Development and Application of a Novel High-order Fully Actuated System Approach: Part II. 6-DOF Quadrotor Control

Traditional cascade controller design based on state-space modeling has been widely applied for quadrotor systems. The state-space representation can effectively model many dynamic systems. Yet, a group of first-order differential equations may not be the most suitable way to model and control inherent high-order dynamic systems, such as quadrotors. This paper proposes a modified high-order fully actuated (HOFA) approach with recursive actions based on a mixed-order quadrotor model. Unlike the existing HOFA approach developed for generalized strict-feedback systems, the modified HOFA method does not require the system in a strict-feedback form. Hence, the 6-DOF quadrotor model can be essentially converted into three HOFA subsystems. Based on the obtained HOFA systems, the control design of 6-DOF nonlinear quadrotor systems can be readily achieved like linear systems with arbitrarily assignable eigenstructure. Simulation and experimental results are shown to verify the effectiveness of the proposed HOFA modeling and control approach.