Large-angle Maneuvers Research Articles

Magnetic Torquing Scheme for Attitude Control of a Wheel-Stabilized Astronomy Satellite

A new pointing control law by magnetic torquing is proposed for a wheelstabilized astronomy satellite. This law is based on a linear feed-back of attitude error and rate, and achieves both angular momentum control and nutation damping. Actuators are magnetic torquers along three axes plus one bias-momentum wheel. Sensors are rate-integrating-gyros and magnetometers. Stability analysis is carried out by root-locus method. A large angle maneuver scheme is also proposed, which utilizes the same pointing control law. The maneuver is carried out around the eigen axis of rotation, and the advantage is a small amount of processing required for the on-board computer. Computer simulation for the Case of ASTRO-C, a Japanese X-ray-observation satellite, shows that the proposed system works satisfactorily.

Optimal distributed control of a flexible spacecraft during a large-angle maneuver

This paper discusses the solution of the necessary conditions obtained from Pontryagin's principle, for the problem of optimal large-angle single-axis maneuvers of a flexible spacecraft possessing a distributed control system. A single-stage continuation method is presented for the solution of the resulting two-point boundaryvalue problem. Starting iteratives for the initial costate variables are obtained by neglecting the kinematic nonlinearity in the state equation which leads to a closed form solution algorithm. The continuation process then increases the participation of the kinematic nonlinearity in a sequence of neighboring optimal solutions (in essence a method of successive linearizations), converging finally to the nonlinear problem of interest.