Wearable Robots that physically connect people to improve joint performance. The results of the european project CONBOTS published in Science Robotics Journal
Robotics is expanding to physical human-human interactions: two exoskeletons connected two violinists, replicating direct physical contact between them. Haptic feedback improved motor coordination between the musicians compared to visual and auditory feedback.
Research study coordinated by Università Campus Bio-Medico di Roma with Scuola Superiore Sant’Anna di Pisa, IUVO, CNR, Newcastle University (UK) and Ghent University (Belgium).
What if two musicians performing together could do more than just seeing and hearing each other? What if they could also physically feel each other’s movements?
When two individuals perform a joint task, such as a violin duet, they rely primarily on visual and auditory cues to coordinate, as they cannot exploit physical contact. Yet physical contact is fundamental in social interactions: for instance, a violin instructor teaching a movement to a student may not simply demonstrate it, but might instead take the student’s arm and guide it toward the correct motion. Through physical contact, the body can receive and transmit motion-related information—often even more efficiently than one might expect—as demonstrated by a recent international study published in the prestigious journal Science Robotics.
The study, coordinated by Università Campus Bio-Medico di Roma, sheds new light on this phenomenon by demonstrating that haptic feedback—the sense of touch and physical interaction forces—can enhance coordination in fine motor tasks, such as violin duets, even more effectively than vision and audition, which musicians traditionally rely on during performance. The research also involved Scuola Superiore Sant’Anna in Pisa, its spin-off company IUVO Srl, the Italian National Research Council (CNR), Newcastle University (UK), and Ghent University (Belgium). It was conducted within the framework of the European project CONBOTS (“CONnected through roBOTS”), coordinated by Professor Domenico Formica and funded by the European Union with nearly €5 million under the Horizon 2020 programme.
To replicate physical contact between two violinists in a context where it is normally absent, the CONBOTS team developed a pair of upper-limb wearable exoskeletons capable of measuring each musician’s movements and, whenever discrepancies arise, applying forces proportional to the difference between them. In this way, the exoskeletons virtually couple the two performers, allowing them to physically perceive their partner’s movements and effectively simulating direct physical interaction.
The team tested the system with twenty violin duos—ten amateur and ten professional—who performed a musical piece under four sensory feedback conditions: hearing each other; hearing and seeing each other; hearing and feeling each other through haptic feedback; and hearing, seeing, and feeling each other. The musicians were unfamiliar with the exoskeletons and were not informed that they were physically coupled. Nevertheless, in the presence of haptic feedback, coordination improved significantly: the performers aligned their arm movements more precisely, synchronized their bow positions more tightly, and achieved greater musical synchrony.
Surprisingly, exoskeleton-mediated haptic feedback enhanced coordination more effectively than visual feedback, even though violinists are extensively trained to rely on vision during duo performances. The most significant improvements were observed when all three forms of sensory feedback were combined, highlighting the role of multisensory integration in fine sensorimotor tasks.
The results of the CONBOTS project suggest that haptic feedback can serve as an effective communication channel in collaborative tasks due to its implicit nature. Unlike visual cues, which require conscious attention, haptic feedback is embodied and immediate, enabling partners to adapt to each other’s movements in a more reflexive manner. Beyond music, this approach could have broader implications for a wide range of collaborative activities, including those involving motor learning.
Statements
“We are entering an era in which robots can mediate physical communication between humans in entirely new ways,” adds Professor Domenico Formica of the Research Unit of Neurophysiology and Neuroengineering of Human–Technology Interaction (NeXTlab) at Università Campus Bio-Medico di Roma and coordinator of the study. “This study represents a first step toward physically connecting systems designed to enhance coordination, learning, and rehabilitation.”
“Haptics, or the tactile and kinesthetic perception, provides information in a fundamentally different way from vision,” explains Francesco Di Tommaso, postdoctoral researcher in the Research Unit of Advanced Robotics and Human-Centred Technologies (CREO Lab) at Università Campus Bio-Medico di Roma. “It is physical, direct, and immediate. Our results suggest that the human motor system can integrate this information very efficiently, even in highly skilled artists.”
“These wearable robots,” says Professor Nicola Vitiello, Rector of Scuola Superiore Sant’Anna and head of the research group that designed the exoskeletons for this experiment, “could support collaborative training, motor learning, and even rehabilitation, where therapists and patients could be physically coupled.”
“It’s a breakthrough in our understanding of the embodied nature of human interaction with music” says Emeritus Professor Marc Leman, former head of IPEM-Musicology and the Art and Science Interaction Laboratory (ASIL) at Ghent University where the testing took place, “Feeling each other’s movements during music playing empowers the synchronisation of joint timing tasks in a way that is more powerful than expected, allowing for applications beyond music, in domains that may involve action coordination at a distance.”
