Robust and Modular Multi-Limb Synchronization in Motion Stack for Space Robots with Trajectory Clamping via Hypersphere

TL;DR

This paper introduces a robust, adaptable method for synchronizing multiple heterogeneous robotic limbs within a modular space robot framework, ensuring smooth motion and disturbance recovery using hypersphere constraints.

Contribution

The study presents a novel, robot-agnostic synchronization approach based on hypersphere constraints, integrated into the open-source Motion-Stack framework for modular robotic systems.

Findings

Successfully synchronized six heterogeneous robotic limbs

Demonstrated robustness against external disturbances

Validated smooth trajectory adherence and recovery

Abstract

Modular robotics holds immense potential for space exploration, where reliability, repairability, and reusability are critical for cost-effective missions. Coordination between heterogeneous units is paramount for precision tasks -- whether in manipulation, legged locomotion, or multi-robot interaction. Such modular systems introduce challenges far exceeding those in monolithic robot architectures. This study presents a robust method for synchronizing the trajectories of multiple heterogeneous actuators, adapting dynamically to system variations with minimal system knowledge. This design makes it inherently robot-agnostic, thus highly suited for modularity. To ensure smooth trajectory adherence, the multidimensional state is constrained within a hypersphere representing the allowable deviation. The distance metric can be adapted hence, depending on the task and system under control, deformation of the constraint region is possible. This approach is compatible with a wide range of robotic platforms and serves as a core interface for Motion-Stack, our new open-source universal framework for limb coordination (available at https://github.com/2lian/Motion-Stack ). The method is validated by synchronizing the end-effectors of six highly heterogeneous robotic limbs, evaluating both trajectory adherence and recovery from significant external disturbances.