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.

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.

6R Instrumented Spatial Linkages for Anatomical Joint Motion Measurement—Part 1: Design

1992 ◽  
Vol 114 (1) ◽  
pp. 92-100 ◽  
Author(s):  
S. J. Kirstukas ◽  
J. L. Lewis ◽  
A. G. Erdman
Keyword(s):  
Numerical Methods ◽  
Design Process ◽  
Joint Motion ◽  
Calibration Technique ◽  
Knee Motion ◽  
Motion Measurement ◽  
Experimental Apparatus ◽  
The Subject ◽  
Spatial Linkages ◽  
Six Degree Of Freedom

Six-revolute-joint instrumented spatial linkages (6R ISLs) have become often-used devices to measure the complete six-degree-of-freedom motion of anatomical joints. Accuracy of motion measurement depends on ISL design and calibration technique. In this paper, a design process is outlined that uses computer graphics and numerical methods as aids in developing 6R ISLs that (i) physically assemble within the desired range of motion of the joint; (ii) do not collide with either the experimental apparatus or the subject joint; (iii) avoid singular linkage configurations that can cause forces to be applied to the joint; and (iv) measure selected anatomical motions most accurately. It is found that a certain subgroup of 6R linkages are suitable for accurate measurement of specific motions, and can be the basis for new ISL designs. General guidelines are developed that can assist in the generation of unique linkage designs for different anatomical joints. The design process is demonstrated in the creation of an ISL to measure knee motion.

General Mathematical Model of Multi-Arm Cooperating Robots With Elastic Interconnection at the Contact

1997 ◽  
Vol 119 (4) ◽  
pp. 707-717 ◽  
Author(s):  
Milovan Z˘ivanovic´ ◽  
Miomir Vukobratovic´
Keyword(s):  
Mathematical Model ◽  
Degrees Of Freedom ◽  
Dynamic Environment ◽  
Six Degrees Of Freedom ◽  
General Mathematical Model ◽  
Cooperating Robots ◽  
Six Degree Of Freedom ◽  
Physical Phenomena ◽  
First Time ◽  
Object Dynamic

The procedure of modeling and the complete general form mathematical model of manipulators with six degrees of freedom in cooperative work are presented in the paper, together with the solution of undefiniteness problem with respect to force distribution. For the first time, a system of active spatial six-degree-of-freedom mechanisms elastically interconnected with the object (dynamic environment) is modeled. The reason for the emergence of the undefiniteness problem with respect to force is explained and the procedure for solving this problem given. Unlike the approaches given in the available literature, the undefiniteness problem with respect to force is solved in accordance with physical phenomena. The modeling procedure is illustrated by a simplified example.

Patellar Maltracking: No Longer Just a 2D Problem

2003 ◽  
Author(s):  
Andrea J. Rebmann ◽  
Barry P. Boden ◽  
Frances T. Sheehan
Keyword(s):  
Degrees Of Freedom ◽  
Measurement Techniques ◽  
Two Dimensions ◽  
Future Research ◽  
Joint Mechanics ◽  
Patellar Tilt ◽  
Six Degrees Of Freedom ◽  
Patellar Maltracking ◽  
Clinical Diagnoses

In order to correctly diagnose and treat pathological knee joint mechanics we must be able to non-invasively quantify the 3D in vivo kinematics of this joint. Unfortunately, the majority of clinical diagnoses, for this joint, are based upon static 2D imaging. This is due to the fact that currently there is a scarcity of noninvasive measurement techniques that acquire 3D in vivo data dynamically. Thus, in vivo patellofemoral (PF) kinematic measurements typically compress a 3D time-dependent joint attitude to a static 2D representation. The purpose of this study was to investigate if patellar maltracking is limited to two dimensions, as assumed clinically, or if it is a complete six-degree of freedom problem. To do this, we quantified the 3D patellofemoral and tibiofemoral (TF) kinematics in both healthy individuals and those with suspected patellofemoral maltracking using fast-phase contrast magnetic resonance imaging, a technique developed in our previous work. Our data suggest that variations in kinematics were not confined to the standard axial plane measures (e.g. patellar tilt, patellar subluxation), but variations are exhibited in all six degrees of freedom. Therefore, future clinical diagnoses and interventions along with future research will be most effective if the measures used are broadened to include all six-degrees of freedom.

The St. Petersburg Wrist: A Prototype Powered Flexion Wrist Unit

2008 ◽  
Author(s):  
Kathryn J. De Laurentis ◽  
Sam L. Phillips
Keyword(s):  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Six Degrees Of Freedom ◽  
Important Addition ◽  
Powered Prosthesis ◽  
Six Degree Of Freedom ◽  
Flexion And Extension

This is the presentation of a prototype wrist, which has powered rotation and flexion. Powered flexion is an important addition to an externally powered prosthesis. Flexion and extension, along with rotation give the prosthesis two additional degrees of freedom, which when added to degrees of freedom for the shoulder and elbow yield a six-degree of freedom system. Six-degrees of freedom are important because they allow placement of the hand throughout the entire workspace. Without flexion, amputees cannot reach some positions, and must use compensatory motions for many other movements.

scholarly journals In-situ measurement technologies for flow behaviour and contact status of fibre-reinforced thermoplastics during forming with a six degree of freedom press

2018 ◽  
Vol 190 ◽  
pp. 07004
Author(s):  
Birk Wonnenberg ◽  
Franz Dietrich ◽  
Klaus Dröder
Keyword(s):  
Degrees Of Freedom ◽  
Optical Measurements ◽  
Image Processing Algorithm ◽  
Forming Process ◽  
Contact State ◽  
Six Degrees Of Freedom ◽  
Reinforced Plastics ◽  
Reinforced Thermoplastics ◽  
Six Degree Of Freedom

The paper presents investigations on a forming process, which is implemented in a forming press based on a Stewart platform. In contrast to common forming techniques, this buildup offers not only one but six degrees of freedom. This is of particular interest when it comes to the forming of materials that show significant anisotropic behaviour such as fibre-reinforced plastics. Therefore, an experimental setup is presented to record characteristic variables during the forming process of fibre-reinforced thermoplastics. The contact state is of particular interest for this kind of forming process because it changes continuously in shape and position as the forming process progresses. For this purpose, temperatures at different places in the tool are recorded to provide information about the flow velocity of the material and the contact state between tool and workpiece. This allows the determination of the exact time and position of the contact between material and forming tool as well as the duration of this contact. The results are compared with optical measurements analysed by image processing algorithm and process forces measured by load cells.

A Six-Degree-of-Freedom Test System for the Study of Joint Mechanics and Ligament Forces

1995 ◽  
Vol 117 (4) ◽  
pp. 383-389 ◽  
Author(s):  
J. M. Hollis
Keyword(s):  
Degrees Of Freedom ◽  
Test System ◽  
Testing System ◽  
Joint Mechanics ◽  
Six Degrees Of Freedom ◽  
Position Feedback ◽  
Six Degree Of Freedom ◽  
Good Agreement

A joint testing system was designed to transmit a specified motion or force to a joint in all six degrees of freedom (d.o.f.) using a spatial linkage system for position feedback. The precise reproducibility of position provided by this method of position feedback allows determination of in situ ligament forces for external joint loadings. Load on the structure of interest is calculated from six d.o.f. load cell output after the loaded position is reproduced with all other structures removed. In a test of this system, measured loads showed good agreement with applied loads.

Test bench development and validation for blocked force measurements in six degree of freedom

2021 ◽  
Vol 263 (3) ◽  
pp. 3933-3943
Author(s):  
Martin Burkhardt ◽  
Eric Hensel ◽  
Welf-Guntram Drossel
Keyword(s):  
Degrees Of Freedom ◽  
Force Measurement ◽  
Product Development Process ◽  
Force Measurements ◽  
Source Characterization ◽  
Structural Dynamic ◽  
Six Degrees Of Freedom ◽  
Transfer Path ◽  
Six Degree Of Freedom ◽  
Development And Validation

For transfer path analysis (TPA) methods, the description of the source is essential. The possibilities of source characterization are as different as the TPA methods. For the classical methods, the source is considered in the installed state with feedback from the receiver structure, while for component-based TPA the source is described without feedback from the coupled structure. In addition to TPA, source characterization is also used in the product development process for evaluation or comparisons. Also in these cases, the source must be characterized without feedback from the test structure, which can generally be realized by measuring free velocities or blocked forces. Because of the need of external load to reach the components operating point, force measurements are often used. However, the realization of a reactionless test setup for the measurement of forces poses some challenges. The paper presents a setup that can be used to perform a direct force measurement at a point in six degrees of freedom. The necessary boundary conditions to approximate the idealized blocked force assumption are discussed, the calculation of the blocked force in six degrees of freedom is presented, the structural dynamic response at a reference point is calculated and compared with operational measurements.

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.

Reconfiguration Analysis of a Fully Reconfigurable Parallel Robot

2013 ◽  
Vol 5 (4) ◽  
Author(s):  
Allan Daniel Finistauri ◽  
Fengfeng (Jeff) Xi
Keyword(s):  
Comparative Study ◽  
Degrees Of Freedom ◽  
Parallel Robot ◽  
Passive State ◽  
Limited Mobility ◽  
Six Degrees Of Freedom ◽  
Revolute Joints ◽  
Six Degree Of Freedom ◽  
The Comparative Study ◽  
Selection Of

This paper presents a new method for the combined topological and geometric reconfiguration of a parallel robot to achieve task-based reconfiguration. Using the existing structure of a six degree-of-freedom (DOF) parallel robot, reconfiguration to limited mobility modes, a configuration with less than six degrees-of-freedom, can be achieved easily without the need to remove branches from the robot structure. Branch modules are instead, reconfigured from an unconstrained-active to a constrained-passive state by means of hybrid active/passive motors and reconfigurable universal-to-revolute joints. In doing so, the robot is capable of assuming a configuration in which the number of task-based degrees-of-freedom match the number of controllable actuators within the robot structure. The selection of branch modules for reconfiguration is independent of the limited mobility mode required and leads to multiple isomorphic configurations. A comparative study is thus needed to understand not only the implication of morphing, but also the capabilities of the reconfigured robot. For this purpose, a branch-based mobility analysis is performed and isomorphic configurations are identified. These isomorphic configurations are then compared based on their workspace and kinematic capabilities for which a parametric kinematic constraint formulation is developed. The comparative study evaluates the abilities of each configuration and is used for guidance in selecting an appropriate configuration for a particular task. The developed tools can also be used for design evaluation purposes.

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