Satellite attitude slew manoeuvres using inverse control

Inverse dynamics is investigated as an efficient means of generating large angle satellite attitude slew manoeuvres. The required slew manoeuvres are specified using high order polynomials which result in a smooth control torque profile. Such smooth torque profiles are of importance in avoiding excitation of elastic modes of the satellite structure. In addition, the polynomial functions may be used to define a slew trajectory between arbitrary initial and final states allowing track-to-track manoeuvres. To compensate for uncertainties in the satellite dynamics, the inverse control is extended to include feedback linearisation about the nominal reference trajectory. It is shown that for rest-to-rest slew manoeuvres the resulting composite control is robust to uncertainties in the satellite inertia matrix and to actuator degradation. In addition, it is shown that complex paths may be generated through the use of high order polynomial functions which contain all the information required to enforce user defined constraints and boundary conditions in a compact, computationally efficient form.