Observer based dynamic control model for bilaterally controlled MU-lapa robot: Surgical tool force limiting

During laparoscopic surgeries, primary surgical tool insertion is the demanding and strenuous task. As the surgeon is unaware of the type of the tissue and associated parameters to conduct the insertion, therefore, to ease the procedure, the movement of the surgical tool needs to be controlled. It’s the operational capabilities that are to be manipulated to perform a smooth surgery even from a distant location. In this study, a robot system is being introduced for laparoscopic primary surgical tool insertion. It will incorporate a novel observer based dynamic control along with robot assisted bilateral control. Moreover, a virtual spring damper force lock system is introduced through which the slave system will notify the master regarding the target achieved and excessive force. The validation of the proposed control system is experimented with bilaterally controlled MU-LapaRobot. The experiment is comprising 3 cases of bilateral control criteria which are non-contact motion, contact motion, and limit force locking. The results defined the same value for contact and non-contact motion by 0.3N. The results depicted a force error of 3.6% and a position error of 5.8% which validated the proposed algorithm

Scaling Method of Force Feedback for Laparoscopic Surgical Robot Using Dynamics of Forceps tip

The field of laparoscopic surgery has significantly developed recently due to the development of new techniques as well as the use of various surgical robots. The da Vinci robot developed by Intuitive Surgical Inc. is currently the most advanced surgical robot. This is a master–slave robot with plural robot arms, stereoscopic imaging by the 3D endoscope, and manipulators that imitate the movement of human wrist with sevendegrees of freedom (DOF) by the wire drive. Moreover, in recent years, with the increasing development of laparoscopic surgery, single-port surgery (SPS) has gained significant popularity. This procedure is more cosmetically favorable than the conventional laparoscopic surgery. SPS that was conducted using the da Vinci robot by replacing manipulators with those with the SPS’s capable shape is reported. However, da Vinci robot for SPS is not yet in clinical use. To date, medical accidents have been reported during laparoscopic surgery using the da Vinci robot because the robot is unable to provide force feedback to the surgeons. Force feedback is known to have many benefits such as the improvement of the surgeon’s dexterity and the enhancement of the operability of surgical robots in telesurgery. To solve this issue of the current surgical robots, in this study, a six-axis force and torque sensor produced by ATI Co. is attached on an independently developed SPS forceps manipulator. The sensor detects an external force at the tip or shaft of the forceps manipulator, enabling the realization of force feedback by using haptic function of the Omega 7 master device produced by Force Dimension Co. Moreover, a new scaling method based on the beam theory is proposed to enable the improvement of the performance of the force feedback in various laparoscopic surgical robots beyond the SPS robot. Specifically, the detected force is amplified using the proposed scaling method and the amplified force is realized through the haptic device Omega 7. Experiments were conducted to verify the effectiveness of the proposed scaling method. The results showed that the operator of the surgical robot can experience a small force that was applied to the forceps more clearly and quickly compared with that realized when the conventional constant scaling method was used.修士(工学)法政大学 (Hosei University