A Class of 2-Degree-of-Freedom Planar Remote Center-of-Motion Mechanisms Based on Virtual Parallelograms

2014 ◽  
Vol 6 (3) ◽  
Author(s):  
Jianmin Li ◽  
Guokai Zhang ◽  
Yuan Xing ◽  
Hongbin Liu ◽  
Shuxin Wang
Keyword(s):  
Synthesis Method ◽  
Body Cavity ◽  
Degree Of Freedom ◽  
Three Dimension ◽  
Robot Assisted ◽  
Revolute Joints ◽  
3D Space ◽  
Surgical Tool ◽  
Main Components ◽  
Actuated Joints

Robot-assisted minimally invasive surgery (MIS) has shown tremendous advances over the traditional technique. The remote center-of-motion (RCM) mechanism is one of the main components of a MIS robot. However, the widely used planar RCM mechanism, with double parallelogram structure, requires an active prismatic joint to drive the surgical tool move in–out of the patient’s body cavity, which restricts the dexterity and the back-drivability of the robot to some extent. To solve this problem, a two degree-of-freedom (DOF) planar RCM mechanism type synthesis method is proposed. The basic principle is to construct virtual double parallelogram structure at any instant during the mechanism movements. Different with the existing ones, both of the actuated joints of the obtained RCM mechanism are revolute joints. Combining the proposed mechanism with a revolute joint whose axis passes through the RCM point to drive the whole mechanism out of the plane, the spatial RCM mechanisms to manipulate surgical tool in three-dimension (3D) space can be obtained; and the 3D RCM mechanism can be used for manipulating multi-DOF instruments in a robot-assisted MIS or can be used as an external positioner in robotic single-port surgeries.

scholarly journals Estimating Tool–Tissue Forces Using a 3-Degree-of-Freedom Robotic Surgical Tool

2016 ◽  
Vol 8 (5) ◽  
Author(s):  
Baoliang Zhao ◽  
Carl A. Nelson
Keyword(s):  
Force Feedback ◽  
Estimation Method ◽  
Interaction Force ◽  
Normal Function ◽  
Degree Of Freedom ◽  
Force Estimation ◽  
Robot Assisted ◽  
Interaction Forces ◽  
Tissue Interaction ◽  
Surgical Tool

Robot-assisted minimally invasive surgery (MIS) has gained popularity due to its high dexterity and reduced invasiveness to the patient; however, due to the loss of direct touch of the surgical site, surgeons may be prone to exert larger forces and cause tissue damage. To quantify tool–tissue interaction forces, researchers have tried to attach different kinds of sensors on the surgical tools. This sensor attachment generally makes the tools bulky and/or unduly expensive and may hinder the normal function of the tools; it is also unlikely that these sensors can survive harsh sterilization processes. This paper investigates an alternative method by estimating tool–tissue interaction forces using driving motors' current, and validates this sensorless force estimation method on a 3-degree-of-freedom (DOF) robotic surgical grasper prototype. The results show that the performance of this method is acceptable with regard to latency and accuracy. With this tool–tissue interaction force estimation method, it is possible to implement force feedback on existing robotic surgical systems without any sensors. This may allow a haptic surgical robot which is compatible with existing sterilization methods and surgical procedures, so that the surgeon can obtain tool–tissue interaction forces in real time, thereby increasing surgical efficiency and safety.

Kinematic Design of a Generalized Double Parallelogram Based Remote Center-of-Motion Mechanism for Minimally Invasive Surgical Robot

2016 ◽  
Vol 10 (4) ◽  
Author(s):  
Kang Kong ◽  
Jianmin Li ◽  
Huaifeng Zhang ◽  
Jinhua Li ◽  
Shuxin Wang
Keyword(s):  
Minimally Invasive ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
Basic Element ◽  
Mathematical Framework ◽  
Minimally Invasive Surgical ◽  
Revolute Joints ◽  
Surgical Tool ◽  
Actuated Joints

Robot-assisted minimally invasive surgery (MIS) has shown tremendous advances over the traditional techniques. To improve dexterity and back-drivability of the existing planar remote center-of-motion (RCM) mechanism, on which an active prismatic joint is required to drive the surgical tool move in–out of the patient's body, a two degrees-of-freedom (DOFs) planar RCM mechanism is proposed by constructing virtual parallelograms in this paper. The mechanism can be considered as a generalized double parallelogram; both of the actuated joints are revolute joints. This feature enhances the intrinsic back-drivability of the mechanism. The mathematical framework is introduced first to prove that the mechanism could execute RCM. Then, the inverse kinematics of the planar mechanism is solved, and the Jacobian matrix is derived in this paper. Further, the singularity and the kinematic performance based on the kinematic equations are investigated, and the workspace of the mechanism is verified. Finally, a prototype was built to test the function of the proposed RCM mechanism. The results show that the mechanism can fulfill the constraint of MIS, and it can be used as the basic element of the active manipulator in an MIS robot.

An Integrated Type and Dimensional Synthesis Method to Design One Degree-of-Freedom Planar Linkages With Only Revolute Joints for Exoskeletons

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Zefang Shen ◽  
Garry Allison ◽  
Lei Cui
Keyword(s):  
Synthesis Method ◽  
Degree Of Freedom ◽  
Knee Joints ◽  
Dimensional Synthesis ◽  
Walking Gait ◽  
Revolute Joints ◽  
First Case ◽  
Planar Linkages ◽  
Four Bar Linkage

Exoskeletons can assist wearers to relearn natural movements when attached to the human body. However, most current devices are bulky and heavy, which limit their application. In this paper, we integrated type and dimensional synthesis to design one degree-of-freedom (DOF) linkages consisting of only revolute joints with multiple output joints for compact exoskeletons. Type synthesis starts from a four-bar linkage where the output link generates the first angular output. Then, an RRR dyad is connected to the four-bar linkage for the second angular output while ensuring that the overall DOF of the new mechanism is 1. A third output joint is added in a similar manner. During each step, dimensional synthesis is formulated as a constrained optimization problem and solved via genetic algorithms. In the first case study, we developed a finger exoskeleton based on a 10-bar-13-joint linkage for a natural curling motion. The second case study presents a leg exoskeleton based on an 8-bar-10-joint linkage to reproduce a natural walking gait at the hip and knee joints. We manufactured the exoskeletons to validate the proposed approach.

scholarly journals Robot-assisted Ultrasound-guided Tracking of Anatomical Structures for the Application of Focused Ultrasound

2020 ◽  
Vol 6 (3) ◽  
pp. 123-126
Author(s):  
Michael Unger ◽  
Johann Berger ◽  
Bjoern Gerold ◽  
Andreas Melzer
Keyword(s):  
Focused Ultrasound ◽  
Varicose Veins ◽  
Tracking System ◽  
Tracking Error ◽  
Uterine Fibroids ◽  
High Intensity Focused Ultrasound ◽  
Robot Assisted ◽  
Anatomical Structures ◽  
Surgical Tool ◽  
Custom Made

AbstractHigh intensity focused ultrasound is used as a surgical tool to treat completely non-invasively several diseases. Examples of clinical applications are uterine fibroids, prostate cancer, thyroid nodules, and varicose veins. Precise targeting is key for improving the treatment outcome. A method for an automated, robot-assisted tracking system was developed and evaluated. A wireless ultrasound scanner was used to acquire images of the target, in this case, a blood vessel. The active contour approach by Chan and Vese was used to segment and track while moving the scanner along the target structure with a collaborative robotic arm. The performance was assessed using a custom made Agar phantom. The mean tracking error, which is defined as the remaining distance of the lesion to the images’ centre line, was 0.27 mm ± 0.18 mm.

scholarly journals A Magnetorheological Fluids-Based Robot-Assisted Catheter/Guidewire Surgery System for Endovascular Catheterization

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 640
Author(s):  
Linshuai Zhang ◽  
Shuoxin Gu ◽  
Shuxiang Guo ◽  
Takashi Tamiya
Keyword(s):  
Collision Detection ◽  
Endovascular Procedures ◽  
Force Feedback ◽  
Force Measurement ◽  
Occupational Hazards ◽  
Robot Assisted ◽  
X Ray ◽  
Surgical Safety ◽  
Surgical Tool ◽  
Haptic Cues

A teleoperated robotic catheter operating system is a solution to avoid occupational hazards caused by repeated exposure radiation of the surgeon to X-ray during the endovascular procedures. However, inadequate force feedback and collision detection while teleoperating surgical tools elevate the risk of endovascular procedures. Moreover, surgeons cannot control the force of the catheter/guidewire within a proper range, and thus the risk of blood vessel damage will increase. In this paper, a magnetorheological fluid (MR)-based robot-assisted catheter/guidewire surgery system has been developed, which uses the surgeon’s natural manipulation skills acquired through experience and uses haptic cues to generate collision detection to ensure surgical safety. We present tests for the performance evaluation regarding the teleoperation, the force measurement, and the collision detection with haptic cues. Results show that the system can track the desired position of the surgical tool and detect the relevant force event at the catheter. In addition, this method can more readily enable surgeons to distinguish whether the proximal force exceeds or meets the safety threshold of blood vessels.

Robot-assisted MRI-guided prostatic interventions

Robotica ◽  
2009 ◽  
Vol 28 (2) ◽  
pp. 215-234 ◽  
Author(s):  
Andrew A. Goldenberg ◽  
John Trachtenberg ◽  
Yang Yi ◽  
Robert Weersink ◽  
Marshall S. Sussman ◽  
...  
Keyword(s):  
Thermal Ablation ◽  
Pulse Sequences ◽  
Robot Assisted ◽  
Surgical Ablation ◽  
Image Guided ◽  
Surgical Tool ◽  
Mri Environment ◽  
Focal Ablation ◽  
Mri Guided ◽  
Magnetic Resonance Imaging Mri

SUMMARYThis paper reports on recent progress made toward the development of a new magnetic resonance imaging (MRI)-compatible robot-assisted surgical system for closed-bore image-guided prostatic interventions: thermal ablation, radioactive seed implants (brachytherapy), and biopsy. Each type of intervention will be performed with a different image-guided, robot-based surgical tool mounted on the same MRI-guided robot through a modular trocar. The first stage of this development addresses only laser-based focal ablation. The robot mechanical structure, modular surgical trocar, control architecture, and current stage of performance evaluation in the MRI environment are presented. The robot actuators are ultrasonic motors. A methodology of using such motors in the MRI environment is presented. The robot prototype with surgical ablation tool is undergoing tests on phantoms in the MRI bore. The tests cover MRI compatibility, image visualization, robot accuracy, and thermal mapping. To date, (i) the images are artifact- and noise-free for certain scanning pulse sequences; (ii) the robot tip positioning error is less than 1.2 mm even at positions closer than 0.3 m from the MRI isocenter; (iii) penetration toward the target is image-monitored in near-real time; and (iv) thermal ablation and temperature mapping are achieved using a laser delivered on an optical fiber and MRI, respectively.

Design of a Teaching Robot with Three Degrees of Freedom

2012 ◽  
Vol 619 ◽  
pp. 325-328
Author(s):  
You Jun Huang ◽  
Ze Lun Li ◽  
Zhi Cheng Huang
Keyword(s):  
Degrees Of Freedom ◽  
Low Cost ◽  
Degree Of Freedom ◽  
Good Repeatability ◽  
Main Components ◽  
Opening And Closing ◽  
Three Degree Of Freedom ◽  
Three Degrees Of Freedom ◽  
Application Prospects

A teaching robot with three degree of freedom is designed. The three degrees of freedom are: waist rotation, lifting and stretching of the arm and opening and closing of the gripper. The designs of the main components are: a mobile chassis, parallel rails, horizontal rails and manipulator. The teaching robot designed has the features of low cost, easy to regulation, good repeatability and it has good promotion and application prospects in the field of teaching.

scholarly journals Structural synthesis of plane kinematic chain inversions without detecting isomorphism

2021 ◽  
Vol 12 (2) ◽  
pp. 1061-1071
Author(s):  
Jinxi Chen ◽  
Jiejin Ding ◽  
Weiwei Hong ◽  
Rongjiang Cui
Keyword(s):  
Mechanism Design ◽  
Adjacency Matrix ◽  
Synthesis Method ◽  
Kinematic Chain ◽  
Degree Of Freedom ◽  
Synthesis Methods ◽  
Creative Design ◽  
Structural Synthesis ◽  
Kinematic Chains

Abstract. A plane kinematic chain inversion refers to a plane kinematic chain with one link fixed (assigned as the ground link). In the creative design of mechanisms, it is important to select proper ground links. The structural synthesis of plane kinematic chain inversions is helpful for improving the efficiency of mechanism design. However, the existing structural synthesis methods involve isomorphism detection, which is cumbersome. This paper proposes a simple and efficient structural synthesis method for plane kinematic chain inversions without detecting isomorphism. The fifth power of the adjacency matrix is applied to recognize similar vertices, and non-isomorphic kinematic chain inversions are directly derived according to non-similar vertices. This method is used to automatically synthesize 6-link 1-degree-of-freedom (DOF), 8-link 1-DOF, 8-link 3-DOF, 9-link 2-DOF, 9-link 4-DOF, 10-link 1-DOF, 10-link 3-DOF and 10-link 5-DOF plane kinematic chain inversions. All the synthesis results are consistent with those reported in literature. Our method is also suitable for other kinds of kinematic chains.

A Novel Synthesis Method of Polygon-Scaling Mechanisms

2014 ◽  
Author(s):  
Guochao Bai ◽  
Shimin Wei ◽  
Duanling Li ◽  
Qizheng Liao ◽  
Xianwen Kong
Keyword(s):  
Synthesis Method ◽  
3D Models ◽  
Degree Of Freedom ◽  
Straightforward Manner ◽  
Novel Synthesis

A polygon-scaling mechanism is a single DOF (degree-of-freedom) mechanism for scaling a polygon. This paper presents a tetragon-elements based synthesis method of polygon-scaling mechanisms. According to movable conditions of radial scaling elements, four basic tetragon elements (rhombus element, parallelogram element, kite element and general tetragon element) are proposed. For a given polygon, these four types of elements can be selected based on the characteristics of target polygons to construct polygon-scaling mechanisms in a straightforward manner. Using this synthesis method, some planar 1-DOF scaling mechanisms are obtained with the characteristics of retracting and deploying. Their 3D models are also presented to proof the validity of the proposed method. Finally, a table of tetragon elements with the characteristics of their associated polygon-scaling mechanisms is summarized using which polygon-scaling mechanisms can be easily constructed.

Sign in / Sign up

Export Citation Format

Share Document