Human Performance in Three-hands Tasks

Abstract

The successful completion of complex tasks like hanging a picture or laparoscopic surgery requires coordinated motion of morethan two limbs. User-controlled supernumerary robotic limbs (SL) have been proposed to bypass the need for coordination witha partner in such tasks. However, neither the capability to control multiple limbs alone relative to collaborative control with partners, nor how that capability varies across different tasks, is well understood. In this work, we present an investigation of tasks requiring three-hands where the foot was used as an additional source of motor commands. We considered: i) how does simultaneous control of three hands compare to a cooperating dyad; ii) how this relative performance was altered by the existence of constraints emanating from real or virtual physical connections (mechanical constraints) or from cognitive limits (cognitive constraints). It was found that a cooperating dyad outperformed a single user in all scenarios in terms of tasks core, path efficiency and motion smoothness. However, while the participants were able to reach more targets with increasing mechanical constraints/decreasing number of simultaneous goals, the relative difference in performance between a dyad and a participant performing trimanual activities decreased, suggesting further potential for SLs in this class of scenario.

Tri-Manipulation: An Evaluation of Human Performance in 3-Handed Teleoperation

“…Compared to the results of [15], which considered the same coupled motion task, the findings of this study suggests that with additional sessions to account for learning to perform trimanual actions, subject can prove similarly capable to a dyad. Throughout the practice phase learning was clearly observed in all metrics.…”

“…It was found that the addition of the foot controlled hand slowed operation time, however, when the hands acted independently of one another there was otherwise no reduced performance when the hands were uncoupled. The relative performance of trimanipulation was then compared to the use of multiple operators [15]. Three different levels of coupling between the hands were considered, where in all cases the couple outperformed a single trimanual subject.…”

“…In this paper, we extend the study of [15] to specifically account for the effect of learning on coupled tri-manipulation. We investigated i) the learning of tri-manipulation with the addition of supernumerary limb in a three hand coordination task; ii) compared the users' performance to dyadic operation of one person performing bi-manipulation and another person using their foot, and iii) studied the effect of an unpredictable environment on the operation.…”

Human movement augmentation and how to make it a reality

“…However, such coupling does result in reduced performance and when continuously tracking additionally leads to increased cognitive load [35]. Finally, when comparing subject performance to that of dyads, the dyad has to date outperformed the single user controlling an SE who had higher mental effort in all tested cases [105], [108]. However, the relative difference between results appears to reduce in coupled motion (all all dependent) [108], and might disappear when haptic feedback and some learning is provided [105], although users still reported increased mental effort.…”

How long does it take to learn trimanual coordination?

“…For trimanipulation to be beneficial in everyday life, it should enable users to perform tasks both independently of the natural limbs and in combination with them. The ability of users to perform trimanual coordination has only recently begun to be explored [9], [10]. These studies have shown that users can learn to perform trimanual reaching tasks with virtual foot-controlled supernumerary limbs.…”