Differential Flatness and Flatness Inspired Control of Aerial Manipulators based on Lagrangian Reduction

TL;DR

This paper demonstrates that a broad class of aerial manipulators are differentially flat, enabling simplified control design through flatness-based transformations and quadratic programming, verified via simulation.

Contribution

It introduces a flatness-based control approach for aerial manipulators using Lagrangian reduction, providing a novel way to simplify their complex dynamics.

Findings

Flatness of general aerial manipulators established

A flatness-based control method using CLF-QP is proposed

Simulation results verify the effectiveness of the control approach

Abstract

This paper shows that the dynamics of a general class of aerial manipulators, consist of an underactuated multi-rotor base with an arbitrary k-linked articulated manipulator, are differentially flat. Methods of Lagrangian Reduction under broken symmetries produce reduced equations of motion whose key variables: center-of-mass linear momentum, vehicle yaw angle, and manipulator relative joint angles become the flat outputs. Utilizing flatness theory and a second-order dynamic extension of the thrust input, we transform the mechanics of aerial manipulators to their equivalent trivial form with a valid relative degree. Using this flatness transformation, a quadratic programming-based controller is proposed within a Control Lyapunov Function (CLF-QP) framework, and its performance is verified in simulation.