Nonlinear H∞ Attitude Control Using Modified Rodrigues Parameters

The attitude control problem can be formulated as a disturbance free regulation or tracking problem. Alternatively, one can view the problem from the disturbance attenuation point of view. That is the approach that will be examined in this note using the MRPs and their shadow set. The attitude control problem for rigid spacecraft has attracted significant attention. The problem is readily formulated using Euler's equation for the evolution of the angular velocity vector and an equation to describe the evolution of the attitude. It is also worth noting that a linear feedback solution, although with MRP switching and hence a local solution, has been found for a problem with nonlinear dynamics.