Dynamic Modeling and Attitude Control of Large-Scale Flexible Parallel Multibody Spacecraft

In this paper, modeling and high-precision attitude control of large-scale flexible parallel multibody spacecraft (FPMS) are addressed. First, for describing the complex constraint relationship between each body of the multibody system, the dynamic model of flexible spacecraft in the form of differential-algebraic equations (DAEs) is established by applying the Lagrange equation of the first kind (augmented Lagrange method). Then, to facilitate numerical integration of the dynamic model and controller design, an independent coordinate method and block matrix operation-based transformation method are proposed to convert DAEs into ordinary differential equations. Based on this model, a two-timescale composite controller is designed by virtue of the singular perturbation theory to attain high-precision attitude control of the FPMS and suppress the vibration of flexible appendages. Finally, numerical simulations are conducted under two mission scenarios to validate the dynamic model and demonstrate that the accurate attitude control can be achieved.