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Abstract-Adaptive control algorithms are of interest in flight control systems design not only for their capability to improve performance and reliability but also for handling aerodynamic parameter uncertainties, external disturbances and modeling inaccuracies. In this paper, a direct adaptive sliding mode control is developed for the quadrotor attitude stabilization and altitude trajectory tracking. First, developed controller is applied without considering disturbances and parameter uncertainties. After, a centered white gaussian noise with some parameter uncertainties are added to the considered output vector, mass and inertia matrix, respectively. The synthesis of the adaptation laws is based on the positivity and Lyapunov design principle. Numerical simulations are performed showing the robustness of the proposed control technique.

With the growth of civil aviation traffic, enhanced accuracy performances are required from guidance systems to maintain efficiency and safety in flight operations. This communication proposes a new representation of aircraft flight dynamics at approach for landing and a space-based nonlinear dynamic inversion control technique for the guidance of transportation aircraft. The main novelty is that the adopted independent variable is distance to land which allows the development of a new guidance approach with a perspective for improved performance. Nomenclaturex Longitudinal displacement, m z Altitude, m V air Airspeed, m/s V G Ground speed, m/s γ air Flight path angle w.r.t airspeed, rad θ Pitch angle, rad α Angle of attack, rad L Lift force, N D Drag force, N T Thrust force, N C Z Lift force coefficient C X Drag force coefficient m Mass, Kg q Pitch rate, rad/s M Pitch moment, N.m I y Pitch inertia moment, Kg.m 2 ρ Air density, Kg/m 3 S Wing surface area, m 2 g Gravity acceleration, m/s 2 τ Engine time constant , s T C Throttle setting , rad δ e Elevator deflection , rad w x Longitudinal wind component , m/s w z Vertical wind component , m/s Subscript k Variable number

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Abstract-With the growth of civil aviation traffic, enhanced accuracy performances are required from guidance systems to maintain efficiency and safety in flight operations. This communication proposes a new representation of aircraft flight dynamics at approach for landing and a space-based nonlinear dynamic inversion control for a transportation aircraft. The main novelty is that the adopted independent variable is the distance to land. This new representation of flight dynamics should support the development of improved aircraft guidance systems.

With the growth of civil aviation traffic capacity, safety and environmental considerations urge today for the development of guidance systems with improved accuracy for spatial and temporal trajectory tracking. This should induce increased capacity by allowing safe operations at minimum separation standards. Also, at take-off and landing, trajectory dispersion should be reduced resulting in controlled noise impacts on airport surrounding communities. Current civil aviation guidance systems operate with real time corrective actions to maintain the aircraft trajectory as close as possible to the planned trajectory. In this paper, we consider the problems of designing new longitudinal guidance control laws for an autopilot so that accurate vertical tracking and overfly time are better insured. Instead of using time as the independent variable to describe the guidance dynamics of the aircraft, we adopt distance to land, which can be considered today to be available online with acceptable accuracy and availability. A new representation of aircraft longitudinal guidance dynamics is developed according to this spatial variable. Then a nonlinear inverse control law based-on this new proposed spatial representation of guidance dynamics is established to make the aircraft follow accurately a vertical profile and a desired airspeed. The desired airspeed is then regulated to make the aircraft overfly different waypoints according to a planned timetable. Then simulations experiments with different wind conditions are performed for a transportation aircraft performing a general descent approach for landing. These simulation results are compared with those obtained from a classical time-based guidance control law.