Papers by Mohammad Gomroki
Astrophysics and Space Science Proceedings, 2016
AIAA/AAS Astrodynamics Specialist Conference, 2014
Formation attitude and relative position tracking control of a two-spacecraft utilizing coulomb f... more Formation attitude and relative position tracking control of a two-spacecraft utilizing coulomb forces as well as thrusters is discussed. The nonlinear optimal tracking control is realized using the Approximating Sequence of Riccati Equations (ASRE) control method. Nonlinear equations of motion of the formation are properly manipulated to obtain suitable state dependent formulations for orbit radial, along track and orbit normal formation configurations. In the ASRE approach, the nonlinear problem is reduced to a sequence of linear-quadratic and time-varying approximating problems. After number of iterations, the converged control input from the approximating sequence is applied to the nonlinear system. The success of the approach in reconfiguring the formation is demonstrated through nonlinear simulations. Nomenclature L = Relative distance between the two-craft formation ,, Downloaded by Ozan Tekinalp on September 23, 2014 | http://arc.aiaa.org |
The relative position control of a collinear spinning three-spacecraft Coulomb formation with set... more The relative position control of a collinear spinning three-spacecraft Coulomb formation with set charges is addressed. Such a formation is assumed to be in deep space without relevant gravitational forces present. The nonlinear control is realized through state dependent Riccati equation (SDRE) control method. Relative position control is used to keep a three-craft Coulomb formation about a desired equilibrium collinear configuration. The equations of motion of the formation are properly manipulated to obtain a suitable form for SDRE control. The state-dependent coefficient (SDC) form is then formulated to include the nonlinearities in the relative dynamics. Numerical simulations illustrate effectiveness of the controllers.
AIAA Guidance, Navigation, and Control Conference, 2015
The dynamic analysis of a two-spacecraft Coulomb formation at Earth-Moon libration points is addr... more The dynamic analysis of a two-spacecraft Coulomb formation at Earth-Moon libration points is addressed. Relative motion control of the two craft coulomb formation are used to keep the distance between them at the desired value. Formation attitude control is realized using low thrust propulsion. The present study utilizes nonlinear controllers for orbit radial, along track, and orbit normal stabilization and tracking control of a two-craft Coulomb formation at Earth-Moon collinear libration points. The nonlinear control is realized using State Dependent Riccati Equation SDRE), and Approximating Sequence of Riccati Equations (ASRE) methods. To this end the equations of motion of the formation is properly manipulated to obtain a suitable State Dependent Coefficient (SDC) form for control. The effectiveness of the controllers are demonstrated through numerical simulations at collinear libration points, showing the capability of the approaches for formation control.
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Papers by Mohammad Gomroki