Robust analysis of the longitudinal control of a civil aircraft using RoMulOC

Recent robust analysis techniques are applied to assess the robust stability and robust performances of the longitudinal control system of an aircraft. Two different uncertain models, polytopic or LFT models are considered. Robust analysis certificates are built by computing unique Lyapunov functions or parameter dependent Lyapunov functions (PDLF). Several criteria are dealt with: Closed-loop pole placement, worst-case H_∞ cost, worst-case H₂ cost and impulse-to-peak response. All tests are done using the RoMulOC toolbox which generates the related LMI optimization problems in YALMIP format that are then solved using available semidefinite programming solvers. Numerical results are analyzed and some preliminary conclusions are drawn.