Comparison of Nonlinear Dynamic Inversion and Backstepping Controls with Application to a Quadrotor
This paper presents a comparison between different control designs using Nonlinear Dynamic Inversion (NDI) and Backstepping methodologies. Most of control design variations of the two mentioned methods, if not all, are concluded here. Similarities and differences are compared not only between NDI and Backstepping, but also between different designs of the same method, where the output tracking error dynamics are used as an important criterion for the comparison. Due to the high maneuverability and agility of the quadrotor, the control bandwidth of the designs is of particular interest, which is related to the requirement on the Time Scale Separation (TSS) in the control system. Through the comparison, the related issues are clarified, e.g. if the additional Backstepping term reduces the TSS compared with the NDI designs; which control designs have the highest control bandwidth. The attitude control of a quadrotor is used as an example system to explain and verify the comparison.