Optimal Feedback Gains for Spacecraft Attitude Stabilization Using Magnetorquers Fabio Celani and Renato Bruni
Outline •
attitude stabilization problem
•
spacecraft model and stabilizing feedback
•
method for designing feedback gains based on minimization of settling time
•
case study
Fabio Celani and Renato Bruni 3rd IAA Conference on University Satellite Missions and CubeSat Workshop
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Attitude stabilization problem spacecraft with magnetorquers on a circular Low Earth Orbit Z
GeoCentric Inertial (GCI) frame
body frame X,
Y
objective: body frame aligned with GCI frame using magnetorquers only parametrize attitude of body frame with respect to GCI frame using quaternion vector part of body frame aligned with GCI frame Fabio Celani and Renato Bruni 3rd IAA Conference on University Satellite Missions and CubeSat Workshop
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Spacecraft model attitude kinematics attitude dynamics
magnetorquers = three coils aligned with body axis vector of coils’ magnetic dipole moments geomagnetic field in body frame
spacecraft model
Fabio Celani and Renato Bruni 3rd IAA Conference on University Satellite Missions and CubeSat Workshop
Fabio Celani and Renato Bruni 3rd IAA Conference on University Satellite Missions and CubeSat Workshop
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Design of feedback gains by optimization 1/2
fix initial state
to significant value
Fabio Celani and Renato Bruni 3rd IAA Conference on University Satellite Missions and CubeSat Workshop
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Design of feedback gains by optimization 2/2
fix initial state analytic expression of
to significant value in terms of
and
not available
Lipschitzian without Lipschitz constant optimization algorithm • does not need analytic expression of • just needs to compute at a number of points use simulations • requires feasible set be bounded rectangle determine
Fabio Celani and Renato Bruni 3rd IAA Conference on University Satellite Missions and CubeSat Workshop
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Case study 1/2
circular orbit
inclination 87°
altitude 450 km
€ • significant initial state • desired final state
Fabio Celani and Renato Bruni 3rd IAA Conference on University Satellite Missions and CubeSat Workshop
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Case study 2/2 design by trial-and-error
design by optimization
Fabio Celani and Renato Bruni 3rd IAA Conference on University Satellite Missions and CubeSat Workshop
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Conclusions •
method for designing gains of PD-like feedback that achieves attitude stabilization using magnetorquers
•
design based on minimization of settling time
•
proposed design more systematic than by trial-and-error
Fabio Celani and Renato Bruni 3rd IAA Conference on University Satellite Missions and CubeSat Workshop
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Optimal Feedback Gains for Spacecraft Attitude ...
GeoCentric Inertial (GCI) frame body frame parametrize attitude of ... spacecraft with magnetorquers on a circular Low Earth Orbit body frame aligned with GCI ...
