Attitude Control of a Tilt Trirotor Using Fast Nonsingular Terminal Integral Sliding Mode

This paper presents a fast nonsingular terminal integral sliding mode (FNTISM) controller for attitude tracking of a tilt trirotor unmanned aerial vehicle (UAV) in vertical takeoff and landing (VTOL) flight mode. The rotation of UAV is described by the matrix group SO(3) to eliminate gimbal lock. Besides, the proposed controller offers fast response, high tracking accuracy, and strong disturbance rejection characteristics. It employs a sliding surface function that includes integral terms which