Command following control law design by linear quadratic optimisation

This paper presents a control law design for a linearised model of a Lynx-like helicopter in the 80 knots forward flight condition, with respect to an appropriate subset of the published handling qualities requirements. The synthesis method used was the Linear Quadratic Regulator (LQR) version of model following. The design is based principally on the rigid body quasi-steady-state rotor model, although a simplified representation of the actuator and blade flapping dynamics as pure delays is used to motivate the choice of the LQR input weighting matrix. The design assumes that all of the rigid body states can be measured. State estimation of actuator and rotor states is not used. The design is evaluated using a linear model which includes representation of the actuator and blade flapping dynamics