Nonlinear H∞ helicopter hovering control and implementation using CSIA

This paper applies the nonlinear H∞ control theory to helicopter hovering manuver whose complete six degree-of-freedom nonlinear equations of motion with coupled rotor and inflow dynamics are considered directly without linearization. Under this approach, the exact nonlinear equations governing both the longitudinal and lateral motions are considered. The control surface inverse algorithm (CSIA) developed in this paper to implement the nonlinear H∞ control surface deflections is based on Moore-Penrose generalized inverse. The implement technique is constructed based on minimizing the global errors between the nonlinear H∞ commands and actual control forces and moments. The separation principle of nonlinear H∞ hovering control is verified by CSIA under actuator with saturation and rate limit.