Quadrotor control using generalized dynamic inversion and terminal sliding mode

This paper presents a two-loops structured control system design for quadrotor´s position/attitude trajectory tracking. The aim of the outer loop is to provide the roll/pitch tilting commands to the inner loop, which in turns generates the quadrotor´s tilting angles required to control the horizontal CG position. To fulfill that purpose, the outer loop utilizes Generalized Dynamic Inversion of a prescribed asymptotically stable differential equation in the errors the two horizontal position coordinates x and y from their reference trajectories. The inner loop employs Nonlinear Terminal Sliding Mode Control to control the two tilting angles φ and θ, in addition to controlling the yaw attitude angle ψ and the vertical position coordinate z. The singularity avoidance problems that are associated with Generalized Dynamic Inversion and Terminal Sliding Mode Control are addressed tactfully, and closed loop stability is guaranteed. For performance evaluation, a six degrees of freedom Quadrotor model is developed, and numerous simulations are conducted in the presence of disturbances and parametric uncertainties for analyzing the effectiveness of the proposed control system.