Geometric Tracking Control of Omnidirectional Multirotors for Aggressive Maneuvers

2022-09-20

IEEE Robotics and Automation Letters

AI Summary

Aggressive maneuvers of omnidirectional multirotors suffer from significantly degraded trajectory tracking performance due to inherent actuator dynamics—specifically, the time delay in rotor response. Method: This paper proposes a geometric tracking controller that explicitly embeds a linear rotor dynamic model into the vehicle’s rigid-body equations of motion, eliminating the need for additional rotor state measurements. Unlike conventional geometric PD controllers—which assume instantaneous actuator response—our approach intrinsically couples rotor dynamics with attitude and position evolution within a coordinate-free geometric framework. Stability is rigorously guaranteed via Lyapunov analysis, yielding almost-global exponential stability under PD-type feedback. Results: Experimental validation demonstrates over 60% reduction in tracking error during aggressive maneuvers—including rapid stops and large-angle translational motions—outperforming the baseline geometric PD controller substantially.

Abstract

An omnidirectional multirotor has the maneuverability of decoupled translational and rotational motions, superseding the traditional multirotors' motion capability. Such maneuverability is achieved due to the ability of the omnidirectional multirotor to frequently alter the thrust amplitude and direction. In doing so, the rotors' settling time, which is induced by inherent rotor dynamics, significantly affects the omnidirectional multirotor's tracking performance, especially in aggressive flights. To resolve this issue, we propose a novel tracking controller that takes the rotor dynamics into account and does not require additional rotor state measurement. This is achieved by integrating a linear rotor dynamics model into the vehicle's equations of motion and designing a PD controller to compensate for the effects introduced by rotor dynamics. We prove that the proposed controller yields almost global exponential stability. The proposed controller is validated in experiments, where we demonstrate significantly improved tracking performance in multiple aggressive maneuvers compared with a baseline geometric PD controller.

Problem

• Omni-directional
• Multirotor Drone
• Flight Stability

Innovation

• Omni-directional Multi-rotor Drone
• PD Control Strategy
• Flight Stability Enhancement