Optimal synthesis of a spherical parallel mechanism for medical application

Robotica ◽  
2014 ◽  
Vol 34 (3) ◽  
pp. 671-686 ◽  
Author(s):  
T. Essomba ◽  
M. A. Laribi ◽  
S. Zeghloul ◽  
G. Poisson
Keyword(s):  
Motion Capture ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Medical Application ◽  
Optimal Synthesis ◽  
Objective Functions ◽  
Ultrasound Probe ◽  
Spherical Parallel Mechanism ◽  
Real Coded Genetic Algorithms ◽  
Probe Holder

SUMMARYThis paper introduces the design and the optimization of a probe holder robot for tele-echography applications. To define its kinematic architecture, an approach based on motion capture of an expert's gestures during ultrasound examinations was proposed. The medical gestures analyzed consisted of ultrasound probe movements and were used to characterize the kinematic specifications of the proposed manipulator. The selected architecture was a Spherical Parallel Mechanism (SPM) with 3 degrees of freedom (DoF) and its optimal synthesis was performed using real-coded Genetic Algorithms (GA). The optimization criteria and constraints were established thanks to the collaboration of medical experts and were successively formulated and solved using mono-objective and multi-objective functions.

Optimal Synthesis of a New Spherical Parallel Mechanism for Application to Tele-Echography Chain

2011 ◽  
Author(s):  
M. A. Laribi ◽  
T. Essomba ◽  
S. Zeghloul ◽  
G. Poisson
Keyword(s):  
Motion Capture ◽  
Parallel Mechanism ◽  
Parallel Manipulators ◽  
Optimal Synthesis ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Real Coded Genetic Algorithm ◽  
Spherical Parallel Mechanism ◽  
Definition Of ◽  
Independent Design

This paper considers the practice of a tele-echography through a new slave holder robot for a remote echographic diagnostic application. This robot is integrated in a master-slave system called ‘Robotic Platform for an Interactive Tele-echographic System’ (PROSIT ANR French national project). The proposed approach is based on motion capture of an expert’s gestures during the echography examination. The medical gestures were analyzed in terms of positions and velocities; the result has been used in the definition of the kinematics specifications of the proposed manipulator. The effective workspace size of a standard echography act, done by the medical expert, is determined through an experimental study. The evaluation of the workspace is based on the use of the Vicon Nexus motion capture system. The spherical parallel mechanism (SPM) has been selected because of its characteristics meeting the constraint requirements. In addition this architecture offers an excellent stiffness, high precision and is light weight. The design problem of a new parallel probe-holder robot according to the identified experimental workspace for the tele-echography system is presented. In this work, in order to increase the workspace volume of the manipulator, a minimal set of geometrical parameters of spherical parallel manipulators are optimized to find the maximum workspace. Seven independent design parameters have been identified. The optimal synthesis of spherical parallel manipulators is performed using a real-coded genetic algorithm (GA) based method. An optimal study of the orientation workspace is also presented.

Kinematic Optimization of a Reconfigurable Spherical Parallel Mechanism for Robotic-Assisted Craniotomy

2019 ◽  
Vol 11 (6) ◽  
Author(s):  
Terence Essomba ◽  
Yang Hsu ◽  
Juan Sebastian Sandoval Arevalo ◽  
Med Amine Laribi ◽  
Said Zeghloul
Keyword(s):  
Motion Capture ◽  
Parallel Mechanism ◽  
Medical Application ◽  
Kinematic Data ◽  
Robotic Assisted ◽  
Motion Trajectories ◽  
Spherical Parallel Mechanism ◽  
Human Cadavers ◽  
New Type ◽  
Kinematic Optimization

Abstract The craniotomy is a surgical task that is required to allow access to the patient's brain. It consists of using neurosurgical drills to open a path through the skull. The high risk resulting from human dexterous limit justifies the use of an accurate robotic system to perform craniotomy. The present work introduces the kinematic design of a mechanism for a robotic manipulator dedicated to craniotomy. Motion capture experiments have been carried out to measure the motion of a surgical drill during the execution of craniotomy on human cadavers. The results of the experiments are discussed. As this medical application requires a remote center of motion (RCM), a new type of 3-RRR spherical parallel mechanism (SPM) is proposed to manipulate the surgical drill. The novelty of this mechanism is the integration of a reconfigurable base that re-orients the first revolute joint of the RRR legs. A mechanical architecture concept is introduced to implement this reconfiguration. It is made of three pantographic linkages that manipulate the base of the SPM. The kinematics of the new mechanism is analyzed. The influence of this reconfigurable parameter is studied on two different aspects: the mechanism workspace and kinematic performances. Based on these kinematic data, the optimization of a mechanism is performed. The drill motion trajectories are used to evaluate the behavior of the optimized mechanism. It is finally compared to the classical SPM with a trihedral base, showing the contribution of the new reconfiguration variable on the mechanism dexterity.

scholarly journals Torque Reduction of a Reconfigurable Spherical Parallel Mechanism Based on Craniotomy Experimental Data

2021 ◽  
Vol 11 (14) ◽  
pp. 6534
Author(s):  
Terence Essomba ◽  
Juan Sandoval ◽  
Med Amine Laribi ◽  
Chieh-Tsai Wu ◽  
Cyril Breque ◽  
...  
Keyword(s):  
Motion Capture ◽  
Parallel Mechanism ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Human Cadaver ◽  
Drilling Tool ◽  
Force Interaction ◽  
Spherical Parallel Mechanism ◽  
Angle Modulation ◽  
Spherical Parallel Manipulator

This paper deals with a robotic manipulator dedicated to craniotomy with a remote center of motion based on a Spherical Parallel Manipulator (SPM) architecture. The SPM is proposed to handle the drilling tool through the requested craniotomy Degrees of Freedom (DoF) with two rotations. The proposed architecture allows one degree of redundancy according to the total DoF. Thus, a first contribution of this work focuses on the experimental analysis of craniotomy surgery tasks. Secondly, its behavior is improved, taking advantage of the redundancy of the SPM using the spinning motion as a reconfiguration variable. The spinning angle modulation allows the reconfigurable manipulator to minimize its motor torques. A series of motion capture and force experimentations is performed for the analysis of the kinematic and force interaction characterizing Burr hole craniotomy procedures. Experimentations were carried out by a neurosurgeon on a human cadaver, ensuring highly realistic conditions.

Architecture Optmization of a 3-DOF Parallel Mechanism

1998 ◽  
Author(s):  
J. A. Carretero ◽  
R. P. Podhorodeski ◽  
M. Nahon
Keyword(s):  
Parallel Mechanism ◽  
Architectural Design ◽  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
Design Parameters ◽  
Objective Functions ◽  
Constraint Equations ◽  
Three Degree Of Freedom ◽  
Architecture Optimization ◽  
Three Degrees Of Freedom

Abstract This paper presents a study of the architecture optimization of a three-degree-of-freedom parallel mechanism intended for use as a telescope mirror focussing device. The construction of the mechanism is first described. Since the mechanism has only three degrees of freedom, constraint equations describing the inter-relationship between the six Cartesian coordinates are given. These constraints allow us to define the parasitic motions and, if incorporated into the kinematics model, a constrained Jacobian matrix can be obtained. This Jacobian matrix is then used to define a dexterity measure. The parasitic motions and dexterity are then used as objective functions for the optimizations routines and from which the optimal architectural design parameters are obtained.

Performance Analysis of 3-URU Spherical Parallel Mechanism Designed Based on Velocity Transmission and Force Constraint Indices

2015 ◽  
Vol 758 ◽  
pp. 71-76
Author(s):  
Syamsul Huda ◽  
Syafri ◽  
Mulyadi Bur
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Output Link ◽  
Kinematic Synthesis ◽  
Platform Motion ◽  
Spherical Parallel Mechanism ◽  
Velocity Transmission ◽  
Maximum Inclination ◽  
Three Degrees Of Freedom ◽  
Spherical Motion

In this paper was observed performances of developed three degrees of freedom (dof) parallel mechanism named 3-URU spherical parallel mechanism. The mechanism is composed of three identical limbs mounted symmetrically to base (fixed link) and platform (output link). The limb is constructed by universal-revolute and universal joints. The kinematic constants of mechanism consisting of link lengths, radius of platform, radius of base, mounting angle of limb and platform to base and platform were determined with consideration of velocity transmission and force constraint indices. To evaluate performance of mechanism, it was manufactured a prototype of mechanism designed base on these two mentioned indices. There are three steps proposed to realize the mechanism, (i) kinematic synthesis to determine of kinematic constants, (ii) design of mechanical components to define shape and dimension of links and joints by considering collision in wokingspace and static analysis, (iii) evaluation of mechanism performances consisting of workingspace, controllability of platform motion and static payload. Based on obtained results, it can be clarified that, the mechanism can produce spherical motion of platform which rotates on steady point recognized as center of platform rotation. The platform can achieve maximum inclination angle, 80 degree and at this posture occurs translational error, 0.0102 mm. On the other hand, the mechanism can support payload ten times of weight of moving parts.

scholarly journals A Sensor Based on a Spherical Parallel Mechanism for the Measurement of Fluid Velocity: Physical Modelling and Computational Analysis

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2867 ◽  
Author(s):  
Roque Saltarén ◽  
Gerardo Portilla ◽  
Alejandro Barroso ◽  
Juan Cely
Keyword(s):  
Parallel Mechanism ◽  
Inertial Measurement Unit ◽  
Degrees Of Freedom ◽  
Fluid Velocity ◽  
Physical Modelling ◽  
Measurement Unit ◽  
Adams Software ◽  
Spherical Parallel Mechanism ◽  
The Impact ◽  
Three Degrees Of Freedom

In this article, a new method was developed to measure the velocity of a fluid using a sensor, based on the use of a spherical parallel mechanism with three degrees-of-freedom (DOF). This sensor transforms the kinetic energy of the fluid into potential energy by deforming the parallel mechanism. This deformation is due to the impact of the fluid on a sphere attached to the platform of the parallel mechanism. Through the acquisition of data from a sensor using an inertial measurement unit (IMU) in the sphere, an algorithm calculates the velocity and direction of the fluid. In this article, a mathematical model of the mechanism and an algorithm for correctly measuring the velocity and direction of the fluid is developed; this algorithm is tested through a simulation in the Adams software, and the MATLAB software is used to execute the algorithm. The results show that the algorithm calculates the velocity and the direction of the fluid correctly, demonstrating the technical feasibility of the sensor.

Kinematics Analysis of a 3-RRR Spherical Parallel Mechanism with Coaxial Input Shafts

2013 ◽  
Vol 404 ◽  
pp. 237-243
Author(s):  
Yu Lei Hou ◽  
Xin Zhe Hu ◽  
Da Xing Zeng
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
Screw Theory ◽  
Inverse Solution ◽  
Kinematics Analysis ◽  
Motion Feature ◽  
Displacement Problem ◽  
Spherical Parallel Mechanism ◽  
Three Degrees Of Freedom

As an important mechanism with special and extensive application, the three degrees of freedom spherical parallel mechanism is always a research hot in the mechanical fields. In this paper, the feature of the 3-RRR spherical parallel mechanism with coaxial input shafts is introduced, and its motion feature is analyzed based on the screw theory. The mobility of the spherical parallel mechanism is calculated by using the Modified Kutzbach-Grübler criterion, and the inverse displacement problem of the mechanism is solved. Then the expression of the Jacobian matrix is deduced based on the kinematics equation and its inverse solution. The contents of this paper should be useful for the further application of the spherical parallel mechanism.

scholarly journals Development and assessment of a telesonography system for musculoskeletal imaging

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Mohammed Obaid ◽  
Qianwei Zhang ◽  
Scott J. Adams ◽  
Reza Fotouhi ◽  
Haron Obaid
Keyword(s):  
Degrees Of Freedom ◽  
Ultrasound Images ◽  
Ultrasound Probe ◽  
Rural And Remote ◽  
Significant Delay ◽  
Remote Communities ◽  
Internet Connection ◽  
Good For ◽  
4 Degrees Of Freedom

Abstract Background Telesonography systems have been developed to overcome barriers to accessing diagnostic ultrasound for patients in rural and remote communities. However, most previous telesonography systems have been designed for performing only abdominal and obstetrical exams. In this paper, we describe the development and assessment of a musculoskeletal (MSK) telesonography system. Methods We developed a 4-degrees-of-freedom (DOF) robot to manipulate an ultrasound probe. The robot was remotely controlled by a radiologist operating a joystick at the master site. The telesonography system was used to scan participants’ forearms, and all participants were conventionally scanned for comparison. Participants and radiologists were surveyed regarding their experience. Images from both scanning methods were independently assessed by an MSK radiologist. Results All ten ultrasound exams were successfully performed using our developed MSK telesonography system, with no significant delay in movement. The duration (mean ± standard deviation) of telerobotic and conventional exams was 4.6 ± 0.9 and 1.4 ± 0.5 min, respectively (p = 0.039). An MSK radiologist rated quality of real-time ultrasound images transmitted over an internet connection as “very good” for all telesonography exams, and participants rated communication with the radiologist as “very good” or “good” for all exams. Visualisation of anatomic structures was similar between telerobotic and conventional methods, with no statistically significant differences. Conclusions The MSK telesonography system developed in this study is feasible for performing soft tissue ultrasound exams. The advancement of this system may allow MSK ultrasound exams to be performed over long distances, increasing access to ultrasound for patients in rural and remote communities.

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