Multi-objective and Multidisciplinary Optimal Design of a Flexible Wing with Multiple Ailerons

In this article, a multidisciplinary and multi-objective optimal design of ailerons' sizes and active control systems for an aircraft's wing with three control surfaces is developed. A Multi-Input-Multi-Output (MIMO) controller is designed using the LQR (Linear Quadratic Regulator) algorithm. The geometrical parameters of the control surfaces and the design details of the LQR penalty matrices are tuned by the NSGA-II (Non-dominated Sorting Genetic Algorithm). Three objectives are considered: minimizing impacts of external gust loads, maximizing stability robustness, and reducing control energy consumption. To investigate the effect of the air stream velocity on the solution of the optimization problem, three multi-objective optimization problems (MOPs) are formulated and solved at three different airspeeds. The optimization results demonstrate competing relationships among the design objectives and the necessity of handling the design problem in multidisciplinary and multi-objective settings. Three major results are obtained 1) a unique control gain can be designed for the entire flight envelope, 2) the flutter boundaries are extended to more than 92% beyond the design envelope, and 3) the MOP designed at higher air stream velocities offers better design options.