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Hybrid LQR-H2 Control of a Kestrel-Based Ornithopter with a Nature-Inspired Flow Control Device for Gust Mitigation
Saddam Hussain1, Ali Hennache2, Nouman Abbasi3
1Department of Intelligent Systems and Control Engineering, Beihang University, Beijing 100191, China.
Biomimetics (Basel, Switzerland)
|February 26, 2026
Summary
This study introduces a biomimetic ornithopter with a Nature-Inspired Flow Control Device (NFCD) that mimics kestrel feathers. This hybrid control system significantly reduces turbulence-induced oscillations for stable flight.
Area of Science:
- Aerospace Engineering
- Biomimetics
- Control Systems
Background:
- Unsteady atmospheric disturbances challenge ornithopter stability.
- Natural flyers use dynamic flow control for aerodynamic adaptability.
- Kestrels exhibit feather deployment for stability in variable winds.
Purpose of the Study:
- To model and develop a hybrid control system for a kestrel-based ornithopter.
- To implement a Nature-Inspired Flow Control Device (NFCD) replicating kestrel feather mechanisms.
- To enhance ornithopter stability and turbulence mitigation.
Main Methods:
- Developed a reduced-order multibody bond-graph model (BGM) including fluid-structure interaction (FSI).
- Implemented a hybrid control strategy with Linear Quadratic Regulator (LQR) and H2 controller.
- Utilized gain-scheduled transition for seamless controller switching in varying gust conditions.
Main Results:
- Simulations showed up to 70% reduction in gust-induced oscillations.
- Achieved 32% gust-mitigation efficiency through NFCD feather actuation and hybrid control.
- Stabilized the ornithopter in under 1.4 seconds during high-intensity gusts.
Conclusions:
- The LQR-H2 governed NFCD offers a viable solution for gust-tolerant ornithopters.
- Merging biomimetic aerodynamics and advanced control enhances flight stability in unsteady environments.
- The approach provides a pathway for resilient and stable flight in challenging atmospheric conditions.
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