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 n^{th} 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).