CONTROLE DE ATITUDE DE NANO SATÉLITE USANDO O MÉTODO FPRE COM SOLUÇÃO VIA FILTRAGEM ADAPTATIVA

Abstract

This work investigates the efficiency of the LQR-based FPRE (forward-propagation Riccati equation) method applied to the control of a nonlinear system factored in SDC (state-dependent coefficients) that represents the attitude dynamics of nanosatellites. To solve the FPRE, it is necessary to obtain the solution of the state-dependent discrete algebraic Riccati equation (SD-DARE) at each time instant, which is complex to determine analytically. The adopted strategy consists of using adaptive filtering algorithms to solve the Bellman equation, which is independent of the dynamic system matrices and whose solution converges to the solution of the SD-DARE. As a result, a control vector is calculated online in order to stabilize the states of the dynamic system. Computational simulations demonstrate the performance of the FPRE when normalized least-mean-square (NLMS) and recursive least-square (RLS) algorithms are used in the face of initial state conditions, disturbances, and choices of matrices in SDC.