The principal research theme is about Fault Tolerant Control in Aerospace where a novel methodology for Active Fault Tolerant Control Systems (AFTCS) has been developed. The AFTCS can be also obtained by keeping the already in-place guidance and control (GC) laws and by adding a loop for feedback of the fault estimate. This ulterior loop contains a Fault Detection and Diagnosis (FDD) module that provides the most update information about the real system's state. It's worth noting that the design of the proposed FDD scheme and the design of the guidance and control (GC) scheme can be done independently. These features could significantly reduce the applicability scope of these approaches since the modification of the validated and certified in-place nominal control law could be a major concern and especially for aerospace systems. Concerning the FDD procedure, a novel nonlinear method based on the Non Linear Geometric Approach has been developed. Thanks to this approach it's possible to obtain a new observable sub-system affected by the fault to be estimate and decoupled from other faults and disturbances such as wind. The resulting fault estimate is unbiased and the reliability of the overall AFTC system increases. Motivated by several literature publications particularly focused on aircraft actuator oscillatory faults, t he mentioned technique has been applied at actuator or sensors multi-faults scenarios as, for example, in the case of oscillatory and step faults on actuators and sensors. Moreover, the potentialities of the depicted approach have been exploited to estimate an actual wind shear during landing phase. Moreover, recent results show how singular perturbations are particularly suitable in aircraft applications. Thanks to this approach it's possible to detect and isolate a single fault affecting aircraft actuators and sensors (i.e. redundant multi fault scenario). The novel Active Fault Tolerant Control is tested by using high fidelity simulators of aircraft and spacecraft systems and the performance show the method's robustness in presence of model-reality mismatches, disturbance effects and measurement errors. The production of a lot of publications about this theme prove the effective work's prolificacy.
The theoretical research work is completed by its practical counterpart. The two main activity are: - Nonlinear simulation environments; - Laboratory work on Unmanned Aerial Vehicles
Nonlinear simulation environments
To understand the effective applicability and the performance of the new AFTC it's necessary to use valid environments of simulations. Particular attention is paid to the most important aerospace models. Aircrafts and spacecrafts have to be modelled in their complete dynamics, with no assumptions or reduction. Simulation tests are obtained including actuators' dynamic, input and output sensors. They are modelled with real noises and measurement errors (bias, drift, …). The environment disturbances aren't left out: wind gusts, wind shears, turbulences for the aircraft and solar, aerodynamic, magnetic, gravitational disturbance momentum for the satellite.
Laboratory work on Unmanned Aerial Vehicles
The goal is to realize a completely autonomous ultra-light aircraft equipped to transport the safety pilot and the research avionics. The first phase of the project has concerned on the definition, calibration, installation, integration of avionics. The second phase consists in the flight tests for aircraft model identification. In the third phase navigation, guidance and controls laws will be developed and tested. The aircraft will be the test-rig for the fault tolerant control systems developed. The first step of the project has been completed by obtaining a Permit To Fly for research activities. The second phase of the project is planned to start in the autumn of 2013.
