation RVD using this method can be applied as a useful backup for autonomous RVD.展开更多
Teleoperation rendezvous and docking can be used as a backup for autonomous rendezvous and docking（RVD） for an unmanned spacecraft when the autonomous system is failure or for guiding the chaser docking with an unco...Teleoperation rendezvous and docking can be used as a backup for autonomous rendezvous and docking（RVD） for an unmanned spacecraft when the autonomous system is failure or for guiding the chaser docking with an uncooperative target.The theoretical model for analyzing the handling qualities in teleoperation RVD process is established based on the previous studies conducted by National Aeronautics and Space Administration（NASA）.The predictive factor is introduced to describe the pilot＇s predictive ability in the teleoperation tasks with time delay,which interrelates with the skills of a pilot and the predictive assist approach used in the tasks such as the predictive display method.Based on the semi-physical simulation system in our laboratory,900 experiments at two levels of time delay are carried out by 18 volunteers for validating the established model.The experimental results demonstrate the correctness of the theoretical model and indicate that a skilled pilot has a predictive ability of approximately 0.9 in teleoperation RVD tasks.The theoretical analysis shows that the handling qualities are greatly affected by the time delay and the predictive factor,and it is impossible to achieve a teleoperation RVD task for the skilled pilot when the time delay is larger than 9.0 s.展开更多
This study focuses on the influence of the monitoring method and control complexity on the operator performance in manually controlled spacecraft rendezvous and docking （RVD）. Two one-factor experiments were designe...This study focuses on the influence of the monitoring method and control complexity on the operator performance in manually controlled spacecraft rendezvous and docking （RVD）. Two one-factor experiments were designed on a simulated RVD system. One examined the video guidance and periscope monitoring methods, and the other examined three control complexity levels using one-axis RVD control, two-axis RVD control, and three-axis RVD control. Eighteen male volunteers aged 22-35 participated in the experiments. The results show that the RVD operating time increases with control complexity. Based on the operators＇ findings, the two-axis control is the easiest. The monitoring method has no significant influence on failure rate with the low complexity using one-axis RVD control.展开更多
Subjective evaluation is one of the most important methods of assessing the fidelity of a virtual dynamic scene,whose results could be seen as a reference to improve a rendering method.In the present study,we apply a ...Subjective evaluation is one of the most important methods of assessing the fidelity of a virtual dynamic scene,whose results could be seen as a reference to improve a rendering method.In the present study,we apply a rendering method to the color rendezvous and docking(RVD) scene,where one shadow algorithm and three tone mapping operator algorithms are used to process the scene based on the distance between two spacecrafts.The grayscale RVD scene is transformed from the color RVD scene,and each RVD scene is desired to make comparisons with the real RVD-video recorded in SZ-10 mission.In addition,we perform an evaluation on 36 subjects to compare the results.The results show that shadow effects have important roles in RVD virtual scenes,where they enhance the sense of realism and immersion.Shadows,high brightness,contrast and luminance are highly correlated with the overall preference,and the grayscale scene receives better evaluations than the color scene.The analysis of these conclusions is vital for improving the algorithms used to render color virtual space scenes when virtual scenes for astronaut training in Chinese space station mission are prepared.展开更多
A relative position and attitude coupled sliding mode controller is proposed by combining the standard super twisting （ST） control and basic linear algorithm for autonomous rendezvous and docking. It is schemed for ...A relative position and attitude coupled sliding mode controller is proposed by combining the standard super twisting （ST） control and basic linear algorithm for autonomous rendezvous and docking. It is schemed for on-orbit servicing to a tumbling non- cooperative target spacecraft subjected to external disturbances. A coupled dynamic model is established including both kinemati- cal and dynamic coupled effect of relative rotation on relative translation, which illustrates the relative movement between the docking port located in target spacecraft and another in service spacecraft. The modified super twisting （MST） control algorithm containing linear compensation items is schemed to manipulate the relative position and attitude synchronously. The correction provides more robustness and convergence velocity for dealing with linearly growing perturbations than the ST control algorithm. Moreover, the stability characteristic of closed-loop system is ana- lyzed by Lyapunov method. Numerical simulations are adopted to verify the analysis with the comparison between MST and ST control algorithms. Simulation results demonstrate that the pro- posed MST controller is characterized by high precision, strong robustness and fast convergence velocity to attenuate the linearly increasing perturbations.展开更多
In view of the probability dilution problem of the existing quantitative indexes of rendezvous trajectory safety performance using collision probability,this paper proposes a new quantitative index of rendezvous traje...In view of the probability dilution problem of the existing quantitative indexes of rendezvous trajectory safety performance using collision probability,this paper proposes a new quantitative index of rendezvous trajectory safety performance by well combining collision probability with warning threshold.The proposed new index increases monotonously as the position errors of the chaser spacecraft increase,therefore it can effectively overcome the problems of the reduction in the largest performance value and the advancement in the most dangerous time induced by the probability dilution.The proposed new index is applied to the safety design of close range rendezvous missions.The mission’s safety requirements for initial navigation precision and the safe region of initial and final keeping points’positions with a certain navigation precision are analyzed,and several valuable conclusions about the relation between position navigation precision and velocity navigation precision as well as the relation between keeping points’positions and navigation precision are obtained.展开更多
The optimal rendezvous trajectory designs in many current research efforts do not incorporate the practical uncertainties into the closed loop of the design.A robust optimization design method for a nonlinear rendezvo...The optimal rendezvous trajectory designs in many current research efforts do not incorporate the practical uncertainties into the closed loop of the design.A robust optimization design method for a nonlinear rendezvous trajectory with uncertainty is proposed in this paper.One performance index related to the variances of the terminal state error is termed the robustness performance index,and a two-objective optimization model(including the minimum characteristic velocity and the minimum robustness performance index)is formulated on the basis of the Lambert algorithm.A multi-objective,non-dominated sorting genetic algorithm is employed to obtain the Pareto optimal solution set.It is shown that the proposed approach can be used to quickly obtain several inherent principles of the rendezvous trajectory by taking practical errors into account.Furthermore,this approach can identify the most preferable design space in which a specific solution for the actual application of the rendezvous control should be chosen.展开更多
Rendezvous on the geostationary orbit(GEO)is much more complex than that on the low earth orbit and has a higher critical requirement for safety performance.This paper presents a safe scenario design method for GEO re...Rendezvous on the geostationary orbit(GEO)is much more complex than that on the low earth orbit and has a higher critical requirement for safety performance.This paper presents a safe scenario design method for GEO rendezvous proximity missions where the safety constraint of a collocated satellite is considered.A recently proposed quantitative index considering trajectory uncertainty is introduced to analyze the safety performance of the scenario parameters including the V-bar keeping positions and the fly-by trajectory radius.Furthermore,an exhaustive analysis is performed to find the dangerous regions of the V-bar keeping positions and the appropriate semi-major axis of the fly-by ellipse,considering the safety requirements of both the target and the collocated satellite.A geometry method is then developed for designing a feasible and suboptimal safe rendezvous scenario.The method is tested by designing four rendezvous scenarios with±V-bar approach directions respectively in the situations with and without one collocated satellite.Safety performance and velocity increments of the scenarios are compared and a conclusion is reached that the collocated satellite has a significant influence on the scenario design.展开更多
基金National Natural Science Foundation of China(U20B2054)。
文摘With the development of space technology,it is possible to build a space station in Earth-Moon space as a transit for Earth-Moon round-trip and entering in the deep space.Rendezvous and docking is one of the key technologies for building an Earth-Moon space station.A guidance strategy for rendezvous and docking from the Earth orbit to the space station in the Earth-Moon NRHO orbit is proposed in this paper,which is suitable for engineering applications.Firstly,the rendezvous and docking process is divided into three sections,i.e.,the large-range orbit transfer section,far-range guidance section,and close-range approaching section.The suitable terminal of large-range orbit transfer is selected according to the eigenvalue of NRHO orbit state transition matrix.The two-impulse guidance method based on the relative motion equation in the three-body problem is adopted for the far-range guidance section.The impulse time and amplitude are solved with the optimization algorithm.The linear constant three-body relative motion equation is proposed for the close-range approaching section,and the rendezvous and docking is completed by a two-stage linear approximation.Finally,a simulation analysis is carried out,and the simulation results show that the adopted dynamics equations and the designed guidance law are effective,and the three flight phases are naturally connected to accomplish the rendezvous and docking mission from the Earth orbit to the space station on the Earth-Moon NRHO.
文摘At 1:36 am on November 3,China's Shenzhou 8 unmanned spaceship and Tiangong 1 space lab spacecraft accomplished the country's first space docking procedure and coupling in space at more than 343km above Earth's surface,marking a great leap in China's space program.
文摘Teleoperation rendezvous and docking can be used as a backup for autonomous rendezvous and docking (RVD) for an unmanned spacecraft or for guiding the chaser docking with an uncooperative target.The inherent teleoperation time delay is a rigorous problem,especially when the chaser is teleoperated on the ground.To eliminate the effect of time delay,a new approach for teleoperation RVD is studied.The characteristics of teleoperation RVD are analyzed by comparisons with the teleoperation robot and with manually controlled RVD;the relative motion of the chaser is predicted based on the C-W equation;and the processed measure information with time delay through the Kalman filter is utilized to correct the current prediction.Experimental results verify that the approach produces an 18% enhanced success rate of teleoperation RVD compared with direct visual feedback,and consumes less time and fuel.The developed approach also solves the time delay problem effectively.Teleoperation RVD using this method can be applied as a useful backup for autonomous RVD.
文摘Teleoperation rendezvous and docking can be used as a backup for autonomous rendezvous and docking（RVD） for an unmanned spacecraft when the autonomous system is failure or for guiding the chaser docking with an uncooperative target.The theoretical model for analyzing the handling qualities in teleoperation RVD process is established based on the previous studies conducted by National Aeronautics and Space Administration（NASA）.The predictive factor is introduced to describe the pilot＇s predictive ability in the teleoperation tasks with time delay,which interrelates with the skills of a pilot and the predictive assist approach used in the tasks such as the predictive display method.Based on the semi-physical simulation system in our laboratory,900 experiments at two levels of time delay are carried out by 18 volunteers for validating the established model.The experimental results demonstrate the correctness of the theoretical model and indicate that a skilled pilot has a predictive ability of approximately 0.9 in teleoperation RVD tasks.The theoretical analysis shows that the handling qualities are greatly affected by the time delay and the predictive factor,and it is impossible to achieve a teleoperation RVD task for the skilled pilot when the time delay is larger than 9.0 s.
文摘This study focuses on the influence of the monitoring method and control complexity on the operator performance in manually controlled spacecraft rendezvous and docking （RVD）. Two one-factor experiments were designed on a simulated RVD system. One examined the video guidance and periscope monitoring methods, and the other examined three control complexity levels using one-axis RVD control, two-axis RVD control, and three-axis RVD control. Eighteen male volunteers aged 22-35 participated in the experiments. The results show that the RVD operating time increases with control complexity. Based on the operators＇ findings, the two-axis control is the easiest. The monitoring method has no significant influence on failure rate with the low complexity using one-axis RVD control.
基金the department of aerospace flight simulator in China Astronaut Research and Training Centerfor providing experimental facility and fund
文摘Subjective evaluation is one of the most important methods of assessing the fidelity of a virtual dynamic scene,whose results could be seen as a reference to improve a rendering method.In the present study,we apply a rendering method to the color rendezvous and docking(RVD) scene,where one shadow algorithm and three tone mapping operator algorithms are used to process the scene based on the distance between two spacecrafts.The grayscale RVD scene is transformed from the color RVD scene,and each RVD scene is desired to make comparisons with the real RVD-video recorded in SZ-10 mission.In addition,we perform an evaluation on 36 subjects to compare the results.The results show that shadow effects have important roles in RVD virtual scenes,where they enhance the sense of realism and immersion.Shadows,high brightness,contrast and luminance are highly correlated with the overall preference,and the grayscale scene receives better evaluations than the color scene.The analysis of these conclusions is vital for improving the algorithms used to render color virtual space scenes when virtual scenes for astronaut training in Chinese space station mission are prepared.
基金supported by the National Natural Science Foundation of China(61104026)
文摘A relative position and attitude coupled sliding mode controller is proposed by combining the standard super twisting （ST） control and basic linear algorithm for autonomous rendezvous and docking. It is schemed for on-orbit servicing to a tumbling non- cooperative target spacecraft subjected to external disturbances. A coupled dynamic model is established including both kinemati- cal and dynamic coupled effect of relative rotation on relative translation, which illustrates the relative movement between the docking port located in target spacecraft and another in service spacecraft. The modified super twisting （MST） control algorithm containing linear compensation items is schemed to manipulate the relative position and attitude synchronously. The correction provides more robustness and convergence velocity for dealing with linearly growing perturbations than the ST control algorithm. Moreover, the stability characteristic of closed-loop system is ana- lyzed by Lyapunov method. Numerical simulations are adopted to verify the analysis with the comparison between MST and ST control algorithms. Simulation results demonstrate that the pro- posed MST controller is characterized by high precision, strong robustness and fast convergence velocity to attenuate the linearly increasing perturbations.
基金supported by the National Natural Science Foundation of China(Grant No.11222215)the National Basic Research Program of China("973" Program)(Grant No.2013CB733100)Hunan Provincial Natural Science Foundation of China(Grant No.13JJ1001)
文摘In view of the probability dilution problem of the existing quantitative indexes of rendezvous trajectory safety performance using collision probability,this paper proposes a new quantitative index of rendezvous trajectory safety performance by well combining collision probability with warning threshold.The proposed new index increases monotonously as the position errors of the chaser spacecraft increase,therefore it can effectively overcome the problems of the reduction in the largest performance value and the advancement in the most dangerous time induced by the probability dilution.The proposed new index is applied to the safety design of close range rendezvous missions.The mission’s safety requirements for initial navigation precision and the safe region of initial and final keeping points’positions with a certain navigation precision are analyzed,and several valuable conclusions about the relation between position navigation precision and velocity navigation precision as well as the relation between keeping points’positions and navigation precision are obtained.
基金supported by the National Natural Science Foundation of China(Grant No.11222215)the National Basic Research Program of China(Grant No.2013CB733100)the Science Project of the National University of Defense Technology(Grant No.CJ12-01-02)
文摘The optimal rendezvous trajectory designs in many current research efforts do not incorporate the practical uncertainties into the closed loop of the design.A robust optimization design method for a nonlinear rendezvous trajectory with uncertainty is proposed in this paper.One performance index related to the variances of the terminal state error is termed the robustness performance index,and a two-objective optimization model(including the minimum characteristic velocity and the minimum robustness performance index)is formulated on the basis of the Lambert algorithm.A multi-objective,non-dominated sorting genetic algorithm is employed to obtain the Pareto optimal solution set.It is shown that the proposed approach can be used to quickly obtain several inherent principles of the rendezvous trajectory by taking practical errors into account.Furthermore,this approach can identify the most preferable design space in which a specific solution for the actual application of the rendezvous control should be chosen.
基金the National Natural Science Foundation of China(Grant Nos.11572345 and 11402257)the National Basic Research Program of China(973 Program,Grant No.2013CB733100).
文摘Rendezvous on the geostationary orbit(GEO)is much more complex than that on the low earth orbit and has a higher critical requirement for safety performance.This paper presents a safe scenario design method for GEO rendezvous proximity missions where the safety constraint of a collocated satellite is considered.A recently proposed quantitative index considering trajectory uncertainty is introduced to analyze the safety performance of the scenario parameters including the V-bar keeping positions and the fly-by trajectory radius.Furthermore,an exhaustive analysis is performed to find the dangerous regions of the V-bar keeping positions and the appropriate semi-major axis of the fly-by ellipse,considering the safety requirements of both the target and the collocated satellite.A geometry method is then developed for designing a feasible and suboptimal safe rendezvous scenario.The method is tested by designing four rendezvous scenarios with±V-bar approach directions respectively in the situations with and without one collocated satellite.Safety performance and velocity increments of the scenarios are compared and a conclusion is reached that the collocated satellite has a significant influence on the scenario design.
