New Insights into Cascaded Geometric Flight Control: From Performance Guarantees to Practical Pitfalls

TL;DR

This paper provides a new stability proof for cascaded geometric control in aerial vehicles, highlighting theoretical guarantees and practical challenges in trajectory tracking.

Contribution

It introduces a novel stability analysis using sliding variables and quaternion-based controllers, revealing new insights and pitfalls of the control strategy.

Findings

Exponential convergence of position tracking is theoretically achievable.

Tracking error in attitude affects position loop performance.

Model uncertainties impact closed-loop stability.

Abstract

We present a new stability proof for cascaded geometric control used by aerial vehicles tracking time-varying position trajectories. Our approach uses sliding variables and a recently proposed quaternion-based sliding controller to demonstrate that exponentially convergent position trajectory tracking is theoretically possible. Notably, our analysis reveals new aspects of the control strategy, including how tracking error in the attitude loop influences the position loop, how model uncertainties affect the closed-loop system, and the practical pitfalls of the control architecture.