Design of a Crashworthy Cable-Driven Four-Bar Link Robotic Landing Gear System

Abstract

In this work a novel crashworthy cable-driven four-bar link mechanism is designed, manufactured, and tested for the development of robotic landing gear for rotorcraft. The paper will demonstrate how combining two such mechanisms through a common driving cable leads to unique advantages in the kinematics of the system and reduced loads applied to the actuators driving the system. The results on the kinematics and static force distributions are presented for such a configuration and show that, for the rotorcraft class under consideration (220–440 lb, 100–200 kg), the leg mechanism can conform to ground slopes up to . A novel design, manufacturing, and a drop testing workflow that allows for rapid design and iteration of robotic landing gear are further developed. The workflow includes the design, simulation, rapid manufacturing, and crash-survivability testing through drop testing with a two week turnaround time for a full design iteration. With regard to rapid manufacturing, this work demonstrates the use of three-dimensionally printed acrylonitrile butadiene styrene mandrels for the production of fully functional carbon fiber polymer reinforced components. This paper concludes with actuation experiments to show practical performance capabilities of the final crashworthy robotic landing gear system designed.