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

Abstract

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

ESO architectures in the trajectory tracking ADR controller for a mechanical system: a comparison

“…for some majorization constant ν x ∈ (0, 1). According to Th 5.1 from [6], multiinput ISS procedure utilized in [9] and [15], and to the relation ( 9), a time response of the dynamics ( 7) is bounded by…”