Dynamical Modelling of FORMOSAT-7 NB-Satellite Multibody System

Abstract

Many space vehicles assume their final configuration after an initial deployment phase. During this phase, one part of the vehicle moves with respect to another part as the configuration evolves from its initial to its final form. Presence of a mobile solar array attached to the satellite bus with a controlled hinge leads to significant complication of the satellite dynamics. A mathematical model as well as corresponding software is necessary for numerical investigation of the satellite arbitrary movements. To combine the computational advantages- the non-working constraint forces and torques do not appear, and the resulting equation set is of minimum dimension- comparative studies suggested that some related generalization of Lagrange's form of d'Alembert's principle most closely meet these needs. For FORMOSAT-7 NSPO built satellite, in order to accommodate the field of view requirements originated mainly from the mission payload, a spacecraft bus attached with single leaf of solar array configuration is designed. The asymmetric configuration constitutes a two body dynamics problem, not one whole rigid body case. In this paper, the FORMOSAT-7 NB-satellite attitude dynamics modelling formulation is managed pragmatically. Its final expression of equations of motion derived systematically through the general dynamical equations of motion based on Lagrange's form of d'Alembert's principle and expressed in terms of kinematics variables, velocity and angular velocity coefficients, and generalized forces is presented meticulously. Finally, the equations of motion are validated through cases of numerical simulations.