Predicting Optimal Maneuvering Time Benefits for Satellite Attitude Control
Abstract
A common goal of satellite control systems is to reduce the time required to change a spacecraft's attitude, which maximizes its mission capability. Time Optimal Attitude control algorithms increase the agility of satellites such as imaging spacecraft, thus allowing a greater frequency of image collection. Eigenaxis based maneuvering, though common in industry and academia, fails to produce the minimum-time solution for actual satellites. Solving the optimal control problem is often challenging and requires evaluating multiple maneuver paths to ensure the shortest path is found for each spacecraft configuration. One of the primary difficulties in predicting optimal control benefits stems from the wide range of satellite configurations and infinite variation in inertia. To mitigate this issue, this research aims to determine an analytical relationship between satellite inertia and the time savings of using optimal control rather than eigenaxis maneuvering on spacecraft with a NASA standard four reaction-wheel configuration. To accomplish this, the development of a script using DIDO R optimization software determines minimum-time paths for satellite maneuvers. Each path was independently verified and validated using Pontryagin's minimization principle to ensure that they are physically feasible and that each solution is optimal. Additionally, this work demonstrates that inertia ratios can be used to characterize the attitude control performance of any spacecraft, allowing for the analysis of satellite inertias and their relationship to maneuver time reduction regardless of the scale of the spacecraft. The calculation of the agility envelope volume is then utilized in conjunction with the DIDO R script and various inertia ratios in order to investigate the mathematical relationship between satellite inertia and time savings from optimal control.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 20, 2019
- Accession Number
- AD1073958
Entities
People
- Yash D. Khatavkar
Organizations
- United States Naval Academy