Nonlinear MPC for attitude system of miniature satellite using multiple MEMS actuators

This paper presents a configuration scheme of multiple MEMS reaction wheels for CubeSat. In this configuration three pairs of arrays of MEMS reaction wheels are installed symmetrically within the CubeSat´s surface, wherein each array is composed by 4 × 4 co-rotating elements. Through counter-rotating of each pair of symmetrical arrays three zero momentum wheels are achieved. Assuming that control moment of MEMS reaction wheel have on-off form, two attitude control methods are designed. When change of angle is very small for attitude stabilization, constraints set of the disturbance and state is described as polytope, and constraint tightening method is used to design control law for linearized attitude equation. When performing large angle for attitude maneuver, an extended state observer is designed to estimate the disturbances. For predicting the attitude angle, the fliess expansion method of nonlinear attitude equation is proposed. The optimal control law is obtained by solve minimum of attitude predicting error finite times. Simulation results show the effectiveness of the proposed methods.