Robust output-feedback VFO-ADR control of underactuated spatial vehicles in the task of following non-parametrized paths

This article concerns the development of Vector Field Orientation - Active Disturbance Rejection (VFO-ADR) cascaded path-following controller for underactuated vehicles moving in a 3-dimensional space. The proposed concept control structure decouples system kinematics from dynamics, resembling approach utilized nonholonomic systems. Thanks to use an ADR dynamic-level controller, is robust even significant model uncertainties and external disturbances. Application error-based form Extended State Observer (ESO), implemented within inner-loop implies output-feedback characteristic structure, i.e., only position attitude vehicle body are expected be measured. kinematic-level designed according VFO method utilizing non-parametrized path representation calculate commanded velocities. description followed by theoretical analysis Input-to-State Stability (ISS) theorem simulation verification solution.