Soft-landing on planetary surfaces is the main challenge in most space exploration missions. In this work, the dynamic modeling and simulation of a three-legged robotic lander based on variable radius drums are presented. In particular, the proposed robotic system consists of a non-reversible mechanism that allows a landing object to constant decelerate in the phase of impact with ground. The mechanism is based on variable radius drums, which are used to shape the elastic response of a spring to produce a specific behavior. A dynamic model of the proposed robotic lander is first presented. Then, its behavior is evaluated through numerical multibody simulations. Results show the feasibility of the proposed design and applicability of the mechanism in landing operations.
