Controle de Atitude de Um Satelite Artificial Atraves DA Extensao DA Teoria Do Regulador Linear Quadratico (Attitude Control of an Artificial Satellite Through the Extension of the Linear Quadratic Regulator Theory)

摘要

A new attitude control law for artificial satellites is presented. It is based on an extension of the linear quadratic regulator theory to the case where the dynamics is described by a weakly nonlinear system of equations (Euler's equations). It focuses the mode of operation in which the satellite has smaller angular velocities and angles but has arbitrary reaction wheel velocities. It includes: (1) a comparison between this law and others simulated under the same conditions in the literature; (2) an evaluation of the behavior of the system output under the regulator and under its extension, while the initial conditions become large; (3) a study of the control system sensitivity with respect to variations in the satellite moments of inertia, and of the system performance when the estimate errors are modeled as random variables. The results obtained suggest that: (1) the implemented control law reduces the angular velocities and angles faster than the other law; (2) the presence of the nonlinear term in the implemented law makes it more robust than the law based on the regulator, for the dynamics considered; (3) the sensitivity of the control system with respect to a variation in the moments of inertia is small, and its performance in the presence of estimate errors is changed slightly.