Robotic surgical assistant systems can transcend the precision of surgical procedure by integrating the position information of patient and robot in the surgical room. There are two conventional integration methods, the real-time position tracking and physically fixing. In clinical cases, the former has the problem of increasing radiation exposure; so physical fixation is more commonly used in robotic surgery. However, the conventional fixing methods are also not optimized and problems of invasiveness and rigidness of fixation are left unsolved.This paper deals with a body-mounted surgical assistance robotic system for percutaneous vertebroplasty. The robot is fixed on the human body surface by fixing device that utilizes jamming transition phenomenon and vacuum cup. The bodymounted robot system sets up the correct pathway for needle insertion. The system was fixed on human shape target with a 166±8 N suction force. The fixing rigidity of our system and accuracy of the needle guide control device has been evaluated by measuring the displacement during needle inserting operation. The displacement of the fixing device by the external force of needle inserting operation was 0.06 mm and 0.02 • in RMS. The total displacement of needle guide was 1.66 mm and 1.24 • in RMS. The total positioning error of the needle guide control device was 0.09 mm and 0.97 • in RMS.

This paper presents a versatile method to install a small machining robot onto a planar or slightly curved object. Normally, gripping tools provide a rigid connection between a robot and a target. However, if there is no graspable area on the target, the gripper cannot perform well. To overcome this problem, we proposed a deformable device that works as a universal suction pad and that can hold an ungraspable target by utilizing the jamming transition phenomenon. We determined the effect of the type of grains on the jamming transition phenomenon in terms of stability under jammed conditions. By comparing the four types of grains, we found that the tetrahedral-shaped grains performed the best. Subsequently, we evaluated the performance of the device. The suction force was 166-N when the proposed device was affixed to a curved target. Next, we evaluated the stiffness of the device. The average deformations of the device were 0.10 mm, 0.35 mm, and 0.04 mm, respectively, when 50-N downward vertical, horizontal, and upward vertical directional loads were applied to the device, which was affixed to the curved target. The results suggest that the proposed device performed well in affixing a robot onto a target.

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The requirement of safe child delivery is increasing in developed countries in these decades. We have developed an obstetric forceps contouring the infant's head surface with stiffness-controlled pads. The stiffness of the pad is controlled by using air pressure regulation based on jamming transition. The proposed forceps has two soft material pads facing to the infant's head. The proposed forceps is first thin to get safely inserted into the delivery cavity. The granular tetrapod particles are then injected into the pads to contour the infant's head surface. By vacuuming the inside air of the pads, the particles interlock each other and the pads move onto the solid-like phase. In the experiments, the proposed method worked effectively to decrease the pressure onto the infant's head during delivery assistance and consequently made the operation safer.