DESIGN OF SATELLITE CONTROL ALGORITM USING THE STATE-DEPENDENT RICCATI EQUATION AND KALMAN FILTER

摘要

A properly attitude control algorithm design and test procedure can dramatically minimize space mission costs by reducing the number of errors that can be transmitted to the next phase of the project. Besides, when attitude control algorithm problems are discovered on-orbit the mission or at least part of it can be lost. One way to increase confidence in the control algorithm is its experimental validation through prototypes. The Space Mechanics and Control Division (DMC) of INPE is constructing a 3D simulator to supply the conditions for implementing and testing satellite hardware and software. The 3D simulator can accommodate various satellites components; like sensors, actuators, computers and its respective interface and electronic. Depending on the manoeuvre the 3D simulator plant can be highly non-linear and if its inertia parameters are not well determined the plant can also present some kind of uncertainty. As a result, controller designed by linear control technique can have its performance and robustness degraded. This paper presents the application of the State-Dependent Riccati Equation (SDRE) method in conjunction with Kalman filter to design and test a attitude control algorithm for a 3D satellite simulator. The control strategy is based on gas jets and reaction wheel torques to perform large angle manoeuvre in three axes. The simulator model allows investigating the dynamics and the control system taking into account effects of the plant non-linearities and system noise. Initially, a simple comparison between the LQR and SDRE controller is performed. Practical applications are presented to address problems like presence of noise in process and measurements and incomplete state information using Kalman filter technique. Simulation has shown the performance and robustness of the SDRE controller applied for angular velocity reduction associated with stringent pointing requirement.