Postural Virtual Fixtures for Ergonomic Physical Interactions with Supernumerary Robotic Bodies

Theodora Kastritsi; Marta Lagomarsino; Arash Ajoudani

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arXiv · 2601.22672

Postural Virtual Fixtures for Ergonomic Physical Interactions with Supernumerary Robotic Bodies

Theodora Kastritsi·Marta Lagomarsino·Arash Ajoudani

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Abstract

Conjoined collaborative robots, functioning as supernumerary robotic bodies (SRBs), can enhance human load tolerance abilities. However, in tasks involving physical interaction with humans, users may still adopt awkward, non-ergonomic postures, which can lead to discomfort or injury over time. In this paper, we propose a novel control framework that provides kinesthetic feedback to SRB users when a non-ergonomic posture is detected, offering resistance to discourage such behaviors. This approach aims to foster long-term learning of ergonomic habits and promote proper posture during physical interactions. To achieve this, a virtual fixture method is developed, integrated with a continuous, online ergonomic posture assessment framework. Additionally, to improve coordination between the operator and the SRB, which consists of a robotic arm mounted on a floating base, the position of the floating base is adjusted as needed. Experimental results demonstrate the functionality and efficacy of the ergonomics-driven control framework, including two user studies involving practical loco-manipulation tasks with 14 subjects, comparing the proposed framework with a baseline control framework that does not account for human ergonomics.

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Theodora Kastritsi, Marta Lagomarsino, Arash Ajoudani. 2026-01-30. Postural Virtual Fixtures for Ergonomic Physical Interactions with Supernumerary Robotic Bodies. https://arxiv.org/abs/2601.22672

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