How a lot can an autonomous robotic arm really feel like a part of the physique

Summary

When AI powered prosthetic arms that transfer autonomously turn into widespread, understanding how individuals really feel about them and settle for them can be essential. In this examine, we used digital actuality to simulate a scenario during which a participant’s personal arm was changed by a robotic prosthetic arm, and examined how the prosthesis motion pace impacts embodiment, together with physique possession, the sense of company, usability, and social impressions of the robotic reminiscent of competence and discomfort. We discovered that each overly quick and overly sluggish actions lowered physique possession and usefulness, whereas a average pace near pure human reaching, with a motion length of about one second, produced essentially the most optimistic impressions.

Contents

When an individual loses a hand or arm, prosthetic limbs are important applied sciences for sustaining on a regular basis operate. To date, a lot prosthetics analysis has centered on management strategies that allow the machine to maneuver in response to the person’s intention, usually through the use of biosignals reminiscent of electromyography (EMG) and electroencephalography (EEG), and on bettering the accuracy of such management. Meanwhile, advances in machine studying and AI are making it more and more practical that future prostheses will assess the scenario and supply help by way of autonomous or semi-autonomous actions. However, when a physique half strikes independently of 1’s will, persons are prone to expertise it as “unsettling” or “not part of my body,” creating a significant barrier to acceptance.

Addressing this problem, prior work has advised that even when a limb strikes by itself, discomfort might be lowered and acceptance as a part of the physique can enhance when the motion’s objective or intention is comprehensible. Building on this concept, Harin Manujaya Hapuarachchi and his colleagues (Hapuarachchi was a doctoral scholar on the time of the examine and is now an Assistant Professor within the School of Informatics at Kochi University of Technology) centered on motion pace. In digital actuality, we offered an avatar whose left forearm was changed with a prosthetic limb, and individuals carried out a reaching process. The prosthetic arm (a digital forearm) autonomously flexed towards a goal, and we systematically assorted its motion length throughout six ranges (125 ms to 4 s). After every situation, individuals rated physique possession, sense of company, usability (SUS), and social impressions of the robotic (RoSAS: competence, heat, and discomfort).

The outcomes have been clear.

• At a average pace (motion length of 1 s), physique possession, company, and usefulness have been highest.

• In the quickest (125 ms) and slowest (4 s) situations, physique possession, company, and usefulness have been considerably decrease.

• Perceived competence was increased at average to barely quicker speeds, whereas discomfort was highest within the quickest situation. Warmth didn’t present a transparent dependence on pace.

These findings point out that, in a future the place AI enabled prostheses present autonomous help, it isn’t adequate to pursue quicker and extra correct efficiency alone. Instead, motion pace must be designed to match what individuals can readily settle for as a part of their very own physique.

The insights might inform not solely the design of autonomous prosthetic arms, but in addition different types of robotic physique augmentation, reminiscent of supernumerary robotic limbs, exoskeletons, and wearable robots, that function as purposeful extensions of the physique.

Looking forward, we may also look at adaptation and studying by way of long-term use. People can come to expertise acquainted instruments as in the event that they have been a part of their physique. If a quick and correct robotic physique half is used repeatedly in day by day life, it could turn into “normal,” really feel simpler to make use of, and be extra readily embodied.

Finally, utilizing VR is essential as a result of it permits researchers to soundly simulate prosthetic applied sciences and management schemes that aren’t but extensively accessible, enabling the psychological, acceptance-related, and design necessities to be evaluated upfront.

Funding company:

This analysis was supported by JSPS KAKENHI (JP22KK0158), the Murata Science and Education Foundation, JST (JPMJFS121), and MEXT (202334Z302).

Reference:

Hapuarachchi, H., Inoue, Y., Shigemasu, H., & Kitazaki, M. (2026).

Movement pace of an autonomous prosthetic limb shapes embodiment, usability and robotic social attributes in digital actuality.

Scientific Reports (Published: 07 February 2026).

DOI: 10.1038/s41598-026-38977-8