Robust trajectory and guidance optimization for guided powered descent and landing

Calkins, Grace Elizabeth

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https://hdl.handle.net/2142/120427 Copy

Description

Title

Robust trajectory and guidance optimization for guided powered descent and landing

Author(s)

Calkins, Grace Elizabeth

Issue Date

2023-05-01

Director of Research (if dissertation) or Advisor (if thesis)

Putnam, Zachary R

Department of Study

Aerospace Engineering

Discipline

Aerospace Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• trajectory optimization
• GNC
• EDL
• aerospace
• safe and precise landing
• navigation

Abstract

A robust trajectory optimization approach for guidance algorithm gain and target vector selection for powered descent and landing is developed. A genetic algorithm is used to determine optimal guidance algorithm parameters that minimize the impact of environment, navigation, vehicle property uncertainty. Vehicle state uncertainties are computed rapidly using linear covariance analysis techniques. When implemented in the guidance algorithm, the optimal gains and target vectors shape a trajectory that has more favorable conditions for a given navigation sensor suite. As a demonstration of this method, the optimal guidance parameters are found for a multi-phase trajectory from powered descent initiation to touchdown for a robotic lunar landing mission. Optimal guidance parameters are found for different optimization variable sets, sensor suite compositions and qualities, and with objective functions to minimize variability in propellant usage or terminal position. Multi-objective optimization showing the tradeoff between terminal position uncertainty and total propellant usage is presented for varying sensor suite fidelities and sensor suite compositions. Results show that the optimal guidance algorithm parameters for a given trajectory differ based on the sensor suite and result in performance improvements over the baseline in propellant usage and terminal accuracy. Improvements of up to a 20% reduction in landed footprint size and up to a 5% reduction in total propellant usage can be seen when using robust trajectory optimization, and operating with a lower quality sensor suite becomes viable when optimal guidance parameters are used.

Graduation Semester

2023-05

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/120427

Copyright and License Information

Copyright 2023 Grace Calkins

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