Abstarct: In this thesis, the fractional-order variable structure control system with the tixtle of "Fractional-Fractional Fast Floating Pole Placement " controller is introduced, and the features and novelties of this controller are described. The newly proposed method, by finding a structured approach to control the speed of the linear fractional-order system, then applying a variable structure control procedure, while keeping the control signal limited, achieves the goal of increasing the speed of the fractional-order control system in the sense of stability region. Also, a robust control discussion is presented to achieve a faster response in the presence of model uncertainties and external disturbances. The proposed method, through the pole placement algorithm, designing appropriate robust polynomials, and applying an optimization routine, guides the system to the desired characteristics within the frxamework of the stability region. In this system, the control signal is continuous and limited. Sufficient conditions of stability are established baxsed on the characteristics of the Mittag-Leffler function and stability theory of linear differential equations of fractional order. In addition to evaluating the efficiency of the control system through computer simulation, in order to bring the research results closer to industrial application, it is tested on a Buck DC/DC converter. This thesis is aد stride in the direction of expanding and facilitating the use of fractional order systems along the general trend toward fractional accounts.