@Article{cmes.2015.104.159,
AUTHOR = {M.  Zaouche, A.  Beloula, R.  Louali, S.  Bouaziz, M.  Hamerlain},
TITLE = {Adaptive Differentiators via Second Order Sliding Mode for a Fixed Wing Aircraft},
JOURNAL = {Computer Modeling in Engineering \& Sciences},
VOLUME = {104},
YEAR = {2015},
NUMBER = {3},
PAGES = {159--184},
URL = {http://www.techscience.com/CMES/v104n3/27196},
ISSN = {1526-1506},
ABSTRACT = {Safety automation of complex mobile systems is a current topic issue in industry and research laboratories, especially in aeronautics. The dynamic models of these systems are nonlinear, Multi-Input Multi-Output (MIMO) and tightly coupled. The nonlinearity resides in the dynamic equations and also in the aerodynamic coefficients’ variability.<br/>
This paper is devoted to developing the piloting law based on the combination of the robust differentiator with a dynamic adaptation of the gains and the robust controller via second order sliding mode, by using an aircraft in virtual simulated environments.     <br/>
To deal with the design of an autopilot controller, we propose an environment framework based on a Software In the Loop (SIL) methodology and we use Microsoft Flight Simulator (FS-2004) as the environment for plane simulation.       <br/>
The first order sliding mode control may be an appropriate solution to this piloting problem. However, its implementation generates a chattering phenomenon and a singularity problem. To overcome these problems, a new version of the adaptive differentiators for second order sliding modes is proposed and used for piloting.<br/>
For the sliding mode algorithm, higher gains values may be used to improve accuracy; however this leads to an amplification of noise in the estimated signals. A good tradeoff between these two criteria (accuracy, robustness to noise ratio) is difficult to achieve. On the one hand, these values must increase the gains in order to derive a signal sweeping of some frequency ranges. On the other hand, low gains values have to be imposed to reduce noise amplification. So, our goal is to develop a differentiation algorithm in order to have a good compromise between error and robustness to noise ratio. To fit this requirement, a new version of differentiators with a higher order sliding modes and a dynamic adaptation of the gains, is proposed: the first order differentiator for the control of longitudinal speed and the second order differentiator for the control of the Euler angles.},
DOI = {10.3970/cmes.2015.104.159}
}