Koopman Operator-Based Data-Driven Identification of Tethered Subsatellite Deployment Dynamics

Waqas A. Manzoor, Graduate Student, University of Michigan-Dearborn
Samir A. Rawashdeh, Ph.D., Associate Professor, Electrical and Computer Engineering Department, University of Michigan-Dearborn
Alireza Mohammadi, Ph.D., Assistant Professor, Electrical and Computer Engineering Department, University of Michigan-Dearborn

Compact tether-based actuation is particularly suitable for deployment of femto-/picosatellite bodies from CubeSats using ultra-small electrodynamic tethers. Despite the unique capabilities of tethered satellite systems, control technologies for these satellites have yet to mature in several domains including system identification under unmodeled disturbances. A promising solution for identification of tethered satellite dynamics under environmental disturbances is to use data-driven online algorithms that learn the dynamics of the tethered satellite over previous orbits. To achieve this goal, this talk presents the Koopman operator associated with the tethered satellite dynamics to extrapolate future motion of a tethered subsatellite subject to unknown disturbances while being deployed from its mothership. Numerical simulations of the constructed Koopman operator-based linear dynamics versus the true nonlinear model of the tethered satellite system demonstrate the prediction capabilities of the proposed Koopman operator-based numerical algorithm for the general flight characteristics including many orbits into the future.