Rotorcraft Hard Landing Mitigation Using Robotic Landing Gear

Abstract

A unique, beneficial feature of rotorcraft is their flexibility in aircraft-to-ground interfacing. For a variety of reasons, hard landings can occur when the descent rate of the aircraft is larger than intended. The resulting impact can result in vehicle damage, structural failure, injuries, etc. To reduce these risks, an attractive solution is the implementation of a robotic legged landing gear (RLLG) system. The system softens a hard landing by acting as a shock absorber with a relatively large stroke, allowing the aircraft to decelerate over a much larger distance compared with a tradition landing gear system. This paper explores the mitigation of rotorcraft hard landings via RLLG through a comprehensive multibody dynamics simulation tool. The purpose of this study is to demonstrate the efficacy of the RLLG as a robust solution to reduce loads during hard landings for multiple landing configurations. The results show that when using RLLG in place of conventional landing gear, peak loads are reduced by approximately 70–90%, depending on the landing conditions. Through Monte Carlo simulation, robotic landing gear system performance is shown to be robust to uncertain conditions.

Crashworthy design and energy absorption mechanisms for helicopter structures: A systematic literature review

“…15 presents the landing process of a helicopter equipped with RLLG. Compared with the traditional landing gears, the shock absorber of RLLG has a larger stroke, leading to a much larger deceleration distance [156].…”

On the Evaluation of a Coupled Sequential Approach for Rotorcraft Landing Simulation

“…In recent years the application of automated robotic landing gears has seen the light. For instance, in [30] a novel solution for the hard landing mitigation is proposed: the implementation of a robotic legged landing gear system, which aims at softening the hard landings by acting as a shock absorber with a relatively large stroke, thus allowing the aircraft to decelerate over a much larger distance compared with a traditional landing gear system. The investigation of such a system was explored using a multibody dynamics simulation tool.…”

Rotorcraft Dynamic Platform Landings Using Robotic Landing Gear

“…Manivannan's concept and theoretical design provided a replacement to skid gear with three or four articulating legs that enabled rotorcraft landings on sloped or rugged static surfaces. This RLG design concept was shown by Kiefer et al [26] to reduce peak loads on rotorcraft occupants through active control of the legs so they act as adaptive shock absorbers. An experimental flight vehicle based on Manivannan's work demonstrated, in a limited fashion, the viability and capability of RLG for rotorcraft on a 120 kg unmanned helicopter using a four-legged design [27].…”