scholarly journals Validation of Marker-Less System for the Assessment of Upper Joints Reaction Forces in Exoskeleton Users

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 3899
Author(s):  
Simone Pasinetti ◽  
Cristina Nuzzi ◽  
Nicola Covre ◽  
Alessandro Luchetti ◽  
Luca Maule ◽  
...  
Keyword(s):  
Motion Capture ◽  
Low Cost ◽  
Motion Capture System ◽  
Upper Limbs ◽  
Expert User ◽  
Reference Motion ◽  
Internal Joint ◽  
Reaction Forces ◽  
Clinical Gait Analysis ◽  
The Impact

This paper presents the validation of a marker-less motion capture system used to evaluate the upper limb stress of subjects using exoskeletons for locomotion. The system fuses the human skeletonization provided by commercial 3D cameras with forces exchanged by the user to the ground through upper limbs utilizing instrumented crutches. The aim is to provide a low cost, accurate, and reliable technology useful to provide the trainer a quantitative evaluation of the impact of assisted gait on the subject without the need to use an instrumented gait lab. The reaction forces at the upper limbs’ joints are measured to provide a validation focused on clinically relevant quantities for this application. The system was used simultaneously with a reference motion capture system inside a clinical gait analysis lab. An expert user performed 20 walking tests using instrumented crutches and force platforms inside the observed volume. The mechanical model was applied to data from the system and the reference motion capture, and numerical simulations were performed to assess the internal joint reaction of the subject’s upper limbs. A comparison between the two results shows a root mean square error of less than 2% of the subject’s body weight.

DEVELOPMENT OF A MOTION CAPTURE SYSTEM USING KINECT

2015 ◽  
Vol 76 (11) ◽  
Author(s):  
Katherina Bujang ◽  
Ahmad Faiz Ahmad Nazri ◽  
Ahmad Fidaudin Ahmad Azam ◽  
Jamaluddin Mahmud
Keyword(s):  
Motion Capture ◽  
Low Cost ◽  
Microsoft Kinect ◽  
Motion Capture Data ◽  
Motion Capture System ◽  
Interface Motion ◽  
Measurement Analysis ◽  
Potential Alternative ◽  
Repeatability And Reproducibility ◽  
Data Tracking

Microsoft Kinect has been identified as a potential alternative tool in the field of motion capture due to its simplicity and low cost. To date, the application and potential of Microsoft Kinect has been vigorously explored especially for entertainment and gaming purposes. However, its motion capture capability in terms of repeatability and reproducibility is still not well addressed. Therefore, this study aims to explore and develop a motion capture system using Microsoft Kinect; focusing on developing the interface, motion capture protocol as well as measurement analysis. The work is divided into several stages which include installation (Microsoft Kinect and MATLAB); parameters and experimental setup, interface development; protocols development; motion capture; data tracking and measurement analysis. The results are promising, where the variances are found to be less than 1% for both repeatability and reproducibility analysis. This proves that the current study is significant and the gained knowledge could contribute

scholarly journals SnakeStrike: A Low-Cost Open-Source High-Speed Multi-Camera Motion Capture System

2020 ◽  
Vol 14 ◽  
Author(s):  
Grady W. Jensen ◽  
Patrick van der Smagt ◽  
Egon Heiss ◽  
Hans Straka ◽  
Tobias Kohl
Keyword(s):  
Open Source ◽  
Motion Capture ◽  
High Speed ◽  
Low Cost ◽  
Camera Motion ◽  
Motion Capture System

scholarly journals Comparison of the Performance of the Leap Motion ControllerTM with a Standard Marker-Based Motion Capture System

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1750
Author(s):  
Amartya Ganguly ◽  
Gabriel Rashidi ◽  
Katja Mombaur
Keyword(s):  
Motion Capture ◽  
Gold Standard ◽  
Low Cost ◽  
Ring Finger ◽  
Healthcare Services ◽  
Leap Motion ◽  
Motion Capture System ◽  
Flexion Extension ◽  
Standard Marker ◽  
Motion Capture Systems

Over the last few years, the Leap Motion Controller™ (LMC) has been increasingly used in clinical environments to track hand, wrist and forearm positions as an alternative to the gold-standard motion capture systems. Since the LMC is marker-less, portable, easy-to-use and low-cost, it is rapidly being adopted in healthcare services. This paper demonstrates the comparison of finger kinematic data between the LMC and a gold-standard marker-based motion capture system, Qualisys Track Manager (QTM). Both systems were time synchronised, and the participants performed abduction/adduction of the thumb and flexion/extension movements of all fingers. The LMC and QTM were compared in both static measuring finger segment lengths and dynamic flexion movements of all fingers. A Bland–Altman plot was used to demonstrate the performance of the LMC versus QTM with Pearson’s correlation (r) to demonstrate trends in the data. Only the proximal interphalangeal joint (PIP) joint of the middle and ring finger during flexion/extension demonstrated acceptable agreement (r = 0.9062; r = 0.8978), but with a high mean bias. In conclusion, the study shows that currently, the LMC is not suitable to replace gold-standard motion capture systems in clinical settings. Further studies should be conducted to validate the performance of the LMC as it is updated and upgraded.

scholarly journals Next-Generation Low-Cost Motion Capture Systems Can Provide Comparable Spatial Accuracy to High-End Systems

2013 ◽  
Vol 29 (1) ◽  
pp. 112-117 ◽  
Author(s):  
Dominic Thewlis ◽  
Chris Bishop ◽  
Nathan Daniell ◽  
Gunther Paul
Keyword(s):  
Motion Capture ◽  
Low Cost ◽  
Three Dimensional ◽  
Gait Kinematics ◽  
Occupational Tasks ◽  
Soft Tissue Artifact ◽  
New Generation ◽  
The Impact ◽  
Linear Accuracy ◽  
Motion Capture Systems

The objective quantification of three-dimensional kinematics during different functional and occupational tasks is now more in demand than ever. The introduction of new generation of low-cost passive motion capture systems from a number of manufacturers has made this technology accessible for teaching, clinical practice and in small/medium industry. Despite the attractive nature of these systems, their accuracy remains unproved in independent tests. We assessed static linear accuracy, dynamic linear accuracy and compared gait kinematics from a Vicon MX-f20 system to a Natural Point OptiTrack system. In all experiments data were sampled simultaneously. We identified both systems perform excellently in linear accuracy tests with absolute errors not exceeding 1%. In gait data there was again strong agreement between the two systems in sagittal and coronal plane kinematics. Transverse plane kinematics differed by up to 3° at the knee and hip, which we attributed to the impact of soft tissue artifact accelerations on the data. We suggest that low-cost systems are comparably accurate to their high-end competitors and offer a platform with accuracy acceptable in research for laboratories with a limited budget.

A Low-Cost Instrumented Spatial Linkage Accurately Determines ASIS Position during Cycle Ergometry

2007 ◽  
Vol 23 (3) ◽  
pp. 224-229 ◽  
Author(s):  
James C. Martin ◽  
Steven J. Elmer ◽  
Robert D. Horscroft ◽  
Nicholas A.T. Brown ◽  
Barry B. Shultz
Keyword(s):  
Motion Capture ◽  
Low Cost ◽  
Cost Effective ◽  
Cycle Ergometry ◽  
Two Dimensional ◽  
Motion Capture System ◽  
Valid Measure ◽  
Kinematic Data ◽  
Vertical Error ◽  
Parasagittal Plane

The purpose of this study was to develop and evaluate an alternative method for determining the position of the anterior superior iliac spine (ASIS) during cycling. The approach used in this study employed an instrumented spatial linkage (ISL) system to determine the position of the ASIS in the parasagittal plane. A two-segment ISL constructed using aluminum segments, bearings, and digital encoders was tested statically against a calibration plate and dynamically against a video-based motion capture system. Four well-trained cyclists provided data at three pedaling rates. Statically, the ISL had a mean horizontal error of 0.03 ± 0.21 mm and a mean vertical error of −0.13 ± 0.59 mm. Compared with the video-based motion capture system, the agreement of the location of the ASIS had a mean error of 0.30 ± 0.55 mm for the horizontal dimension and −0.27 ± 0.60 mm for the vertical dimension. The ISL system is a cost-effective, accurate, and valid measure for two-dimensional kinematic data within a range of motion typical for cycling.

Design, Implementation, and Evaluation of Optical Low-Cost Motion Capture System

2011 ◽  
Author(s):  
Abhinav Chadda ◽  
Wenjuan Zhu ◽  
Ming C. Leu ◽  
Xiaoqing F. Liu
Keyword(s):  
Measurement Error ◽  
Software Architecture ◽  
Motion Capture ◽  
Real World ◽  
Virtual World ◽  
Low Cost ◽  
Architecture Design ◽  
Motion Capture System ◽  
Design Development ◽  
Coordinate Frames

This paper describes the design, implementation and evaluation of a low-cost motion capture system with support of interfaces for practically any types of cameras. We present the system’s software architecture design, development of software to implement and integrate several existing algorithms, and effective approaches to address practical issues such as object calibration and synchronizing the real-world and virtual-world coordinate frames. The motion capture system is developed to work with active markers and all the processing is done by the software on a mid-level workstation. With the Firefly MV cameras used, the developed system is capable of working at 60 frames per second, having the ability to simultaneously track the positions and orientations of five objects, with latency averaging about 15 ms, and with an average measurement error of about 0.65 mm between the distance of each pair of four LEDs mounted on a target that is placed 1.5–3.5 m from the cameras.

Characteristics of Falling Impact of Head Using a Test Dummy

2013 ◽  
Author(s):  
Marzieh Hajiaghamemar ◽  
Morteza Seidi ◽  
Vincent Caccese ◽  
Mohsen Shahinpoor
Keyword(s):  
Effective Mass ◽  
Motion Capture ◽  
Head Impact ◽  
Motion Capture System ◽  
Hip Joints ◽  
Permanent Disability ◽  
Impact Forces ◽  
Hybrid Iii ◽  
The Impact ◽  
Backward Fall

Traumatic Brain Injury (TBI) contributes to a major number of deaths and cases of permanent disability each year. Falls are the leading cause of TBI with the highest rates for children 0–4 years old and for adults age 75 and older. Accordingly, there is a significant interest in fall-related injury mechanism and head impact. Since the dynamics of human fall and head injury mechanisms are highly variable due to the inherent and complex nature of human falling, the aim of the present study is to describe the dynamics of backward falls and risk of injury due to head impact. In order to have a better understanding of head impact, A HYBRID III 5th Percentile Female test (Denton ATD, Inc.) instrumented with a tri-axial accelerometer with measuring range of ±500g at the center of gravity of the head was dropped from standing posture by using a controlled release mechanism. The dynamic model of fall was captured using a T-series Vicon motion capture system synchronized with a force plate to measure the impact force and a tri-axial accelerometer to measure the impact acceleration of the head. The acceleration impact data measured at 20 KHz and the motion capture system was capable to retrieve 500 samples per second. The primary objective of this study was to determine the equivalent mass involved during head impact due to a backward fall. This effective mass is a key quantity to design the head impact experimental setups, protection devices and computer simulations of head impact. Based on the force and acceleration measurements in several tests, the head impact effective mass is approximately found to be the mass of head itself plus 48% the neck mass. Two scenarios of backward fall were studied and discussed. First, falling while the hip joints are involved and the trunk moves forward and second, falling while the hip joints act like a fixed joint. For the first scenario the impact forces and accelerations peak measured using the HYBRID III were found to be 10±1.8KN and 255±42g, respectively, and for the second scenario the larger impact forces, 14.5±0.9KN, and acceleration peaks, 364±27g, were measured in all tests.

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