design and development of rehabilitation device for...

DESIGN AND DEVELOPMENT OF REHABILITATION DEVICE FOR

HEMIPARETIC PATIENTS

KHAIRUL FADZLI BIN SAMAT

A thesis submitted in fulfilment of the

requirements for the award of the degree of

Master of Engineering (Mechanical)

Faculty of Mechanical Engineering

Universiti Teknologi Malaysia

FEBRUARY 2012

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To my beloved mother, father and wife

iv

ACKNOWLEDGMENT

Firstly, I would like to express my greatest gratitude to Allah S.W.T., for His

will, this project has finally completed. Thousands of thanks to my supervisor, Assoc.

Prof. Dr Mohamed Hussein for his kind and patience, his valuable advices, concern,

guidance and support throughout the process of completing my master project.

Nevertheless, my great appreciation dedicated to my wife Yuhaniz binti Anuar for all her

helps and encouragement that she had given to me.

I would also like to express my sincere gratitude to my parents and family, who

had continuously giving out their support financially and emotionally for me to complete

my project. Also lots of thanks to my dearest friends and lectures for all the knowledge,

helps, and guidance to complete this project. I am also indebted to Universiti Teknikal

Malaysia Melaka (UTeM) for its financial support and assistance on various matters.

Last but not least, I have the greatest hope that my master project, ‘Design and

Development of Rehabilitation Device for Hemiparetic Patients’ will give its benefit in

making more discovery of new technology in the future.

v

ABSTRACT

In this thesis, the development of rehabilitation device for patients who

encounter walking weakness due to post-stroke effect is presented. . In order to

design an efficient new mechanism, studies were carried out regarding kinematic of

human walking. In the study, the motion of a healthy physical subject in walking

situation of 1 km/h speed is used as guide to design the device. Thereafter, a

mechanism was developed to produce similar motion. The device functions to

actuate knee and hip rotation. The device is driven by a single actuator to drive both

the hip and the knee joints mechanism. The kinematic analysis of constructed

device has been performed and the results conformed the functionality of the

suggested mechanism. The fabricated prototype shows the combination of DC

motor and cam mechanism can actuated the movement of hip and knee joint

simultaneously and may significantly reduced the power consumption. The

computer based controller has also been developed with simple and practical

application. With the combination of the controller and the fabricated model, the

output profile of the rehabilitation device is acceptable by comparing with profile of

actual data.

vi

ABSTRAK

Dalam tesis ini, pembangunan rekaan peranti pemulihan untuk pesakit-

pesakit yang mengalami gajala lemah untuk berjalan disebabkan oleh kesan sakit

strok dibentangkan. Dalam usaha untuk mereka bentuk mekanisma baru yang

cekap, kajian telah dijalankan berkaitan dengan kinematik manusia berjalan. Dalam

kajian ini, profil pergerakan subjek yang sihat dengan kelajuan 1 km/h digunakan

sebagai panduan untuk reka bentuk peranti. Oleh itu, satu mekanisma telah

dibangunkan untuk menghasilkan pergerakan yang sama. Peranti berfungsi untuk

menggerakkan pergerakan lutut dan pangkal peha yang dipacu oleh satu putaran

motor. Analisis kinematik peranti yang dibina telah dijalankan dan semua

keputusan menepati fungsi mekanisma yang disyorkan. Prototaip yang dibina

membuktikan bahawa gabungan DC motor dan mekanisma cam boleh

menggerakkan pergerakan kaki untuk berjalan dan pada masa yang sama kurang

menggunakan sumber kuasa. Kawalan berasaskan komputer juga telah dibangunkan

dengan penggunaan yang mudah dan praktikal. Dengan kombinasi kawalan dan

model peranti yang telah direka, profil pergerakan bagi proses pemulihan dapat

dihasilkan dan diterima pakai apabila ia dibandingkan dengan profil data sebenar.

vii

TABLE OF CONTENTS

CHAPTER TITLE PAGE

DECLARATION OF THESIS ii

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES ix

LIST OF FIGURES x

LIST OF SYMBOLS xiv

LIST OF APPENDICES xvi

1 INTRODUCTION

1.1 Background of the problem 1

1.2 Statement of the problem 2

1.3 Objective of the study 3

1.4 Scope of the study 3

1.5 Significant of the study 4

1.6 Research Methodology 4

1.6.1 Procedure of the Project 4

1.6.2 Flow chart of the Project 6

1.6.3 Project Schedule 7

2 THEORY AND LITERATURE REVIEW

2.1 Kinematics of Lower Extremity 8

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2.2 Gait Cycle 9

2.3 Powered Exoskeleton and Orthosis Device 15

2.4 Orthotics help prevent and heal injuries 16

2.5 Active Devices of Exoskeletons or Orthoses for

Patients with Hemiplegia 16

2.6 Other Research 23

3 METHODOLOGY

3.1 Development of Design Model 28

3.1.1 Design Specification 29

3.1.2 Conceptual Design 31

3.1.3 Concept Evaluation and Selection 38

3.1.4 Final Design Model 42

3.1.5 Designation of Cam 54

3.2 Fabricated Model 61

3.4 Experimental Setup 63

4 RESULT AND DISCUSSION

4.1 Force Analysis 66

4.2 Computer Based Controller 72

4.3 Experimental Results and Discussion 74

4.4 Validation 77

4.4.1 Kinematic Analysis of Link 78

4.4.2 Kinematic Analysis of Link 81

5 CONCLUSION AND RECOMMENDATION

5.1 Conclusion 93

5.2 Recommendation of Future Work 95

REFERENCES 96

APPENDICES (A-B) 100-117

ix

LIST OF TABLES

FIGURE NO. TITLE PAGE

1.1 Project schedule for Master Project 1 7

1.2 Project schedule for Master Project 2 7

2.1 Descriptions of Gait Sub-Phases 11

3.1 Weighted Decision Matrix 40

3.2 Relation Angle versus Linear Motion 53

4.1 Maximum Force at Thigh Link 65

4.2 Maximum Force at Inline Follower 67

4.3 Maximum Force at Shaft Follower 68

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LIST OF FIGURES

FIGURE NO. TITLE PAGE

1.1 Flow chart of Project 6

2.1 Kinematic angles definition 9

2.2 Phases of the gait cycle 11

2.3 Location of each joint angle [3] 13

2.4 Ankle, knee, and hip joint angular position presented as

Angle 1, Angle 2 and Angle 3 respectively [3] 13

2.5 Comparable of profiles of hip joint angles for normal human

walking on treadmill 14

2.6 Comparable of profiles of knee joint angles for normal

human walking on treadmill 14

2.7 Active devices of exoskeleton/orthosis for patients with

Hemiplegia. Examples are Lokomat robotic gait orthosis

(Hocoma, AG , Volketswil, Switzerland) [10], Prototype

SBO orthosis [11] and Powered leg orthosis [12] shown in a,

b and c, respectively 19


Hemiplegia. Examples are Hybrid Assistive Limb suit

(HAL-5), Hybrid Assistive Leg-3 or HAL-3 [15] and

Powered Gait Orthosis (PGO) with a tests subject/patient

[17] shown in a, b and c, respectively 21


Hemiplegia. Examples are knee-ankle foot orthosis (KAFO)

with artificial pneumatic muscles [18] and a leg exoskeleton

with an MR actuator [19] shown in a and b, respectively

22

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2.10 Passive devices of exoskeleton/orthosis for patients with

Hemiplegia. Examples are Horton Stance Control Orthosis

[20] [21] and Otto Bock Free Walk shown in a and b,

respectively

25

2.11 Passive devices of exoskeleton/orthosis for patients with

Hemiplegia. Mechanisms of gravity-activated Fillauer Swing

Phase Lock with pawl weighted [27], Swing Phase Lock 2

[29] and a magnetically activated one-way dog clutch [30]

shown in a, b and c, respectively 27

3.1 Design Concept 1 32





3.6 Final Design of Rehabilitation Device 42

3.7 Perspective View of Rehabilitation Device 43

3.8 Side View of Rehabilitation Device 44

3.9 Perspective View of Thigh Links 45

3.10 Perspective View of Shank Links 47

3.11 Exploded View of Hip Joint Assembly 49

3.12 Perspective View of Waist Frames and Hip Assembly

Embodiment 50

3.13 Perspective View of Actuators System 51

3.14 Side View of Actuators System 52

3.15 General procedure to develop a cam profile 55

3.16 Relation between Angle and Linear Motion 56

3.17 Relative difference of knee angle 56

3.18 Displacement Diagram of Cam 57

3.19 Shifted position of Displacement Diagram 58

3.20 Base circle Rb, prime circle Rp, and pitch curve of a radial

cam with roller follower 58

3.21 Cam pressure angle and forces in a radial cam with offset

translating roller follower 59

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3.22 Modeling stage of the cam profile 61

3.23 Front view and side view of fabricated model 62

3.24 View of movements for the fabricated model (prototype) 63

3.25 Experimental setup for data collection 64

3.26 Brushless DC Motor (AXH450-GFH4G200) 64

3.27 Data Acquisition Device and Motor Driver 65

3.28 Angular potentiometer (100kΩ) and related angular position

for data collection(knee angle) shown in a and b respectively 65

4.1 Stress Distribution on Thigh Link 66

4.2 Displacement of Thigh Link 66

4.3 Stress Distribution on Inline Follower 67

4.4 Displacement of Inline Follower 67

4.5 Stress Distribution on Shaft Follower 68

4.6 Meshing of Shaft Follower 68

4.7 Displacement of Shaft Follower 69

4.8 Manual Operation 70

4.9 Operation by Timer 71

4.10 Comparison between Experimental Data and Actual Data for

Hip Angles 72

4.11 Data obtained from potentiometer 72

4.12 Comparison between Experimental Data and Actual Data for

Knee Angles 73

4.13 Comparison between Experimental Data and Actual Data

(following the Gait Cycle Position) 74

4.14 Label of linkages, joint and rotation 75

4.15 Kinematic study Link1 and Link2 76

4.16 Angular Displacement of Link 1 for one cycle 78

4.17 Angular Velocity of Link 1 for one cycle 78

4.18 Absolute Velocity of Link 1 for one cycle 79

4.19 Interpolated follower displacement and real data for one

cycle 80

4.20 The absolute velocity of VA1 for one cycle 80

4.21 The absolute velocity of VA2 for one cycle 81

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4.22 The absolute velocity of VA for one cycle 82

4.23 Case 1-Velocity vector diagram for knee joint 83





4.28 Case 1-Velocity vector diagram for ankle joint 86





4.33 Definitive absolute velocity of VAnkle for one cycle 88

4.34 Definitive angular position of knee for one cycle 89

4.35 Definitive angular position of hip for one cycle 89

4.36 Actual data of knee and hip angles 89

4.37 Human step size during each stage of the gait 90

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LIST OF SYMBOLS

� - Angle

Rb - Base circle of cam

Rp - Prime circle of cam or radius on the cam

∅ - Pressure angle of the cam

V - Velocity

s - Instantaneous displacement of the follower

�� - Time derivative in units of length per second

� - Velocity of the follower in units of length per radian

� - Angular speed

b - The distance to the instant center of the cam

� - Eccentricity

L - Length

d - Displacement

Pa - Pascal

Abbreviations

PT - Physical Therapy

OT - Occupational Therapy

SBO - Spring Brake Orthosis

MIT - Massachusetts Institute of Technology

PhAFO - Power harvesting ankle-foot orthosis

HAL-5 - Hybrid Assistive Limb Suit

HAL-3 - Hybrid Assistive Leg-3

DC - Direct Current

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PC - Personal Computer

PGO - Powered Gait Orthosis

KAFO - Knee-ankle foot orthosis

AFO - Ankle-foot-orthosis

MR - Magnetorheological

SCKAFO - Stance-control knee-ankle-foot orthosis

SCOKJ - Stance Control Orthotic Knee Joint

GUI - Graphical User Interface

xvi

LIST OF APPENDICES

APPENDIX TITLE PAGE

A Engineering Drawing 100

B Main Code for GUI: Microsoft Visual -C++ 105

CHAPTER 1

INTRODUCTION

1.1 Background of the problem

According to fact, stroke disease is reported as the second biggest cause of

death worldwide. A stroke occurs when blood supply to part of the brain is

disrupted, causing brain cells to die [1]. Although stroke is a disease of the brain, it

can affect the entire body. Some of the disabilities that can result from a stroke

include paralysis, cognitive deficits, speech problems, emotional difficulties, daily

living problems, and pain. Paralysis is a common disability that results from stroke.

Paralysis can be on any part of the body. Paralysis on one side of the body is called

Hemiplegia. However, there is another type of paralysis that relates to one-sided

weakness, which is called Hemiparesis. The weakness may affect only the arm, face

or leg.

Basically, there are three types of treatments for stroke: prevention, therapy

directly after stroke, and post-stroke rehabilitation. Hemiparesis patient can be able

to walk again if a right rehabilitation therapy is applied. That is why the third stage

of stroke treatment (post-stroke rehabilitation) is important for the post-stroke

patients to prevent disabilities damage from becoming more serious. There are four

types of post-stroke rehabilitation: Physical Therapy (PT), Occupational Therapy

2

(OT), Speech Therapy and Psychological/Psychiatric Therapy. If a stroke patient

has a problem of walking weakness, generally the treatments of Physical Therapy

and Psychological or Psychiatric Therapy are used to cure disabilities. Usually

Physical Therapy consists of scheduled training, exercises and physical

manipulation of the stroke patient’s body with the intent of restore movement,

balance, and coordination.

As stroke patients frequently have difficulty with everyday functional

movement and activities; the lost of function can be decreased through rehabilitation

therapy during the critical post-stroke period. Such rehabilitation therapy involves

carefully designed repetitive exercise, which can be passive and active. In passive

exercise, the therapist or a robot actively helps the patient to repeatedly move the

stroke-affected limb as prescribe. In active exercises, the patient does the work by

him/herself, with no physical assistance. From that particular therapist, assistive

robotic technology has the potential to provide novel means for monitoring,

motivating and coaching.

1.2 Statement of the problem

There are several methods of training for the physical therapy such as using a

rehabilitation device. Most of the rehabilitation devices currently used high power

consumption to perform the therapy and having a complex control system. This

may be solved by proposing a new design of mechanism for the rehabilitation

device. The rehabilitation device should provide a physical assistance through

rehabilitation therapy to increase the possibility to cure the walking weakness.

3

1.3 Objective of the study

The objectives of this project are:

To design and develop a rehabilitation device base on the best selected

mechanism of knee and hip joint

To fabricate a prototype for testing the functioning of the designed

mechanism

To develop a computer-based control system for the rehabilitation device

system

1.4 Scope of the study

In this study, designations of the assistive robotic system only focus on the

one side of the leg. It will encompass the development of mechanism at knee and

hip joint. In order to make sure the project will achieve the objectives stated, the

scopes of this project comprise the following aspects:

To design a device called orthosis device (known as exoskeleton) for lower

extremity (leg)

The mechanism focuses on the hip and knee joint only

The device is classified as Rehabilitation Device

The device does not support the balance of stroke patient’s body

The subject/patient is a Hemiparesis patient (leg weakness)

4

1.5 Significant of the study

The results from this study has the potential to help stroke survivor in

activities they do in real life and decrease long-term healthcare costs on stroke

patients. This study is important in order to give a new hope to post-stroke patients

who had lost their ability to walk. The possibility is high to be a device that will

help any patients who experience leg weakness and disability.

1.6 Research Methodology

Basically, the project has been carried out in regular procedure of research.

This section briefly shows the general procedure of the project and the flow chart of

the project (Figure 1.1). The time consumed on the specific task and the target time

to finish the particular activity is presented in the project schedules shown in Table

1.1 and Table 1.2.

1.6.1 Procedure of the Project

i. Development of conceptual design: to conceptually design based on

data and information obtained from literature, patents, discussions,

brainstorming, and reviewing of proposed design concept.

ii. Final Design Concept: to carry out the completed engineering drawing

subsequently for kinematic analysis purpose in order to obtain the most

appropriate final design.

5

iii. Fabrication of prototype: to fabricate all components based on the

completed engineering drawing, hence to test the proposed design

concept.

iv. Development of Computer-based control system: using Visual C++

to develop user interface (control) which able to handle the operation of

the device and carry out the best performance according to gait cycle of

subject/patient.

v. Testing, Performance evaluation and Validation: to carry out the

experiments (measurement of knee joint angle of the device) to evaluate

the prototype performance and validate the results of experimental knee

data angles.

6

1.6.2 Flow chart of Project

Figure 1.1: Flow chart of the Project

7

1.6.3 Project Schedule

Table 1.1: Project schedule for Master Project 1

Activities/

Time Scale* 1* 2* 3* 4* 5* 6* 7*

Literature Review

Development of

Conceptual Design

Final Conceptual

Design

Kinematic Study (Model)

Prototype

Fabrication

Report Writing

*1 unit = 2 weeks

Table 1.2: Project schedule for Master Project 2

Activities/

Time Scale* 1* 2* 3* 4* 5* 6* 7*

Modification

Development of

Controller

Performance Testing and Data Collection

Data Analysis

Report Writing

*1 unit = 2 weeks

96

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