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

With a third hand a human subject could be able to perform tasks that they would otherwise be incapable of. Foot-controlled interfaces have proven suitable for controlling robot arms, however, when it is best to use such devices and what limitations they place when controlling a supernumerary robotic limb (SL) in combination with the natural limbs (NLs) is unknown. Here, we report an investigation of three-handed manipulation with a foot interface. We analysed i) what effect the addition of a SL has on the performance of the NLs; and ii) how mechanical and/or cognitive coupling alters user performance. When the subjects moved the three limbs without coupling, only the motion's completion time was observed to be significantly affected. In contrast with coupling, the incorporation of the foot controlled hand was found to affect the success rate, and planning of the motion, however it did not affect motion characteristics such as smoothness.