Control Strategy for Direct Teaching of Non-Mechanical Remote Center Motion of Surgical Assistant Robot with Force/Torque Sensor

Abstract

This paper presents a control strategy that secures both precision and manipulation sensitivity of remote center motion with direct teaching for a surgical assistant robot. Remote center motion is an essential function of conventional laparoscopic surgery, and the most intuitive way a surgeon manipulates a robot is through direct teaching. The surgical assistant robot must maintain the position of the insertion port in three-dimensional space during the four-degree-of-freedom motions such as pan, tilt, spin, and forward/backward. In addition, the robot should move smoothly when controlling it with the hands during the surgery. In this study, a six-degree-of-freedom collaborative robot performs the cone-shaped trajectory with pan and tilt motion of an end-effector keeping the position of the remote center. Instead of the bulky mechanically constrained remote center motion mechanism, a conventional collaborative robot is used to mimic the wrist movement of a scrub nurse. A force/torque sensor that is attached between the robot and end-effector estimates the surgeon’s intention. A direct teaching control strategy based on position control is applied to guarantee precise remote center position maintenance performance. A motion generation algorithm is designed to generate motion by utilizing a force/torque sensor value. The parameters of the motion generation algorithm are optimized so that the robot can be operated with uniform sensitivity in all directions. The precision of remote center motion and the torque required for direct teaching are analyzed through pan and tilt motion experiments.

Robotics in laparoscopic surgery - A review

“…The firm grasping algorithm and force control combine position measurements with force measurements to ensure that the gripper firmly grasps the [191]. [192]. surgical tool.…”

“…A control strategy for RCM and direct teaching is proposed in ref. [192] that enables the surgical robot to mimic the movements of a nurse's wrist. The assistant robot has an end-effector attached to a 6-joint cooperative robot that holds the laparoscope.…”

Force-Free Control for Direct Teaching of a Surgical Assistant Robot End Effector with Wire-Driven Bidirectional Telescopic Mechanism

“…To derive a static model, the tension model of the first wire and the tension of the second and third wires are divided, as shown in Figure 4. The tension T 1 received by the first wire is determined by the weight M 1 of the first slide and the external force F 1 received by the first slide, as shown in Equation (1). The external force F 1 received by the first slide is determined by the weight M 2 of the second slide and the additional load M ext and the external force F ext applied to the second slide, as shown in Equation (2).…”

“…For efficient motion distribution, the cooperative robot maintains a remote center position and serves to control the orientation of the surgical tool, and the end effector can move back and forth by inserting the surgical tool. In this work, we developed an end effector specialized for surgical support for a commercial collaborative robot, and mounted it as shown in Figure 1a [1]. First, the cooperative robot is manipulated so that the trocar-a port for laparoscopic surgery-can be attached to the trocar mounting of the end effector attached to the end of the cooperative robot.…”

Special Issue on Advances in Bio-Inspired Robots

“…A novel transmission is proposed for DC motor-based flapping-wing micro aerial vehicles. The proposed origami-based fabrication method reduces the number of relative moving components by replacing rigid links and pin joints with facets and folding joints, which shortens the assembly process and reduces friction between components [3].…”