Two is not always better than one: Effects of teleoperation and haptic coupling

Human-human dyads have been shown to out-perform individuals in a variety of movement tasks and develop specialized roles through haptic communication. Dyadic collaboration is a promising approach for teleoperated tasks that can benefit from the collaboration of multiple agents. In teleoperation, haptic communication depends on physical properties of the master and slave manipulators, as well as control parameters for position tracking and haptic feedback. We performed experiments to compare the performance of dyads and individuals in a teleoperated 1-degree-of-freedom target acquisition task using the da Vinci Research Kit surgical robot platform. In order to test the role of haptic communication in the collaborative task, two modes of force feedback were implemented for the dyad trials: a strong haptic coupling between the two master manipulators that attempts to simulate a physical link, and a weak haptic coupling that relates position differences through a soft linear spring. Results showed that participants were not able to improve their performance significantly by collaboration, and role specialization was not observed. We hypothesize that this result is due to limited haptic feedback and the dynamics of the teleoperated system. However, we demonstrated that most users accommodated to their partners to some extent, and users who had similar individual performance were more likely to improve as dyads.