ORIGINAL RESEARCH article
Front. Robot. AI
Sec. Human-Robot Interaction
Volume 12 - 2025 | doi: 10.3389/frobt.2025.1660691
Effect of Presenting Robot Hand Stiffness to Human Arm on Human-Robot Collaborative Assembly Tasks
Provisionally accepted- 1Nara Institute of Science and Technology (NAIST), Ikoma, Japan
- 2Kyushu Daigaku, Fukuoka, Japan
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In response to the growing need for flexibility in handling complex tasks, research on human–robot collaboration (HRC) has garnered considerable attention. Recent studies on HRC have achieved smooth handover tasks between humans and robots by adaptively responding to human states. Collaboration was further improved by conveying the state of the robot to humans via robotic interactive motion cues. However, in scenarios such as collaborative assembly tasks that require precise positioning, methods relying on motion or forces caused by interactions through the shared object compromise both task accuracy and smoothness, and are therefore not directly applicable. To address this, the present study proposes a method to convey the stiffness of the robot to a human arm during collaborative human-robot assembly tasks in a manner that does not affect the shared object or task, aiming to enhance efficiency and reduce human workload. Sixteen participants performed a collaborative assembly task with a robot, which involved unscrewing, repositioning, and reattaching a part while the robot held and adjusted the position of the part. The experiment examined the effectiveness of the proposed method, in which the robot’s stiffness was communicated to a participant’s forearm. The independent variable, tested within-subjects, was the stiffness presentation method, with three levels: without the proposed method (no presentation) and with the proposed method (real-time and predictive presentations). The results demonstrated that the proposed method enhanced task efficiency by shortening task completion time, which was associated with lower subjective workload scores.
Keywords: Human-robot collaboration, Human-robot Interactions, Human-MachineTeaming, human-machine interface, assembly task, Robotics
Received: 06 Jul 2025; Accepted: 06 Oct 2025.
Copyright: © 2025 Yamamoto, Tahara and Wada. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Takahiro Wada, t.wada@is.naist.jp
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