Kinematic Analysis and Design of a Six-Degrees of Freedom 3-RRPS Mechanism for Bone Reduction Surgery

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Terence Essomba ◽  
Sinh Nguyen Phu
Keyword(s):  
Degrees Of Freedom ◽  
Vertical Axis ◽  
Velocity Model ◽  
Analysis And Design ◽  
Six Degrees Of Freedom ◽  
Bone Fragments ◽  
Kinematic Models ◽  
Surgery First ◽  
Forward Kinematic ◽  
Classical Mechanism

Abstract Robot-assisted bone reduction surgery consists in using robots to reposition the bone fragments into their original place prior to fracture healing. This study presents the application of a 3-RRPS augmented tripod mechanism with six degrees-of-freedom for longitudinal bone reduction surgery. First, the inverse and forward kinematic models of the mechanism are investigated. Particularly, the forward kinematic is solved by applying Sylvester's dialytic method. Second, the velocity model is studied and its singular configurations are identified. The workspace of the 3-RRPS mechanism is then outlined and compared with the Stewart platform, which is a classical mechanism for the targeted application. The results show that this mechanism provides a larger workspace, especially its rotation angle about the vertical axis, which is an important aspect in the bone reduction. A series of simulations on the numerical and graphic software is performed to verify the entire analysis of the parallel mechanism. A physiguide and mscadams software are used to carry out a simulation of a real case of femur fracture reduction using the proposed mechanism to validate its suitability. Finally, a robotic prototype based on the mechanism is manufactured and experimented using an artificial bone model to evaluate the feasibility of the mechanism.

Kinematic analysis of an augmented 3-RPSP tripod mechanism with six degrees of freedom for bone reduction surgery

2021 ◽  
pp. 095440622110480
Author(s):  
Sinh Nguyen Phu ◽  
Terence Essomba
Keyword(s):  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Femoral Shaft ◽  
Polynomial Equation ◽  
Velocity Model ◽  
Inverse Kinematic ◽  
Reachable Workspace ◽  
Bone Fragments ◽  
Forward Kinematic ◽  
Six Degree Of Freedom

Robotic-assisted bone reduction surgery consists in using robots to reconnect patients’ bone fragments prior to fracture healing. The goal of this study is to propose a novel augmented 3-RPSP tripod mechanism with six degree of freedom for longitudinal bone reduction surgery. Its inverse kinematic model is studied and its forward kinematic model is solved by establishing the constraint equations, applying Sylvester’s dialytic method and finding the solutions of the resulting polynomial equation. The velocity model is calculated and its Jacobian matrix is used to identify its singular configurations. In comparison to the Stewart–Gough platform that is a typical mechanism used in this application, the proposed mechanism offers larger reachable workspace which is an important aspect in the femoral shaft bone reduction. A Physiguide and Msc Adams software are used to carry out a simulation of a real femur fracture reduction using the proposed mechanism to validate its suitability. A robotic prototype has been designed and manufactured in order to test its capability of performing diaphyseal femur reduction surgery.

scholarly journals Orthopedic hexapods: history, present and prospects

2015 ◽  
Vol 3 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Viktor Aleksandrovich Vilensky ◽  
Aleksander Pavlovich Pozdeev ◽  
Edgar Valentinovich Bukharev ◽  
Andrey Aleksandrovich Pozdeev ◽  
Timur Faizovich Zubairov ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Deformity Correction ◽  
Long Bone ◽  
Computer Assisted ◽  
Software Application ◽  
Six Degrees Of Freedom ◽  
Fixation Devices ◽  
Special Software ◽  
History Of ◽  
Bone Fragments

The article is dedicated to computer-assisted external fixation devices, so-called hexapods. The main advantage of these frames is capability to make mathematically precise correction of bone fragments in three planes and six degrees of freedom on the base of calculations made in special software application. Recently these devices are mostly applied in long bone deformity correction but the sphere of its effective useis not limited by only this direction. The article presents the history of investigation of these devices, their development, implemented comparative analysis of the basic hexapods: TSF (Taylor Spatial Frame), IHA (Ilizarov Hexapod Apparatus) and Ortho-SUV Frame.

THE PROPERTIES OF THE MECHANISMS WITH SIX DEGREES OF FREEDOM

2021 ◽  
pp. 28-33
Author(s):  
S. V. Kheylo ◽  
O. A. Garin ◽  
S. V. Palochkin ◽  
S. D. Dorofeev
Keyword(s):  
Degrees Of Freedom ◽  
The Novel ◽  
Parallel Mechanisms ◽  
Kinematic Scheme ◽  
Output Link ◽  
Kinematic Chains ◽  
Analysis And Design ◽  
Six Degrees Of Freedom ◽  
Robotic Assisted Surgery ◽  
Coupling Equations

Parallel mechanisms analysis and design are the main trends of advance robotic engineering. This article is devoted to the novel parallel mechanisms with six degrees of freedom. The presented mechanisms can be applied in additive technologies, robotic–assisted surgery. The proposed mechanisms contain six drives and six kinematic chains. They have the properties of a partial kinematic decoupling, which allows realized separately translational and rotational movements. The presented mechanisms is a simple kinematic scheme. The drives can provide a ratio 1:1 of with the movement of the output link. The paper considers the solution of kinematics problems, velocity analysis, singularities. The velocity problem is solved by differentiating the coupling equations. Singularities were detected by studying the properties of Jacobi matrices. The singularities depend only on the orientation of the output link. These mechanisms have a large working area free of singularities. The working area is determined by solving the coupling equations. The solved problems allow to solve the control such mechanisms in the future.

Vibration of a Spring-Supported Body

1965 ◽  
Vol 7 (2) ◽  
pp. 185-192 ◽  
Author(s):  
P. Grootenhuis ◽  
D. J. Ewins
Keyword(s):  
Rigid Body ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Vertical Axis ◽  
The Body ◽  
Stiffness Ratio ◽  
Six Degrees Of Freedom ◽  
Centre Of Gravity ◽  
Longitudinal Stiffness ◽  
The Matrix

The equations of motion for a rigid body supported on four springs are derived for the general case of the centre-of-gravity being anywhere within the body and allowing for the sideways as well as the longitudinal stiffnesses of the springs. This constitutes a six-degrees-of-freedom case with three degrees of asymmetry. Coupling between motions in all directions occurs even when the centre-of-gravity is at the geometric centre with the exception then of vertical oscillations and rotation about the vertical axis. Any number of additional springs can be allowed for by adding terms to the expression for the potential energy stored in the springs. Allowance is made in the expression for kinetic energy for the products of inertia which arise with an offset centre-of-gravity. The real case is simulated for purposes of analysis by replacing the rigid body by a rectangular box with a light framework and all the mass concentrated at the eight corners. The matrix solution is changed into dimensionless parameters and the effect of an offset centre-of-gravity upon the eigenvalues and eigenvectors studied. Only the proportions of the box and the stiffness ratio between sideways to longitudinal stiffness of the springs remain as factors. The numerical example given is for proportions of height to width to length of 3/4/5 and for a stiffness ratio of 5. Small amounts of offset of the centre-of-gravity from the geometric centre do not alter the dynamic behaviour of the system much but displacing the total mass towards either a lower or an upper corner has marked effects. Some of the natural frequencies associated with motion in rotation when the system is symmetric become less than the frequencies connected with motion in translation for the centre-of-gravity being close to a corner connected to a spring. A large region free from any natural frequency arises when the centre-of-gravity is moved towards a corner furthest removed from the plane containing the springs. The asymptotic conditions for the position of the centre-of-gravity are also considered.

Visual Judgments in Motion

1954 ◽  
Vol 7 (3) ◽  
pp. 233-251 ◽  
Author(s):  
E. S. Calvert
Keyword(s):  
Degrees Of Freedom ◽  
Vertical Axis ◽  
Moving Surface ◽  
Practical Result ◽  
Six Degrees Of Freedom ◽  
Three Degrees Of Freedom

Introduction. The judgments discussed in this paper are mainly those which the pilot of an aircraft has to make in order to land. Some of these, as, for instance, the judgment of alignment, are similar to those made by the driver of a moving surface vehicle, but some, as, for instance, the judgment of approach slope, are peculiar to the pilot, and are very much more difficult. The main difficulties of the pilot arise, however, from the fact that an aircraft has six degrees of freedom and is controllable about all three axes, whereas the surface vehicle has only three degrees of freedom and is controllable only about the vertical axis. In bad visibility these extra freedoms confuse the visual indications in ways of which the person who has only driven a surface vehicle has no conception. The result of this has been that until recently most of the engineers concerned in the layout of airports have not realized that pilots have special difficulties; while the pilots, not having studied visual psychology and perspective, have been unable to analyse these difficulties, or even explain them in terms intelligible to the engineers. In this country, we have been able to find methods of bridging the gap, and enabling both parties to talk the same language. The practical result of this can be seen at London Airport.

Control of processing at multi-tool two-support setup

2020 ◽  
pp. 67-73
Author(s):  
N.D. YUsubov ◽  
G.M. Abbasova
Keyword(s):  
Degrees Of Freedom ◽  
Factor Model ◽  
Angular Displacement ◽  
Factor Models ◽  
Technological System ◽  
Displacement Control ◽  
Model Accuracy ◽  
Six Degrees Of Freedom ◽  
Angular Displacements ◽  
And Control

The accuracy of two-tool machining on automatic lathes is analyzed. Full-factor models of distortions and scattering fields of the performed dimensions, taking into account the flexibility of the technological system on six degrees of freedom, i. e. angular displacements in the technological system, were used in the research. Possibilities of design and control of two-tool adjustment are considered. Keywords turning processing, cutting mode, two-tool setup, full-factor model, accuracy, angular displacement, control, calculation [email protected]

scholarly journals Design and Calibration of a Hall Effect System for Measurement of Six-Degree-of-Freedom Motion within a Stacked Column

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3740
Author(s):  
Olafur Oddbjornsson ◽  
Panos Kloukinas ◽  
Tansu Gokce ◽  
Kate Bourne ◽  
Tony Horseman ◽  
...  
Keyword(s):  
Hall Effect ◽  
Degrees Of Freedom ◽  
Reactor Core ◽  
Degree Of Freedom ◽  
Life Extension ◽  
Scale Model ◽  
Design Development ◽  
Seismic Safety ◽  
Six Degrees Of Freedom ◽  
Six Degree Of Freedom

This paper presents the design, development and evaluation of a unique non-contact instrumentation system that can accurately measure the interface displacement between two rigid components in six degrees of freedom. The system was developed to allow measurement of the relative displacements between interfaces within a stacked column of brick-like components, with an accuracy of 0.05 mm and 0.1 degrees. The columns comprised up to 14 components, with each component being a scale model of a graphite brick within an Advanced Gas-cooled Reactor core. A set of 585 of these columns makes up the Multi Layer Array, which was designed to investigate the response of the reactor core to seismic inputs, with excitation levels up to 1 g from 0 to 100 Hz. The nature of the application required a compact and robust design capable of accurately recording fully coupled motion in all six degrees of freedom during dynamic testing. The novel design implemented 12 Hall effect sensors with a calibration procedure based on system identification techniques. The measurement uncertainty was ±0.050 mm for displacement and ±0.052 degrees for rotation, and the system can tolerate loss of data from two sensors with the uncertainly increasing to only 0.061 mm in translation and 0.088 degrees in rotation. The system has been deployed in a research programme that has enabled EDF to present seismic safety cases to the Office for Nuclear Regulation, resulting in life extension approvals for several reactors. The measurement system developed could be readily applied to other situations where the imposed level of stress at the interface causes negligible material strain, and accurate non-contact six-degree-of-freedom interface measurement is required.

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