Design of passive fault-tolerant attitude controller for a fractional order flexible satellite model

Several recent developments in fractional calculus have led to an increased interest in fractional-ordered modeling of physical systems. In this paper, complex dynamics of a flexible satellite in the fractional setting are proposed and investigated for the first time in the literature. The dynamic equations are derived using generalised fractional-order Euler-Lagrange equation, in which a strong coupling exists between the motions of the rigid body and the vibrations of its appendages. Thanks to the long-term memory effects of the nonlocal fractional derivatives, the developed fractional-order model of the satellite provides a way to compensate for the unpredictable space environment by adding a further degree of freedom. For attitude control, a feedback linearization method is proposed based on the approximated fractional-order chain rule to linearize the system in the presence of actuator faults. To investigate the effectiveness of the proposed fractional order scheme in tracking the reference signal and damping the appendage vibrations in presence of known faults affecting the actuator reasonably, a variety of nonlinear simulations in fractional and integer settings are performed.