Design of Supernumerary Robotic Limbs for the Augmentation of Astronauts Performing Partial-Gravity Extra-Vehicular Activities (EVAs)

Erik Ballesteros

Keywords: Supernumerary Robotic Limbs, wearable robotics, human augmentation, EVA, astronaut fall recovery, design optimization

TL;DR: A pair of wearable robotic extra-limbs, optimized via biomechanical modeling and two-staged rigorous design search, enable suited astronauts to recover from falls on the Moon — reducing physical burden by up to 55%.

Abstract:

This paper presents a design methodology for Supernumerary
Robotic Limbs (SuperLimbs)—wearable robotic
appendages intended to augment astronauts performing partial-gravity
Extra-Vehicular Activities (EVAs) on the Moon. NASA
has identified post-fall recovery as a high-risk process requiring
an effective countermeasure. Human studies reveal that suited
astronauts converge on a deterministic, sagittal-plane recovery
path. A quasi-static biomechanical model quantifies the joint torque
gap between what a suited astronaut can exert and
what the task demands. A two-phase design optimization-coarse grid
backtracking search over 5.4 million permutations followed by fine grid
localized parameter sweep-identifies a 4-degree-of-freedom
SuperLimbs kinematic structure that minimizes actuator energy
dissipation and CoM tracking error. The resulting Earth prototype,
built at an anonymous research laboratory, successfully
demonstrates a full prone-to-upright recovery and reduces the
load borne by a human wearer by up to 55%. Critically,
the deterministic recovery trajectories uncovered by this work
provide a structured foundation for developing autonomous
SuperLimbs control, enabling robots to act as intelligent safety
partners for astronauts in future planetary missions.

Submission Number: 3