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Nonlinear H∞ normal matrix attitude control of spacecraft

The attitude control problem for rigid spacecraft with disturbances is addressed. A feedback control law for rigid spacecraft attitude was proposed by combining the normal matrix design approach for robust control systems, the feedback perturbation description for systems uncertainties, and the Hamilton-Jacobi-Isaacs partial differential inequality for nonlinear H∞ control. The control law is built based on the normal matrix control theory, and the tuning guidelines are established by using the Hamilton-Jacobi-Isaacs inequality. The control law is H∞ solution for the linearized attitude dynamics and nonlinear H∞ solution for the nonlinear attitude motion of attitude tracking problem. Furthermore, no additional assumption about the inertia of spacecraft is needed in the designing process. Computer simulation are performed to demonstrate the effectiveness of the control law proposed.