A parallel implementation of the genetic algorithm applied to the flight control problem

The technique of eigenstructure assignment (A.N. Andry et al., 1983) is applied to the flight control problem in order to produce specific aircraft handling qualities. Eigenstructure assignment, however, does not directly consider system robustness. The robustness problem may be addressed by the use of the linear quadratic regulator or LQR which allows the choice of the state feedback gains in an optimal manner such that multivariable gain and phase margins of +∞, -6 dB and ±60° respectively may be guaranteed. The behaviour of the LQR controller is determined by the choice of two weighting matrices Q and R within a quadratic cost function. The problem is then the choice of these positive definite symmetric weighting matrices such that an eigenstructure is assigned to the system via the LQR. This will provide a controller which both satisfies handling quality requirements and is robust