Multi-manipulation with a metamorphic instrumental hand for robot-assisted minimally invasive surgery

Human hand is an efficient manipulator in many aspects for multi-manipulation capability. This ability of hand is prevented from being employed in minimally invasive surgery (MIS) as in open surgery because human hand can´t get into patient abdomen through small incision. We have developed a 10-DOF robotic metamorphic instrumental hand (MIH) prototype as a physical carrier of multi-manipulation. It is expected to enhance manipulation in robot-assisted MIS. Inspired from metamorphic mechanism theory, structure of the instrumental hand is designed to be variable. It can pass patient´s abdomen skin in a straight cylinder shape through an incision of 24 mm in diameter. A three-fingered hand shape surgical device is rebuilt from this straight cylinder inside abdomen. The metamorphic instrumental hand is controlled with an isomorphic master glove. Master-slave mapping method is analyzed in system setup. Mapping errors are measured and compensated for the instrumental hand control. Eight preliminary manipulation experiments have been carried out on phantom tissue to validate multi-manipulation concept of this metamorphic instrumental hand.