scholarly journals THE EFFECT OF COLLATERAL LIGAMENT INJURY ON CARTILAGE CONTACT IN KNEE JOINTS MODELED WITH SIX DEGREES OF FREEDOM

2016 ◽  
Vol 16 (03) ◽  
pp. 1650080
Author(s):  
NERIMAN ÖZADA
Keyword(s):  
Knee Joint ◽  
Degrees Of Freedom ◽  
Contact Point ◽  
Kinematic Model ◽  
Surface Geometry ◽  
Collateral Ligament ◽  
Point Distribution ◽  
Six Degrees Of Freedom ◽  
Six Dof ◽  
Intact Knee

The purpose of this study was to create a kinematic model of the knee joint with six degrees of freedom (DOF) and evaluate the effect of medial collateral ligament (MCL) and lateral collateral ligament (LCL) rupture on cartilage contact point distribution on the tibia during flexion. We hypothesized that collateral ligament contributions vary over six DOF of knee joint articulation and affect the cartilage contact point distribution during joint articulation. The ligament contributions and distribution of joint cartilage contact points cannot be fully assessed with simplified joint models or invasive experiments. Therefore, we developed a new model in which the tibia and femur centers of mass were determined from their surface geometry, and the displacement of the moving tibia was determined from the displacements of the attached ligaments. Compared to the intact knee, the tibia with the LCL removed had higher medial translation and lower valgus rotation. The tibia with the MCL removed had higher lateral translation and higher valgus rotation than the intact knee. At 0[Formula: see text], 30[Formula: see text], and 60[Formula: see text], the tibia with the LCL removed had more internal rotation than the intact knee. Understanding six DOF knee joint kinematics with integration of ligament contributions and cartilage contact positions is useful for the diagnosis of ligament injuries and the design of articulating surfaces for total arthroplasty.

Kinematic model to control the end-effector of a continuum robot for multi-axis processing

Robotica ◽  
2015 ◽  
Vol 35 (1) ◽  
pp. 224-240 ◽  
Author(s):  
Salvador Cobos-Guzman ◽  
David Palmer ◽  
Dragos Axinte
Keyword(s):  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Euler Angle ◽  
Inverse Kinematic ◽  
End Effector ◽  
Six Degrees Of Freedom ◽  
Hazardous Environments ◽  
Continuum Robot ◽  
Novel Method ◽  
Six Dof

SUMMARYThis paper presents a novel kinematic approach for controlling the end-effector of a continuum robot for in-situ repair/inspection in restricted and hazardous environments. Forward and inverse kinematic (IK) models have been developed to control the last segment of the continuum robot for performing multi-axis processing tasks using the last six Degrees of Freedom (DoF). The forward kinematics (FK) is proposed using a combination of Euler angle representation and homogeneous matrices. Due to the redundancy of the system, different constraints are proposed to solve the IK for different cases; therefore, the IK model is solved for bending and direction angles between (−π/2 to +π/2) radians. In addition, a novel method to calculate the Jacobian matrix is proposed for this type of hyper-redundant kinematics. The error between the results calculated using the proposed Jacobian algorithm and using the partial derivative equations of the FK map (with respect to linear and angular velocity) is evaluated. The error between the two models is found to be insignificant, thus, the Jacobian is validated as a method of calculating the IK for six DoF.

A multi-configuration kinematic model for active drive/steer four-wheel robot structures

Robotica ◽  
2015 ◽  
Vol 34 (10) ◽  
pp. 2309-2329 ◽  
Author(s):  
Edgar A. Martínez-García ◽  
Erik Lerín-García ◽  
Rafael Torres-Córdoba
Keyword(s):  
Degrees Of Freedom ◽  
Rotation Axis ◽  
Contact Point ◽  
Linear Equations ◽  
Kinematic Model ◽  
Robotic Systems ◽  
Control Law ◽  
Special Design ◽  
Wheel Drive ◽  
Four Wheel Drive

SUMMARYIn this study, a general kinematic control law for automatic multi-configuration of four-wheel active drive/steer robots is proposed. This work presents models of four-wheel drive and steer (4WD4S) robotic systems with all-wheel active drive and steer simultaneously. This kinematic model comprises 12 degrees of freedom (DOFs) in a special design of a mechanical structure for each wheel. The control variables are wheel yaw, wheel roll, and suspension pitch by active/passive damper systems. The pitch angle implies that a wheel's contact point translates its position over time collinear with the robot's lateral sides. The formulation proposed involves the inference of the virtual z-turn axis (robot's body rotation axis) to be used in the control of the robot's posture by at least two acceleration measurements local to the robot's body. The z-turn axis is deduced through a set of linear equations in which the number of equations is equal to the number of acceleration measurements. This research provides two main models for stability conditions. Finally, the results are sustained by different numerical simulations that validate the system with different locomotion configurations.

Dynamics Simulation of a Six-DOF Tunnel Segment Erector for Tunnel Boring Machine Based on Virtual Prototype

2012 ◽  
Vol 251 ◽  
pp. 231-234
Author(s):  
Gang Li ◽  
Ya Dong Chen ◽  
Bo Wang ◽  
Wan Shan Wang
Keyword(s):  
Degrees Of Freedom ◽  
Tunnel Boring Machine ◽  
Virtual Prototype ◽  
Dynamics Simulation ◽  
Design Parameters ◽  
Six Degrees Of Freedom ◽  
Tunnel Boring ◽  
Six Dof ◽  
Freedom Movement ◽  
Segment Erector

In this paper, we present the modeling and dynamics simulation of a six-DOF tunnel segment erector for tunnel boring machine (TBM), which is performed in the virtual prototype platform. The 3D virtual assembling model of a tunnel segment erector is built based on Pro/E software according to its design parameters such as structure and size. After the interference inspection, the model is imported into ADAMS through the interface module of Mech/Pro. The model is simplified and optimized reasonably and various constraints are applied under variety working conditions. The results of simulation show that the design has six degrees of freedom movement capacity which meets the design requirements. At the same time the dynamics characteristics of drives and the forces of each part are obtained and they will provide a boundary condition for strength check and basis for the power system design which is important for the further optimal design.

General inverse solution of six-degrees-of-freedom serial robots based on the product of exponentials model

2018 ◽  
Vol 38 (3) ◽  
pp. 361-367 ◽  
Author(s):  
Haixia Wang ◽  
Xiao Lu ◽  
Wei Cui ◽  
Zhiguo Zhang ◽  
Yuxia Li ◽  
...  
Keyword(s):  
Design Methodology ◽  
Degrees Of Freedom ◽  
Screw Theory ◽  
Complex Problem ◽  
Content Type ◽  
Geometrical Properties ◽  
Closed Form Solutions ◽  
Six Degrees Of Freedom ◽  
Serial Robots ◽  
Six Dof

Purpose Developing general closed-form solutions for six-degrees-of-freedom (DOF) serial robots is a significant challenge. This paper thus aims to present a general solution for six-DOF robots based on the product of exponentials model, which adapts to a class of robots satisfying the Pieper criterion with two parallel or intersecting axes among its first three axes. Design/methodology/approach The proposed solution can be represented as uniform expressions by using geometrical properties and a modified Paden–Kahan sub-problem, which mainly adopts the screw theory. Findings A simulation and experiments validated the correctness and effectiveness of the proposed method (general resolution for six-DOF robots based on the product of exponentials model). Originality/value The Rodrigues rotation formula is additionally used to turn the complex problem into a solvable trigonometric function and uniformly express six solutions using two formulas.

Joint Models, Degrees of Freedom, and Anatomical Motion Measurement

1983 ◽  
Vol 105 (1) ◽  
pp. 55-62 ◽  
Author(s):  
G. L. Kinzel ◽  
L. J. Gutkowski
Keyword(s):  
Measurement Technique ◽  
Degrees Of Freedom ◽  
Measurement Techniques ◽  
Kinematic Model ◽  
Joint Motion ◽  
Review Of The Literature ◽  
Joint Models ◽  
Motion Measurement ◽  
Six Degrees Of Freedom ◽  
Six Degree Of Freedom

When the motion associated with an anatomical joint is to be measured, a kinematic model for the joint must first be established. The joint model will have from one to six degrees of freedom, and both the measurement technique and the means used to describe the motion will be influenced by the model and its degrees of freedom. This paper discusses the modeling and measurement of anatomical joint motion from a kinematics viewpoint. A review of the literature pertaining to measurement techniques, kinematic assumptions, and motion descriptions for anatomical joint motion is presented. One, two, three and six degree-of-freedom models for various anatomical joints have appeared in the literature, and the applicability of these models is compared and discussed.

Kinematics of the Translational 3-URC Mechanism1

2004 ◽  
Vol 126 (6) ◽  
pp. 1113-1117 ◽  
Author(s):  
Raffaele Di Gregorio
Keyword(s):  
Explicit Form ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Industrial Applications ◽  
Parallel Architectures ◽  
Six Degrees Of Freedom ◽  
Spatial Mechanisms ◽  
Six Dof ◽  
And Control ◽  
Spherical Motion

The use of less than six degrees of freedom (dof) mechanisms instead of six-dof ones is always recommended when the application makes it possible, since their architectures and control are simpler to manufacture and implement respectively. Three-dof mechanisms constitute an important subset of less-than-six-dof mechanisms, since either translational or spherical motion can be obtained through three-dof spatial mechanisms and many industrial applications require the only translational or spherical motion. This paper presents a new translational parallel mechanism (TPM), named translational 3-URC. The new mechanism belongs to the parallel architectures with 3-URC topology, which contain another architecture that is a spherical parallel wrist. The proposed TPM is not overconstrained and has three equal legs whose kinematic pairs are three revolute pairs and one passive cylindrical pair per leg. Its actuated pairs are three revolute pair located on the frame. The position and velocity analyses of the translational 3-URC will be addressed and solved. Its singularity conditions will be written in explicit form and geometrically interpreted.

An Analytical Model for Calculating the Workspace of a Flexure Hexapod Nanopositioner

2013 ◽  
Vol 5 (4) ◽  
Author(s):  
Hongliang Shi ◽  
Hai-Jun Su
Keyword(s):  
Analytical Model ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Parallel Mechanisms ◽  
Torsion Angles ◽  
Maximum Deformation ◽  
Practical Applications ◽  
Six Degrees Of Freedom ◽  
Workspace Analysis ◽  
Flexure Joints

This paper presents an analytical model for calculating the workspace of a flexure-based hexapod nanopositioner previously built by the National Institute of Standards and Technology (NIST). This nanopositioner is capable of producing high-resolution motions in six degrees of freedom by actuating linear actuators on a planar tri-stage. However, the workspace of this positioner is still unknown, which limits its uses in practical applications. In this work, we seek to derive a kinematic model for predicting the workspace of such kinds of flexure based platforms by assuming that their workspace is mainly constrained by the deformation of flexure joints. We first study the maximum deformation including bending and torsion angles of an individual flexure joint. We then derive the inverse kinematics and calculation of bending and torsion angles of each wire flexure in the overall mechanism with given position of the top platform center of the hexapod nanopositioner. At last, we compare results with finite element models of the entire platform. This model is beneficial for workspace analysis and optimization for design of compliant parallel mechanisms.

Accuracy estimation of a stretch-retractable single section continuum manipulator based on inverse kinematics

2019 ◽  
Vol 46 (5) ◽  
pp. 573-580
Author(s):  
Hao Wang ◽  
GuoHua Gao ◽  
Qixiao Xia ◽  
Han Ren ◽  
LianShi Li ◽  
...  
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Content Type ◽  
Kinematics Model ◽  
Six Degrees Of Freedom ◽  
Single Section ◽  
Motion Range ◽  
Continuum Manipulator ◽  
Three Degrees Of Freedom

Purpose The purpose of this paper is to present a novel stretch-retractable single section (SRSS) continuum manipulator which owns three degrees of freedom and higher motion range in three-dimension workspace than regular single continuum manipulator. Moreover, the motion accuracy was analyzed based on the kinematic model. In addition, the experiments were carried out for validation of the theory. Design/methodology/approach A kinematics model of the SRSS continuum manipulator is presented for analysis on bending, rotating and retracting in its workspace. To discuss the motion accuracy of the SRSS continuum manipulator, the dexterity theory was introduced based on the decomposing of the Jacobian matrix. In addition, the accuracy of motion is estimated based on the inverse kinematics and dexterity theory. To verify the presented theory, the motion of free end was tracked by an electromagnetic positioning system. According to the comparison of experimental value and theoretical analysis, the free end error of SRSS continuum manipulator is less than 6.24 per cent in the region with favorable dexterity. Findings This paper presents a new stretch-retractable continuum manipulator that the structure was composed of several springs as the backbone. Thus, the SRSS continuum manipulator could own wide motion range depending on its retractable structure. Then, the motion accuracy character of the SRSS continuum manipulator in the different regions of its workspace was obtained both theoretically and experimentally. The results show that the high accuracy region distributes in the vicinity of the outer boundary of the workspace. The motion accuracy gradually decreases with the motion position approaching to the center of its workspace. Research limitations/implications The presented SRSS continuum manipulator owns three degrees of freedom. The future work would be focused on the two-section structure which will own six degrees of freedom. Practical implications In this study, the SRSS continuum manipulator could be extended to six degrees of freedom continuum robot with two sections that is less one section than regular six degrees of freedom with three single section continuum manipulator. Originality/value The value of this study is to propose a SRSS continuum manipulator which owns three degrees of freedom and could stretch and retract to expend workspace, for which the accuracy in different regions of the workspace was analyzed and validated based on the kinematics model and experiments. The results could be feasible to plan the motion space of the SRSS continuum manipulator for keeping in suitable accuracy region.

Quaternion-Based Algorithm for Direct Kinematic Model of a Kawasaki FS10E Articulated Arm Robot

2015 ◽  
Vol 762 ◽  
pp. 249-254 ◽  
Author(s):  
Stelian Popa ◽  
Alexandru Dorin ◽  
Florin Adrian Nicolescu ◽  
Andrei Mario Ivan
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Kinematic Model ◽  
Three Dimensional ◽  
Number System ◽  
Simulation Software ◽  
Six Degrees Of Freedom ◽  
Mathematical Algorithm ◽  
Development And Validation ◽  
Three Dimensional Space

This article follows a detailed description of development and validation for the direct kinematic model of six degrees of freedom articulated arm robot - Kawasaki FS10E model. The development of the kinematic model is based on widely used Denavit-Hartenberg notation, but, after the initial parameter identification, the mathematical algorithm itself follows an approach that uses the quaternion number system, taking advantage of their efficiency in describing spatial rotation - providing a convenient mathematical notation for expressing rotations and orientations of objects in three-dimensional space. The proposed algorithm concludes with two quaternion-based relations that express both the position of robot tool center point (TCP) position and end-effector orientation with respect to robot base coordinate system using Denavit-Hartenberg parameters and joint values as input data. Furthermore, the developed direct kinematic model was validated using the programming and offline simulation software Kawasaki PC Roset.

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