International journal of Mechanics and Controlmogi.bme.hu/files/resdev.OTKA/2018/115894/JoMaC_accurancy.pdf · 1 Hungary, 1521 Budapest, Pf. 91. E-mail: [email protected] These are

ISSN 1590-8844

Vol. 19 No 02

2018

International Journal

of

Mechanics and Control

Editor: Andrea Manuello Bertetto

Scopus Indexed Journal

Reference Journal of IFToMM Italy

International Federation for the Promotion

of Mechanism and Machine Science

International Journal of Mechanics and Control

Associate Editors

Published by Levrotto&Bella – Torino – Italy E.C.

Honorary editors

Guido Belforte Kazuo Yamafuji


General Secretariat: Matteo D. L. Dalla Vedova

Mario Acevedo

Universidad Panamericana

Mexico City – Mexico

Elvio Bonisoli

Politecnico di Torino

Torino – Italy

Giovanni Boschetti

University of Padova

Vicenza – Italy

Luca Bruzzone

Università degli Studi di Genova

Genova – Italy

Giuseppe Carbone

University of Cassino

Cassino – Italy

Marco Ceccarelli

University of Cassino

Cassino – Italy

Francesca Di Puccio

University of Pisa

Pisa – Italy

Carlo Ferraresi


Torino – Italy

Walter Franco


Torino – Italy

Rafael Lopez Garcia

University of Jaen

Jaen – Spain

Viktor Glazunov

Mechanical Engineering Research Institute of the

Russian Academy of Sciences (IMASH RAN)

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Waseda University

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Giovanni Jacazio


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Universidad Autonoma de Queretaro

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Paolo Maggiore


Torino – Italy

Paolo Emilio Lino Maria Pennacchi

Politecnico di Milano

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Giuseppe Quaglia


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Belgrade – Serbia

Mauro Velardocchia


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Free University of Bolzano

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Ion Visa

Transilvania University of Brasov

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VSB - Technical University of Ostrava

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Direttore responsabile:

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Direttore responsabile:

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ISSN 1590-8844

International Journal of Mechanics and Control, Vol. 19, No. 02, 2018

1

Preface for the special issue

of the International Journal of Mechanics and Control (JoMaC)

dedicated to BIOMECHANICAL ENGINEERING

Biomechanical Engineering applies principles of Engineering Mechanics to biological systems, and originates from the

wider discipline of Biomechanics. Biomechanical Engineers work in a variety of fields including medicine, sports and

rehabilitation.

Biomechanical Engineering can be declined into a variety of topics, for example biomechanics of human body,

motion/equilibrium/postural analysis, articular kinematics, soft tissue mechanics, mechanics of fluid systems (cardio-

circulatory, respiratory, …). Particular attention should be paid to human-machine interaction, comprising rehabilitation

devices, orthoses, internal and external prostheses, exoskeletons, medical application of robotics, robotic surgery, and

haptic systems.

The interest for Biomechanical Engineering has continuously increased in last years, and a large number of specialized

journals populate the international editorial panorama. In addition, many international conferences, specifically devoted to

Biomechanical Engineering, or including dedicated special sessions, are yearly organized.

It is worth reporting that a world organization such as IFToMM (the international federation for the promotion of

mechanism and machine science) counts, among others, an especially dedicated Technical Committee for the

Biomechanical Engineering. This TC has strongly grown up in the last period, evidencing an increasing interest in this

discipline, and nowadays it counts 36 members from 20 Countries, spread over 4 Continents. In July 2018, the International

Scientific Committee of MESROB (International Workshop on New Trends in Medical and Service Robotics) has

deliberated to become the official conference of the IFToMM TC for Biomechanical Engineering.

JoMaC, the International Journal of Mechanics and Control, which is the official journal of IFToMM Italy, decided to

dedicate in the current issue a special space to the Biomechanical Engineering.

Four valuable contributions, covering a wide range of biomechanical applications, have been invited and are here presented.

Kristóf Rácz et al. propose new suitable standards to examine how a set of changes to a calibration protocol affects accuracy

in gait analysis. Alberto Concu et al. evaluate the correlation between the mechanical and the metabolic energy, during the

gait cycle of a subject equipped with and without energy storage devices called “Jump Stilts”. Wen Chih Wu et al. analyze

changes in the metabolic power and energy cost, due to cardio-respiratory and metabolic adaption induced in a 52-aged élite

sailor engaged in the Onestar Atlantic solo race from Plymouth (UK) to Newport (USA). Carlo De Benedictis et al. present

an elbow static progressive brace equipped with special sensors, aimed at objective evaluation of the physiological response

of the articulation during treatments for recovery of the functional range of motion.

I wish to express my sincere appreciation to all researchers having contributed to this special issue, for their valuable

support to the growth of this fascinating discipline.

Carlo Ferraresi

Associate Editor of JoMaC

Chair of IFToMM TC for Biomechanical Engineering

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3

ACCURACY OF ANATOMICAL LANDMARK PLACEMENT

METHODS FOR GAIT ANALYSIS

Kristóf Rácz* Gergely Nagymáté* Tamás Kovács** Tamás Bodzay** Rita M. Kiss*

* Budapest University of Technology and Economics, Department of Mechatronics, Optics and Mechanical Engineering

Informatics

** National Trauma Institute Budapest, Hungary

ABSTRACT

A key step in gait analysis is the denotation of anatomical landmarks, often called calibration.

Before, no standardised framework existed for determining and comparing the accuracy of this

procedure. The goal of the present study was to develop suitable standards and utilize these to

examine how a set of changes to a calibration protocol affects accuracy. Standardised

conditions were established for the measurement of the quality of the denotation process.

Seven orthopaedic doctors performed calibrations on six healthy male participants aged 30±2.5

years. For each set of measurements three out of seven randomly selected doctors each

performed a calibration of 24 anatomical landmarks on a subject, for a total of 10 independent

sets. The calibration procedure featured a redesigned calibration wand, and further

clarifications of locations of the anatomical landmarks compared to the previous protocol.

Newly defined metrics of 3D error and 3D deviation were used to examine the change in

accuracy compared to the old protocol. Results showed that the accuracy of calibrations

between multiple examiners has improved by approximately 23%. However, calibrations made

by a single examiner are still more accurate with smaller deviations. The standardised

conditions and metrics provide a solid foundation for comparing the accuracy of calibration

methods. A general increase of accuracy can be observed from updating the calibration

protocol, but the personal interpretation of anatomical landmark locations still plays a major

role, making calibration performed by different examiners inconsistent.

Keywords: motion analysis, calibration, comparability, accuracy, standard

1 INTRODUCTION

Motion analysis is a way of quantifying and analysing

human movements. It is widely used in research [1][2],

healthcare (orthopaedics) [3][4], and sport sciences [5]–[7].

The principle of motion analysis is recording the 3-

dimensional (3D) positions of anatomical landmarks (ALs)

during motor tasks [8]. These measurements suffer from

large artefacts caused by the diverse and organic nature of

the human body. Besides instrumental artefacts [9], non-

invasive methods for the denotation and tracking of ALs

introduce errors known as anatomical landmark location

and soft tissue artefacts [10][11].

Contact author: Rita M. Kiss1

1 Hungary, 1521 Budapest, Pf. 91.

E-mail: [email protected]

These are caused by the relative motion between ALs and

the observable skin surface and the variations in each

person’s anatomy. Except for rare cases in research

[12][13], motion analysis must be conducted non-

invasively, thus these artefacts have a massive role in

measurement accuracy. Various ways of compensation for

these artefacts have been demonstrated [14]–[16], and

different methods generated different techniques for the

denotation of ALs [17][18]. While there is no consensus on

a universally accepted one, the Calibrated Anatomical

Systems Technique (CAST) introduced by Cappozzo et al.

[18] (commonly referred to as the calibration method) is

most commonly used. In this method, the ALs are denoted

in a local coordinate system in which they are fixed. This is

usually a local coordinate system of the body segment

corresponding to the AL (e.g. the greater trochanter is

denoted in a local coordinate system of the thigh). This is

practical because measuring a whole segment’s movement

instead of a single point is more precise and less affected by

soft tissue artefacts [19].

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The present study focuses on AL placement accuracy, i.e.

the accuracy with which the ALs can be denoted. There

have been studies exploring the accuracy in different

circumstances, but the results are difficult to compare

[20][21]. There has been no standardized procedure and

metric with which the comparison of the accuracy of

different calibration or other denotation methods is

possible. No previous studies focusing on this subject using

an OptiTrack motion capture system were found [22].

In a previous study [23] it was established that the old

calibration procedure is adequate for the examiners (the

persons denoting the location of ALs) to make accurate

calibrations. However, the two examiners had bad inter-

examiner accuracy. The examiners denoted the same ALs

to 10-20 millimetres apart on average, but in cases, more

than 40 millimetres apart. This meant that gait analysis

measurements with calibrations by different examiners

would yield noticeably different results with the old

calibration protocol. The cause for these discrepancies

could have been the not-so-accurate calibration procedure,

and the significantly different background and experience

of the examiners. The aim of this article is to examine how

an update to the calibration procedure improved inter-

examiner accuracy, and if it improved enough for

calibrations by different examiners to be comparable. This

time the calibrations were performed by examiners with

similar backgrounds (all orthopaedic doctors).

In the present study a set of guidelines is established, which

can be used to standardize the measurement of the quality

of the AL calibration process. Newly defined metrics are

used to compare the accuracy of the updated calibration

procedure to previous results [23].

2 METHODS

2.1 DEFINITION OF COMPARISON METHOD AND

METRICS

Due to the varied methods and conditions in studies

[20][21] regarding AL placement accuracy (referring to the

accuracy with which the ALs are denoted), comparisons

between them are difficult. For these results to be directly

comparable, a clear guideline for the measurement

conditions, and standardized metrics for the accuracy of a

calibration method should be established. The following

definitions were developed, which describe a standardised

framework for measuring and comparing AL placement

accuracy:

Conditions of comparability: the measured calibrated

anatomical landmark positions are comparable if, during

the measurement, the position of the actual anatomical

landmark is constant in the measurement coordinate

system, meaning that it is in some way rigidly fixed to the

origin of the measurement coordinate system.

3D error (TDE): the 3D error of an anatomical landmark

placement is the 3-dimensional distance between the

individual calibrated anatomical landmark positions and the

mean calibrated anatomical landmark position, for a set of

measurements where the conditions of comparability apply.

The formula for TDE is given in eq. (1), where xi, yi, and zi

represent the 3-dimensional coordinates of the ith calibrated

anatomical landmark position in the set, and x , y and z

represent the 3-dimensional coordinates of the mean

calibrated anatomical landmark position.

2 2 2( ) ( ) ( )i i i iTDE x x y y z z (1)

3D deviation (TDD): the 3D deviation of an anatomical

landmark placement is the mean 3-dimensional distance

between the individual calibrated anatomical landmark

positions and the mean calibrated anatomical landmark

position, for a set of measurements where the conditions of

comparability apply. The formula for TDD is given in eq.

(2), where n is the number of measurements in the set.

1

n

ii

TDE

TDD TDEn

(2)

2.2 MEASUREMENT ENVIRONMENT AND

METHOD

Measurements were conducted in the motion capture

laboratory of the Department of Mechatronics, Optics and

Mechanical Engineering Informatics at the Budapest

University of Technology and Economics, Hungary. The

laboratory is set up with an OptiTrack optical motion

capture system, with 18 cameras arranged around a 4 x 2.5

m measurement area on steel consoles 3 m above ground

level. The cameras operate in the domain of infrared light,

with a sample rate of 120 Hz. The windows are

permanently darkened to eliminate interference from

natural light. Information from the cameras is processed by

the dedicated software of the motion capture system. The

accuracy of this motion capture system is sub millimetre

[24]. The motion capture system uses passive markers to

track objects in the 3D space. Objects can be single

markers, ‘rigid clusters’ or full skeletal models. Markers are

8 mm diameter plastic spheres, with an infrared reflective

surface.

Figure 1 Rigid cluster object with 3 markers.

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Rigid clusters are a set of 3 or more markers, rigidly

attached to each other. Markers arranged in a rigid cluster

can be seen in Figure 1. The motion capture system

measures the 3D coordinates of the markers in its defined

coordinate system (laboratory coordinate system). Rigid

clusters are tracked with 2 3D vectors, describing their

position and orientation in space. During measurements,

rigid clusters are secured to the body segments of the lower

extremities using wide, elastic bands. This way, the position

and orientation of a local coordinate system associated with

each body segment can be tracked with the motion capture

system. AL are denoted in these local coordinate systems

during the calibration procedure. By knowing the AL’s

coordinates in this local coordinate system and by

measuring the position and orientation of the body segment

in the laboratory coordinate system, the AL’s position in

the laboratory coordinate system can be reconstructed.

Attachment of clusters with wide elastic bands has been

shown to be the method with the lowest amounts of soft-

tissue artefacts [19]. Together with the denotation of ALs

performed with the participant in a neutral standing

position, the conditions of comparability for the calibrations

are met: the position of the actual AL is constant in the

segment’s local coordinate system.

Denotation of ALs (measurement of their coordinates in the

segment’s local coordinate system) – referred to as

calibration – is done with the use of a calibration wand. The

first of the two improvements to the calibration procedure

was the improvement of the calibration wand. The first

version of the wand used a ‘virtual’ calibration point, which

was located one marker radius outwards from the tip of the

wand. The improved wand has a calibration point right on

the tip of the wand. The old version of the wand can be

seen in Figure 2. The new calibration wand can be observed

in Figure 3. The wand is tracked with a rigid cluster. The

wand has a determined calibration point, which point’s

local coordinates in the calibration wand’s local coordinate

system are known. The process of calibration consists of:

reconstructing the coordinates of the calibration point in the

laboratory coordinate system and calculating its coordinates

in the segments of the local coordinate system. These

calculations are handled by a custom software which

receives the necessary information from the motion capture

software through a network connection.

2.3 EXPERIMENTAL PROCEDURES

Measurements used a biomechanical model of the lower

extremities, which included 24 ALs distributed on 7 body

segments: the pelvis, left and right thighs, shanks, and foot.

The location of the 24 ALs can be seen in Figure 4.

Examiners previously only had the ALs’ names and

locations in a picture and calibrated these according to their

personal interpretations. In addition to this, the examiners

in the present measurements have collectively discussed

these locations and mutually agreed on further clarifications

as to where exactly these ALs should be calibrated. This

was the second improvement to the calibration procedure.

Clarifications made for this measurement are as follows:

MH-V: most prominent palpable point of the 5th

Metatarsal Head

MH-I: most prominent palpable point of the 1st

Metatarsal Head

MM: most caudal palpable point of the medial

malleolus

CT: tuber - tendon border

LM: most caudal palpable point of the lateral malleolus

TT: most cranial palpable point of the tuberosity in the

centre

FH: most caudal palpable point of the fibula head

LFE: most prominent palpable point of the lateral

femoral epicondyle

MFE: most prominent palpable point of the medial

femoral epicondyle

GT: dorsal and cranial palpable point of the greater

trochanter

ASIS: spina iliaca anterior superior

PSIS: spina iliaca posterior superior

The first step in a measurement was securing the rigid

clusters to the participant’s body segments. All

measurements are conducted with the participants wearing

only underwear on the lower extremities, to minimize

layers between the rigid cluster and the body segment,

which could increase the chance of slippage. The rigid

clusters were applied according to the biomechanical model

using wide elastic bands, and further secured with

leucoplast tape to prevent slippage of the bands.

The calibration of an AL is as follows: the AL in question

is palpated by the examiner. The calibration point of the

calibration wand is placed on the palpated location (Figure

3), and the appropriate button in the custom software is

pressed by an assistant (alternatively, the examiner can use

a remote control for this purpose). The software takes a

snapshot of the rigid cluster data delivered by the motion

capture system and calculates the local coordinates of the

AL in the body segment’s coordinate system.

Calibrations in the previous study [23] (which the results

here are compared to) were conducted using the same

biomechanical model, by the same method. The only

differences were the previously described two points, the

calibration wand, and the interpretation of AL locations.

Results of a calibration is stored numerical data, containing

the 3 calibrated local coordinates of every AL. Conditions

of comparability apply for sets of calibrations of the same

AL of a subject measured within one application of the

rigid clusters (i.e. measurements on the same subject are not

comparable if the rigid clusters were removed and applied

again).

2.4 SUBJECTS AND EXAMINERS

The measurement was conducted on six healthy male

participants aged 30±2.5 years. Data from the previous

study [23] was measured on 8 healthy participants (3

female and 5 male) of various ages.

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Figure 2 Old calibration wand.

Figure 3 Calibration of the right lateral malleolus

anatomical landmark.

Each person in both studies was able-bodied, without

musculoskeletal injuries or disorders that would result in

abnormal body morphology. A written consent was given

by the participants, after all necessary information about the

procedure was presented. The study was approved by the

National Science and Research Ethics Committee

(21/2015). In the present study 7 orthopedic doctors with

similar backgrounds and experience participated as

examiners. Every set of measurements contained 3

calibrations on the participant, by 3 different examiners

randomly selected from the 7 available ones. Examiners

were not necessarily the same for each participant. 10 sets

of measurements were conducted in total, with 4 out of 6

participants being measured twice. These measurements

happened with different applications of the rigid clusters,

on separate days. Because of this, these can be considered

independent measurements. Data from the previous study

was measured by two examiners with different backgrounds

(both examiners had ample knowledge to conduct

measurements). Both examiners measured all 8 participants

10 times.

2.5 EVALUATION METHODS

TDD values were calculated for every AL for the following

4 types of sets:

Type 1. From present measurements, 3 calibrations on each

participant for every AL, measured by 3 different

examiners, for a total of 10 sets for each AL

(multiple-examiner TDD)

Type 2. From the previous study, 10 calibrations on each

participant for every AL, by the first examiner, for

a total of 8 sets for each AL (single-examiner

TDD)

Type 3. From the previous study, 10 calibrations on each

participant for every AL, by the second examiner,

for a total of 8 sets for each AL (single-examiner

TDD)

Type 4. From the previous study, 10-10 calibration by the

two examiners, for a total of 8 sets for each AL

(multiple-examiner TDD)

Sets of type 1 were compared to sets of type 4. This

measured the improvement in inter-examiner accuracy

through the comparison of multiple-examiner TDD values.

Sets of type 1 were compared to sets of types 2 and 3 to

determine if the improved calibration method makes it

possible for various examiners to calibrate ALs with similar

accuracy between them compared to the accuracy of a

single examiner (multiple-examiner TDD of present study

compared to single-examiner TDD of previous

measurement).

Figure 4 Anatomical landmark locations, and their

respective body segments: R-MH-V - 5th Metatarsal Head

(right foot); R-MH-I - 1st Metatarsal Head (right foot); R-

MM - Medial Malleolus (right shank); R-CT - Calcaneal

Tuberosity (right foot); R-LM - Lateral Malleolus (right

shank); R-TT - Tibial Tuberosity (right shank); R-FH -

Fibular Head (right shank); R-LFE - Lateral Femoral

Epicondyle (right thigh); R-MFE - Medial Femoral

Epicondyle (right thigh); R-GT - Greater Trochanter (right

thigh); R-ASIS - Anterior Superior Iliac Spine (pelvis); R-

PSIS - Posterior Superior Iliac Spine (pelvis); L-MH-V -

5th Metatarsal Head (left foot); L-MH-I - 1st Metatarsal

Head (left foot); L-MM - Medial Malleolus (left shank); L-

CT - Calcaneal Tuberosity (left foot); L-LM - Lateral

Malleolus (left shank); L-TT - Tibial Tuberosity (left

shank); L-FH - Fibular Head (left shank); L-LFE - Lateral

Femoral Epicondyle (left thigh); L-MFE - Medial Femoral

Epicondyle (left thigh); L-GT - Greater Trochanter (left

thigh); L-ASIS - Anterior Superior Iliac Spine (pelvis); L-

PSIS - Posterior Superior Iliac Spine (pelvis);. Picture was

made using OpenSim [25]

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Values were examined using box-plots and numerical

comparison by calculating the mean and standard deviation

of TDD values for the 4 types of sets. Approximate

percentage values were calculated to indicate the difference

in accuracy between the sets.

3 RESULTS

Figure 5 shows the comparison of multiple-examiner TDD

with and without the update to the calibration procedure

(type 1 and type 4 sets).

Figure 5 Comparison of multiple-examiner TDD values

between the old and the improved calibration method.

Mean multiple-examiner TDD was lower by an average of

approximately 23%, but the standard deviation of TDD was

higher by approximately 10% on average. Figure 6 shows

the comparison of the multiple-examiner TDD of the

present study (type 1) with the single-examiner TDD of the

previous one (types 2 and 3). Mean multiple-examiner TDD

was higher by an average of approximately 33%, and 12%

higher than single-examiner TDD. Standard deviation of

the multiple examiner TDD was higher by approximately

147% and 116% on average. Numerical TDD values for

each AL in all 4 types of sets is shown in Table I in a

“mean ± standard deviation” format.

Figure 6 Comparison of multiple-examiner TDD with the

improved calibration method to the single-examiner TDD.

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Table I - Numerical results

Anatomical landmark

name

TDD (mean ± standard deviation, mm)

Type 1 sets Type 2 sets Type 3 sets Type 4 sets

R-MH-V 4.11 ± 2.49 3.27 ± 0.42 4.07 ± 0.71 6.36 ± 2.70

R-MH-I 4.11 ± 1.52 3.11 ± 0.90 3.93 ± 1.05 5.82 ± 3.66

R-MM 4.50 ± 1.53 4.06 ± 0.62 5.82 ± 1.36 6.09 ± 1.45

R-CT 5.87 ± 2.30 4.95 ± 1.08 5.59 ± 1.30 10.69 ± 7.35

R-LM 4.43 ± 1.71 4.61 ± 1.83 4.76 ± 1.07 5.47 ± 1.67

R-TT 7.42 ± 3.28 4.68 ± 1.45 4.80 ± 1.20 6.92 ± 2.57

R-FH 9.85 ± 4.40 5.02 ± 1.41 8.70 ± 2.30 10.02 ± 5.08

R-LFE 7.90 ± 2.65 5.66 ± 1.50 7.31 ± 2.15 16.06 ± 5.21

R-MFE 11.61 ± 5.40 6.95 ± 1.07 8.10 ± 1.19 19.20 ± 6.24

R-GT 12.56 ± 6.81 9.79 ± 2.11 11.10 ± 3.61 13.50 ± 2.83

R-ASIS 9.76 ± 6.65 7.73 ± 3.67 8.31 ± 2.23 12.95 ± 5.10

R-PSIS 9.75 ± 5.39 5.74 ± 2.16 6.25 ± 1.23 9.42 ± 2.96

L-MH-V 5.01 ± 1.43 3.05 ± 0.41 4.00 ± 1.28 6.06 ± 1.88

L-MH-I 3.64 ± 0.84 3.75 ± 0.46 5.40 ± 1.14 6.49 ± 1.67

L-MM 6.63 ± 3.36 5.22 ± 1.76 6.53 ± 1.50 7.29 ± 2.04

L-CT 6.22 ± 2.45 4.78 ± 0.87 6.78 ± 1.70 8.07 ± 1.60

L-LM 4.57 ± 1.57 3.86 ± 0.89 5.06 ± 0.86 5.52 ± 1.22

L-TT 6.54 ± 1.54 5.05 ± 1.67 5.69 ± 0.52 6.49 ± 1.05

L-FH 11.13 ± 5.78 6.81 ± 3.35 9.99 ± 2.75 13.68 ± 4.03

L-LFE 5.66 ± 1.85 7.00 ± 1.79 9.63 ± 2.09 19.56 ± 4.57

L-MFE 8.67 ± 3.03 10.06 ± 2.12 9.74 ± 2.25 21.28 ± 8.63

L-GT 12.87 ± 7.46 11.21 ± 2.39 8.67 ± 3.19 15.07 ± 3.97

L-ASIS 10.63 ± 4.87 8.19 ± 1.89 9.47 ± 3.44 14.56 ± 5.27

L-PSIS 9.72 ± 5.83 5.35 ± 1.50 5.40 ± 1.36 9.27 ± 3.64

4 DISCUSSION

Comparing the numerical results and observing Figure 5, it

is visible that the update to the calibration procedure did

improve inter-examiner accuracy (approximately by 23%).

The calibrations were a little less consistent (10% increase

in the standard deviation of TDD), but this is not as

significant as the accuracy improvement.

However, multi-examiner measurements are still less

accurate on average (33% and 12% higher mean TDD), and

much more inconsistent (146% and 116% higher standard

deviation of TDD) than single-examiner calibrations. This

means that in real application, where only one calibration is

made per measurement (e.g. the tracking of recovery after

hip or knee surgery using gait analysis) based on Figure 6,

in best case scenarios multi-examiner measurements can be

just as consistent as if calibrations would have been done

by the same examiner. However, in the majority of cases it

will more likely result in much less consistent calibrations.

These inconsistencies could show up as noise in the end

results, which could mask important tendencies. Because of

this, even with the improved calibration protocol, it is

highly recommended that the same examiner perform the

calibrations for all measurements, from which results need

to be compared. Based on Figure 5 and Figure 6, some kind

of correlation can be observed between TDD values and the

ALs. Points higher on the body generally had worse

accuracy.

Potential causes for this can be the amount of soft tissue

covering the ALs, difficulty of differentiation of the ALs

from their surroundings, and the size of the ALs. An

increase in these parameters is likely to correlate with the

increase of TDD. This topic should be explored in its own

dedicated study. The limits of present study were the

relatively small number of participants and examiners,

meaning their individual contribution affected the statistical

results much more, possibly skewing the results if any of

them produced significantly different results. No signs of

this were observed either during the measurements or the

processing of the results.

5 CONCLUSION

A standardised way to compare the accuracy of AL

denotation methods in motion analysis was presented. The

introduced metrics were used to compare results from a

calibration method from before and after an update to the

procedure. This update consisted of a more precisely

useable calibration wand, further specifying the ALs’

location for the examiners. It was shown that the update

increased the accuracy of calibration. However, calibrations

by a single examiner are still much more consistent

compared to multiple examiners performing the

denotations. Because of this, it is still recommended that the

same examiner perform calibrations for measurements

where results need to be compared.

ISSN 1590-8844


9

ACKNOWLEDGEMENTS

This work was supported by the Hungarian Scientific

Research Fund OTKA [grant number K115894].

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[6] Malinzak R. A., Colby S. M., Kirkendall D. T., Yu

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TEMPLATE FOR PREPARING PAPERS FOR PUBLISHING IN

INTERNATIONAL JOURNAL OF MECHANICS AND CONTROL

Author1* Author2**

* affiliation Author1

** affiliation Author2

ABSTRACT

This is a brief guide to prepare papers in a better style for publishing in International Journal of

Mechanics and Control (JoMaC). It gives details of the preferred style in a template format to

ease paper presentation. The abstract must be able to indicate the principal authors’

contribution to the argument containing the chosen method and the obtained results.

(max 200 words)

Keywords: keywords list (max 5 words)

1 TITLE OF SECTION (E.G. INTRODUCTION)

This sample article is to show you how to prepare papers in

a standard style for publishing in International Journal of

Mechanics and Control.

It offers you a template for paper layout, and describes

points you should notice before you submit your papers.

2 PREPARATION OF PAPERS

2.1 SUBMISSION OF PAPERS

The papers should be submitted in the form of an electronic

document, either in Microsoft Word format (Word‘97

version or earlier).

In addition to the electronic version a hardcopy of the

complete paper including diagrams with annotations must

be supplied. The final format of the papers will be A4 page

size with a two column layout. The text will be Times New

Roman font size 10.

Contact author: author11, author2

2

1Address of author1.

2Address of author2 if different from author1’s address

E-mail: [email protected] , [email protected]

2.2 DETAILS OF PAPER LAYOUT

2.2.1 Style of Writing

The language is English and with UK/European spelling.

The papers should be written in the third person. Related

work conducted elsewhere may be criticised but not the

individuals conducting the work. The paper should be

comprehensible both to specialists in the appropriate field

and to those with a general understanding of the subject.

Company names or advertising, direct or indirect, is not

permitted and product names will only be included at the

discretion of the editor. Abbreviations should be spelt out in

full the first time they appear and their abbreviated form

included in brackets immediately after. Words used in a

special context should appear in inverted single quotation

mark the first time they appear. Papers are accepted also on

the basis that they may be edited for style and language.

2.2.2 Paper length

Paper length is free, but should normally not exceed 10000

words and twenty illustrations.

2.2.3 Diagrams and figures

Figures and Tables will either be entered in one column or

two columns and should be 80 mm or 160 mm wide

respectively. A minimum line width of 1 point is required at

actual size. Captions and annotations should be in 10 point

with the first letter only capitalised at actual size (see

Figure 1 and Table VII).

ISSN 1590-8844


104

Figure 1 Simple chart.

Table VII - Experimental values

Robot Arm Velocity (rad/s) Motor Torque (Nm)

0.123 10.123

1.456 20.234

2.789 30.345

3.012 40.456

2.2.4 Photographs and illustrations

Authors could wish to publish in full colour photographs

and illustrations. Photographs and illustrations should be

included in the electronic document and a copy of their

original sent. Illustrations in full colour …

2.2.5 Equations

Each equation should occur on a new line with uniform

spacing from adjacent text as indicated in this template. The

equations, where they are referred to in the text, should be

numbered sequentially and their identifier enclosed in

parenthesis, right justified. The symbols, where referred to

in the text, should be italicised.

point 1

point 2

point 3

1. numbered point 1

2. numbered point 2

3. numbered point 3

dteAT

dAGdWd

0

200

2

2

1),,()( (1)

3 COPYRIGHT

Authors will be asked to sign a copyright transfer form prior

to JoMaC publishing of their paper. Reproduction of any

part of the publication is not allowed elsewhere without

permission from JoMaC whose prior publication must be

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4 PEER REVIEW

Papers for publication in JoMaC will first undergo review

by anonymous, impartial specialists in the appropriate field.

Based on the comments of the referees the Editor will

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The papers in the reference list must be cited in the text. In

the text the citation should appear in square brackets [ ], as

in, for example, “the red fox has been shown to jump the

black cat [3] but not when...”. In the Reference list the font

should be Times New Roman with 10 point size. Author’s

first names should be terminated by a ‘full stop’. The

reference number should be enclosed in brackets.

The book titles should be in italics, followed by a ‘full

stop’. Proceedings or journal titles should be in italics. For

instance:

REFERENCES (EXAMPLE)

[1] Smith J., Jones A.B. and Brown J., The title of the

book. 1st edition, Publisher, 2001.


paper. Proc. of Conference Name, where it took place,

Vol. 1, paper number, pp. 1-11, 2001.


paper. Journal Name, Vol. 1, No. 1, pp. 1-11, 2001.

[4] Smith J., Jones A.B. and Brown J., Patent title, U.S.

Patent number, 2001.

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CONTENTS – Special Issue for Biomechanical Engineering

1 Preface for the Special Issue of the International Journal of Mechanics and Control (JoMaC) dedicated

to BIOMECHANICAL ENGINEERING

C. Ferraresi

3 Accuracy of Anatomical Landmark Placement Methods for Gait Analysis

K. Rácz, G. Nagymáté, T. Kovács, T. Bodzay and R.M. Kiss*

11 Portable Low-Cost Smart Brace for Elbow Rehabilitation

C. De Benedictis, C. Ferraresi, W. Franco, L. Franzoso, R. Grassi, D. Maffiodo and D. Zanin

19 Metabolic Power and Energy Cost of Mechanical Work Carried Out by a Sailor Engaged in a Solo

Ocean Race: a Case Study

W.C. Wu, A. Concu, R. Solinas, L. Meloni, A. Manuello Bertetto, A. Fois, A. Loviselli, A. Deledda and F. Velluzzi

33 Correlation Between Mechanical and Metabolic Energy During the Gait Cycle With and Without

Jumping Stilts

A. Concu, M. Garau, A. Manuello Bertetto and M. Ruggiu

CONTENTS – Regular Issue

39 Development of the Mathematical Description of a Overhead Crane in Large Spatial Movements,

taking into account the Dissipation of Swing Energy

M.S. Korytov and I.V. Breus

45 Self Learning Neuro-Fuzzy Modeling Using Hybrid Genetic Probabilistic Classifier for Engine Air/Fuel

Ratio Prediction

B.A. Al-Himyari, A. Yasin and H. Gitano

55 Optimal Proportional-Derivative Controllers Based on a Multi-Objective Combined Optimization

Algorithm

M.J. Mahmoodabadi, M. Andalib Sahnehsaraei, S. Hadipour Lakmesari and H. Yaghoubi Nia*

65 Analysis and Design of a Picking System

A. Aresu, F. Leppori and M. T. Pilloni

81 Logistics Service Providers’ Performance Measurement: Insights for Improvement

A. Carlin, A.C. Cagliano and C. Rafele

95 Novel Metaheuristic Bio-Inspired Algorithms for Prognostics of On-Board Electromechanical Actuators

M.D.L. Dalla Vedova, P.C. Berri and S. Re

next issue titles will be from the selected and awarded papers of:

RAAD 2018 - 27th

International Conference on Robotics in Alpe-Adria-Danube Region

Patras, Greece,

6 – 8 June 2018

Documents

International journal of Mechanics and Controlmogi.bme.hu/files/resdev.OTKA/2018/115894/JoMaC_accurancy.pdf · 1 Hungary, 1521 Budapest, Pf. 91. E-mail: [email protected] These are