A Method for Computing the Three-Dimensional Angular Velocity and Acceleration of a Body Segment From Three-Dimensional Position Data

1990 ◽  
Vol 112 (2) ◽  
pp. 114-118 ◽  
Author(s):  
M. C. Verstraete ◽  
R. W. Soutas-Little
Keyword(s):  
Angular Velocity ◽  
Three Dimensional ◽  
The Body ◽  
Position Vector ◽  
Body Segment ◽  
Method Of Least Squares ◽  
System Noise ◽  
Position Data ◽  
Soft Tissue Motion ◽  
Tissue Motion

A theoretical technique, based on the Method of Least Squares, was employed to solve for the three-dimensional components of the angular velocity and acceleration of a limb segment directly from experimentally recorded three-dimensional position data. Results showed that a minimum of four targets placed on the body segment, forming six relative position vector equations, were required to produce the most accurate results. It was also found that this method eliminates the errors due to soft tissue motion and system noise.

Simulating Acceleration From Stereophotogrammetry For Medical Device Design

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Philip A. Tresadern ◽  
Sibylle B. Thies ◽  
Laurence P. J. Kenney ◽  
David Howard ◽  
Christine Smith ◽  
...  
Keyword(s):  
Medical Device ◽  
The Body ◽  
Coordinate Frame ◽  
Body Segment ◽  
Medical Device Design ◽  
Position Data ◽  
Order Of Magnitude ◽  
Tangential Acceleration ◽  
Virtual Signal ◽  
Acceleration Signals

When designing a medical device based on lightweight accelerometers, the designer is faced with a number of questions in order to maximize performance while minimizing cost and complexity: Where should the inertial unit be located? How many units are required? How is performance affected if the unit is not correctly located during donning? One way to answer these questions is to use position data from a single trial, captured with a nonportable measurement system (e.g., stereophotogrammetry) to simulate measurements from multiple accelerometers at different locations on the body. In this paper, we undertake a thorough investigation into the applicability of these simulated acceleration signals via a series of interdependent experiments of increasing generality. We measured the dynamics of a reference coordinate frame using stereophotogrammetry over a number of trials. These dynamics were then used to simulate several “virtual” accelerometers at different points on the body segment. We then compared the simulated signals with those directly measured to evaluate the error under a number of conditions. Finally, we demonstrated an example of how simulated signals can be employed in a system design application. In the best case, we may expect an error of 0.028 m/s2 between a derived virtual signal and that directly measured by an accelerometer. In practice, however, using centripetal and tangential acceleration terms (that are poorly estimated) results in an error that is an order of magnitude greater than the baseline. Furthermore, nonrigidity of the limb can increase error dramatically, although the effects can be reduced considerably via careful modeling. We conclude that using simulated signals has definite benefits when an appropriate model of the body segment is applied.

scholarly journals Quantifying Forearm Soft Tissue Motion from Massless Skin Markers following Forward Fall Hand Impacts

2018 ◽  
Vol 6 (3) ◽  
pp. 1
Author(s):  
Danielle L. Gyemi ◽  
Don Clarke ◽  
Paula M. van Wyk ◽  
William J. Altenhof ◽  
David M. Andrews
Keyword(s):  
Soft Tissue ◽  
High Speed ◽  
Soft Tissues ◽  
Skin Pigmentation ◽  
Single Layer ◽  
The Body ◽  
Shock Attenuation ◽  
Skin Marker ◽  
Soft Tissue Motion ◽  
Tissue Motion

Background: Investigating soft tissue motion related to impact events is important for understanding how the body mitigates potentially injurious forces through shock attenuation. Objectives: The aims of this study were to: 1) quantify displacement and velocity of the forearm soft tissues following forward fall impacts; and 2) compare two massless skin marker designs (single layer, uniform (SLU) design; stacked, non-uniform (SNU) design) in terms of how well they could be tracked over varying skin pigmentations using automated motion capture software. Methods: Two participant groups (skin pigmentation: light – 9F, 8M; dark – 9F, 6M) underwent simulated forward fall hand impacts for each marker design using a torso-release apparatus. Marker positions associated with planar motion of forearm soft tissues during impact were automatically tracked (ProAnalyst®) in the proximal-distal and anterior-posterior axes from high speed recordings (5000 f/s). Mean peak displacements and velocities for eight forearm regions were then calculated (LabVIEW®). Results: Overall, soft tissue displacement and velocity increased from distal to proximal forearm regions. The greatest displacement (1.47 cm) and velocity (112.8 cm/s) occurred distally toward the wrist. Soft tissue impact responses between sexes did not differ, on average (p > 0.05). The SLU and SNU markers produced different kinematic values (p < 0.05); however, the magnitudes of, and consequently meaningfulness of these statistical differences for automatically tracking soft tissue motion, were negligible (displacement: ≤ 0.05 cm; velocity: ≤ 2.5 cm/s). Conclusions: Forearm soft tissue motion was successfully quantified for forward fall hand impacts; both marker designs were deemed functionally equivalent.

IP AND RESISTIVITY TYPE CURVES FOR THREE‐DIMENSIONAL BODIES

Geophysics ◽  
1969 ◽  
Vol 34 (4) ◽  
pp. 615-632 ◽  
Author(s):  
K. Dieter ◽  
N. R. Paterson ◽  
F. S. Grant
Keyword(s):  
Arbitrary Shape ◽  
Apparent Resistivity ◽  
Three Dimensional ◽  
Spherical Shape ◽  
The Body ◽  
Electrode Arrays ◽  
Method Of Least Squares ◽  
Straightforward Manner ◽  
Type Curves ◽  
Actual Field

A new method for calculating anomaly patterns and type curves of apparent resistivity and apparent chargeability over three‐dimensional bodies imbedded in a half‐space is practicable. The solution of the boundary‐value problem for a point source of current near a body of arbitrary shape in the form of an inhomogeneous integral equation is solved numerically by the method of least squares. The solution is then used to construct the apparent resistivity and apparent chargeability functions for three and four‐electrode arrays in the vicinity of the body in a straightforward manner. Type curves show the application to an actual field example. Finally, some simple, direct aids for interpreting anomalies over mineralized zones of compact (i.e. roughly spherical) shape result. This study represents the results of the first phase of a continuing program of research into resistivity and IP interpretation theory.

New Mathematical Definition and Calculation of Axial Rotation of Anatomical Joints

1991 ◽  
Vol 113 (3) ◽  
pp. 270-275 ◽  
Author(s):  
Shinji Miyazaki ◽  
Akimasa Ishida
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Axial Rotation ◽  
The Body ◽  
Body Segment ◽  
Angular Velocity Vector ◽  
Mathematical Definition ◽  
Stationary Coordinate System ◽  
The Difference ◽  
Definition Of

In the field of joint kinematics, clinical terms such as internal-external, or medical-lateral, rotations are commonly used to express the rotation of a body segment about its own long axis. However, these terms are not defined in a strict mathematical sense. In this paper, a new mathematical definition of axial rotation is proposed and methods to calculate it from the measured Euler angles are given. The definition is based on the integration of the component of the angular velocity vector projected onto the long axis of the body segment. First, the absolute axial rotation of a body segment with respect to the stationary coordinate system is defined. This definition is then generalized to give the relative axial rotation of one body segment with respect to the other body segment where the two segments are moving in the three-dimensional space. The well-known Codman’s paradox is cited as an example to make clear the difference between the definition so far proposed by other researchers and the new one.

scholarly journals A low-cost three-dimensional laser surface scanning approach for defining body segment parameters

2017 ◽  
Vol 231 (11) ◽  
pp. 1064-1068 ◽  
Author(s):  
Petros Pandis ◽  
Anthony MJ Bull
Keyword(s):  
Low Cost ◽  
Three Dimensional ◽  
Dynamic Modelling ◽  
The Body ◽  
Parameter Estimates ◽  
Body Segment ◽  
Subject Specific ◽  
Actual Volume ◽  
System Body ◽  
Body Segment Parameters

Body segment parameters are used in many different applications in ergonomics as well as in dynamic modelling of the musculoskeletal system. Body segment parameters can be defined using different methods, including techniques that involve time-consuming manual measurements of the human body, used in conjunction with models or equations. In this study, a scanning technique for measuring subject-specific body segment parameters in an easy, fast, accurate and low-cost way was developed and validated. The scanner can obtain the body segment parameters in a single scanning operation, which takes between 8 and 10 s. The results obtained with the system show a standard deviation of 2.5% in volumetric measurements of the upper limb of a mannequin and 3.1% difference between scanning volume and actual volume. Finally, the maximum mean error for the moment of inertia by scanning a standard-sized homogeneous object was 2.2%. This study shows that a low-cost system can provide quick and accurate subject-specific body segment parameter estimates.

Three-dimensional acceleration of the body center of mass in people with transfemoral amputation: Identification of a minimal body segment network

2021 ◽  
Vol 90 ◽  
pp. 129-136
Author(s):  
Emeline Simonetti ◽  
Elena Bergamini ◽  
Joseph Bascou ◽  
Giuseppe Vannozzi ◽  
Hélène Pillet
Keyword(s):  
Center Of Mass ◽  
Three Dimensional ◽  
The Body ◽  
Body Segment ◽  
Transfemoral Amputation ◽  
Body Center

scholarly journals Three-dimensional integral dry friction model for the motion of a rectangular body

2021 ◽  
Vol 21 (1) ◽  
pp. 14-21
Author(s):  
M. S. Salimov ◽  
I. V. Merkuriev
Keyword(s):  
Angular Velocity ◽  
Dry Friction ◽  
Three Dimensional ◽  
Friction Model ◽  
The Body ◽  
Horizontal Surface ◽  
Padé Approximations ◽  
Pade Approximations ◽  
Analytical Expressions ◽  
Rectangular Body

Introduction. A three-dimensional dry friction model in the interaction of a rectangular body and a horizontal rough surface is considered. It is assumed that there is no separation of the body from the horizontal surface. The body motion occurs under the conditions of combined dynamics when, in addition to the longitudinal movement, the body participates in twisting.Materials and Methods. Linear fractional Pade approximations are proposed, which replaced the cumbersome analytical expressions that most accurately describe the motion of bodies on rough surfaces. New mathematical models describing sliding and twisting of bodies with a rectangular base are proposed.Results. Analytical expressions of the principal vector and moment of friction for rectangular contact areas are developed and scientifically established. A friction model that takes into account the relationship between sliding and twisting speeds, which provides finding solutions for Pade dependences, is developed. After numerical solution to the equations of motion, the dependences of the sliding speed and angular velocity on time were obtained and constructed. Graphs of the dependences of the friction forces and their moment on two parameters (angular velocity and slip velocity) were constructed, which enabled to compare the integral and normalized models of friction. The comparison results showed good agreement of the integral model and the model based on Pade approximations.Discussion and Conclusions. The results obtained provide considering the dynamic coupling of components, which determines the force interaction of a rectangular body and a horizontal surface. These results can be used in mobile robotics. The analyzed motion of the body occurs through the motion control of a material point inside the body. Such mobile robots can be used when solving a wide class of problems: when creating autonomous robots for the exploration of outer space and planets; in the diagnosis and treatment in case of passing through complex structures of veins and arteries; in research under water, in places of large differential temperature; in underground operations.

Scanning electron microscopy of freeze-fractured prescapular lymph node of caprine

1984 ◽  
Vol 42 ◽  
pp. 244-245
Author(s):  
O. Faroon ◽  
F. Al-Bagdadi ◽  
T. G. Snider ◽  
C. Titkemeyer
Keyword(s):  
Lymph Node ◽  
Lymph Nodes ◽  
Lymphatic System ◽  
Three Dimensional ◽  
Meat Products ◽  
The Body ◽  
Morphological Data ◽  
The World ◽  
Cellular Constituent ◽  
Scanning Electron

The lymphatic system is very important in the immunological activities of the body. Clinicians confirm the diagnosis of infectious diseases by palpating the involved cutaneous lymph node for changes in size, heat, and consistency. Clinical pathologists diagnose systemic diseases through biopsies of superficial lymph nodes. In many parts of the world the goat is considered as an important source of milk and meat products.The lymphatic system has been studied extensively. These studies lack precise information on the natural morphology of the lymph nodes and their vascular and cellular constituent. This is due to using improper technique for such studies. A few studies used the SEM, conducted by cutting the lymph node with a blade. The morphological data collected by this method are artificial and do not reflect the normal three dimensional surface of the examined area of the lymph node. SEM has been used to study the lymph vessels and lymph nodes of different animals. No information on the cutaneous lymph nodes of the goat has ever been collected using the scanning electron microscope.

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