Dynamic programming based attitude trajectories for underactuated control systems

V. Vedant, Alexander Ghosh

Research output: Chapter in Book/Report/Conference proceedingConference contribution


purely magnetic Attitude Control System (ACS), utilizing only magnetorquers, on a satellite in low Earth orbit is an underactuated system. The control torque is limited to an S1 sphere, such that the S1 sphere is always perpendicular to the local magnetic field. Since the local magnetic field is a relatively wellknown function of the orbital position, attitude and time, the directions of the under actuation can be estimated beforehand. This study demonstrates ways to generate attitude trajectories while minimizing the control effort, assuming the final desired point is within the reachable set of the system dynamics and the time horizon. Such trajectories are generated by discretizing the state space and obtaining the optimal paths between any two reachable states, and then solving the Bellman equation, composing a set of optimal paths to obtain the final trajectory. The optimal paths between the discretized points can be determined beforehand, thereby only requiring the Bellman equation to be solved, consequently providing speed benefits over traditional methods. The proposed dynamic programming based solutions are presented for attitude trajectories for the upcoming CubeSat missions flying on the University of Illinois' IlliniSat-2 CubeSat bus, which uses a purely magnetic attitude determination and control system.

Original languageEnglish (US)
Title of host publicationGuidance, navigation, and control, 2018
EditorsCheryl A. H. Walker
PublisherUnivelt Inc.
Number of pages12
ISBN (Print)9780877036494
StatePublished - 2018
Event41st Annual AAS Rocky Mountain Section Guidance and Control Conference, 2018 - Breckenridge, United States
Duration: Feb 1 2018Feb 7 2018

Publication series

NameAdvances in the Astronautical Sciences
ISSN (Print)0065-3438


Other41st Annual AAS Rocky Mountain Section Guidance and Control Conference, 2018
Country/TerritoryUnited States

ASJC Scopus subject areas

  • Aerospace Engineering
  • Space and Planetary Science


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