Design of ight control laws for a civil aircraft using - synthesis

Design of ight control laws for a civil aircraft using -synthesis S. Bennani G.H.N. Looyey Faculty of Aerospace Engineering Group for Control and Simulation Delft University of Technology The Netherlands E-mail: [email protected] Abstract This paper demonstrates the use of H1 and synthesis to develop control laws for a civil aircraft in the approach for landing. The controller has to provide decoupled tracking of altitude, speed and lateral position demands, and disturbance rejection to constant winds, turbulence and wind shear. The system has to be robust against varying system parameters and time delays, and has to cope well with an engine failure. The controller architecture consists of a longitudinal and a lateral part, of which the latter is discussed in detail. Performance speci cations are translated into weighting functions, while robustness is addressed using a simple uncertainty model in LFT form. The performance speci cations and the LFT-model are incorporated in the interconnection structure. Next, the robust performance indicator is optimized via DK-iteration. Performance of the control laws is demonstrated by ying a landing trajectory, while several disturbances occur. The robustness is assessed via realanalysis, with a detailed parametric uncertainty model.