Whole-Body Control for Autonomous Landing of Unmanned Helicopter Equipped With Antagonistic Cable-Driven Legged Landing Gear

Traditional skid or wheeled landing gears fall short in meeting the rigorous requirements of challenging surfaces, such as rugged terrain and swaying deck, which restraints the application in extreme tasks including disaster rescue, cargo transportation as well as ship-relevant operations. This letter proposes a novel legged landing gear scheme for the unmanned helicopter in dealing with terrain irregularity by fully leveraging the antagonistic mechanism of cables to effectively reduce the power demand of indispensable actuators. The tailored control framework combining the whole body control (WBC) and the contact force optimization is developed for the legged landing gear to ameliorate internal force conflicts amongst individual legs at the landing stage. Experiments on an unmanned helicopter prototype are conducted to demonstrate the effectiveness of the legged landing gear in achieving stable slope landing and fuselage posture adjusting, enhancing the adaptation of the unmanned helicopter in unstructured environments.