New remote centre of motion mechanism for robot-assisted minimally invasive surgery

Xiaoqin Zhou,Yili Fu,Ji Zhao,Haijun Zhang,Mei Feng

doi:10.1186/s12938-018-0601-6

Xiaoqin Zhou, Yili Fu + Show 3 more

Open Access

https://doi.org/10.1186/s12938-018-0601-6

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Abstract

BackgroundRobot-assisted minimally invasive surgery (RMIS) is promising for improving surgical accuracy and dexterity. As the end effector of the robotic arm, the remote centre of motion mechanism is one of the requisite terms for guaranteeing patient safety. The existing remote centre of motion mechanisms are complex and large in volume, as well as high assembly requirement and unsatisfactory precise. This paper aimed to present a new remote centre of motion mechanism for solving these problems.MethodsA new mechanism based on the RMIS requirements is proposed for holding the laparoscope and generating a remote centre of motion for the laparoscope. The mechanism kinematics is then analysed from the perspective of the structural function, and its inverse kinematics is determined with a small number of calculations. Finally, the position deviation of the laparoscope rotational point is chosen as the index to evaluate the mechanism performance. The experiments are performed to test the deviation.ResultsThe position deviations of the laparoscope rotational point do not exceed 2 mm, which is lower than that of the existing remote centre of motion mechanism. The 2 mm positioning error of the laparoscope won’t affect surgeon observation of the surgical field, and the pressure caused by the positioning error was acceptable for the skin elasticity. The proposed mechanism meets the RMIS requirement.ConclusionsThe proposed mechanism can achieve the remote centre of motion for the laparoscope. Its simple and compact structure is beneficial to avoid the collision of robotic arms, and it can be applied on other robots for providing the instrument necessary motion in minimally invasive surgery.

Highlights

Robot-assisted minimally invasive surgery (RMIS) has had a revolutionary impact on surgery, having the ability to satisfy the requirements of higher precision and dexterity for surgery operations
In view of the importance of safety for MIS, this paper reports realisation of remote centre of motion (RCM)-based motion using the mechanical approach
As mentioned above, during surgery, to alleviate patient skin stress, the fixed point achieved by the mechanical structure of RCM mechanism is set to keep the coincidence with the incision port, to evaluate the mechanism “certring” performance under the Results The experimental results in Fig. showed that the position deviations of the testing point in the group 1 and 2 experiments were not greater than 1.5 mm while the joints moved from the zero position to the left and right limited positions, and Fig. showed the position deviation and its components in group 3 in every step

Summary

Introduction

Robot-assisted minimally invasive surgery (RMIS) has had a revolutionary impact on surgery, having the ability to satisfy the requirements of higher precision and dexterity for surgery operations. In traditional minimally invasive surgery (MIS), a surgeon holds instruments to perform a surgical operation [1]. The concept of the remote centre of motion (RCM) has been devised to describe the pitching and yawing movements around the incision port [6], and RCM generation is one of the requisite terms for an MIS robot that is directly related to patient safety. Robot-assisted minimally invasive surgery (RMIS) is promising for improving surgical accuracy and dexterity. As the end effector of the robotic arm, the remote centre of motion mechanism is one of the requisite terms for guaranteeing patient safety. This paper aimed to present a new remote centre of motion mechanism for solving these problems

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Results