Identification of Multiple Limbs Coordination Strategies in a Three-Goal Independent Task

Many surgical tasks require three or more tools operating together. A supernumerary robotic arm under the surgeon’s control could enable one surgeon to control three surgical tools simultaneously without assistance, thereby avoiding the common communication errors of the operation room. However, how do humans consider the complexity of controlling more than two arms together? In this paper, the coordination strategy used during three limb independent motion tasks is studied. The level of coordination increased over a two-day pilot study, and the resulting coordination pattern was in general consistent within subjects. Whether the subject used a fixed order of targets or a random sequence was found to reduce the improvement of pattern consistency after practice. The foot-controlled third hand exhibited less consistent patterns.