Parsing homotopy method for generating Martian atmosphere entry phase longitudinal accessible region

Abstract

The invention discloses a parsing homotopy method for generating a Martian atmosphere entry phase longitudinal accessible region, and belongs to the field of deep space exploration. The parsing homotopy method comprises the following steps that a Martian atmosphere entry phase longitudinal dynamic model is built; based on the parsing homotopy method, known auxiliary problems are parsed from an optimum solution, and by constructing homotopy parameters, a maximum flying range is subjected to continuation; based on the homotopy method, the known auxiliary problems are parsed with the optimum solution, and through constructing the homotopy parameters, a minimum flying range is subjected to continuation and obtained; based on the parsing homotopy method, the known auxiliary problems are parsedwith the optimum solution, and by constructing the homotopy parameters, a maximum umbrella opening height is subjected to continuation and obtained; based on the parsing homotopy method, according tothe maximum flying range, the minimum flying range and the maximum umbrella opening height which are obtained through continuation, and by constructing the homotopy parameters, the longitudinal accessible region is obtained through continuation. The parsing homotopy method for generating the Martian atmosphere entry phase longitudinal accessible region can avoid co-state initial value conjecture and internal point accessibility verification, and thus improves the generating efficiency of the accessible region.

Description

technical field [0001] The invention relates to an analytic homotopy method for generating the longitudinal reachable area of ​​the Martian atmosphere entry section, and belongs to the field of deep space exploration. Background technique [0002] The Mars atmosphere entry section refers to the flight stage from the probe entering the Martian atmosphere to the deployment of the parachute. The analysis of the reachable area of ​​the Mars atmosphere entry section is of great significance for mission design, landing site selection, and risk assessment. The solution of the reachable area involves the trajectory optimization problem of the entry section, which can be solved by direct method or indirect method. For the direct method, scholars have solved the accessible area of ​​the atmospheric entry section through grid division and numerical optimization method. This method needs to solve the optimization problem separately for each grid point, which requires a large amount of ...

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Problems solved by technology

This method needs to solve the optimization problem separately for each grid point, the calculation amount is large, the solution depends on the initial value guessing, and the convergence and reliability of the solution process are difficult to guarantee

The theoretical basis of the indirect method is Pontryagin's minimum value principle, which is solved by converting the original optimization problem into an equivalent two-point boundary value problem. Since the co-state in the minimum value theory lacks physical meaning, and the optimization problem It is sensitive to the initial value of the co-state, so the indirect method has the problem of difficulty in guessing the initial value of the co-state

Especially for the Mars entry probe with small lift-drag ratio that can be decoupled horizontally and vertically, the optimal control problem based on its longitudinal dynamic equation generally belongs to bang-bang control, and the initial value convergence domain is small and sensitive to the initial value

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