This paper considers the systematic design of robust stabilizing state feedback controllers for fractional order nonlinear systems with time-varying delay being possibly unbounded. By using the fractional Halanay inequality and the Caputo fractional derivative of a quadratic function, stabilizability conditions expressed in terms of bilinear matrix inequalities are derived. The controllers can then be obtained by computing the gain matrices. In order to derive the gain matrices, two algorithms are proposed by using the existing computationally linear matrix inequality techniques. Two numerical examples with simulation results are provided to demonstrate the effectiveness of the obtained results.
- bilinear matrix inequality
- fractional Halanay inequality
- fractional order system
- time-varying delay