خلاصة:
When the orbital altitude of a small satellite is near-Earth, passive stabilization can be considered. The purpose of this paper is to combine the passive gravity gradient and aerodynamic stabilization methods together so that all the three axes stabilizations can be obtained. In this regard, the set of nonlinear equations of motion will be solved numerically with specified initial condition. The history of the attitude stabilization will be investigated and discussed in detail. The paper demonstrates the feasibility of passive gg-aero stabilization and provides guidelines for the satellite design to obtain the best attitude performance without sacrificing satellite lifetime
ملخص الجهاز:
Gravity Gradient(GG) Torque, Aerodynamic(Aero) Torque, Small Satellite, Low Earth Orbit, Passive GG-Aero Stabilization, Attitude Control, GG Boom, Vertical Tail Stabilizer INTRODUCTION Satellites are continuously subjected to perturbation torques while in orbit.
Passive stabilization of satellites, based on aerodynamic drag and gravity gradient torques, could be a desirable low cost, low power consumption, low weight control principle for low altitude missions in the future.
Aerodynamic drag torques are used to compensate ftir the gravity Iranian Journal of Inloririation Science & Technology, Volume 3, N umber 1 Januarv/June,2(t0S gradient effects that provide a passive stabilization of the satellite.
Satellite linearized equations of motion, with gravity gradient and aerodynamic torques, are obtained from combination of Eqs. 10, 11, 13 and 15 as follows: (View the image of this page) In Eq. 16, gravity gradient torque influences roll and pitch axes, and aerodynamic torque has an effect on the yaw axis.
Satellite linearized equations Jgnugz•y/June, 2g05 lrsni•n Journal of Information Science & Technology, Volume 3, Number I of motion with gravity gradient torque can be used from Eq. 16.
When the gravity gradient January/June, 2005 Iranian Journal of Information Science & Technology, Yolume 3, Number 1 torque was added, the roll and pitch angles ware gradually converged to zero, but the yaw motion still had an oscillation.
Number I(View the image of this page) January/June, 2005 (View the image of this page) Figure 3: Satellite with gravity gradient boom and yaw stabilizer.