Background: Sensing the grasping force and displaying the force for the operator are important for safe operation in robot‐assisted surgery. Although robotic forceps that senses the force by force sensors or driving torque of electric motors is proposed, the force sensors and the motors have some problems such as increase in weight and difficulty of the sterilization. Method: We developed a pneumatically driven robotic forceps that estimates the grasping torque and display the magnified torque for the operator. The robotic forceps has a master device and a slave robot, and they are integrated. In the slave side, the grasping torque is estimated by the pressure change in the pneumatic cylinder. A pneumatic bellows display the torque through a linkage. Results: We confirmed that the slave robot follows the motion of the master, and the grasping torque is estimated in the accuracy of 7 mNm and is magnified and displayed for the operator. Conclusions: The pneumatically driven robotic forceps has the capability in the estimation of the grasping torque and display of the torque. Regarding future work, the usability and fatigues of the surgeons must be evaluated.

In this study, we developed a vertical articulated robotic arm for laparoscopic surgery and proposed a method of controlling the robot. The robotic arm operates surgical instruments around a virtually fixed remote center of motion (RCM) calculated from the robot kinematics. The robotic arm has six degrees of freedom and is driven by pneumatic actuators. The features of the pneumatic actuators of compactness, high backdrivability, and low heat generation allow the robotic arm to be moved passively by the human hand and prevent the risk of heat accumulation in the drape. We made the upper arm and forearm lightweight by mounting the pneumatic actuators on the base of the robot. The joint angles are controlled by pneumatic servo systems. The inertia of the forearm and upper arm was estimated by measuring the joint angles. We also proposed variable gain control of the yaw joint to compensate for changes in inertia. We experimentally confirmed that the variable gain improves the controllability of the robot and improves its operability around the virtual fixed RCM.

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