SIMULTANEOUS STRUCTURE CONTROL DESIGN OPTIMIZATION OF A WING STRUCTURE WITH A GUST LOAD ALLEVIATION SYSTEM

Simultaneous design optimization is considered for structure and control parameters of a wing with a gust load alleviation (GLA) control system. The application of a goal programming (GP) formulation to the design synthesis of an aeroservoelastic system is carried out by the use of a simple mathematical model in conjunction with a wind-tunnel model having a GLA control system. Numerical applications are based on a cantilever wing having an aileron surface controlled by wing-tip accelerometer feedback signals. System equations are obtained in the form of state equations, thus enabling the statistical characteristics of both the gust-induced wing stress and the control surface deflection angle to be evaluated using their standard deviations. The wing spar height and the controller feedback gain are simultaneously optimized to obtain the minimum spar weight while satisfying the following structure and control design constraints: 1) the spar stress is limited with the control system either on or off; 2) the control surface deflection angle is restricted; and 3) system stability should be guaranteed by incorporating a controller stability margin. Numerical examples demonstrate the successful application of a GP formulation for the simultaneous structure/control design synthesis by specifying priorities to the conflicting design constraints.