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1

Effects of eliminating visual cues on kinetic and kinematic parameters in back tuck somersault: A comparison between artistic gymnasts and parkour athletes

Abahnini Nour Mohamed, Abahnini Khemais, Mkaouer Bessem

Acta of Bioengineering and Biomechanics

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2023

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Vol. 25, no. 2

93--101

EN

The aim of this study was to compare the effect of vision (i.e., open and closed eyes) on the kinetic and kinematic parameters of the standing back tuck somersault (SBTS) in artistic gymnasts and parkour athletes. Methods: Eleven male parkour athletes (age 22.53 ± 2.36 years; height 1.72 ± 0.08 m; weight 69.58 ± 3.72 kg) and seven male artistic gymnasts (age 21.96 ± 2.64 years; height 1.62 ± 0.02 m; weight 63.54 ± 1.35 kg) participated in this study. Each subject was asked to perform the SBTS in the same condition (i.e., first open-eyes then closed-eyes). 2D kinetic and kinematic analysis was conducted. Results: The results showed significant interaction (i.e., vision and sport) obtained at the take-off angle ( p < 0.05 and d = 1.992), horizontal displacement ( p < 0.05 and d = 1.906) and technical execution ( p < 0.05 and d = 1.972). This interaction indicates that when vision is permitted, artistic gymnasts and parkour athletes were similar in all kinetic and kinematic parameters, and technical execution ( p > 0.05). However, the elimination of vision during SBTS only affected parkour athletes (i.e., landing angle, ground reaction force, vertical velocity and technical execution, p < 0.05 and d >1.20) while artistic gymnasts remain unchanged. Conclusion: We conclude that the specificity of the practice in each of the two sports disciplines influences the kinetic and kinematic control of the SBTS and suggests that with closed-eyes, the integration of afferent information relating to the vestibular and proprioceptive systems is different and specific to each discipline’s goal. Artistic gymnasts seem to be better skilled in the mechanical and technical control of the SBTS than parkour athletes.

2

Numerical analysis and experimental trial of axial feed skew rolling for forming bars

Zhang Huibo, Wang Baoyu, Lin Longfei, Feng Pengni, Zhou Jing, Shen Jinxia

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 1

art. no. e17, 2022

EN

Axial feed skew rolling (AFSR) is a novel flexible forming process suitable for the production of multi-specification and small-batch bars. This work presents a systematic investigation of AFSR process via numerical analysis and experimental method. The finite-element (FE) simulation was conducted to analyze the distributions of strain and stress, temperature evolution, axial feed motion, rolling force and torque. The results show that the stress state of the workpiece central in the deformation zone is compressive in radial direction and tensile in axial and tangential directions. During the whole process, the workpiece temperature remains in hot-rolling temperature range. The bite stage lasts less than 1 s, and the initial thrust required is about 3.17 kN (rolling from Ø 60 mm to Ø 40 mm). The axial sliding coefficient of workpiece is determined to be 0.63 via comprehensive analysis of simulation results and theoretical calculation. Moreover, based on the single-factor design, the effects of process parameters on axial feed velocity, rolling force, and torque were studied by FE simulation. The axial feed velocity, rolling force, and torque increase with increasing feeding angle and sizing length, but decrease with increasing forming angle. The experiments were performed on a newly designed rolling mill, and experimental results show consistency with FE simulation results. No central defects are observed, while there are surface helical grooves and end concave centers on the rolled piece. The diameter deviation of rolled piece is within ± 0.3 mm. The ultimate tensile strength (UTS) is increased by about 58 MPa.

3

The effect of three run-up techniques on kinetic and kinematic variables of the stag ring leap with throw-catch of the ball in rhythmic gymnastics

Akkari-Ghazouani Hounaida, Amara Samiha, Chtara Mokhtar, Mkaouer Bessem

Acta of Bioengineering and Biomechanics

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2022

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Vol. 24, no. 4

109--118

EN

The aim of this study was to compare the effect of three run-up steps on the kinetic and kinematic variables of the stag ring leap, with throw-catch of the ball, in high-level rhythmic female gymnasts. The three run-up steps used are a chassé step, glissade, and assemblé. Methods: Seven high-level rhythmic female gymnasts participated in this study. Three run-up steps (i.e., chassé step, glissade and assemblé) were used randomly to perform a stag ring leap with throwing a ball on the jump take-off. 2D kinetic and kinematic analysis was conducted. Results: The results indicated that the assemblé step used in the run-up technique generated greater values of the rate of force development, the highest values of vertical velocity, and the best vertical displacement. In addition, the assemblé step allows for the best opening angle of the split leap and the best closest angle of the ring leg. The same was noted for the front leg’s angular velocity. Conclusion: We concluded that the assemblé step used in the run-up technique appears to favor a greater stag ring leap that meets the Code of Points’ condition for admitting the jump, as well as numerous studies that focus on improving jumping abilities in rhythmic gymnastics.

4

Comparison of the optoelectronic BTS Smart system and IMU-based MyoMotion system for the assessment of gait variables

Bartoszek Amadeusz, Struzik Artur, Jaroszczuk Sebastian, Woźniewski Marek, Pietraszewski Bogdan

Acta of Bioengineering and Biomechanics

|

2022

|

Vol. 24, no. 1

104--116

EN

Although inertial measurement unit (IMU)-based systems have been validated against optoelectronic systems for recording joint kinematics, the accuracy of each system must be evaluated, and measurements from different systems cannot be easily compared. Therefore, this study compared the joint angles recorded using the IMU-based MyoMotion system and the optoelectronic BTS Smart-DX 700 system during Nordic walking. Methods: The study subject, a long-time Nordic walking instructor, was assigned to walk 12 m/trial (14 trials with 5 sampled gait cycles) at a velocity preferred for Nordic walking. The trials were simultaneously recorded by both systems. The instantaneous lower (ankle, knee, hip) and upper (shoulder, elbow, wrist) limb joint angles were recorded. Results: The joint angles from MyoMotion were significantly larger or smaller (depending on the joint and plane) than those from BTS. Conclusions: Joint angles measured by MyoMotion are not interchangeable with values from BTS, and IMU-recorded values should be interpreted carefully. However, MyoMotion can still provide information about intra-individual changes based on the joint angle profiles, e.g., following Nordic walking training.

5

Evaluating measurement accuracy and repeatability with a new device that records spatial knee movement

Tian Fei, Huang Qiuyue, Zheng Zhi, Li Ningwei, Zhu Ting, Dai Wei, Wang Shaobai

Acta of Bioengineering and Biomechanics

|

2020

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Vol. 22, no. 3

55--67

EN

Purpose: A novel portable system has been used to evaluate spatial knee movement, but its accuracy and repeatability is not known. The aim of this study was to investigate the accuracy and repeatability of the measurement. Methods: Ten healthy participants were included, and the knee motion trajectory during walking were assessed. Six evaluations were conducted (three days by two raters) for each participant. The motion parameters at the key points and the range of motion were statistically analyzed. Intraclass correlation coefficients (ICC), standard error of the measurement (SEM), and the Bland–Altman method were used. Results: For intra-rater repeatability, 1) the ICC values range from 0.75 to 0.9 for rotations; and 0.64 to 0.96 for translations. Among the ICC values, 100% of rotations and 90% of translations were not less than 0.70; 2) among the SEM values, 100% of rotations were not more than 5°, while 73.3% of translations were less than 3 mm. For inter-rater repeatability, 1) the ICC values range from 0.68 to 0.99 for rotations; and 0.57 to 0.93 for translations. Among the ICC values, 95.6% of rotations and 82.2% of translations were not less than 0.70; 2) among the SEM values, 100% of rotations were not more than 5°, and 48.9% of translations were less than 3 mm. The Bland–Altman plots showed good agreement for intra- and inter-repeatability. Conclusions: The results indicated that the accuracy and repeatability of the measurement were acceptable, except for the inter-rater repeatability for translation. This may help researchers and physicians better interpret the measurement data.

6

Attaching mass to the upper arm can increase throw distance in a modified javelin throw

Linthorne Nicholas, Heys Martin, Reynolds Tomas, Eckardt Nils

Acta of Bioengineering and Biomechanics

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2020

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Vol. 22, no. 2

55--67

EN

The effectiveness of the whip-like coordination in throwing might be influenced by the inertial properties of the athlete’s arm. This preliminary study investigated the acute effect of attaching mass to the upper arm on the distance achieved in a modified javelin throw. The aim was to identify the optimum upper arm mass that maximizes throw distance. Methods: Three well-trained adult male athletes performed maximum-effort throws with an 800-g javelin training ball. A wide range of masses (0–1.5 kg) were attached to the upper arm and a 2D video analysis was used to obtain measures of the projection variables for each attached mass. Results: All three athletes showed an effect of attached arm mass on throw distance, and with the optimum mass the athlete’s throw distance was increased by 2.2 m, 1.2 m, and 0 m (7%, 4%, and 0%), respectively. The optimum mass was specific to the athlete (0.6 kg, 0.2 kg, and 0 kg) and changes in throw distance were mostly due to changes in release velocity rather than changes in release angle or release height. The experimental results were broadly similar to those obtained using a simple 2D mathematical model of throwing. Conclusions: These results indicate that some javelin throwers might see an increase in throwing performance when a mass is attached to their upper arm. However, the relationship between upper arm mass and throwing performance should be investigated further with studies on more athletes, projectiles of different mass, and other throwing events.

7

Rejestracja ruchu żuchwy względem podstawy czaszki

Bukała Jakub, Małachowski Jerzy, Pietroń Kamil, Sybilski Kamil, Szafrańska Aleksandra

Aktualne Problemy Biomechaniki

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2019

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z. 17

11--17

PL

W pracy przedstawiono metodę badawczą pozwalającą na wyznaczenie krzywych opisujących ruch żuchwy względem podstawy czaszki człowieka bazującą na wideo-analizie. Do pomiaru wykorzystuje się markery pasywne odbijające promieniowanie podczerwone, które umieszczane są na nakładkach mocowanych do tkanek twardych osoby badanej.

EN

The study presents a research method for determining movement curves of the human mandible in relation to the base of the skull. The method is based on video analysis of passive markers reflecting IR radiation. Markers are placed on the personalized overlays fastened to the hard tissues of the examined person.

8

Kinematic Modeling and Analysis of a Walking Machine (Robot) Leg Mechanism on a Rough Terrain

Terefe Tesfaye O., Lemu Hirpa G, K/Mariam Addisu, Tuli Tadele B.

Advances in Science and Technology. Research Journal

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2019

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Vol. 13, no 3

43--53

EN

Many manmade machines and mechanisms, including robots, function based on the concept of nature-inspired design, so that they can perform their intended duties by mimicking the working mechanisms of animals and insects. Accordingly, walking machines (robots) use wheels and tracks to cross rough terrain efficiently and in a more stable way than conventional robots. Legged walking robots in particular remain in a discontinuous contact with the ground that provides them with the capability to select routes to avoid obstacles or holes. This article reports a study conducted on kinematic modelling and analysis of a walking machine (robot) leg mechanism that can operate on rough terrain. Its kinematic mechanisms were analyzed using the Denavit-Hartenberg (DH) convention approach. Symbolic computations are also implemented to parametrically optimize the motion parameters of the robot leg mechanism. The equation of motion was derived from the dynamic analysis using the Euler-Lagrange method which involves kinetic and potential energy expressions. In order to validate the performance of the robot leg mechanism and motion behaviors, the kinematic motion analysis was performed in SolidWorks and MATLAB. The leg mechanism used is effective for rough terrain areas because it is capable of walking on the terrain with different amplitudes in terms of surface roughness and aerodynamics.

9

Miary i mapy kinetyczne do automatycznej analizy ruchu w systemach CCTV

Parzych M., Marciniak T., Dąbrowski A.

Elektronika : konstrukcje, technologie, zastosowania

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2018

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Vol. 59, nr 4

19--23

PL

W artykule przedstawiono metodę obliczania miar ruchu dla inteligentnej analizy wideo. Obliczane są cztery miary: dwukierunkowa długość-łuku, kierunek-w-przód, kierunek-wstecz oraz krawędzie segmentów-ruchu. Wszystkie miary bazują na mapie przepływu obliczonej przy użyciu algorytmu przepływu optycznego. Segmenty-ruchu wykorzystują pola typu finite-time Lyapunov exponent (FTLE). Przeprowadzono eksperymentalne testy dla nagrań wideo z ruchem ludzi. Sprawdzono także czasochłonność obliczeń poszczególnych etapów proponowanego rozwiązania.

EN

This paper presents a calculation of the motion measures for intelligent video analysis. Four measures are proposed: bidirectional length, forward direction, backward direction and motion edges. All measures are based on a flow map obtained with the use of the optical flow algorithm. Motion edges utilizes finite-time Lyapunov exponent (FTLE) fields. Experimental tests were performed for video recordings with the people movement. The computation times of particular steps of the proposed solution were also checked.

10

Log „NavQuest 600” oraz żyrokompas „KVH 1750” jako system nawigacyjny do wyznaczania współrzędnych pozycji

Naus K.

Autobusy : technika, eksploatacja, systemy transportowe

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2017

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R. 18, nr 12

1159--1162, CD

PL

W artykule opisano badania mające na celu ocenę przydatności systemu nawigacyjnego złożonego z logu „NavQuest 600” oraz żyrokompasu optycznego „KVH 1750” do wyznaczania współrzędnych pozycji w warunkach morskich. W pierwszej części przedstawiono system pomiarowy, metodę badań oraz sposób wykonywania pomiarów w trudnych warunkach hydrometeorologicznych. Część zasadnicza przedstawia analizę dokładności wyznaczania parametrów ruchu i pozycji testowanym systemem nawigacyjnym polegającą na porównywaniu wyników pomiarów wzorcowych – wykonanych kompasem satelitarnym „NovAtel OEM617D-D2S-Z0G-0T0” oraz Inercjalnym Systemem Nawigacyjnym wspomaganym „VN-200” z pomiarami ocenianymi – wykonywanymi logiem „NavQuest 600” oraz żyrokompasem „KVH 1750”. Część końcowa zawiera uogólnione wnioski wyprowadzone na podstawie wyników z przeprowadzonych badań.

EN

This article describes the research that was aimed at evaluating suitability of the navigation system consisting of Doppler Velocity Log "NavQuest 600" and Fiber Optic Gyros "KVH 1750" to determining position coordinates in marine conditions. The first part shows the measurement system, the test method and the way of performing measurements in difficult hydrometeorological conditions. The main part contains analysis of the accuracy of determination of the parameters of motion and position tested by the navigation system performed by comparing the results of the reference measurements - made with the satellite compass "NovAtel OEM617D-D2S-Z0G-0T0" and the Inertial Navigation System assisted "VN-200" with test measurements - performed DVL "NavQuest 600" and FOG "KVH 1750". The final section contains generalized conclusions derived from the results of the studies.

11

Frictional Sound Analysis by Simulating the Human Arm Movement

Yosouf K., Latroch H., Schacher L., Adolphe D. C., Zimpfer V.

Autex Research Journal

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2017

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Vol. 17, no. 1

12--19

EN

Fabric noise generated by fabric-to-fabric friction is considered as one of the auditory disturbances that can have an impact on the quality of some textile products. For this reason, an instrument has been developed to analyse this phenomenon. The instrument is designed to simulate the relative movement of a human arm when walking. In order to understand the nature of the relative motion of a human arm, films of the upper half of the human body were taken. These films help to define the parameters required for movement simulation. These parameters are movement trajectory, movement velocity, arm pressure applied on the lateral part of the trunk and the friction area. After creating the instrument, a set of soundtracks related to the noise generated by fabric-to-fabric friction was recorded. The recordings were treated with a specific software to extract the sound parameters and the acoustic imprints of fabric were obtained.

12

Influence of additional loads on chosen gait parameters and muscles activity

Ludwicki M., Zagrodny B., Wojnicz W., Mrozowski J., Awrejcewicz J.

Vibrations in Physical Systems

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2016

|

Vol. 27

227--236

EN

This paper is devoted to human motion analysis and comparison of chosen kinematics parameters during normal gait with and without additional load in a form of backpack. A stability in both cases were compared in both frontal and sagittal planes, by applying a video tracking system. Experimental tests performed on treadmill, passive markers, placed on volunteers bare skin were used. Additionally, an infra-red camera was employed to evaluate muscle activity and its groups involved in the movement. The change of body temperature and distribution of the thermal maps were observed. Analysing these thermograms, loading of different muscle groups was evaluated. During the experiment, an attempt to correlate a results obtained from a thermal imaging camera and video tracking system were made. It is shown that thermal imaging can help to evaluate an asymmetry in muscle load and in some cases can help to detect pathological cases, what was confirmed with motion analysis. Advantages and disadvantages of this method were also described.

13

Projekt i analiza ruchu silnika z wirującym tłokiem

Budny Ł., Sosnowski M., Dembiczak T., Sawicki P., Gospodarek K., Ciesielska K., Orkisz M.

Prace Naukowe Akademii im. Jana Długosza w Częstochowie. Technika, Informatyka, Inżynieria Bezpieczeństwa

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2016

|

T. 4

69--76

PL

W ramach badań opracowano model przykładowego silnika z wirującym tłokiem oraz przeprowadzono analizy dynamiki ruchu poszczególnych jego elementów w celu identyfikacji ewentualnych problemów eksploatacyjnych wynikających z przemieszczenia translacyjnego wkładki uszczelniacza rotora.

EN

The rotary engine model was designed within the research. Moreover the analysis of dynamics of engine components were performed in order to identify the possible exploitation problems concerning displacement of rotor sealer insert.

14

Budowa i animacja realistycznego modelu 3D mięśnia dwugłowego ramienia

Poleszak S., Kopniak P.

Journal of Computer Sciences Institute

|

2016

|

Vol. 2

93--97

PL

Artykuł dotyczy opracowania sposobu budowy modelu trójwymiarowego mięśnia dwugłowego ramienia człowieka tak aby mięsień wyglądał i zachowywał się realistycznie podczas animacji. Dane do animacji są pozyskiwane przez systemy akwizycji ruchu - Motion Capture. Do zaprojektowania modelu bryły wykorzystano oprogramowanie Blender v.2.76. Na jego podstawie możliwe jest przeprowadzanie badań dotyczących analizy ruchu ramienia z wykorzystaniem danych zapisanych w plikach BVH.

EN

The article concerns the development of three-dimensional model of how to build biceps human with the muscle looked and behaved realistically when animation. Data for animation are obtained by acquisition systems Motion - Motion Capture. Blender software v.2.76 was used to design a solid model. On this basis it is possible to carry out research on the analysis of the movement of the arm using data stored in BVH files.

15

The relationship between trunk and pelvis kinematics during pregnancy trimesters

Eldeeb A. M., Hamada H. A., Abdel-Aziem A. A., Youssef A. M.

Acta of Bioengineering and Biomechanics

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2016

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Vol. 18, no. 4

79--85

EN

Purpose: Pregnancy is characterized by many musculoskeletal changes that affect daily living activities and walking. The purpose of this study was to examine the effect of pregnancy on pelvic and trunk kinematics, and their relationship during the three pregnancy trimesters. Methods: Three-dimensional pelvis and trunk motions were measured using Qualisys Gait Analysis System in the first, second and third trimesters of pregnancy. The maximum anterior pelvic tilt and maximum trunk flexion during stance phase, pelvic tilt, obliquity and rotation, as well as trunk flexion-extension, lateral bending and rotation were measured. Results: Repeated-measures analysis of variance showed a significant increase in the maximum anterior pelvic tilt during stance phase (p=0.005), and a significant decrease in the pelvic obliquity (p=0.011), maximum trunk flexion during stance phase (p=0.0006), trunk lateral bending (p=0.005) and trunk rotation (p=0.004). A significant negative correlation was found between maximum anterior pelvic tilt and maximum trunk flexion in the first (r=-0.72, p=0.008), second (r=-0.61, p=0.03), and third (r=-0.61,p=0.03) trimesters of pregnancy. Also, there was a significant positive correlation found between pelvic obliquity and trunk lateral bending in the first (r=0.76, p=0.04), second (r=0.59, p=0.04), and third (r=0.59, p=0.04) trimesters of pregnancy. Conclusions: The pregnant women walk with an increased maximum anterior pelvic tilt, a decreased maximum trunk flexion, a decreased pelvic obliquity, as well as a decreased trunk lateral bending and rotation. Pregnancy does not affect the relationship between pelvis and trunk motions.

16

Badania wspomagające przygotowanie spersonalizowanych ortez typu AFO/DAFO

Jochymczyk-Woźniak K., Chuchnowska I., Wolański W., Michnik R., Śmiech M., Czyrnia R., Gzik M.

Modelowanie Inżynierskie

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2015

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T. 25, nr 56

40--47

PL

W ramach pracy przeprowadzone zostały badania wspomagające proces przygotowania i doboru zindywidualizowanych ortez kończyny dolnej. Badania obejmowały analizę chodu pacjentów z mózgowym porażeniem dziecięcym MPD o różnej postaci i stopniu upośledzenia ruchowego. W przypadku wszystkich przebadanych dzieci wyniki badań chodu wykorzystano do przygotowania zaopatrzenia ortopedycznego w postaci ortez stopy i stawu skokowego AFO lub dynamicznej ortezy stopy i stawu skokowego DAFO. W artykule przedstawiono również metodykę analizy wytrzymałościowej ortez z wykorzystaniem metody elementów skończonych (MES). W procesie przygotowania indywidualnych ortez do rehabilitacji wykorzystano ręczny skaner 3D. Na podstawie rezultatów skanowania opracowano model geometryczny 3D spersonalizowanej ortezy stawu skokowego, a następnie model dyskretny 3D. Obliczenia wytrzymałościowe modelu MES ortezy pozwoliły dobrać optymalną grubość ortezy.

EN

The research is concerned with support of the process of preparation and selection of lower limb individual orthosis. The paper presents the analysis of gait in patients with cerebral palsy CP in varying forms and degrees of motor impairment. The results obtained from laboratory tests of children’s gait were used for the preparation of orthopedic orthosis in the form of AFO (ankle foot orthosis) type or DAFO (dynamic ankle foot orthosis) type. The article also describes the methodology of strength analysis of orthosis with the use of the Finite Element Method (FEM). A manual 3D scanner was applied in the process of the preparation of individual orthosis. A 3D geometrical model was developed for individual ankle orthosis based on the results of the scan. Further a devised 3D discretized model FEM allowed to carry out of strength analysis and choose the optimum orthosis thickness.

17

Quantitative comparison of marker attachment methods for hand motion analysis

Lee K. S., Jung M.- C.

International Journal of Occupational Safety and Ergonomics

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2015

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Vol. 21, No. 1

30--38

EN

The purpose of this study was to compare and quantify the angle difference among marker attachment methods for kinematic evaluation. For static evaluation, a hand mock-up was designed and used in single trials of different marker attachment methods. The mean absolute angle difference between the marker attachment methods and hand mock-up was not statistically significant. For dynamic evaluation, the gripping task began when a participant gripped a cylinder. The main effect of the marker set (p < .049) was significant. Thus, the use of one marker per joint is recommended for static evaluation because it causes less discomfort when a patient moves his/her hand and because utilizing the same marker placements for each subject is easy. For dynamic evaluation, the use of three markers per segment or a cluster marker is recommended because they are less affected by skin movement.

18

Differences in driving performance due to headway distances and gender: the application of jerk cost function

Choi J.-S., Kim H.-S., Shin Y.-H., Choi M.-H., Chung S.-C., Min B.-C., Tack G.-R.

International Journal of Occupational Safety and Ergonomics

|

2015

|

Vol. 21, No. 1

111--117

EN

Driving is directly controlled by the driver's movement. This study tried to compare differences in gender and headway distances between the DRIVING phase and the SUDDEN STOP phase by using subjects’ movement during driving in the simulator. To quantify subjects’ movement, the jerk cost function (JC) was used, and conventional vehicle control parameters such as the coefficient of variation of the mediolateral trajectory (MLCV) for lane keeping and the brake time (BT) were also used. As the headway distance increased, MLCV and JC decreased significantly in the DRIVING phase. In the SUDDEN STOP phase, BT was increased and, MLCV and JC were decreased. Differences between genders were detected for both MLCV (males < females) and JC (males > females). The results of this study demonstrate that JC may be used as a variable in evaluating driving performance as influenced by driving conditions and gender.

19

Evaluation of functional methods for human movement modelling

Gastaldi L., Lisco G., Pastarelli S.

Acta of Bioengineering and Biomechanics

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2015

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Vol. 17, no. 4

31--38

EN

Purpose: accurate assessment of human joint parameters is a critical issue for the quantitative movement analysis, due to a direct influence on motion patterns. In this study three different known functional methods are experimentally compared to identify knee joint kinematics for further gait and motion analysis purposes. Methods: taking into account the human knee physiology complexity, within its roto-translation, the study is conducted on a lower limb mechanical analogue with a polycentric hinge-based kinematic model. The device mimics a joint with a mobile axis of rotation whose position is definable. Sets of reflective markers are placed on the dummy and flexion-extension movements are imposed to the shank segment. Marker positions are acquired using an optoelectronic motion capture system (Vicon 512). Results: acquired markers’ positions are used as input data to the three functional methods considered. These ones approximate the polycentric knee joint with a fixed single axis model. Different ranges of motion and number of markers are considered for each functional method. Results are presented through the evaluation of accuracy and precision concerning both misalignment and distance errors between the estimated axis of rotation and the instantaneous polycentric one, used as reference. Conclusion: the study shows the feasibility of the identification of joint parameters with functional approaches applied on a polycentric mechanism, differently from those usually conceived by the reviewed algorithms. Moreover, it quantifies and compares the approximation errors using different algorithms, by varying number and position of markers, as well ranges of motion.

20

Zastosowanie technik CAD/CAE do projektowania i analiz nożycowych podnośników samochodowych

Jereczek J., Budniak Z., Karaczun A.

Autobusy : technika, eksploatacja, systemy transportowe

|

2014

|

R. 15, nr 6

138-144

PL

W artykule przedstawiono możliwości wykorzystania technik komputerowych CAD/CAE do modelowania i analizy ruchu nożycowego podnośnika samochodowego. Opracowany model symulacyjny, zawierający szkieletowy model podnośnika, pozwala na symulowanie pracy mechanizmu nożycowego podczas wykonywania przez niego złożonego cyklu pracy. Wyniki analiz wykorzystano do opracowania wirtualnego modelu konstrukcji podnośnika.

EN

This article presents the possibilities of using computer technology of CAD/CAE for modeling and analysis motion of the scissor car jacks Developed a simulation model that contains skeletal model of jack, allows you to present simulation of the scissor mechanism during the performance of composite work cycle. The results of this analysis were used to develop of the virtual model of the jacks structure.