Dynamics of Oleo-Pneumatic Landing Gear Systems for Carrier-Based Unmanned Aerial Vehicles

This paper presents a comprehensive analysis of the dynamics and design of oleo-pneumatic shock absorbers for the landing gear of carrier-based Unmanned Aerial Vehicles (UAVs). Carrier-based operations impose unique challenges due to high-impact landings, necessitating robust landing gear systems capable of withstanding significant g-forces. The study investigates the performance of landing gears designed for carrier operations under various sink rates, utilizing computer simulations to model the dynamics of both sprung and unsprung masses. The design process for an oleo-pneumatic main landing gear of an 8500 kg UAV includes detailed calculations for stroke, shock absorber strut sizing, spring and damping characteristics, and impact force analysis. The research employs both isothermal and adiabatic models to evaluate the variation in pneumatic pressure and air spring force under static and dynamic loadings, revealing the nonlinear behavior of the shock absorber. The damping characteristics are thoroughly analyzed, demonstrating the superior performance of oleo-pneumatic systems in vibration damping. The simulation results confirm that the current design effectively mitigates impact forces, maintaining vertical accelerations within the design constraints and ensuring structural integrity during landing maneuvers. Key findings include the ability of the shock absorber to handle high sink rates typical of carrier-based operations, with calculated vertical accelerations and force values indicating robust performance. The study identifies areas for future research, such as the development of automated loads and stress analysis tools for rapid weight quantification, exploration of active control systems for vibration alleviation, and potential benefits of multi-service applications for landing gear designs. By addressing the challenges of performance and robustness in carrier-based operations, this research advances landing gear technology for UAVs, enhancing their safety and efficiency in various operation environments. The insights gained provide a solid foundation for optimizing landing gear systems, ensuring reliable performance under demanding conditions.