Structural and Attitude Dynamics and Control of a Solar Sail using Two Degrees of Freedom Tip Vanes

Displaced solar orbits for spacecraft propelled by electric sails are investigated. Since the propulsive thrust is induced by the sail attitude, the orbital and attitude dynamics of electric-sail-based spacecraft are coupled and required to be investigated together. However, the coupled dynamics and control of electric sails have not been discussed in most published literatures. In this paper, the equilibrium point of the coupled dynamical system in displaced orbit is obtained, and its stability is analyzed through a linearization. The results of stability analysis show that only some of the orbits are marginally stable. For unstable displaced orbits, linear quadratic regulator is employed to control the coupled attitude-orbit system. Numerical simulations show that the proposed strategy can control the coupled system and a small torque can stabilize both the attitude and orbit. In order to generate the control force and torque, the voltage distribution problem is studied in an optimal framework. The numerical results show that the control force and torque of electric sail can be realized by adjusting the voltage distribution of charged tethers.

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Attitude Dynamics and Control of Liquid Filled Spacecraft with Large Amplitude Fuel Slosh

Journal of Mechanics ◽

10.1017/jmech.2016.60 ◽

2016 ◽

Vol 33 (1) ◽

pp. 125-136 ◽

Cited By ~ 2

Author(s):

M.-L. Deng ◽

B.-Z. Yue

Keyword(s):

Control Strategy ◽

Attitude Control ◽

Large Amplitude ◽

Lyapunov Theory ◽

Attitude Dynamics ◽

Equivalent Mechanical Model ◽

Attitude Maneuver ◽

Dynamics And Control ◽

Fuel Slosh ◽

And Control

AbstractThis paper focuses on the attitude dynamics and control of liquid filled spacecraft, and the large amplitude fuel slosh dynamics is included by using an improved moving pulsating ball model. The moving pulsating ball model is an equivalent mechanical model that is capable of imitating the whole liquid reorientation process, specifically for the occurrence of large amplitude slosh. This model is improved by incorporating a static capillary force and an effective mass factor. The improvements on this model are validated with previously published experiment results. The spacecraft attitude maneuver is implemented by the momentum transfer technique, and the feedback control strategy is designed based on Lyapunov theory. The effects of liquid viscosity, tank location and desired steady time on sloshing torque and control torque are investigated. The attitude control strategy applied in this paper is proved to be applicable for the coupled liquid filled spacecraft system. The obtained conclusions are useful to aid in liquid filled spacecraft overall design.

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