Multi-DOF forceps manipulator for an approach to the dorsal aspect of an organ

Recently, minimally invasive surgery that reduces the patient's burden is under development. In cardiovascular surgery, these techniques are also used as minimally invasive direct coronary artery bypass grafting and robotassisted coronary artery bypass grafting. The forceps manipulator of a conventional surgical robot has a long, straight shaft equipped with a gripper or knife. Therefore, the approach path from the incision on the surface of the body to the lesion is straight. When surgical site is on the dorsal aspect of the heart, the approach path is not a straight line. It is difficult to treat lesions with the conventional forceps manipulator. In this paper, a prototype of the forceps manipulator, which allows an approach to the dorsal aspect of an organ, is proposed. The developed forceps manipulator has an additional elbow joint. It has 3 degrees of freedom in assuming the position and posture (bending, winding, and twisting) and a gripper to allow fine-enough manipulation. In addition, we evaluate the accuracy of the angle of the bending motion. As a result, the error is within 1.7 degrees by backlash compensation.