Rotorcraft Dynamic Platform Landings Using Robotic Landing Gear

Articulating landing gear that use closed-loop feedback control are proven to expand the landing capabilities of rotorcraft on sloped and rough terrain. These systems are commonly referred to as robotic landing gear (RLG). Modern RLG systems have limitations for landing on dynamic platforms because their controllers do not incorporate fuselage roll and roll rate feedback. This work presents a proven crashworthy cable-driven RLG system for the commercial S-100 Camcopter that expands static landing zone limits by a factor of three and enables dynamic platform landings in rough sea state (SS) conditions. A new roll and foot-force feedback fused control algorithm is developed to enable ship deck landings of an RLG equipped S-100 without the need for deck lock or advanced vision-based landing systems. Multibody dynamic simulations of the aircraft, landing gear, and new control system show the benefits of this combined roll and force feedback approach. Results include experimental dynamic landings on platforms rolling under sinusoidal motion and simulated SS conditions. The experiments demonstrate, in a limited fashion, the usability of the RLG through ground experimentation, and the results are compared to simulations. Additional simulations of landings of the S-100 with rigid and active landing gear with more challenging landing conditions than experimentally tested are presented. Such results aid in understanding how RLG with this new roll and contact force fused controller prevent dynamic rollover.

Automated summary

Closed-loop feedback control articulating landing gear, also known as robotic landing gear (RLG), have been proven to increase rotorcraft landing capabilities on sloped and rough terrain. However, modern RLG systems have limitations for landing on dynamic platforms due to a lack of fuselage roll and roll rate feedback. This study presents a cable-driven RLG system for the S-100 Camcopter which expands landing zone limits and enables dynamic platform landings in rough sea state conditions. An innovative roll and foot-force feedback fused control algorithm is developed for ship deck landings without the need for advanced vision-based landing systems.