A passivity perspective for the synthesis of robust terminal guidance

This note proposes a robust guidance synthesis based on the passivity approach. The method is applied to missiles whose flight control dynamics are modeled as linear uncertain systems with bounded uncertainties. The robust guidance laws are obtained by means of an appropriate subsystem decomposition, providing passivation by feedback and feedforward control. Hence, L₂ stability of the missile-target closed-loop system is warranted by direct application of the passivity theorem. The resulting terminal guidance laws ensure robust stability of the miss distance in the case of 1) a maneuvering target whose acceleration lies in L₂, and 2) bounded parametric uncertainties of second-order models of the missile flight control dynamics. Numerical simulations demonstrate the effectiveness of the proposed guidance laws.