Nonlinear H_∞ microsatellite attitude control

Because of a great decrease in size and weight, the pointing accuracy of microsatellite is vulnerable to space environmental disturbance and the internal uncertainty of moment-of-inertia variation. This paper demonstrates to model a microsatellite and design a nonlinear H_∞ attitude controller, which is determined via the solution of Hamilton-Jacobi partial differential inequality corresponding to nonlinear H_∞ state feedback control law. Considering the constraints in accuracy of sensors and actuators, and the disturbance from gravity-gradient torque, geomagnetic torque and aerodynamic torque, the microsatellite attitude control is designed to validate the robust performance of nonlinear H_∞ attitude controller.