ETNAC Design Enabling Formation Flight at Liberation Points


This study considers the feasibility of an event-triggered neuro-adaptive controller (ETNAC) providing precision flying control for microsatellites used for deep space missions. For 'smallsats' factors including limited capabilities of the microsatellite platform, minimal communication, restricted controls and actuation, overly sensitive response to uncertainties, etc. make the controller design challenging. To cope with such challenges, an ETNAC design is proposed in this study. Its performance analysis is given along with its derivation and implementation. ETNAC is based on an observer, known as Modified State Observer (MSO), which is used for online approximation of the uncertainties in the system. The MSO formulation has two tunable gains that allow for fast estimation without inducing high frequency oscillations in the system. At the same time, an event triggering mechanism (ETM) is used in an aperiodic fashion to transmit state information and update the control only when required. In this way, it reduces communication and computational efforts, simplifying onboard implementations. A Lyapunov analysis is used to prove stability. Simulation and performance results show that ETNAC can be an excellent solution for highly nonlinear resource-constrained problems.

Meeting Name

2019 American Control Conference, ACC 2019 (2019: Jul. 10-12, Philadelphia, PA


Mechanical and Aerospace Engineering


This research was supported in part by the National Aeronautics and Space Administration under Grant NNX15AM51A and NNX15AN04A.

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Document Type

Article - Conference proceedings

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© 2019 American Automatic Control Council, All rights reserved.

Publication Date

01 Jul 2019