Fuzzy Hybrid Super-Twisting Sliding Mode Controller Design for a Class of Non-linear Dynamics of a Quadrotor

Controller design for non-linear multi-input, multi-output systems, such as unmanned quadrotor vehicles, has always been a challenging issue due to the strong interconnection between state variables and highly nonlinear dynamic equations. In addition, quadrotor is an under-actuated non-linear dynamic device. Due to being under-actuated for moving in the horizontal direction, the combination of changes in the speed of the existing quadruple operators should be used. So that, by creating the angle between the quadrotor hypothetical plane and the horizon surface, the device can be forced to move in the longitudinal or transverse direction. Therefore, in the quadrotor control system, two nested control loops are required. An outer loop to determine the appropriate angle of the device relative to the horizon for horizontal movements and an inner loop that is required to angle of the device panel is equal to this angle. In this paper, a fuzzy hybrid super-twisting sliding mode non-linear controller for controlling a sample quadrotor is designed. For this purpose, a fuzzy controller in the outer loop and a super twisting sliding mode controller in inner loop are used. An important advantage of this strategy is that it optimizes the horizontal speed of the device. If the distance from the target is too high, the angle of the device panel also increases, and if the distance is reduced, the angle also decreases. As a result, the device reaches the target with the desired speed. The performed simulation results confirmed this fact.