Rapid and reliable onboard optimization of bank angle profiles is crucial for mitigating uncertainties during Mars atmospheric entry.This paper presents a neural-network-accelerated methodology for optimizing parametr...Rapid and reliable onboard optimization of bank angle profiles is crucial for mitigating uncertainties during Mars atmospheric entry.This paper presents a neural-network-accelerated methodology for optimizing parametric bank angle profiles in Mars atmospheric entry missions.The methodology includes a universal approach to handling path constraints and a reliable solution method based on the Particle Swarm Optimization(PSO)algorithm.For illustrative purposes,a mission with the objective of maximizing terminal altitude is considered.The original entry optimization problem is converted into optimizing three coefficients for the bank angle profiles with terminal constraints by formulating a parametric Mars entry bank angle profile and constraint handling methods.The parameter optimization problem is addressed using the PSO algorithm,with reliability enhanced by increasing the PSO swarm size.To improve computational efficiency,an enhanced Deep Operator Network(Deep ONet)is used as a dynamics solver to predict terminal states under various bank angle profiles rapidly.Numerical simulations demonstrate that the proposed methodology ensures reliable convergence with a sufficiently large PSO swarm while maintaining high computational efficiency facilitated by the neural-network-based dynamics solver.Compared to the existing methodologies,this methodology offers a streamlined process,the reduced sensitivity to initial guesses,and the improved computational efficiency.展开更多
The various uncertainties of Mars environment have great impact on the process of vehicles entering the atmosphere.To improve the robustness of control system against the model errors and to reduce the computational b...The various uncertainties of Mars environment have great impact on the process of vehicles entering the atmosphere.To improve the robustness of control system against the model errors and to reduce the computational burden, an optimal feedback based tracking control law is developed. The control scheme presented in this paper determines the amplitude and the reversals of bank angle respectively in the longitudinal and lateral flight plane. At each control cycle, the amplitude of the bank angle is obtained by an optimal feedback controller to minimize tracking errors. The control gains are tuned according to the closed-loop error dynamics by using optimization methods. The bank reversals are executed if the crossrange exceeds a predetermined corridor which is designed by setting a boundary function. The accuracy and robustness of the proposed closed-loop optimal feedback based control law in tracking the reference trajectory is verified via500 deviation simulations, in which modeling errors and external disturbances are considered.展开更多
On May 15,2021,the Tianwen-1 lander successfully touched down on the surface of Mars.To ensure the success of the landing mission,an end-to-end Mars entry,descent,and landing(EDL)simulator is developed to assess the g...On May 15,2021,the Tianwen-1 lander successfully touched down on the surface of Mars.To ensure the success of the landing mission,an end-to-end Mars entry,descent,and landing(EDL)simulator is developed to assess the guidance,navigation,and control(GNC)system performance,and determine the critical operation and lander parameters.The high-fidelity models of the Mars atmosphere,parachute,and lander system that are incorporated into the simulator are described.Using the developed simulator,simulations of the Tianwen-1 lander EDL are performed.The results indicate that the simulator is valid,and the GNC system of the Tianwen-1 lander exhibits excellent performance.展开更多
Abstract With low-lifting capability taken into account, a robust guidance law for Mars entry vehicles with low lift-l：o-drag ratios, such as Mars Science Laboratory （MSL）, is presented. Consider the nonlinear term...Abstract With low-lifting capability taken into account, a robust guidance law for Mars entry vehicles with low lift-l：o-drag ratios, such as Mars Science Laboratory （MSL）, is presented. Consider the nonlinear term in the drag dynamic equation and bounded disturbances as a lumped disturbance, and design a linear disturbance observer （DOB） to estimate it. With the consideration of the control input saturation, an innovative sliding surface and a virtual system are introduced to design the guidance law. Analyses of disturbance observer performance and Lyapunov-based transient performance are also presented. It is shown explicit choices of design parameters. Simulation guidance law. that the drag tracking error can be adjustable by results confirm the effectiveness of the proposed展开更多
The clear differences between the atmosphere of Mars and the Earth coupled with the lack of a domestic research basis were significant challenges for the aerodynamic prediction and verification of Tianwen-1.In additio...The clear differences between the atmosphere of Mars and the Earth coupled with the lack of a domestic research basis were significant challenges for the aerodynamic prediction and verification of Tianwen-1.In addition,the Mars entry,descent,and landing(EDL)mission led to specific requirements for the accuracy of the aerodynamic deceleration performance,stability,aerothermal heating,and various complex aerodynamic coupling problems of the entry module.This study analyzes the key and difficult aerodynamic and aerothermodynamic problems related to the Mars EDL process.Then,the study process and results of the design and optimization of the entry module configuration are presented along with the calculations and experiments used to obtain the aerodynamic and aerothermodynamic characteristics in the Martian atmosphere.In addition,the simulation and verification of the low-frequency free oscillation characteristics under a large separation flow are described,and some special aerodynamic coupling problems such as the aeroelastic buffeting response of the trim tab are discussed.Finally,the atmospheric parameters and aerodynamic characteristics obtained from the flight data of the Tianwen-1 entry module are compared with the design data.The data obtained from the aerodynamic design,analysis,and verification of the Tianwen-1 entry module all meet the engineering requirements.In particular,the flight data results for the atmospheric parameters,trim angles of attack,and trim axial forces are within the envelopes of the prediction deviation zones.展开更多
基金supported in part by the National Defense Basic Scientific Research Program of China(No.JCKY2021603B030)the Shenzhen Fundamental Research Program,China(No.JCYJ20220818102601004)the Science Center Program of National Natural Science Foundation of China(No.62188101)。
文摘Rapid and reliable onboard optimization of bank angle profiles is crucial for mitigating uncertainties during Mars atmospheric entry.This paper presents a neural-network-accelerated methodology for optimizing parametric bank angle profiles in Mars atmospheric entry missions.The methodology includes a universal approach to handling path constraints and a reliable solution method based on the Particle Swarm Optimization(PSO)algorithm.For illustrative purposes,a mission with the objective of maximizing terminal altitude is considered.The original entry optimization problem is converted into optimizing three coefficients for the bank angle profiles with terminal constraints by formulating a parametric Mars entry bank angle profile and constraint handling methods.The parameter optimization problem is addressed using the PSO algorithm,with reliability enhanced by increasing the PSO swarm size.To improve computational efficiency,an enhanced Deep Operator Network(Deep ONet)is used as a dynamics solver to predict terminal states under various bank angle profiles rapidly.Numerical simulations demonstrate that the proposed methodology ensures reliable convergence with a sufficiently large PSO swarm while maintaining high computational efficiency facilitated by the neural-network-based dynamics solver.Compared to the existing methodologies,this methodology offers a streamlined process,the reduced sensitivity to initial guesses,and the improved computational efficiency.
基金supported by the National Natural Science Foundation of China(11372345)
文摘The various uncertainties of Mars environment have great impact on the process of vehicles entering the atmosphere.To improve the robustness of control system against the model errors and to reduce the computational burden, an optimal feedback based tracking control law is developed. The control scheme presented in this paper determines the amplitude and the reversals of bank angle respectively in the longitudinal and lateral flight plane. At each control cycle, the amplitude of the bank angle is obtained by an optimal feedback controller to minimize tracking errors. The control gains are tuned according to the closed-loop error dynamics by using optimization methods. The bank reversals are executed if the crossrange exceeds a predetermined corridor which is designed by setting a boundary function. The accuracy and robustness of the proposed closed-loop optimal feedback based control law in tracking the reference trajectory is verified via500 deviation simulations, in which modeling errors and external disturbances are considered.
基金This work was supported by the National Natural Science Foundation of China(No.61803028)and Civil Aerospace Advance Research Project.
文摘On May 15,2021,the Tianwen-1 lander successfully touched down on the surface of Mars.To ensure the success of the landing mission,an end-to-end Mars entry,descent,and landing(EDL)simulator is developed to assess the guidance,navigation,and control(GNC)system performance,and determine the critical operation and lander parameters.The high-fidelity models of the Mars atmosphere,parachute,and lander system that are incorporated into the simulator are described.Using the developed simulator,simulations of the Tianwen-1 lander EDL are performed.The results indicate that the simulator is valid,and the GNC system of the Tianwen-1 lander exhibits excellent performance.
基金co-supported by the National Basic Research Program of China(No.2012CB720000)the National Natural Science Foundation of China(No.61174201)
文摘Abstract With low-lifting capability taken into account, a robust guidance law for Mars entry vehicles with low lift-l：o-drag ratios, such as Mars Science Laboratory （MSL）, is presented. Consider the nonlinear term in the drag dynamic equation and bounded disturbances as a lumped disturbance, and design a linear disturbance observer （DOB） to estimate it. With the consideration of the control input saturation, an innovative sliding surface and a virtual system are introduced to design the guidance law. Analyses of disturbance observer performance and Lyapunov-based transient performance are also presented. It is shown explicit choices of design parameters. Simulation guidance law. that the drag tracking error can be adjustable by results confirm the effectiveness of the proposed
基金This research comes from the Tianwen-1 Mars exploration mission.The authors gratefully acknowledge the contributions of the entire Tianwen-1 design team.
文摘The clear differences between the atmosphere of Mars and the Earth coupled with the lack of a domestic research basis were significant challenges for the aerodynamic prediction and verification of Tianwen-1.In addition,the Mars entry,descent,and landing(EDL)mission led to specific requirements for the accuracy of the aerodynamic deceleration performance,stability,aerothermal heating,and various complex aerodynamic coupling problems of the entry module.This study analyzes the key and difficult aerodynamic and aerothermodynamic problems related to the Mars EDL process.Then,the study process and results of the design and optimization of the entry module configuration are presented along with the calculations and experiments used to obtain the aerodynamic and aerothermodynamic characteristics in the Martian atmosphere.In addition,the simulation and verification of the low-frequency free oscillation characteristics under a large separation flow are described,and some special aerodynamic coupling problems such as the aeroelastic buffeting response of the trim tab are discussed.Finally,the atmospheric parameters and aerodynamic characteristics obtained from the flight data of the Tianwen-1 entry module are compared with the design data.The data obtained from the aerodynamic design,analysis,and verification of the Tianwen-1 entry module all meet the engineering requirements.In particular,the flight data results for the atmospheric parameters,trim angles of attack,and trim axial forces are within the envelopes of the prediction deviation zones.
