A New Human-Likeness and Comfort Index for Robot Movements Along Prescribed Paths
2026-07-09 • Robotics
Robotics
AI summaryⓘ
The authors studied why people feel comfortable or not when interacting physically with robots. They found that just looking like a human isn’t enough; the way a robot moves matters a lot. They created a way to measure how human-like a robot's movements are using a math model of human motion. Then, they showed that people generally feel more comfortable when robot movements score higher on this human-likeness scale. This means better movement design can help robots be accepted more easily.
human-robot interactionrobot acceptancehumanoid robotscomfortergonomicskinematicsend-effectorlognormality principletrajectory generationhuman-likeness index
Authors
Rosanna Coccaro, Enrico Ferrentino, Antonio Parziale, Angelo Marcelli, Pasquale Chiacchio
Abstract
As human-robot interaction rapidly spreads in numerous fields, the subject of robot acceptance gains increasing importance. Visual similarity to the human body, as occurs for humanoids, is generally not enough to ensure acceptance in physical interaction, as acceptance directly links to comfort and ergonomics, which are measured in terms of the quality of the robot movement perceived by the human. This paper discusses the connection between comfort and similarity of the robot movement to the human one. By considering the kinematic characterization of human movement, this paper focuses on the time laws of such movements, wherein the end-effector path is prescribed. Based on the lognormality principle for modeling human movements, a human-likeness index is defined and used to provide an a priori characterization of trajectories. Such an index can be used to evaluate the performance of trajectory generation algorithms in producing human-like movements before they are actually executed. For validation purposes, 68 subjects are required to judge their comfort. The results of three experimental campaigns involving a physical interaction with a robot demonstrate a globally consistent trend between the preference in terms of perceived comfort and the distribution of the suggested human-likeness index.