P. Baldi

Summary: This paper presents a novel scheme for diagnosis of faults affecting sensors that measure the satellite attitude, body angular velocity, flywheel spin rates, and defects in control torques from reaction wheel motors. The proposed methodology uses adaptive observers to provide fault estimates that aid detection, isolation, and estimation of possible actuator and sensor faults. The adaptive observers do not need a priori information about fault internal models. A nonlinear geometric approach is used to avoid that aerodynamic disturbance torques have unwanted influence on the fault estimates. An augmented high‐fidelity spacecraft model is exploited during design and validation to replicate faults. This simulation model includes disturbance torques as experienced in low Earth orbits. This paper includes an analysis to assess robustness properties of the method with respect to parameter uncertainties and disturbances. The results document the efficacy of the suggested methodology.

This paper presents a novel approach to the longitudinal guidance and control issue for an aircraft in presence of wind shear. The main contribution concerns the adaptive estimation of the wind shear disturbances affecting the aircraft and the development of a control scheme suitable to compensate these effects during a precision approach procedure. The work proposes the design, based on the Nonlinear Geometric Approach, of three adaptive filters providing the estimate of the wind shear disturbance components. These estimates are exploited, in an original way, by a BackStepping based controller, thus resulting in an Adaptive BackStepping Controller. Simulation results, obtained by means of a detailed flight simulator implementing the real wind shear condition which caused the 1975 crash of Eastern Flight 066 at JFK airport and a Montecarlo robustness test, demonstrates the effectiveness of the proposed method.