Nowadays, surgical applications, entering the body through a small incision with laparoscopic procedures are performed and are expanding the use of robots for these operations. In existing systems, conventional robots are used for the body. Surgical procedure is carried out by a separate mechanism which is attached to the end of the robot and robot is used to positioning this mechanism. These mechanisms are called Remote Center of Motion (RCM) mechanism. In this paper, the literature on studies performed about the parallel, spherical and hybrid RCM mechanisms are examined and classified.

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Remote Center of Motion (RCM) Mechanisms for Surgical Operations

In surgical procedures such as brachytherapy, biopsies and drainages, how to precisely place the needle inside the body is crucial for the performance of such surgeries. In last two decades, robot-aided needle placement has gradually been a trend for better security and accuracy. However, existing successful medical robot systems leave some common drawbacks: expensive, bulky, and high operation complexity, which motivates the development of more compact, affordable, and functional robots. This paper introduces a novel robot based on a 2-CRRR-CRR parallel manipulator (PM) for single needle insertion with high accuracy, where C denotes a cylindrical joint and R a revolute joint. Via screw theory, the mobility of the robot is analyzed, which meets the requirement of remote-center-of-motion (RCM). Its kinematic analysis is presented and singular configurations are identified based on the Jacobian matrix. Furthermore, the link dimensions of the robot are optimized by considering motion/force transmissibility and practical limits to generate singularity-free and high-performance workspace around the incision point. The design and feasibility of the proposed robot are validated by preliminary motion experiments with a prototype. The two advantages of the proposed robot are a singularity-free workspace with good motion/force transmissibility and high rigidity due to three fixed linear actuators in parallel architecture.

Modeling, design and experiment of a remote-center-of-motion parallel manipulator for needle insertion

The purpose of this study is to design and manufacture a new remote center of motion (RCM) mechanism for use in laparoscopic surgical operations. In addition, obtaining the forward and inverse kinematic equations of the RCM mechanism and performing real-time position control with the Proportional–Integral–Derivative (PID) control method.,At the design stage, it is benefited from similar triangle rule. To obtain the kinematic equations in a simple way and facilitate control, two-fold displacement ratio is provided between the limbs where linear motion occurs. The rotation and displacement amounts required to move at the RCM point have been calculated by using the kinematic equations of the mechanism. Limb dimensions and motion limits are determined in the manner to avoid singularities and collisions. The x, y and z coordinates of the end effector have been defined as the reference point. Control of the mechanism was provided by PID control. To generate the user interface and control algorithm, MATLAB/Simulink real-time toolbox has been used. Four reference points were determined, control was performed and position error values were examined. MF634 Humusoft data acquisition card has been preferred to collect data from encoders.,A novel RCM mechanism has been designed and manufactured. Kinematic equations of this mechanism have been obtained. Position control of the cannula tip has been performed using PID control method for four different reference points. After settlement, maximum position error has been observed as 0.45 mm.,Structure of the designed mechanism is quite simple. Thus, costs are quite low. The operation area of the operator is widened by hanging the mechanism from the ceiling, so operational capability of health personnel is increasing. It helps to decrease the operation time and increase the success of the operation.,With this study, it is aimed to contribute to the literature by designing a new RCM mechanism. The rotation of the mechanism around the RCM point is provided by only one rotary motor, and the displacement of the RCM point in the vertical axis is provided by only one linear motor. The mechanism is also a surgical robot. The designed system is suitable for use in robot-assisted laparoscopic surgery in terms of maneuverability.

Real-time PID control of a novel RCM mechanism designed and manufactured for use in laparoscopic surgery

A robotic surgical system capable of performing minimally invasive surgery (MIS) is proposed in this paper. Based on the requirements of MIS, a compliant, seven- degrees of freedom (7-DOF) pneumatically actuated mechanism is designed. A remote center of motion (RCM) as a parallelogram mechanism for holding the laparoscopic camera is also developed. The operating workspace of robotic surgical system is determined considering the physical constraints imposed by mechanical joints. The simulation results show that the robotic system meets the design requirement. This research will lay a good foundation for the development of a compliant surgical robot to assist in MIS.

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A novel compliant surgical robot: Preliminary design analysis.

: Nowadays, the use of robot technologies has become widespread. Robots that have been confronted in many sectors have also been used in surgical operations in recent years. RCM (Remote Center of Motion) mechanisms take the place of these robots, which have less space-consuming and specially designed for operation. Reduced space requirements and lower maintenance costs are the greatest advantages of these mechanisms. In this study, some of the RCM mechanisms which used in surgical operations are mentioned. A unique and original surgical robot designed for laparoscopic surgical purposes which is not in the literature of robots, has been described. This surgical robot was designed with a 3D CAD program and motion of robot was analyzed. Robot control was performed using fuzzy control method. Dynamic equations of robot which used at fuzzy control were obtained with Lagrangian mechanics. MATLAB software has been used for robot control. Used membership function parameters of fuzzy control were optimized with genetic algorithm method. Obtained fuzzy control graphics with MATLAB were given in the result section.

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Fuzzy Control of Laparoscopic Surgical Robot Designed for Use in Minimally Invasive Surgery

A compact mechanism is designed to enable manipulation about a pivot point, different kinds of surgical tools which are commonly used in minimally invasive surgery such as therapy laser delivery tools, biopsy and bracytherapy needles. The robot's special configuration will enable it to reorient a surgical tool about a pivot point conveniently; achieve and control small-scale movement for precision manipulation in two independent degrees of freedom, and allow for miniaturization so it can overcome problems associated with the limited surgical workspaces. The manipulator can be used in manual, autonomous or remote-control modes. Performance analysis showed that the robot can operate with an average angular accuracy of 1.4 and 1.1 degrees for the joints. The features of the proposed mechanism make it well suited for use in a broad range of medical interventions.

Farah M. T. Aiash

Papers

A mechanism for surgical tool manipulation