Solution of n-th order interval fuzzy differential IAL equations using the backstepping method

There are two key points in this work as the main objectives. The first is how to convert nth order fuzzy differential equation into a first-order system of fuzzy differential equations using the notion of upper and lower bounds of the fuzzy solution to constitute the so-called interval fuzzy solution. The second is to solve the obtained system from the first step using a powerful method (the backstepping method) to provide an asymptotically stable solution by applying direct methods of stability (Lyapunov direct method).