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Continuous Thrust Trajectory Optimization Method Considering Engine Shutdown and Strong Parameter Nonlinearity

A trajectory optimization and non-linear technology, applied in the field of aerospace, can solve problems such as the inability to adopt, optimize, and accurately determine orbit variable parameter engines, and achieve the effects of strong applicability, increased efficiency, and a wide range of applications

Active Publication Date: 2022-05-10
BEIJING INSTITUTE OF TECHNOLOGYGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] In order to solve the problem that the engine shutdown and parameter strong nonlinearity cannot be accurately determined in actual engineering, and the variable parameter engine cannot be optimized by traditional trajectory optimization methods, the main purpose of the present invention is to provide an engine shutdown and parameter strong The non-linear continuous thrust trajectory optimization method, through successive convex programming, realizes the efficient solution of the continuous thrust trajectory optimization problem when considering the limitations of measurement and control and needs to be shut down periodically and carries an ion engine similar to the thrust and specific impulse that changes with the heliocentric distance. Continuous Thrust Trajectory Optimization with Engine Shutdown and Strong Parameter Nonlinearity

Method used

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  • Continuous Thrust Trajectory Optimization Method Considering Engine Shutdown and Strong Parameter Nonlinearity
  • Continuous Thrust Trajectory Optimization Method Considering Engine Shutdown and Strong Parameter Nonlinearity
  • Continuous Thrust Trajectory Optimization Method Considering Engine Shutdown and Strong Parameter Nonlinearity

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Embodiment 1

[0078] The target celestial body is selected as comet 67P, and the continuous thrust transfer trajectory from the earth to comet 67P is designed. Detector initial mass m ( t 0 ) is 1217.7 kg. Considering that the regular shutdown of the engine is constrained to be the maximum continuous startup time t on = 14 days, the minimum single shutdown time t off = 1 day. The departure date from the earth is 0:0:0, October 28, 2021, and the rendezvous date between the probe and comet 67P is 0:0:0, October 28, 2028. According to the ephemeris, we can get the root number of the improved vernal equinox for the state of the detector when the earth departs and rendezvous with 67P Expressed as shown in Table 1.

[0079] Table 1 Earth-67P transfer initial and terminal states

[0080] Improved equinox root count P, m f g h k L, rad initial value 1.495568e+11 -0.0038 0.0163 -2.4755e-5 2.2439e-6 13.1684 end value 3.051940e+11 0.2917 0.5707 0.0394 ...

Embodiment 2

[0145] The target celestial body is selected as the asteroid 2011UW158, and the continuous thrust transfer trajectory from the earth to 2011UW158 is designed. Detector initial mass m ( t 0 ) is 1217.7 kg. Considering that the regular shutdown of the engine is constrained to be the maximum continuous startup time t on = 7 days, minimum single shutdown duration t off = 1 day. The departure date from the earth is 0:0:0, October 28, 2021, and the rendezvous date between the probe and comet 67P is 0:0:0, October 28, 2026. According to the ephemeris, we can obtain the root number of the improved vernal equinox for the state of the probe when the earth departs and when it rendezvous with the asteroid 2011UW158 Expressed as shown in Table 1.

[0146] Table 1 Earth-2011UW158 transfer initial and terminal states

[0147] Improved equinox root count P, m f g h k L, rad initial value 1.495568e+11 -0.0038 0.0163 -2.4755e-5 2.2439e-6 13.1684 end ...

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Abstract

The invention discloses a continuous thrust trajectory optimization method considering engine shutdown and strong nonlinear parameters, which belongs to the field of aerospace technology. The implementation method is as follows: firstly, a strong nonlinear thrust and specific impulse change model is given according to the on-off constraints and the engine type; then a transfer trajectory dynamics model is established based on the improved vernal equinox root number considering engine shutdown and strong nonlinear parameters; and then according to the task requirements , the constraints and performance metrics for the continuous thrust trajectory optimization problem considering engine shutdown and strong parameter nonlinearity are given; then by linearizing the dynamics and relaxing the nonlinear equation constraints, the continuous thrust trajectory considering engine shutdown and parameter strong nonlinearity will be The optimization problem is convex; then the variable parameter continuous thrust trajectory optimization problem considering the shutdown constraint is quickly solved through numerical integration and successive approximation, the optimal transfer trajectory and the corresponding optimal control direction are obtained, and related problems in the field of thrust control are solved according to the optimization results. The invention is applicable to both the continuous thrust transfer of low-earth orbit and the continuous thrust transfer of deep space orbit, and has wide application range and strong robustness.

Description

technical field [0001] The invention relates to a continuous thrust trajectory optimization method considering engine shutdown and strong nonlinear parameters, especially suitable for carrying variable specific impulse and thrust engine detectors, while having a continuous thrust trajectory fast optimization calculation with regular shutdown constraints, belonging to aerospace technology field. Background technique [0002] Compared with the traditional chemical propulsion engine, due to the high specific impulse of the continuous thrust engine, the probe can carry less weight of fuel to achieve the same speed increment, thus obtaining more abundant returns for space exploration missions. The increasingly complex detection tasks have an increasing demand for airborne autonomous capabilities, and autonomous trajectory planning capabilities are of particular concern. However, for a probe equipped with a continuous thrust engine, it is very challenging to achieve fast online t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F30/15G06F30/20G06F111/04G06F119/14
CPCG06F30/15G06F30/20G06F2111/04G06F2119/14
Inventor 乔栋贾飞达韩宏伟李翔宇
Owner BEIJING INSTITUTE OF TECHNOLOGYGY