In laparoscopic surgery, operators can use only rod-shaped forceps and therefore high techniques are required. To overcome this problem, much work has been done to develop multi-dof forceps. However they are still inappropriate to handle or retract large objects like organs. This paper proposes mechanical hands that can be assembled in the abdominal cavity. Each part is inserted through trocars. Two types of such three-fingered hands are developed. The three fingers of one are independently driven and those of the other are not. Experimental results verify that both hands can grasp a large and oily objects like organs. The goal of this study is to develop robot hands that can replace HALS (Hand-Assist Laparoscopic Surgery).
