IJRCS International Journal of Robotics and Control Systems Vol. 2, No. 2, 2022, pp. 240-252 ISSN 2775-2658 http://pubs2.ascee.org/index.php/ijrcs https://doi.org/10.31763/ijrcs.v2i2.574 ijrcs@ascee.org MRAC Adaptive Control Design for an F15 Aircraft Pitch Angular Motion Using Dynamics Inversion and Fractional- Order Filtering Amani R. Ynineb a,1 , Samir Ladaci b,2,* a Signal Processing Laboratory, Depart. Electronics, Mentouri Brothers University, Constantine, 25000, Algeria b National Polytechnic School of Algiers, Depart. Automatics, Algiers, 16200, Algeria 1 ynineb.amani@gmail.com; 2 samir.ladaci@g.enp.edu.dz * Corresponding Author 1. Introduction Controlling a military aircraft is a very challenging task for automation engineers because of the complexity of the plant model: huge nonlinearities, multiple coupled outputs, very disturbing environment, and extreme maneuvering conditions. In this study, the main motivation is to design a simple fractional adaptive controller that is able to guarantee stability and a high level of performance for this kind of system. Many control strategies have been proposed to deal with aircraft and flight supervision like Fuzzy Logic Controllers [1], PD control [2], robust H∞ control [3], Fault-tolerant control [4], and adaptive control [5]. Model reference adaptive control (MRAC) schemes are proving to be efficient with nonlinear control problems, as they allow us to deal with uncertainties in the model and unknown or slowly varying parameters. An adaptive learning algorithm makes it possible to track the modifications in the plant dynamics [6][7]. This is a major advantage of such adaptive controllers, as the majority of practical plants’ models are nonlinear, with unknown parameters and unconsidered nonlinear dynamics [8]. Besides, there are multiple possible actuator failures and an infinite variety of possible surface damages for the military aircraft, and any discrepancy between the model and reality can lead to false detection [9]. Many different approaches have been successfully flown on manned aircraft [10], like the retrospective cost adaptive control (RCAC) to a linearized aircraft dynamic ARTICLE INFO ABSTRACT Article history Received January 16, 2022 Revised March 04, 2022 Accepted March 14, 2022 This study proposes a fractional adaptive control scheme design for a longitudinal pitch angular motion control of a military F15 aircraft. The aircraft behavior will be forced to follow a chosen model reference in an MRAC (Model Reference Adaptive Control) configuration combined with dynamics inversion technique such that the transient response becomes invariant even in the presence of uncertainties or variations for a reference input by introducing a fractional-order transfer function pre- filter. Based on Lyapunov theory, the updating control law minimizes the error between the plant output and the model reference one. This controller is set in a cascade with a linear dynamic compensator. Simulation results on a military aircraft model with comparison to preceding results illustrate the effectiveness and the superiority of the proposed control strategy. Keywords Fractional MRAC control; F15 aircraft; Fractional order system; Shaping filter; Dynamics Inversion; Stability This is an open-access article under the CC–BY-SA license.