Autolanding Controller for a Fixed Wing Unmanned Air Vehicle

This paper addresses the autolanding guidance and control problem for unmanned autonomous vehicles (UAV) based on the information provided by the onboard Navigation System. The proposed solution relies on a path-following and velocity profile tracking controller synthesized using an accurate aircraft dynamic model, referred to as SymAirDyn, which was designed with the objective of exploiting the whole aircraft’s flight envelope. A suitable polytopic Linear Parameter Varying (LPV) representation with piecewise affine dependence on the parameters is adopted to accurately model the desired aircraft dynamics over a set of predefined operating regions. The synthesis problem is stated as a continuous-time H2 control problem for LPV systems and solved using Linear Matrix Inequalities (LMIs). During the controller design stage, the aircraft landing maneuver is decomposed in the two standard phases: the glideslope and the flare. For each phase, the required control objectives are identified and specific controllers are designed. The controller implementation is tackled within the framework of gain-scheduling control theory using the D-methodology. The performance and effectiveness of the resulting nonlinear gain scheduling controller is illustrated in simulation, using the nonlinear model SymAirDyn under different types of disturbances, namely Dryden spectrum generated wind during the glideslope and wind gusts near touchdown.