Application of Automated Balancing Methods for an Attitude Control Test Platform with Non Orthogonal Masses

Date of Award

6-14-2018

Document Type

Thesis

Degree Name

Master of Science in Astronautical Engineering

Department

Department of Aeronautics and Astronautics

First Advisor

Andrew J. Lingenfelter, PhD

Abstract

Ground-based spacecraft simulators provide an accessible and necessary platform for testing and evaluating control systems. The Attitude Control System Proving Ground ACSPG at the Air Force Research Laboratory AFRL allows for testing and verifying the performance of attitude control systems. Through the use of an air bearing, the frictionless environment is replicated, but gravitational torques are still prevalent. Gravitational torques distort and negatively affect the sustained performance of simulators, limiting experimentation time. Cost effective validation efforts require decreasing current set up times and increasing current experimentation times. The distance between the center of rotation COR and the center of mass COM of the simulator results in unwanted gravitational torques, causing a tilting and unbalanced platform. Developing an automated system to precisely co-locate the COR and the COM will reduce said torques. This research demonstrates two control techniques to improve the current system balancing procedures. The first method is a non-linear adaptive control and is validated with three primary scenarios, demonstrating an ability to reduce angular velocities to zero. Through tuning, the control algorithm balances the platform according to design constraints. The second method estimates the offset between the COM and COR utilizing a least squares estimation method. The second method is validated with two tests of varying lengths and is able to estimate the offset within 0.5 percent.

AFIT Designator

AFIT-ENY-MS-18-J-076

DTIC Accession Number

AD1056661

Comments

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