INSTRUMENTATION FOR GAIT ANALYSIS MEASUREMENT USING MEMS BASED

(1)

PORTABLE SHOE INTEGRATED

DEVICES

by

Norantanum Binti Abu Bakar (1030110551)

A thesis submitted

In fulfilment of the requirements for the degree of Master of Science (Microelectronic Engineering)

School of Microelectronic

UNIVERSITI MALAYSIA PERLIS

2013

item is protecte

d by

original

copyr

ight

(2)

ii

UNIVERSITI MALAYSIA PERLIS

NOTES : * If the thesis is CONFIDENTIAL or RESTRICTED, please attach with the letter from the organization with period and reasons for confidentially or restriction.

DECLARATION OF THESIS

Author’s full name : ………...

Date of birth : ……….

Title : ………...

………...

Academic Session : ……….

I hereby declare that the thesis becomes the property of Universiti Malaysia Perlis (UniMAP) and to be placed at the library of UniMAP. This thesis is classified as :

CONFIDENTIAL (Contains confidential information under the Official Secret Act 1972)*

RESTRICTED (Contains restricted information as specified by the organization where research was done)*

OPEN ACCESS I agree that my thesis is to be made immediately available as hard copy or on-line open access (full text)

I, the author, give permission to the UniMAP to reproduce this thesis in whole or in part for the purpose of research or academic exchange only (except during a period of _____ years, if so requested above).

Certified by:

_________________________ _________________________________

SIGNATURE SIGNATURE OF SUPERVISOR

___________________________ _________________________________

(NEW IC NO. / PASSPORT NO.) NAME OF SUPERVISOR

item is protecte

d by

original

copyr

ight

(3)

iii

ACKNOWLEDGEMENT

In the name of Allah, invocation and greetings to adoration of Nabi Muhammad (S.A.W.), thanks to Allah because giving me strength and patience in finishing this Master of Science in Microelectronic Engineering. Alhamdulillah.

First of all, I would like to thank to my supervisor, Dr. Yufridin Wahab and my co-supervisor, Mdm Safizan Saari for giving me the opportunity and trust to undergo Master of Science in Microelectronic Engineering under their supervisions. A high appreciation to Ministry of higher Education Malaysia (MOHE) for funding this project through Fundamental Research Grants Scheme (FRGS) and for scholarship through MyMaster, MyBrain15 Program.

In particular, I wish to express my sincere appreciation to my lovely family, my colleagues and others who have provided assistance in various occasions. I sincerely appreciate all of the efforts and precious time to be spent together in making this project successful. Not to be forgotten, my deepest thanks to Muhamad Firdaus Muhamad Dali for all the support and motivation.

The great cooperation and kindheartedness that have been shown by them will be always appreciated and treasured by me, thank you.

item is protecte

d by

original

copyr

ight

(4)

iv

TABLE OF CONTENTS

APPROVAL AND DECLARATION SHEET ii

ACKNOWLEDGMENT iii

TABLE OF CONTENTS iv

LIST OF TABLES ix

LIST OF FIGURES x

LIST OF ABBREVIATIONS xv

LIST OF SYMBOLS xvii

ABSTRACT xviii

ABSTRAK xix

CHAPTER 1 INTRODUCTION

1.0 Introduction 1

1.1 Problem Statements 3

1.2 Research Objectives and Contribution 4

1.3 Research Methodology 5

1.4 Thesis Organization 7

CHAPTER 2 TECHNOLOGY REVIEW

2.0 Chapter Overview 8

2.1 Trends in Human Motion Measurement 8

2.2 The Foot Clearance Measurement 10

item is protecte

d by

original

copyr

ight

(5)

v

2.2.1 Overview of Foot Clearance Measurement 11 2.2.2 The Foot Clearance Measurement Requirement 13 2.2.3 Distance Measurement Techniques 14 2.3 MEMS Technology for Gait Measurement 25 2.4 Physical Implementation and Design Execution 25

2.5 Chapter Summary and Discussion 28

CHAPTER 3 SHOE INTEGRATED DESIGN

3.1 Sensor Selection and Description 29

3.1.1 Ultrasonic Sensor 30

3.1.1.1 Working Principle of Ultrasonic Sensor 31 3.1.1.2 Analysis and modeling of ultrasonic measurement 32 technique for gait analysis

3.1.2 Initial Measurement Unit 36

3.2 Other Components 38

3.2.1 PIC16F877A Microcontroller 38

3.2.2 Arduino Microcontroller 39

3.2.3 2.4 GHz IEEE 802.15.4 XBee Transmitter 40

3.2.4 Power 41

3.3 Sensory Board 43

3.3.1 Sensory Board V1 43

3.3.2 Sensory Board V2 50

3.3.2.1 Hardware 50

item is protecte

d by

original

copyr

ight

(6)

vi

3.3.2.2 Arduino Integrated Development Environment (IDE) 53

3.4 Physical Implementation Design 55

3.4.1 Design I: Gait Analysis Hardware V1 56 3.4.2 Design II: Gait Analysis Hardware V2 57 3.4.3 Design III: Gait Analysis Hardware V3 58 3.4.4 Design IV: Gait Analysis Hardware V4 59 3.4.5 Design V: Gait Analysis Hardware V5 60 3.4.6 Design VI: Gait Analysis Hardware V6 62

CHAPTER 4 GAIT ANALYSIS SOFTWARE DESIGN

4.1 LabVIEW Visualization 65

4.2 Gait Analysis Software Design 63

4.2.1 GAS-Ultrasonic (GAS-US) 66

4.2.2 GAS-Inertial Measurement Unit (GAS-IMU) 70 4.2.3 GAS-Combination of Ultrasonic and IMU (GAS-COM) 72

4.2.3.1 Main Page 73

4.2.3.2 Left and Right Feet Page 73

4.2.3.3 Receive Data Page 74

4.2.3.4 COM Port Configuration Page 75

4.2.3.5 Data Table Page 76

4.2.3.6 GAS-COM Block Diagram 77

item is protecte

d by

original

copyr

ight

(7)

vii CHAPTER 5 TESTING AND VERIFICATION

5.1 Clearance Measurement 92

5.1.1 Ultrasonic Sensor Reading 93 5.1.2 Verification of Ultrasonic Sensor Reading 95

5.2 Orientation Measurement 98

5.2.1 Development of Orientation Measurement Platform 100 5.2.2 Verification of Orientation Measurement Reading 101 5.3 Gait Analysis Software Verification 103

CHAPTER 6 RESULT AND DISCUSSION

6.1 Analysis of GAS-US System 106

6.2 Analysis of GAS-IMU System 108

6.3 Error Correction of Ultrasonic System Using Initial Measurement Unit 110

6.4 Analysis of GAS-COM 112

6.5 Gait Analysis Measurement System 112

CHAPTER 7 CONCLUSION AND RECOMMENDATION

7.1 Conclusion 114

item is protecte

d by

original

copyr

ight

(8)

viii

7.2 Summary of Achievement 116

7.3 Future Work 117

REFERENCES 119 LIST OF PUBLICATIONS AND AWARDS 124 APPENDICES Appendix A 126

Appendix B 132

Appendix C 134

Appendix D 136

item is protecte

d by

original

copyr

ight

(9)

ix

LIST OF TABLES

NO. PAGE

3.1 Comparison Between Commonly Used Ultrasonic Sensors for Minimum Foot Clearance Measurement Application

30

3.2 Comparison between 9v and 7.4v Battery Used 42 3.3 Summary of Improvement for Each Version 64 4.1 The Sample of Serial Data with the Associated Properties 80

4.2 Summary of GAS Design 91

5.1 Measurement of Clearance in range 1cm to 15cm 93 5.2 Distance Measurement of Ultrasonic Sensor after IMU Correction 97

5.3 Orientation Measurement Reading 101

5.4 Summary of Testing and Verification 105

6.1 Data Collection for Walking Gait Pattern using Inertial Measurement Unit System

111

6.2 The Overall System Designed 113

7.1 The Summary of Achievements 117

item is protecte

d by

original

copyr

ight

(10)

x

LIST OF FIGURES

NO. PAGE

1.1 Gait Cycle 2

2.1 A Proposed Patient Monitoring System That Includes Human Movement Monitoring

10

2.2 Foot Trajectory During Gait Detailing The Vertical Displacement of Foot For One Gait Cycle Showing MFC During Mid Swing

12

2.3 A Foot Clearance Measurement During Stair Decent Using Passive Markers

12

2.4 High-End Laboratory Setup 13

2.5 The Working Principle of Electric Field Sensing for Height Determination 15 2.6 The Working Principle of Accelerometer Sensing 17 2.7 The Prototype for Measuring The Toe Clearance 18 2.8 The Pocket Sized Polaroid Sx-70 Sonar Onestep Land Camera with The

First Mobile Ultrasound Distance Measurement

20

2.9 A 40 kHz Ultrasonic Car Height Measurement for 0^oc-40^oc Operating Temperature, 0.1m-0.6m Range and Better Than 1mm Resolution

20

2.10 Ultrasound Sensor is Used By Robot to Measure Height (Ysens) With Resolution of 0.3 Mm

21

2.11 A Direct Ultrasound Ranging System In Gait Analysis 21

2.12 A Simple Time of Flight Concept 22

2.13 Measured ultrasound signal attenuation and the maximum distance measurable for each signal frequency based on the conventional piezorelectric technology. The two ‘x’ marks in the graph indicates the current maximum ultrasound measurement range based on CMUT technology.

23

2.14 The total ultrasound attenuation for various measurement distance and frequencies.

23

item is protecte

d by

original

copyr

ight

(11)

xi NO.

2.15

LIST OF FIGURES

Approximation of best ultrasound frequency for distance of 30 cm from simulation which is about 1.05 MHz. The horizontal dotted line touches the y axis at ~120dB point. Even though the target distance is just 5 cm, this long range measurement capability may enable application in more human activities

PAGE 24

2.16 Electric Field Distance Sensor Electrode Attached To The Gaitshoe Outsole for Foot Clearance Measurement

26

2.17 2.18 2.19

The Instrumented Shoe for Ground Reaction Forces Determination SmartShoe for Gait Analysis Measurement

Mobile Shoe

26 26 27

3.1 A Simple Time of Flight Concept 31

3.2 Graph of the Vertical Displacement versus Percentage of Stride Duration 32 3.3 Graph of the Vertical Displacement versus Time as in Figure 1 originally

produced by Winter (1992)

33

3.4 Orientation of IMU Sensor On Top of Portable Shoe Integrated 36 3.5 Foot Angle ( θ ) During Landing Phase Where The Distance Measured Is

Not The Actual Foot Clearance

37

3.6 Foot Angle ( θ ) During Toe-Off Phase Where The Distance Measured Is Not The Actual Foot Clearance

38

3.7 The Surface-Mount Technology based PIC16F877A 39

3.8 ArduIMU V2 Flat 40

3.9 ( Left ) The X-Bee 1m Wire Antenna and ( Right ) The X-Bee Starter Kit 41 3.10 The Maxell Super 9V (Left), 7.4V, 500mAh Lithium Polymer battery

(Middle) and the 7.4V, 1000mAh Lithium Polymer battery (Right)

42

3.11 Microcontroller Board 44

3.12 The in-house fabricated PCB with SMT PIC16F877A mounted 44

3.13 The 5 DOF IMU with Respective Axis 45

3.14 The Schematic Design 46

3.15 The Layout Design 47

3.16 The MPLAB IDE Software 48

3.17 Flow Chart for Programming Structure 49

item is protecte

d by

original

copyr

ight

(12)

xii

LIST OF FIGURES

NO. PAGE

3.18 Sensory Board V2 50

3.19 Shape of Attachment Unit before Formation 52 3.20 Top View ( Left ) and Bottom View ( Right ) of Attachment Unit after

Formation

52

3.21 In-Sole Implementation 52

3.22 The Arduino IDE Software 53

3.23 The Ultrasonic Sensor Programming using Arduino IDE 54 3.24 Physical Implementation Design As Seen From The Back of The Right

Shoe

55

3.25 GAH V1, Physical Implementation by Sensory Board V1 56 3.26 GAH V2, Physical Implementation by Sensory Board V1 with Box for

Ultrasonic Sensor

57

3.27 GAH V3, Physical Implementation by Sensory Board V1 with Zero Offset and Box for Ultrasonic Sensor

58

3.28 GAH V4, In-Sole Implementation by Sensory Board V2 60 3.29 GAH V5, In-Sole Implementation with Attachment Unit by Sensory

Board V2

61

3.30 GAH V6, Portable Shoe Integrated with Attachment Unit 62

4.1 Sensory Board Placement 67

4.2 The Walking Graph of Gait Pattern Using Ultrasonic Sensor 68

4.3 GAS-US Block Diagram 70

4.4 The Running Graph of Gait Pattern Using IMU Sensor without Ultrasonic Sensor

71

4.5 GAS-IMU Block Diagram without Ultrasonic Sensor 72

4.6 The Main Page of GAS-COM 73

4.7 The Left Feet Page in GAS-COM 74

4.8 The Receive Data Page 75

4.9 The COM Port Configuration Page 76

4.10 The Data Table Page 76

4.11 Block Diagram for GAS-COM 77

item is protecte

d by

original

copyr

ight

(13)

xiii

LIST OF FIGURES

NO. PAGE

4.12 COM Port Configuration Block Diagram 78

4.13 COM Port Configuration Front View 78

4.14 The Format of Serial Packet Data 79

4.15 Data String Match Pattern Block Diagram 81 4.16 The Decimal String to Number Function 82 4.17 The Detail of Decimal String to Number Function 82 4.18 Feet Angle (φtoe-off) During Toe-Off Phase 83 4.19 Feet Angle (φlanding) During Landing Phase 84

4.20 Error Correction Block Diagram 85

4.21 Simulation Block Diagram 86

4.22 The Output Graph for The Subsystem 1 87

4.23 The Output Graph for The Subsystem 2 88

4.24 (a) The Input Graph and (b) The Output Graph for Simulation 88 4.25 Bar, Graph and Numerical Value Display 89

4.26 Data Logging Block Diagram 90

5.1 Hysteresis Graph 94

5.2 The Experiment Setup for Ultrasonic Sensor Reading 95 5.3 Experiment Setup for Verification of Ultrasonic Sensor Reading 96 5.4 Verification of Ultrasonic Sensor Reading 97

5.5 Orientation Measurement Platform 98

5.6 Development of Orientation Measurement Platform Steps 100 5.7 Verification of Orientation Measurement Platform 102 5.8 Gait Analysis Software-Inertial Measurement Unit 104 5.9 Gait Analysis Software-Combination of IMU and Ultrasonic 104 6.1 Gait Pattern for Walking Subject using GAS-US System 107 6.2 (a) Gait Pattern by (Begg et al., 2007) and (b) Gait Pattern by GAS-US

System

108

6.3 Gait Pattern for Walking Subject using GAS-IMU System 109 6.4 (a) Gait Acceleration Signal (Gafurov et al., 2006) and (b) Gait Signal by

GAS-IMU System

109

item is protecte

d by

original

copyr

ight

(14)

xiv

LIST OF FIGURES

NO. PAGE

6.5 Motion Recording Device Attached to the Lower Leg 110

6.6 GAS-IMU System Attachment 110

6.7 Gait Pattern for Walking Subject using Ultrasonic Sensor combined with IMU Sensor

111

item is protecte

d by

original

copyr

ight

(15)

xv

LIST OF ABBREVIATIONS

3D 3 Dimension

ABS Accelerometer Based Sensing

AC Alternating Current

ADL Activity of Daily Living

AHRS Attitude Heading Reference System

CMOS Complementary metal-oxide-semiconductor DoF Degree of Freedom

EEPROM Electrically Erasable Programmable Read-Only Memory EFS Electric Field Sensing

GAH Gait Analysis Hardware GAS Gait Analysis Software

GAS-US Gait Analysis Software-Ultrasonic

GAS-IMU Gait Analysis Software-Inertial Measurement Unit

GAS-COM Gait Analysis Software- Combination of Ultrasonic and IMU GUI Graphical User Interface

IDE Integrated Development Environment

IEEE Institute of Electrical and Electronics Engineers IMU Inertial Measurement Unit

IPC Institute of Printed Circuit LED Light Emitting Diode

LiPO Lithium Polymer

MEMS Micro Electro Mechanical System MFC Minimum Foot Clearance

MIT Massachusetts Institute of Technology

item is protecte

d by

original

copyr

ight

(16)

xvi

LIST OF ABBREVIATIONS

PCA Printed Circuit Assembly PCB Printed Circuit Board

PCBA Printed Circuit Board Assembly PIC Peripheral Interface Controller PWB Printed Wiring Board

SMT Surface-Mount Technology SONAR Sound Navigation and Ranging US Ultrasonic Sensing

item is protecte

d by

original

copyr

ight

(17)

xvii

LIST OF SYMBOLS

bps Bit per Second

g Gram

mAh Miliampere per Hour Speedmax Speed required

t10 Time for 10 measurements t1 Time for one measurement

tclearance Time of flight to measure the actual clearance tof Time-of-flight

tstride Time of stride

l Distance

t Time

c Ultrasonic wave moving speed θ Foot Angle

v Velocity V Volt

φlanding Landing Phase

φtoe-off Toe-off Phase

° Degree

°C Degree of Celsius µs Microsecond

item is protecte

d by

original

copyr

ight

(18)

xviii

PORTABLE SHOE INTEGRATED INSTRUMENTATION FOR GAIT ANALYSIS MEASUREMENT USING MEMS BASED DEVICES

ABSTRACT

Gait analysis measurement is a method to access and identify gait events and the measurements of dynamic and motion parameters involving the lower part of body. This significant method is widely used in sports, rehabilitation as well as the health diagnostic towards improving the quality of life. Many researchers has proposed various ways to access gait features that require specially set-up motion laboratories, high-end video based-motion imaging systems, and professionals to visually observe the gait, this makes current way of accessing gait to be very costly and limited in many ways.

Therefore, this research focuses on design and development of a portable shoe integrated wireless MEMS-based and recent microelectronic based foot clearance measurement system that is cheap, portable, real life and can be used by more people.

The foot clearance measurement is representing the measurement of the distance between foot and ground. A complete system called Portable Shoe Integrated Instrumentation for Gait Analysis Measurement Using MEMS Based Devices in real- time is proposed. This system is the combination of the ultrasonic sensor with the inertial measurement unit sensor. The ultrasonic sensor is used for clearance measurement and the inertial measurement unit sensor is used for orientation measurement. Based on the orientation measurement, the clearance measurement is corrected by trigonometry algorithm. The correction is due to the positioning of foot during landing phase and toe off phase. In both situations, the positioning of ultrasonic is not perpendicular to the ground. So, the algorithm is required to present the accurate data. This system comes with the custom design software called Gait Analysis Software to analyze and present the gait information of user based on gait parameters which include foot clearance and foot orientation. Thus, this research produces three custom made systems namely GAS-US System, GAS-IMU System and GAS-COM System.

Each system has its own purpose. The system was tested and proven to satisfy the gait analysis requirement. From this research, it is found that the system is able to measure the gait parameter wirelessly with ease and efficiently. Hence, to conclude this system can be used as the best method for real life gait analysis measurement. The novelty of this research is the first design combination of ultrasonic sensor with the initial measurement unit sensor for foot clearance measurement.

item is protecte

d by

original

copyr

ight

(19)

xix

INSTRUMENTASI KASUT MUDAH ALIH BERSEPADU UNTUK ANALISA PENGUKURAN GAYA BERJALAN MENGGUNAKAN PERALATAN

BERASASKAN MEMS ABSTRAK

Analisa pengukuran gaya berjalan adalah kaedah untuk mengakses dan mengenal pasti gaya berjalan dan pengukuran parameter dinamik dan gerakan yang melibatkan bahagian bawah badan. Kaedah ini digunakan secara meluas dalam bidang sukan, pemulihan serta kesihatan diagnostik dalam meningkatkan kualiti hidup. Ramai penyelidik telah mencadangkan pelbagai cara untuk mengakses ciri-ciri gaya berjalan termasuk makmal gerakan khas, sistem pengimejan gerakan yang termaju, dan memerlukan pakar untuk memerhatikan gaya berjalan, ini menyebabkan kaedah semasa mengakses gaya berjalan menjadi mahal dan terhad dalam keadaan tertentu. Oleh itu, kajian ini memberi tumpuan kepada reka bentuk dan pembangunan kasut bersepadu tanpa wayar mudah alih berasaskan MEMS dan sistem pengukuran kaki terkini berasaskan mikroelektronik yang murah, mudah alih, kegunaan kehidupan seharian dan boleh digunakan semua orang. Dimana, pengukuran kaki merujuk kepada pengukuran jarak antara kaki dengan lantai. Satu sistem lengkap yang dipanggil Instrumentasi Kasut Mudah Alih Bersepadu berasaskan MEMS untuk Analisa Pengukuran Gaya Berjalan dalam masa sebenar dicadangkan. Sistem ini adalah gabungan antara pengesan ultrasonik dan juga pengesan unit pengukuran inersia. Pengesan ultasonik digunakan untuk mengukur jarak kaki dengan lantai dan pengesan unit pengukuran inersia digunkan untuk mengukur orintasi. Berdasarkan pengukuran orientasi, pengukuran jarak kaki diperbaiki dengan algoritma trigonometri. Pembetulan disebabkan oleh kedudukan kaki pada fasa kaki mendarat dan kaki diangkat. Dalam kedua-dua situasi, kedudukan pengesan ultrasonik serenjang dengan lantai. Maka, algoritma diperlukan untuk mendapatkan data yang lebih tepat. Sistem datang dengan perisian khusus yang dipanggil Perisian Analisa Gaya Berjalan untuk menganalisa dan memaparkan maklumat gaya berjalan pengguna berdasarkan parameter gaya berjalan iaitu jarak kaki dengan lantai dan orientasi kaki. Oleh itu, kajian ini menghasilkan tiga system yang khusus iaitu Sistem GAS-US, Sistem GAS-IMU dan Sistem GAS-COM. Sistem ini telah diuji dan terbukti memenuhi keperluan analisa gaya berjalan. Daripada kajian ini, didapati bahawa sistem ini dapat mengukur parameter gaya berjalan tanpa wayar dengan mudah dan berkesan. Oleh itu, dapat disimpulkan bahawa sistem ini boleh digunakan sebagai kaedah yang terbaik untuk analisa pengukuran gaya berjalan dalam kehidupan seharian. Keunikan sistem ini adalah rekabentuk pertama dalam gabungan pengesan ultrasonik dan pengesan unit pengukuran inersia untuk pengukuran jarak kaki.

item is protecte

d by

original

copyr

ight

(20)

1 CHAPTER 1

INTRODUCTION

1.0 Introduction

Gait analysis is a very important procedure in assessing and improving many quality of life indicators. It is widely used in sports, rehabilitation and health diagnostics. Gait analysis is the study of lower limb movement patterns and involves the identification of gait events and the measurements of kinetics and kinematics parameters. These include for example, toe-off, landing, stance, swing, displacement, speed, acceleration, force, pressure and the pressure-time-integral as state in (Wahab, 2009).

Trip or fall is events which may lead someone or person to unstable position that causing the person to collapse accidently. It is a very dangerous incident among the elderly as it may cause death (Chisholm et al., 2010). Study in (Chisholm et al., 2010) state that higher ratio of mechanism caused the deaths among the elderly is fall. The very important moment that can lead to the trip or fall occurrence is identified as when the foot movement in stage of mid-swing phase. This important stage of foot movement is referred to as minimum foot clearance (MFC). Study in (Begg et al., 2007) shows the minimum foot clearance is below 5 cm while the foot trajectory during gait may go up to 17 cm. It is therefore important that the parameter foot clearance and MFC are taken as the focus of this research which in particular required the design of foot clearance measurement system. Figure 1.1 shows the gait cycle for normal human.

item is protecte

d by

original

copyr

ight

(21)

2

Figure 1.1: Gait Cycle (Wahab, 2009)

These days, gait analysis is still mostly carried out in a specially set-up motion laboratory using high-end motion imaging systems. In another measurement set-up, the analysis requires a physician to visually observe the gait. These two approaches are undoubtedly expensive (Morris & Joseph, 2008). For example, the use of gait mats, force sensing platforms, motion analysis systems with efficient computer processing and ultrasonic ranging system are used for indoor analysis (Wahab, 2009).

Despite the current practices, the reality proves that the demand for real life portable measurement and monitoring devices are surging fast. As an example, a portable shoe integrated system should perform better in real environment to allow comprehensive analysis and intensive monitoring. In situ measurement where the actual activities and measurement are performed such as reported in (Wahab et al., 2007; Aminian & Najafi, 2004; Wahab et al., 2006) reduces cost as the time requiring the presence of physician is reduced in addition to the cheaper device cost demanded.

Otherwise, this demands that the devices be small, lightweight and easily attached to the shoes or feet. One possible way of satisfying such exclusive demands is, of course, through the application of newer device which now mostly realized using MEMS and microelectronic technology. It is this research’s motivation, which is to produce and

item is protecte

d by

original

copyr

ight

(22)

3

verify that the use of the most recent technology such as MEMS and microelectronic to enhance the measurement technique of foot clearance are very required.

1.1 Problem Statement

As roughly mentioned in the previous section, the current status of the development of untethered in-shoe gait stability measurement devices is still lacking behind the reality of technology achievement. Specifically, with respect to their measurand, the current devices are not fully optimized in many aspects as follows:

 Not suitable for real world or outdoor measurement.

 Not cost effective

 Not enabling efficient signal processing

 Not fully integratable for better reliability and long lasting use

 Mostly laboratory based

 Big and complex setup

 Uncomfortable for user

 Wired connectivity

Therefore, this research focuses on design and development of a wearable shoe integrated wireless MEMS-based and recent microelectronic based foot clearance measurement system.

item is protecte

d by

original

copyr

ight

(23)

4 1.2 Research Objective and Contribution

The goals of this research are:

• Design, develop, calibrate, and analyze a wireless real-time Clearance Measurement System for gait analysis.

• Wirelessly in real-time and real world gait analysis measurement.

• Proving the concept of MEMS-based clearance measurement system towards future realization.

• Consider MEMS realizable devices such as ultrasonic sensor and inertial measurement unit sensor.

Based on requirement of gait analysis measurement, the system design consists of six parts, there are:

• Gait Analysis Hardware design

• Gait Analysis Software design

• Error correction algorithm

• System integration

• Testing setup design

• Data collection and analysis.

This system is self corrected, ready to use, hence the graphical data visualization output can be analyzed for information on the gait of the user which is known as foot clearance.

This research is aimed at developing such system but using MEMS sensor and system component purchase off-the-shelf to prove the concept. Feasibility of developing Portable Shoe Integrated Instrumentation for Gait Analysis Measurement Using MEMS

item is protecte

d by

original

copyr

ight

(24)

5

Based Devices for clearance measurement is therefore considered in this research. If the system is realizable using MEMS based devices, it can then be integrated with microelectronic circuitry on the same silicon in future researches. So, eventhough this work does not involve MEMS realization, it is aimed at proving the concept. Finally, the novelties of this research are:

• Wireless monitoring

• Real life measurement

• New custom design software for gait analysis

• First design combination of US & IMU for foot clearance measurement

1.3 Research Methodology

This section elaborates on the steps and tools used during throughout the research duration to accomplish the research target. This research takes the advantages of LabVIEW 2010 as a graphical user interface for data visualization. In addition, the PIC and Arduino microcontroller is used along with the ultrasonic sensor and IMU sensor to determine the foot clearance and orientation. The steps involved in the research for this system design and analysis are enlisted below:

1.3.1 Designing gait analysis hardware

This step involves designing and realizing the gait analysis hardware. Several designs have been made with certain improvement through the experiment finding.

There are six designs of gait analysis hardware with each design had difference approach.

item is protecte

d by

original

copyr

ight