Stabilization of the Two-Axis Gimbal System Based on an Adaptive Fractional-Order Sliding-Mode Controller

ABSTRACT

This paper introduces an adaptive fractional-order sliding-mode controller for stabilization of a two-axis gimbal platform in the presence of the torque disturbance effects. To tend the angular velocities of the inner gimbal in the elevation and azimuth axes to zero, an adaptive fractional-order sliding-mode approach is utilized. To achieve this goal, fractional-order sliding surfaces in both azimuth and elevation axes and the corresponding adaptive controllers with adjustable parameters tuned according to Lyapunov-based adaptation mechanisms are employed. The optimal value of the fractional order is obtained through an integral square error performance index minimization. The moments products uncertainties are incorporated in the design procedure. The numerical simulations demonstrate that the proposed control approach is robust against the moments products variations.

KEYWORDS:

• Fractional calculus
• Fractional-order sliding-mode controller
• Line of sight (LOS)
• Lyapunov-based adaptation mechanism
• Two-axis gimbal system

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Amir Naderolasli

Amir Naderolasli was born in 1984. He received the MA degree in Electrical Engineering from the Islamic Azad University, Khomeinishahr branch, Isfahan, Iran, in 2015. His current research interests include adaptive controllers design and two-axis gimbal system stabilization.

E-mail: [email protected]

Mohammad Tabatabaei

Mohammad Tabatabaei received the BE degree in electrical engineering from Sharif University of Technology in 1999. He received the MA degree in Biomedical Engineering from Amirkabir University of Technology, in 2002. In December 2011, he received the PhD degree in Control Engineering from Islamic Azad University, Science and Research Branch. At present, he is an Assistant Professor in the Department of Electrical Engineering, Khomeinishahr Branch, Islamic Azad University, Isfahan, Iran. His current research interests involve the control theory, especially adaptive control and fractional-order systems and controllers.

E-mail: [email protected]