YawSitter: Modeling and Controlling a Tail-Sitter UAV with Enhanced Yaw Control

2025-10-03

AI Summary

Tail-sitter UAVs suffer from modeling difficulties and severe control coupling in lateral motion during hover, primarily due to strong aerodynamic coupling and ill-defined lateral dynamics. To address this, we propose an enhanced yaw-driven decoupled control strategy: first, we model the lateral force induced by propeller slipstream under differential thrust; second, we directly control yaw about the body y-axis using a YXZ Euler angle sequence, thereby avoiding singularities and eliminating roll–yaw coupling. Integrating slipstream force modeling, gravity compensation, and attitude decoupling, we establish a physically interpretable lateral position control framework. Unity-based simulations demonstrate that the method achieves low mean absolute position tracking errors on both rectangular and circular trajectories, with maximum yaw deviation bounded by 5.688°, significantly improving accuracy and robustness of lateral motion during hover.

Technology Category

• Intelligent Robots: Behavior Learning & Control
• Planning, Routing, and Scheduling: Model-Based Reasoning
• Humans and AI: Planning and Decision Support for Human-Machine Teams

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• User Modeling, Personalization and Recommendation: Fairness-aware retrieval and ranking
• Semantics and Knowledge: Methods to enhance, augment, integrate or synergize semantic models such as knowledge graphs and LLMs

Abstract

Achieving precise lateral motion modeling and decoupled control in hover remains a significant challenge for tail-sitter Unmanned Aerial Vehicles (UAVs), primarily due to complex aerodynamic couplings and the absence of welldefined lateral dynamics. This paper presents a novel modeling and control strategy that enhances yaw authority and lateral motion by introducing a sideslip force model derived from differential propeller slipstream effects acting on the fuselage under differential thrust. The resulting lateral force along the body y-axis enables yaw-based lateral position control without inducing roll coupling. The control framework employs a YXZ Euler rotation formulation to accurately represent attitude and incorporate gravitational components while directly controlling yaw in the yaxis, thereby improving lateral dynamic behavior and avoiding singularities. The proposed approach is validated through trajectory-tracking simulations conducted in a Unity-based environment. Tests on both rectangular and circular paths in hover mode demonstrate stable performance, with low mean absolute position errors and yaw deviations constrained within 5.688 degrees. These results confirm the effectiveness of the proposed lateral force generation model and provide a foundation for the development of agile, hover-capable tail-sitter UAVs.

Problem

• Enhancing yaw authority for tail-sitter UAVs in hover
• Decoupling lateral motion control from roll coupling effects
• Modeling lateral dynamics using differential propeller slipstream forces

Innovation

• Sideslip force model from differential propeller slipstream
• YXZ Euler rotation for singularity-free attitude control
• Yaw-based lateral position control without roll coupling