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.