High-order ESO based output feedback dynamic surface control for quadrotors under position constraints and uncertainties

This paper investigates the trajectory tracking and attitude stabilization problem with only position measurements for quadrotors subject to position constraints and uncertainties. By introducing the one-to-one nonlinear mapping (NM) to prevent position state violation, an output constrained trajectory tracking law is developed by transforming the original restricted translational dynamics into an equivalent unconstrained subsystem. To address the uncertainties arising from parametric deviations and external disturbances, with given model information incorporated into observer design, we develop a high-order extended state observer (ESO), capable of simultaneously online estimating the uncertainties and full-states of quadrotors. Then, an output feedback based trajectory tracking and attitude stabilization approach is synthesized by integrating NM and high-order ESO via dynamic surface control (DSC), leading to a much simpler control structure and reduced implementation costs. The salient feature is that position constraints, uncertainties as well as output feedback difficulties can be comprehensively handled with acceptable control performance. It is shown via Lyapunov stability that all signals in the closed-loop system are guaranteed to be uniformly ultimately bounded. Simulation results are provided to validate the benefits and effectiveness of the proposed method.