A Trajectory Optimization Method for the Entry Segment of the Martian Atmosphere Considering the Influence of Uncertainties

Abstract

The invention discloses a Mars atmosphere entrance section trajectory optimization method considering uncertainty effects, relates to Mars atmosphere entrance section trajectory optimization methods, and belongs to the field of deep-space exploration. The implementation method comprises steps as follows: a Mars atmosphere entrance section lander dynamic model is established; a state uncertainty propagation model under effects of uncertainty factors of initial state deviations and parameter modeling deviations is established; a trajectory optimization model considering the uncertainty effects is established, an optimization performance index is reconstructed into the weighed form of the mean value and a standard deviation of an optimized object, the nominal value and the dispersion performance of the optimized object are considered comprehensively, and the trajectory of the optimized object is met by adjusting the weight; besides, process constraint is reconstructed into the weighed form of the mean value and the standard deviation of constraint, the feasible region of the trajectory is reduced reasonably, the process violation probability of a lander when the lander flights in an uncertainty environment is decreased, and the flight safety is improved. The method is applicable to Mars atmosphere entrance section trajectory optimization in the field of deep-space exploration.

Description

technical field [0001] The invention relates to a trajectory optimization method for the Martian atmosphere entry section considering the influence of uncertainty, and belongs to the field of deep space exploration. Background technique [0002] The trajectory optimization of the Martian atmosphere entry stage is an important means to improve mission safety, and it is also the basis of trajectory tracking and guidance. During the process of the lander entering the atmosphere, there will be uncertain factors such as initial state deviation and parameter modeling deviation. The traditional trajectory optimization method based on deterministic dynamic system does not consider the influence of uncertain factors, and the actual trajectory will be Deviations from the optimized nominal trajectory also lead to process constraint violations, which affect the safety and accuracy of the incoming process. [0003] Aiming at the uncertain factors of the Martian atmosphere entry section,...

AI Technical Summary

Problems solved by technology

During the process of the lander entering the atmosphere, there will be uncertain factors such as initial state deviation and parameter modeling deviation. The traditional trajectory optimization method based on deterministic dynamic system does not consider the influence of uncertain factors, and the actual trajectory will be Deviations from the optimized nominal trajectory, while also causing process constraint violations that affect the safety and accuracy of the incoming process

[0003] Aiming at the uncertain factors of the Martian atmosphere entry section, some scholars have used the desensitization optimal control theory to introduce the sensitivity function into the original performance index in a weighted form. However, since the sensitivity function does not have a clear physical meaning, it is difficult to pass the weight The adjustment of the coefficient intuitively weighs the performance index; on the other hand, the sensitivity function is difficult to add to the process constraints, and the safety of the lander during the actual flight cannot be guaranteed.

There are also studies using chaotic polynomials to analyze the propagation characteristics of uncertainties in the atmospheric entry section, but the calculation amount will increase sharply with the increase of chaotic polynomial order and uncertainty factors

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