Nonlinear Modeling and Control Design of Active Helicopter Blades

This paper presents the theoretical basis for the simulation and control of active helicopter blades. The analysis is based on a model that considers the structural dynamics, the aerodynamics, as well as the integrated blade actuation and sensing. The effect of the integral actuation enters the beam model via an active beam cross-sectional analysis. A two-dimensional incompressible, inviscid, quasi-steady aerodynamic model is coupled to the active structural model. For simulation, analysis, and control design, the blade model is discretized in space using a Galerkin approach. The resulting nonlinear model of high order is reduced using the aeroelastic modes of the blade. Finally, the usefulness of a reduced-order model is demonstrated by designing an energy optimal linear-quadratic-Gaussian (LQG) control.