Aimed at complex distributed no-fly zones avoidance problems,a novel adaptive lateral reentry guidance algorithm is proposed.Firstly,by introducing the improved attractive and repulsive potential fields,an improved ar...Aimed at complex distributed no-fly zones avoidance problems,a novel adaptive lateral reentry guidance algorithm is proposed.Firstly,by introducing the improved attractive and repulsive potential fields,an improved artificial potential field method is developed.Combined with the proposed judgment criterion for whether a no-fly zone has been avoided,the proposed improved artificial potential field method effectively solves the reference heading angle determination problem under the constraints of complex distributed no-fly zones.Then,based on the proposed no-fly zone’s threat quantitative evaluation method and the reference heading angle determined by the proposed improved artificial potential field method,the heading corridor is improved to increase its sensitivity to the threat changes of the no-fly zones.Finally,for satisfying the requirements of complex distributed no-fly zones avoidance,a novel guidance logic via improved heading corridor is proposed to update the reference heading corridor adaptively in real time according to the threat and constraint changes of the no-fly zones,and the bank reversal logic is employed to control the lateral motion.The simulation results for nominal and dispersed cases indicate that the proposed guidance algorithm has high robustness,stability,and applicability,and is feasible and effective to deal with the complex distributed no-fly zones avoidance problems.展开更多
Two different entry vehicles are presented here： the Inflatable Reentry and Descent Demonstrator （IRDT）, and Huygens. Both missions involve （re）entries at conditions close to orbital, and have been performed in 2...Two different entry vehicles are presented here： the Inflatable Reentry and Descent Demonstrator （IRDT）, and Huygens. Both missions involve （re）entries at conditions close to orbital, and have been performed in 2005. Specific aspects of the design and the mission of IRDT are briefly outlined. The preliminary results of the recent flight of IRDT and the methodology followed at ESTEC for the assessment of radiative fluxes for Huygens are summarised.展开更多
Uncertain factors such as atmospheric density,aerodynamic coefficients,and aircraft mass can have a catastrophic impact on the flight safety of entry vehicles(EVs).It is crucial for EVs to quickly generate safe entry ...Uncertain factors such as atmospheric density,aerodynamic coefficients,and aircraft mass can have a catastrophic impact on the flight safety of entry vehicles(EVs).It is crucial for EVs to quickly generate safe entry trajectories that consider the impact of uncertainties to execute complex flight tasks such as online target changing.Given this challenge,a rapid generation method of safe entry trajectories is proposed,which is based on the drag-acceleration-profile method employed during space shuttle entry flights.This method can efficiently generate a safe,feasible trajectory while accounting for the influence of uncertain factors.Compared to traditional drag-acceleration-profile methods,the proposed method incorporates the influence of uncertain factors on the boundaries of the flight corridor.It establishes an uncertain flight corridor model,thereby ensuring the safety of the reference flight profile designed within this corridor under actual uncertain flight conditions.Additionally,a simplified design approach for the reference flight profile enables the rapid generation of satisfactory profiles through straightforward parameter iteration or optimization.Simulations demonstrate that this method can efficiently plan gliding flight trajectories that meet safety requirements,exhibiting potential for online trajectory generation and maneuverability assessment.展开更多
基金supported by the National Natural Science Foundation of China(No.12072090)。
文摘Aimed at complex distributed no-fly zones avoidance problems,a novel adaptive lateral reentry guidance algorithm is proposed.Firstly,by introducing the improved attractive and repulsive potential fields,an improved artificial potential field method is developed.Combined with the proposed judgment criterion for whether a no-fly zone has been avoided,the proposed improved artificial potential field method effectively solves the reference heading angle determination problem under the constraints of complex distributed no-fly zones.Then,based on the proposed no-fly zone’s threat quantitative evaluation method and the reference heading angle determined by the proposed improved artificial potential field method,the heading corridor is improved to increase its sensitivity to the threat changes of the no-fly zones.Finally,for satisfying the requirements of complex distributed no-fly zones avoidance,a novel guidance logic via improved heading corridor is proposed to update the reference heading corridor adaptively in real time according to the threat and constraint changes of the no-fly zones,and the bank reversal logic is employed to control the lateral motion.The simulation results for nominal and dispersed cases indicate that the proposed guidance algorithm has high robustness,stability,and applicability,and is feasible and effective to deal with the complex distributed no-fly zones avoidance problems.
文摘Two different entry vehicles are presented here： the Inflatable Reentry and Descent Demonstrator （IRDT）, and Huygens. Both missions involve （re）entries at conditions close to orbital, and have been performed in 2005. Specific aspects of the design and the mission of IRDT are briefly outlined. The preliminary results of the recent flight of IRDT and the methodology followed at ESTEC for the assessment of radiative fluxes for Huygens are summarised.
基金supported by the National Nature Science Foundation of China(92271108,62173336)
文摘Uncertain factors such as atmospheric density,aerodynamic coefficients,and aircraft mass can have a catastrophic impact on the flight safety of entry vehicles(EVs).It is crucial for EVs to quickly generate safe entry trajectories that consider the impact of uncertainties to execute complex flight tasks such as online target changing.Given this challenge,a rapid generation method of safe entry trajectories is proposed,which is based on the drag-acceleration-profile method employed during space shuttle entry flights.This method can efficiently generate a safe,feasible trajectory while accounting for the influence of uncertain factors.Compared to traditional drag-acceleration-profile methods,the proposed method incorporates the influence of uncertain factors on the boundaries of the flight corridor.It establishes an uncertain flight corridor model,thereby ensuring the safety of the reference flight profile designed within this corridor under actual uncertain flight conditions.Additionally,a simplified design approach for the reference flight profile enables the rapid generation of satisfactory profiles through straightforward parameter iteration or optimization.Simulations demonstrate that this method can efficiently plan gliding flight trajectories that meet safety requirements,exhibiting potential for online trajectory generation and maneuverability assessment.
