Geometric Maneuvering for Underactuated VTOL Vehicles

The geometric maneuvering problem for underactuated vertical takeoff and landing vehicles is considered in this article. First, driven by the demands in this study, the input-to-state stability (ISS) theory is extended to the closed set case with input restriction considered. Then, the inner-outer loop hierarchical paradigm, originally proposed for tracking, is modified for the maneuvering problem, based on which the maneuvering problem is formulated as a closed set stabilization problem. Then, a novel singularity-free outer-loop maneuvering control law is proposed, whose ISS property is proved under the above extended ISS theory framework. Then, the geometric maneuvering controller is designed for thrust and torque inputs by combining such outer-loop control law with the existing attitude controller, and the interconnected closed-loop system is proved to be uniformly asymptotically stable. Real-time flight experimental results are presented to illustrate the efficacy of the proposed controller.