Prosthetic Co ntrol using Implanted Electrode Signals

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Prosthetic Control using

Implanted Electrode Signals

STEFANÍA HÁKONARDÓTTIR

Master of Science Thesis in Medical Engineering

Stockholm 2014

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This master thesis project was performed in collaboration with

Össur

Supervisor at Össur: Ólafur Haukur Sverrisson

Prosthetic Control using Implanted Electrode Signals

Protesstyrning genom Signaler från

Implanterade Elektroder

S T E F A N Í A H Á K O N A R D Ó T T I R

Master of Science Thesis in Medical Engineering

Advanced level (second cycle), 30 credits

Supervisor at KTH: Mats Nilsson

Examiner: Tobias Nyberg

School of Technology and Health

TRITA-STH. EX 2014:75

Royal Institute of Technology

KTH STH

SE-141 86 Flemingsberg, Sweden

http://www.kth.se/sth

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Abstract

This report presents the design and manufacturing process of a bionic signal message

broker (BSMB), intended to allow communication between implanted electrodes and

prosthetic legs designed by Ossur. The BSMB processes and analyses the data into

relevant information to control the bionic device. The intention is to carry out event

detection in the BSMB, where events in the muscle signal are matched to the events of

the gait cycle (toe-off, stance, swing).

The whole system is designed to detect muscle contraction via sensors implanted

in residual muscles and transmit the signals wireless to a control unit that activates

associated functions of a prosthetic leg. Two users, one transtibial and one transfemoral,

underwent surgery in order to get electrodes implantable into their residual leg muscles.

They are among the first users in the world to get this kind of implanted sensors.

A prototype of the BSMB was manufactured. The process took more time than

expected, mainly due to the fact that it was decided to use a ball grid array (BGA)

microprocessor in order to save space. That meant more complicated routing and higher

standards for the manufacturing of the board. The results of the event detection indicate

that the data from the implanted electrodes can be used in order to get sufficient control

over prosthetic legs. These are positive findings for users of prosthetic legs and should

increase their security and quality of life.

It is important to keep in mind when the results of this report are evaluated that all

the testing carried out were only done on one user each.

Keywords:

Myoelectric Control, Prosthesis, Lower Limb Prosthesis, Event Detection, Gait Cycle,

PCB Layout, Electrical Design

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Sammanfattning

Denna rapport redogor for design- och tillverknings processen av en s.k.bionic signal

message broker (BSMB), vars syfte ar att tillata kommunikation mellan implanterade

elektroder och aktiva benproteser designade av Ossur. BSMB analyserar och behandlar

data fran elektroderna till relevant information for att kunna kontrollera den bioniska

protesen. Detta gors genom handelsedetektering i BSMB, dar handelser i muskelsignalen

matchas till handelserna i gangcykeln (franskjut, stodfas och svingfas).

Systemet ar utformat for att upptacka muskelsammandragningar via sensorer som ar

implanterade i kvarvarande benmuskler for att sedan overfora signalerna tradlost till en

styrenhet som aktiverar de tillhorande funktionerna hos en benprotes. Tva anvandare,

en transtibial och en transfemoral, genomgick operation for att fa elektroder implanter-

ade i de kvarvarande benmusklerna.

Prototypen av BSMB blev tillverkad men processen tog langre tid an vantat, framst

pa grund av att det beslutades att anvanda en ball grid array(BGA) mikroprocessor

for att spara utrymme. Det innebar en mer komplicerad operationsfoljd och striktare

standarder for tillverkningen av kretskortet. Resultaten av handelsedetektionen pavisar

att data fran implanterade elektroder kan anvandas for att fa tillracklig kontroll over

benproteser. Detta ar positiva ron for dem som ar i behov av benproteser da det bor

forhoja bade sakerheten och livskvaliteten.

Det ar dock viktigt att understryka att de resultat som har presenterats i den har

rapporten ar baserade pa tester av enbart tva anvandare.

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Acknowledgements

This report was written as a Master Degree Project in Medical Engineering at the Royal

Institute of Technology (KTH). The project presented in the report was carried out in

cooperation with the company Ossur R©.

I would like to thank my supervisors for their help and input towards my project.

My professor, Mats Nilsson, for his guidance and the freedom he allowed me during the

project, and Olafur Haukur Sımonarson and Stefan Pall Sigurthorsson for all their help

and support during my project work at Ossur. Sincere thanks to the two users at Ossur

for their cooperation and patience which made all the necessary testing possible.

Last but not least I want to thank my family and friends who always support me

and believe in me. Special thanks to my father, Hakon, who is always ready and willing

to share his knowledge and interest in my studies.

Stefanıa Hakonardottir

Reykjavik, Iceland

May 2014

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Abbreviations and Explanations

AI Artificial Intelligence

BGA Ball Grid Array

BSMB Bionic Signal Message Broker

CDM Coil Driver Module

DC Direct Current

DOF Degree of Freedom

EMG Electromyograph

IMES Implantable Myoelectrical Sensor

LED Light Emitting Diode

PCB Printed Circuit Board

PCI Prosthetic Control Interface

Amputee A person who has lost all or part of limb

Antagonist Muscle A muscle that opposes the action of another muscle

Mechanoreceptors Any of the neuronal receptors that respond

to vibration, stretching, pressure, or other mechanical stimuli

Myoelectric Of, relating to, or utilizing electricity generated by muscles

Prosthesis A device, either external or implanted, that substitutes

for or supplements a missing or defective part of the body

Transtibial amputation Amputation of the lower limb between the ankle and the knee

Transfemoral amputation Amputation of the lower limb between the knee and the hip

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Contents

1 Introduction 1

1.1 Aim of the Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 Ossur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2 Background 5

2.1 Anatomy of the Leg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.1.1 The Ankle Joint . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.1.2 The Knee Joint . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.2 Human Movement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.2.1 Muscle Contraction and Electromyogram . . . . . . . . . . . . . . 8

2.2.2 The Gait Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.3 Electronic Design and Components . . . . . . . . . . . . . . . . . . . . . 11

2.3.1 Component Description . . . . . . . . . . . . . . . . . . . . . . . 12

2.4 Prosthetic Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2.4.1 Mechanical Prosthesis . . . . . . . . . . . . . . . . . . . . . . . . 13

2.4.2 Microprocessor Controlled Prosthesis . . . . . . . . . . . . . . . . 14

2.5 Bionic Devices by Ossur . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

2.5.1 Proprio Foot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2.5.2 Rheo Knee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3 Methods 19

3.1 Implementation of the System . . . . . . . . . . . . . . . . . . . . . . . . 19

3.1.1 Implantable Myoelectrical Sensors . . . . . . . . . . . . . . . . . . 19

3.1.2 External Controller . . . . . . . . . . . . . . . . . . . . . . . . . . 21

3.1.3 The BSMB Module . . . . . . . . . . . . . . . . . . . . . . . . . . 22

3.1.4 The Bionic Device . . . . . . . . . . . . . . . . . . . . . . . . . . 23

3.2 The Design Process of the BSMB Module . . . . . . . . . . . . . . . . . 24

3.2.1 Design and Component Selection . . . . . . . . . . . . . . . . . . 24

3.2.2 The Processing of the BSMB . . . . . . . . . . . . . . . . . . . . 26

3.2.3 Control Algorithms . . . . . . . . . . . . . . . . . . . . . . . . . . 27

3.3 Event Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

3.3.1 Experimental Set-up . . . . . . . . . . . . . . . . . . . . . . . . . 28

4 Results 29

4.1 The BMSB Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.2 Event Detection during Gait Cycle . . . . . . . . . . . . . . . . . . . . . 30

4.2.1 Transfemoral User . . . . . . . . . . . . . . . . . . . . . . . . . . 30

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4.2.2 Transtibial User . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.3 Current Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

5 Discussion 37

5.1 The Design Process of BSMB . . . . . . . . . . . . . . . . . . . . . . . . 37

5.2 The System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

5.3 Ethical Perspectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

5.4 Future Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

6 Conclusions 41

References 43

Appendix A - Technical Drawings

Appendix B - Pinout List

Appendix C - PCB Layout in 3D

Appendix D - Variance of Peak Values during Gait

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1 Introduction

The prosthetic profession has changed rapidly over the past few years. Going from

replacing the basic structural elements of limbs following amputation to now restoring

lost muscle function. People who have suffered from disease, trauma or congenital

disorders and therefore lost a body part or the function of a body part, experience

difficulties in performing everyday tasks. We use our legs for walking, jumping, going

up and down stairs and other tasks everyday without thinking. Those are things we take

for granted, but are actually remarkable, sensitive and rigorous cooperation of muscles

and joints. If one link in the system breaks, everything gets more complicated.

Lower limb amputation has great impact on daily living, all activity and indepen-

dence of the person. Our legs are not only vital for our movements but they are also

vital weight bearing elements of our bodies. It is important that we are able to trust

that our legs are able to support us no matter what. It is important for amputees to

have the possibility to regain their mobility and independence. Therefore different types

of prosthetic legs are available.

Nowadays, prosthetic legs controlled by microprocessors and control schemes are

available. But would it not be better if the users intentions were not simulated by some

potential control schemes, but its own muscle contractions? What would it mean for

the prosthetic control if it were possible to use muscle signals to predict and control

the function of the prosthetic device? Is it possible to detect some trend in the muscle

signals that are usable for control of the prosthetic device?

A myoelectrically controlled prosthesis is the next step in this field. The intention

is to be able to control the prosthetics by the electric signal produced by muscles dur-

ing contraction. To make it even more convenient for the amputee, the electrodes are

implanted into the muscle. The project described in this report was made for and in

cooperation with the company Ossur, which will be introduced in chapter 1.2.

1.1 Aim of the Project

This project focuses on one of the key factors in the building process of an myoelctrically

controlled prosthetic device, the communication between implanted electrodes and a

prosthetic device. Electrodes have been implanted into users and the aim is to control

pre-existing prosthetic devices with signals from the implanted electrodes. In order

to do so a well established and secure communication between the electrodes and the

prosthetic device is needed.

The goal of this project is to design a Bionic signal message broker (BSMB) which

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communicates with the implanted electrodes and returns a processed EMG signal that

can be used to control a Bionic device from Ossur. The BSMB module has to be

small and light for the best possible solution for the user. The project also includes

signal analyses of the EMG data from the implanted electrodes to see if it is possible to

notice some pattern in the signals that can be used to control a prosthetic device. This

project is built on a system made for muscle controlled hand-prostheses from Alfred

Mann Foundation [1]. The intention is to customize that system for use with the Bionic

devices from Ossur and make the system more user-friendly. The project consisted of

electronic design, PCB layout design, building and testing a prototype, gait analysis on

test users and EMG event detection.

Altium Designer is used to make the printed circuit board (PCB). That is an elec-

tronic design automation software tool for electronic systems. Within this program the

schematics of the system and the PCB layout are created. The calculation software

MATLAB is used for EMG signal analyses and event detection.

1.2 Ossur

Ossur is a global company operating in the healthcare sector. Designing and manu-

facturing prosthetics, osteoarthritis and bracing and support products. The company

was founded in 1971 in Iceland by Ossur Kristinsson, prosthetist. It started as a small

prosthetic workshop which grew into being a leading company in the area of prosthetic

solutions design. Over 40 years of experience in materials technology and innovative

design have made Ossur one of the leading innovator and global manufacturer of pros-

thetic devices. The company has its headquarters in Iceland but is operated in 18 places

around the world with over 2.200 employees [2]. Ossur’s policy is to improve the mo-

bility of people with technology, research and innovation. The company works closely

with those that have need for their products in order to come up with the best possible

solutions. Their goal is to help people over physical obstacles, allowing them to enjoy

life without limitations.

Ossur offers a full spectrum of premium lower limb prosthetic components that are

designed to reflect the unique nature of their customers. Their focus is on getting the

best possible outcome and a Life Without Limitations R© for all of their customers, with

the underlying goal of transforming their customers experience [3].

Ossur offers both active and passive solutions for lower limb amputees. Their passive

limbs are made of carbon fiber, which is known for its strength and flexibility. Their

passive joints are built on specific locking moments using hydraulic systems. Then it is

their active prosthetics, the Bionic devices, that use intelligent structures that mimic the

residual limbs responses. ”The Bionic Technology by Ossur is a powerful technological

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platform to create intelligent devices that behave like human limbs.” [3].

The company’s intention with their Bionic devices is to be able to develop prostheses

that replace the functionality lost when a person loses a limb. Using EMG signals along

with sensory, motor and artificial intelligence techniques, is the next step towards the

design of a prosthesis that replaces the lost limb and its function.

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2 Background

2.1 Anatomy of the Leg

2.1.1 The Ankle Joint

The ankle joint and the foot are quite complex structures made up of 26 bones, 30 joints,

100 ligaments and 30 muscles. For smooth motion all of these joints and muscles must

work in a synchronized manner. The foot is important for efficient walking and also in

weight bearing of the whole body. During ground contact the foot and the ankle joint

also serve as a shock absorber, attenuating the large forces that are generated. The

range of motion of the joint varies with how much load is on the ankle joint. Bones and

ligaments also limit the range of motion [4].

Dorsiflexion is the movement of the ankle joint when the toes are lifted from the

ground. The average range of dorsiflexion motion is 20◦, but only 10◦ is enough for

efficient walking. Plantarflexion is the movement of the foot when the toes are pushed

downward, e.g. when rising up to the toes. The average range of motion for plantarflex-

ion is 50◦, where 20◦ − 25◦ are needed during normal walking [4]. Figure 1 shows how

dorsi - and plantarflexion are defined.

Figure 1: Dorsi and plantarflexion of the foot [5]

Dorsiflexion is important during the swing phase of walking for so called foot clear-

ance and in the stance phase for lowering down the heel after ground contact. The most

active dorsiflexor is the Tibialis anterior which is located on the front of the leg, as can

be seen in figure 2 [4].

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Figure 2: The location of the Tibialis anterior muscle on the front of the leg. The muscle isconnected between the ankle and the knee joint. [6]

The plantarflexion of the ankle contributes to the lifting up of the body. It moves

the weight towards the toes, which is used both for forward and upward movement of

the body. The muscles that contribute the most force for plantarflexion are the Gas-

trocnemius and the Solues, which are located at the back of the leg, see figure 3. The

Gastrocnemius muscle is fixed between the ankle and the knee joint and functions also

as a knee flexor [4].

Figure 3: The Gastrocnemius muscle, the calf muscles controlling plantarflexion. [6]

2.1.2 The Knee Joint

The knee joint is one of the largest joint in the body. It is a vital part in the weight

bearing of the body and in all walking. The knee joint mainly moves in two directions,

so called flexion and extension. Flexion is when the knee is bent so the backside of the

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calf is closer to the backside of the thigh, and extension the opposite, see figure 4. [7]

Figure 4: Explanation figure demonstrating flexion and extension around the knee joint

The extension of the knee is controlled by the Quadriceps femoris muscle group and

is vital in power generation for any projection or translation of the lower extremities.

The Quadricep muscle group consist of three muscle: Vastus intermedius, Vastus later-

alis and Vastus medialis, where Vastus lateralis is the strongest one of them, see figure 5.

Figure 5: The three Quadricep muscles of the front of the thigh. For this project the Vastuslateralis muscle was used. [6]

The range of the knee flexion is from 130−145◦. The flexion of the knee is strongest

during support of downward movement of the body and when the leg is in swing phase,

not touching the ground. The Hamstring, the Bicep femoris, muscle is the main muscle

operating as a knee flexor [4]. The muscle is located at the back of the thigh, see figure 6.

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Figure 6: The Hamstring muscle of the backside of the thigh. [6]

2.2 Human Movement

2.2.1 Muscle Contraction and Electromyogram

One of the focus in this report is if and how signals generated by muscle contraction

can be used to control a prosthetic device. Therefore it is important to understand how

the muscles work and contribute to human movement. There are three types of muscle

types in the body: skeletal-, cardiac-, and smooth muscles. Here the focus will only be

on skeletal muscles.

The skeletal muscles main functions are to produce movement, maintain postures

and positions, and to stabilize the joints [8]. Skeletal muscle is a structure made up

of muscle fibres and motor neurons which together form a so-called motor unit. Each

muscle is made up of many motor units. The muscles are activated by reflexes and our

will and intention, which comes from the brain through the nervous system, to the motor

neurons in the muscles which stimulate the muscle fibres. The muscles generate force

by contraction, which is the muscle response to stimulation produced by an electrical

nerve impulse. The electrical nerve impulse is a response to signals, in the form of

action potentials, from the brain. The contracting force of skeletal muscles varies with

the number of stimulated muscle fibres and the frequency of the action potential.

During contraction the length of the muscle changes. It is called concentric contrac-

tion when the muscle shortens due to stimulation, eccentric contraction when the muscle

lengthens and generates tension, and isometric contraction when the muscle generates

power without any change in muscle length [9]. The muscles in our body are the main

contributors to our movement. The muscles cross joints and their pulling forces create

the motion of the limbs. It is the combination of concentric and eccentric contractions

of the muscles that allows movement of the joint and therefore the body itself [8].

Electromyogram (EMG) is the profile of the signal generated from normal muscle

contraction, the action potential. This signal is easily detected with electrodes located

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on the muscles. In order to use the signal for some kind of control it is vital to process

and analyse the signal rigorously. The signal has low amplitude, only a few mV, and

is consumed by noise without any processing. During clinical analysis of the human

walking, the gait cycle, EMG signals are often used in order to determine which muscles

are activated during particular gait phases [10].

2.2.2 The Gait Cycle

The gait cycle is normally defined as the period of time when the heel of one foot strikes

the ground until that foot hits the ground again. It is a synchronised event where one

limb performs the support function while the other one moves itself forward into the

next step. The gait cycle is divided into two main phases, referred to as stance and

swing phase. As can be understood from the names of the phases, the stance phase

refers to when the foot is in contact with the ground, and the swing phase when the

foot is in the air swinging forward. The stance phase is further divided into [4];

Initial Contact(Heel strike): The exact moment when the foot contacts the ground.

Load response: The period from the time the foot contacts the ground until the other

leg has left the ground, the leg takes over the weight bearing.

Mid stance: The body starts to move over the leg and weight bearing moves towards

the toes.

Terminal stance (Heel off) and pre swing (Toe off): The foot is prepared to leave

the ground, with all the weight on the toes.

The swing phase is the period when the foot is not in contact with the ground. During

the swing phase the leg is moved forward and prepared for the next contact with the

ground. The swing phase subdivision is normally as follows [4];

Initial swing (Acceleration): The moment when the leg leaves the ground, knee

flexion and dorsi flexion of the ankle for ground clearance (Toe off)

Mid swing: The knee is in full flexion and the leg starts to move in front of the body

Terminal swing phase (Deceleration): The knee is extended and the leg is prepared

for ground contact [4].

See figure 7 for explanation of the gait cycle.

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Figure 7: Graphical presentation of the gait cycle, showing the main events during one cycle.The moment of the events are often presented as percent of the whole gait cycle. As can beseen in the figure the stance phase takes 60% of the cycle and the swing phase 40%. [4]

The electrical activity of the muscle gives insight into when and which muscles are

active at each time in the gait cycle. For this research the Hamstring and Quadriceps

muscles of the thigh were used for controlling the knee, and Tibialis anterior and Gas-

trocnemius muscle in the calf for controlling the ankle. Therefore we will look more

closely at the function of those four muscles during normal gait cycle.

The main function of the Hamstring is helping with the flexion of the knee. The

Hamstring is most activated around the initial contact where the Hamstring decelerates

the knee extension and prevents hyperextension of the knee. The Quadriceps and the

Hamstring are antagonist muscles which means that since the main function of the

Hamstring is knee flexion, the Quadriceps is a knee extensor. The Quadriceps extends

the knee concentrically before the initial contact and then controls the knee flexion and

absorbs shock in the loading response phase. Those two muscles are mostly activated

in the stance phase.

The two antagonist muscles of the calf, Gastrocnemius and Tibialis anterior, control

the dorsi and plantar flexion of the ankle. Gastrocnemius, which is located in the back

of the calf, controls the plantar flexion while Tibialis anterior, in the front, controls dorsi

flexion. The main function of the Gastrocnemius in the gait cycle is therefore to lift

the heel from the ground in the stance phase. Tibialis anterior is more activated in the

swing phase where it brings the toe up for ground clearance, and controls the foot drop

in the loading response phase. See figure 8 for a graphical presentation.

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Figure 8: The muscle activation of the hamstring, the Quadricep (vasti), the gastrocnemiusand tibialis anterior during one gait cycle.

2.3 Electronic Design and Components

Electronic design starts with defining the function of the circuit and set up of a block

diagram. After the circuits requirements have been defined the right components can

be selected and a schematic drawing created. The schematic drawing turns the block

diagram into a detailed design, showing all the components and their connections. It is

important that all of the connections in the schematic are right since the final electronic

circuit is based on the schematic drawing.

Printed circuit board (PCB) is an important part of the electronic design. Well

designed PCB ensures that the electronic circuit works as intended. The board itself is

made of a non-conductive material with conductive layers. Holes or pads for soldering

the components on the board and traces for the connections are made of those conductive

layers. All of the components of the schematic drawing are placed on the board in a

way which allows all required connections. The boards can have different numbers of

layers. So-called multi-layered boards have inner conductive layers. The inner layers are

most often used as power and ground layers. That helps to eliminate extra noise [11].

For complicated PCB boards, boards with a lot of components and connections or

complicated components, it is often essential to have the board in few layers. In figure

9 an example of PCB construction can be seen.

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Figure 9: Example of a 4-layer PCB. The figure shows how the board is stacked up in layers.The orange color represents the conductive layer. The figure is made in AltiumDesign.

The components can be through hole (TH) components or based on surface mounted

technology (SMT). The TH components have legs that are soldiered to conductive holes

in the PCB. SMT components have pads instead of legs and are placed directly onto

conductive pads on the PCB. The biggest benefit of using SMT instead of TH is increased

circuit density and better performance. It is also possible to place the components on

the board with special pick and place machines which makes the manufacturing process

more accurate, easier and faster. Surface mounted boards also allow for a smaller and

lighter design, mostly due to the fact that the components can be mounted on both

sides of the board, the SMT components are smaller in size and having no holes that

need to go through the board saves space [12].

2.3.1 Component Description

A microprocessor can be said to be the brain of computers and other electronic de-

vices. The main function of microprocessors in this project is to receive input from

a peripheral device. Then the processor processes and analyses the input data and

changes it to appropriate output data, which is sent out as control signals. The mi-

croprocessor contains memory which stores information and commands about how the

processor should respond to and process the input data. Microprocessors can be found

in all computers and most digital devices [13].

A voltage regulator generates a constant, desired voltage level, regardless of changes

in the input voltage. Regulators are widely used in order to feed microprocessors and

other electrical components that need stable supply voltage, independent of battery

voltage variation [14]. Linear regulators, as the ones used in this project, need higher

input than output voltage in order to function. So if the battery voltage drops too low,

the device stops to function.

Communication between electrical devices can be either wired or wireless. Here in this

project three different kinds of communication were used, two wired and one wireless.

A short description of those three standards comes below.

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Serial Peripheral Interface(SPI) is a synchronous serial data protocol that is used

for communication between microprocessors and other peripheral devices, or between

two microprocessors within the same equipment. The SPI communication is always

based on master-slave control. That means that one of the devices has the control, the

master which normally is the microprocessor, over the peripheral device, the slave. SPI

allows fast communications over short distances [15].

Universal Asynchronous Receiver/Transmitter (UART) is another type of serial

communication, used for communication between computers, microprocessors or other

peripheral devices. It converts parallel data to serial for transmission and vice versa for

reception [16]. UART allows communications over up to tens of meters, through cable.

Bluetooth technology is a global wireless standard. It allows secure wireless com-

munication over short distances (10-50 m) using radio transmission at 2.4 to 2.485 GHz.

The Bluetooth technology is widely used for all kind of communications and data shar-

ing. To be able to share data with Bluetooth, both the sending and receiving devices

need to have a Bluetooth module installed and the devices need to be paired [17].

2.4 Prosthetic Technology

Lower limb amputees are mainly divided into two sub-groups. Transfemoral amputees

which refers to lost limb above the knee joint, and transtibial which is below the knee

joint. Transfemoral amputees have two joints missing, both the ankle and the knee,

which makes it more complicated to build a replacement system. There exist few types

of lower limb prosthetics which can be divided into two main categories, mechanical or

microprocessor controlled devices.

2.4.1 Mechanical Prosthesis

Mechanical prosthetic devices are simple, functional, non-microprocessor controlled de-

vices. They are designed to provide the amputee a basic function of the lost leg. The

main function of a mechanical prosthetic is to provide support, and allow rotation around

the lost joint. Mechanical prosthesis are passive devices since they do only provide sup-

port and allow rotation around joints, and do not add any energy to the system [18].

Prosthetic feet are often made of carbon fibre which is a material know for its energy

storing properties, that along with the shape of the feet helps with forward movement

by storing energy throughout the step, see figure 10. Sometime these feet allow rotation

13

around the ankle which makes it possible to adjust the heel height [18].

Figure 10: Example of a prosthetic foot. The foot is made of carbon fibre and is shaped in aspecial way for energy storing properties. [19]

Mechanical knees main purpose is to provide secure and stable ground contact during

the stance phase. The stance support is controlled by a kind of locking mechanism

which can be geometrical, hydraulic, manual or weight activated. Swing phase control

and dampening are also important for the function of the knee prosthesis. The swing

control can be implemented using a simple friction brake. Those systems however are

very limited and need to be readjusted regularly according to the users needs [18]. Figure

11 shows an example of a prosthetic knee.

Figure 11: Example of a prosthetic knee. This one has a geometrical locking mechanism. [20]

2.4.2 Microprocessor Controlled Prosthesis

Prosthetic devices are controlled by microprocessors in order to increase their function-

ality and control. The microprocessor controlled prostheses can be active or passive

devices. An active prosthetic device provides powered motion during walking and by

that makes up for lost muscle energy, while the passive provide support and rotation

but not add any energy into the system. Their system is built up of sensors which

14

are able to sense the environment and adjust the device accordingly. The device learns

and adapts to the environment and the user over time. They normally use information

from [18]

• Gyroscopes - Measures angular velocity. The signal can be used to track orien-

tation changes by integrating the signal.

• Accelerometers - Can determine the location with integration of the signal and the

acceleration of the leg.

• Angle sensor - Measures the angle between two established points. Used for mea-

suring the position of the joints.

• Load cells - Measure load, can measure both the absolute load or changes in load.

The microprocessor controlled prosthesis are designed to imitate natural walking more

closely and offer more stable and effective control. Nevertheless it is impossible to pre-

dict everything which limits the function of these prostheses. People use their legs for

much more than only walking. The walking pattern also changes according to circum-

stance. For example it is not possible to use the same walking pattern for walking up

stairs as for walking down a hill. This limits the usefulness of these kind of prosthesis.

The best and safest solution would be that the user had direct control over the device,

just as if it were his own leg. That would be possible to implement by using EMG

signals from the residual muscles that have lost their previous function.

2.5 Bionic Devices by Ossur

Bionics = bi(o) + (electr)onics: the application of biological principles to the study

and design of engineering systems, especially electronic systems [21].

The goal of the Bionic Technology by Ossur is to restore the true nature of the lost

limb using intelligent structures. This technology is built on knowledge from mechan-

ical, software and electronic engineering. The Bionic system is made up of sensors,

artificial intelligence and actuator technology.

The sensors purpose is to replace the mechanoreceptors of the lost limb. Their pur-

pose is to sense the location of the limb in space, which is done by tracking orientation,

load and angular placement of the device. That information is passed on to the artificial

intelligence (AI), which is able to process the information and determine the next act

of the Bionic device which is controlled by actuator technology. The AI part of the

system can be said to be replacing the function of the brain, the central nervous sys-

15

tem. The AI sends out a control signal to the actuator technology which responds with

appropriate prosthetic control. The actuator technology is based on motor function and

battery power. [3] Figure 12 shows the human system versus the Bionic model from

Ossur schematically.

Figure 12: The human system versus the Bionic model from Ossur

For this project the following Bionic devices from Ossur were used; the Rheo knee

and Proprio foot.

2.5.1 Proprio Foot

PROPRIO FOOT is an active, adaptive, below-knee prosthetic device that mimics nat-

ural ankle motion. The main function of PROPRIO FOOT is to bend and straighten the

”ankle joint”. The motor-powered ankle motion increases the ground clearance which

reduces the risk of tripping and falling. This technology allows the user to walk on

different surfaces in a more natural and safe manner, allowing more natural gait cycle

with better efficiency [3]. The key features of the PROPRIO FOOT are [22]:

• Better ground clearance, reducing risk of falling.

• Moves the users attention from the walking surface to their surroundings with secure

environmental reading.

• Reduced strain on knees, hips and back.

• Makes it easier to walk in stairs and hills.

• Heel hight can be re-adjusted with a button sequence. Practical when using high-heel

shoes.

16

Figure 13: The PROPRIO FOOT from Ossur [22]

The PROPRIO FOOT is made for low to moderate impact activities, which means

that it is suitable for daily activities. The foot is powered by a 14.8 V and 1800 mAh

rechargeable lithium-ion battery. The battery needs to be recharged after 24-48 hours

of use, depending on activity level [23].

2.5.2 Rheo Knee

RHEO KNEE 3 is an advanced, active, prosthetic device for above-knee amputees. It is

the first microprocessor controlled prosthetic knee with artificial intelligence. It provides

natural knee function since it continuously adapts to the user and the environment [3].

The main functions of the RHEO KNEE are [24]:

• Effortless swing initation which means smoother gait.

• Advanced actuator and resistance, allowing more stable and secure support.

• Natural swing phase thanks to a constant power spring.

• Five-sensor technology for gait phase detection, giving more stable and dynamic re-

sponse.

• Magnetorheological technology that gives an instant response, which allows more pre-

cise and secure control of the Bionic device.

17

Figure 14: The RHEO KNEE from Ossur [24]

The RHEO KNEE is made for low to moderate impact level and low, moderate and

high activity level. That means that the knee is well suited for daily activity involving

longer walks and low to moderate sports activities such as golf. The knee is powered

with a rechargeable 1880 mAh, lithium-ion battery, which needs to be charged after

48-72 hour use depending on activity [25].

18

3 Methods

3.1 Implementation of the System

The prosthetic control system is composed of implanted electrodes which pick up the

muscle signal, a coil around the residual limb which powers up and allows data trans-

mission, an external controller that controls the communication between the implant

and the coil, a bionic signal message broker which allows communication between the

implant and the bionic device, and last but not least the bionic device. A flow chart,

explaining the system can be seen in figure 15.

Figure 15: Flow chart showing the prosthetic control system

3.1.1 Implantable Myoelectrical Sensors

The first part of the system is the implanted electrode sensors. The implants used in

this project, so-called IMES, are developed by the Alfred Manning Foundation [1]. They

are designed for permanent implantation with no service requirements [26]. The IMES

implant is a ceramic tube, 16.74 mm long and 2.44 mm in diameter, see figure 16.

19

Figure 16: The size and shape of the implantable myoelectrical sensor, IMES [27]

The IMES has metal end caps on each end serving as electrodes for picking up the

EMG signal from the muscle contraction. The IMES acts like a differential amplifier,

taking the difference between the two signals from each end cap, which eliminates all

common noise. Then the implant amplifies, rectifies and integrates the signals as can be

seen in figure17. The processing is important to reduce the amount of data that needs

to be transmitted as digital data over a magnetic link produced by a coil around the

residual limb [28].

Figure 17: Amplification, rectification and integration of the EMG signal by the IMES device

One IMES device is needed for each degree of freedom (DOF), which means that in

order to be able to control the bionic device in both directions there is need for two elec-

trodes, implanted into antagonist muscles. For this project one electrode was implanted

into the medial head of the Gastrocnemius muscle and another into the Tibialis Anterior

muscle for the transtibial amputee. For the transfemoral amputee, the electrodes were

implanted into the Lateral Quadriceps muscle (Vastus Lateralis) and into the Hamstring

muscle (Bicep Femoris). See figure 18.

20

Figure 18: The muscles of the legs

The IMES device is inserted into the muscle using a surgical probe, dilator and

ejection tool. One of the end caps of the implant has an eyelet onto which sutures are

attached in order to fix the IMES in place. The IMES is implanted deep inside the

muscles which minimizes cross-talk and gives a stable and robust signal since the mus-

cle tissue holds the implant in place. One of the main advantages of using implanted

electrodes instead of surface electrodes is that they are closer to the source of the elec-

trical activity, which means more precise signal. By using implanted electrodes, a noise

introduced by environmental factors and movements is also eliminated. It should also

be better from the users perspective to have the electrode implanted since he does not

notice them or has to change them, as is needed with the surface electrodes.

3.1.2 External Controller

The next part of the system is a coil that is located inside the prosthetic socket around

the residual limb. The coil is used to transmit power and configuration settings to

the IMES device. The coil and the IMES are controlled by an external control system

which is divided into two main parts: The prosthetic controller interface (referred to as

PCI) which handles powering, set up and reading from the IMES. A coil driver module

(referred to as CDM) which powers up the coil and handles sending and receiving of

telemetry data to and from the coil. The PCI is a belt-worn device, powered by a 7.6 V

battery and is connected by cable to the CDM. The CDM is mounted on the prosthetic

socket. See figure 21 It is connected via cable to the next part of the system, the bionic

signal message broker (BSMB).

21

The PCI is large in size, 11.7 cm(L) x 9.9 cm(W) x 4.9 cm(H), and weights around

0.5 kg. The size and weight of the device is mainly due to the battery on the PCI. See

figure 19.

Figure 19: The PCI is the only part of the system that is not attached to the prosthetic. Thedevice is both big and heavy and has an external battery.

In the original system, where this setup is used to control the myoelectrically con-

trolled hand prosthesis, the PCI is used to determine the users intent and control the

prosthetic device accordingly. In this project the PCI was only used to power up and

control the CDM and to send the signal onto the BSMB module which is designed spe-

cially to control bionic devices from Ossur. The PCI is currently powered with a 7.2 V,

2200 mAh lithium-ion battery with max current consumption of 275 mA.

3.1.3 The BSMB Module

The purpose of the bionic signal message broker (referred to as BSMB) is to create a

layer of abstraction between the implant system and the Bionic device. The BSMB must

be able to read EMG data from the PCI, transform the data into readable form and

then forward it to the Bionic device. The module scales and shifts the EMG signal to

minimize the impact of system changes, due to muscle fatigue or other factors affecting

the signal amplitude. The BSMB also provides two different interfaces, SPI and UART,

for the Bionic devices. See block diagram for explanation in figure 20. The goal is to

implement an event detection into this part of the system. That means the BSMB mod-

ule will be able to detect a certain pattern in the EMG data which indicates a certain

event in the gait cycle. This gives information about the users intention, which allows

more secure control of the Bionic device.

22

Figure 20: Block diagram of the BSMB and connections

The BSMB is located in a small box on the upper edge of the prosthetic socket. See

figure 21. The module is connected by one cable to the coil driver module and another

cable to the Bionic device. The BSMB can be powered either from the implant system

(the PCI) or from the Bionic device. The user does not have access to the module

since it does not require any direct interference. The design and function of the BSMB

module will be described in the chapter 3.2.

3.1.4 The Bionic Device

The last link in the system is the active prosthetic device. The system will be able to

control both the PROPRIO FOOT and RHEO KNEE, which are both Bionic devices

made by Ossur. The use and the intention of the EMG signal will be interpreted

differently for those two devices since the PROPRIO FOOT is a transtibial prosthetic

and RHEO KNEE a transfemoral prosthetic. The already existing firmware of those

devices will be modified to implement the EMG signals. The communication between

the BSMB and PROPRIO will be an UART connection, and SPI connection to the

RHEO. See chapter 2.5.1 and 2.5.2 for detailed information about the Bionic devices.

A figure of the whole system can be seen in figure 21.

23

Figure 21: The whole system used for this project. The figure shows the prosthetic socketcontaining coil, the location of the CDM and BSMB modules, the external PCI and the Bionicdevice. This is the system for the transfemoral amputee which means that the Bionic deviceshowed is the RHEO KNEE.

3.2 The Design Process of the BSMB Module

The main part of this project was to make a functioning prototype of the BSMB device.

That process consisted of choosing appropriate components which would fulfil the design

criteria of the device. Below the choice of components is described.

3.2.1 Design and Component Selection

The BMSB module should be able to:

• Communicate with the implanted electrode system and sample data

• Process the data stream from the electrodes into relevant biological metric recogniz-

able by the bionic device, involving event detection

• Communicate with the Bionic device, sending a control signal

• Allow communication through Bluetooth

• Be powered from the battery in the Bionic device, and power the PCI module

A simple flowchart of the system showing all the different parts needed to fulfil the

BSMB intention can be seen in figure 22.

24

Figure 22: Flowchart showing all the different parts of the BSMB module

In order to fulfil the bionic message brokers intention the circuit contains a micro-

processor, memory and a Bluetooth module for wireless communication. The micro-

processor is one of the most vital parts of the circuit. There all the sampling, signal

processing and control is performed. Further description of the BSMB software can be

found in chapter 3.2.3. It was decided to use a ball grid array (BGA) microprocessor to

save space on the PCB board for further development of the circuit. BGA means that

the connectors of the processor are located underneath the processor house. A processor

using BGA is a square of 7x7mm while the same processor in normal surface mounted

house is a square of 16x16mm. See figure23 for explanation and comparison of those

two houses.

Figure 23: How the BGA microprocessor (on the right) looks like versus a normal surfacemounted processor (on the left). The figure shows the right proportions between the two housingbut not the right sizes.

The Bluetooth module is used in order to be able to connect to the module easily

through a computer. It facilitates both software updates and data sampling. The built

25

in memory is set for long term monitoring of muscle activation. This is vital in the

design process of the device since it gives good insight of signal drifting and changes in

muscle activation. The circuit contains two 3.3 VDC regulators, in order to distribute

the load, and one 7.2 VDC regulator for feeding the system. The circuit has two differ-

ent interfaces; one for receiving the signal from the PCI through an SPI connection and

one to send information to the Bionic device, through either SPI or UART, depending

on which Bionic device is used. Extra sets of LEDs are implemented into the system in

order to be able to match the EMG data to the gait cycle during testing. Those LEDs

are only intended for testing and will be temporarily added to the prosthetic socket

during testing periods. The choice of components along with a short description of the

components purpose can be found in table 1.

Table 1: The main components of the BSMB, showing name and link to datasheet.

Microcontroller MSP430F5438AZQW [29]

Sample data from the implant system

Process data for sufficient control of the Bionic device

Send out the data to the prosthetic control

Regulators Allow different supply voltage

MAX8881EUT33 + T [30] 3.3V for Microcontroller

MAX8881EUT33 + T [30] 3.3V for Bluetooth

LM2841Y [31] 5VDC Battery voltage

Bluetooth LMX9838SB [32]

Allows wireless communication with the module

Memory AT45DB321D [33]

Connectors Interference with Bionic device and implant system

Bionic 8 pins

Implant 7 pins

LED In order to match the EMG data to the gait cycle using video

3.2.2 The Processing of the BSMB

After all the components had been chosen, they had to be put together into one func-

tioning device. A schematic of the BSMB device was drawn using Altium design. See

in appendix A for technical drawings.

26

The next step was then to produce the PCB layout of the circuit. This was also done

using Altium design. The size of the PCB board was predefined according to space in

the Bionic device in order to fit it inside in future versions. As can be seen in figure 24

the size of the board is 50.2 x 33.5mm The PCB board ended up being 4 layers, surface

mounted with components on both sides. See chapter 2.2 for explanations. In order to

ease the routing of the microprocessor a so-called pin-out list was made. The pin-out

list gives good overview over all the connections that have to be made, which helps a

lot when planning the routing. See the full pin-out list in appendix B.

The manufacturing and the assembly of the circuit was carried out by ADVANCED

CIRCUITS which is a leading company in the PCB industry located in the US [34]. See

the outline of the PCB board in figure 24 and a more detailed 3D layout of the PCB

board in appendix C.

Figure 24: The outline of the PCB board.

3.2.3 Control Algorithms

The EMG signal can drift over time, mainly due to muscle fatigue along with other

environmental factors. Those changes in the signal can have bad effects on the control,

so it is important that the parameters can be adjusted to some extent. The simplest

way to manage the signals is to define a threshold level that filters out low amplitude

noise and uses the signal above the threshold for control of the Bionic device. To be

able to use this method the amplitude range of the EMG signal has to be known, from

the threshold to the highest registered amplitude. The threshold can be implemented

using dynamic interpretation of the amplitude.

3.3 Event Detection

The goal of the event detection is to be able to determine if some gait initiation can

be detected from the EMG data from the IMES sensors. The detection needs to be

27

at an early stage in order to be able to use it to support the gait initiation in the

prosthetic control. In order to synch together the walking event from a video and the

EMG data from the IMES, a LED system was put together. Two LEDs were fixed

to the prosthetic socket at a visible place for video recording. The LEDs were then

connected to the microprocessor which activates them when recording of the IMES data

starts. Using this it is possible to synch together the gait cycle and the muscle signal,

and determine how the gait initiation appears in the EMG data.

3.3.1 Experimental Set-up

The user was asked to walk in normal speed, 20 meters on a flat surface. One of the

LEDs was programmed so it lit up as the sampling of the IMES data started and was

turned off when the sampling stopped. The other LED was set to blink every second.

The testing was carried out as follows:

• The user stands upright with the weight equally distributed on both legs

• The video recording is turned on

• A few seconds later the data recording starts, indicated by the LEDs

• The user starts walking with the residual limb as the leading leg and walks 20 m at

even speed

The test were repeated three times without resting. The sampled data were then

plotted using MATLAB and the video and the figures synced together for analyses. See

the results in chapter 4.2.

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4 Results

4.1 The BMSB Module

The PCB of the BSMB module came fully assembled from the manufacturer Advanced

Circuit, as can be seen in figure 25.

Figure 25: The manufactured prototype of the BSMB module.

Simple tests were carried out in order to see if the PCB was functioning correctly.

By powering the module it was possible to establish a connection both to the Bluetooth

module and the microprocessor. Then the powering setup was tested, which revealed

that it is possible to use the battery from the Bionic device to power up the module and

the PCI. Removing the battery from the PCI yields a noticeable difference in both the

size and weight of the device as can be seen in figure 26.

When all main features had been tested separately the whole system was connected

together. That test showed that the BSMB module was able to communicate with the

IMES and Bionic devices. The setup can be se

29

Figure 26: The test set-up for the BSMB. Battery as is used for the RHEO Knee was used forpowering the system.

The event detection has not been implemented into the system. That will be the

next step in the future design of this system.

4.2 Event Detection during Gait Cycle

4.2.1 Transfemoral User

EMG data was sampled and video taken while the transfemoral user walked 20 m, three

times. The LED system had been implemented in order to sync the data afterwards.

The LED system used for the first test set-up was not working well enough. How

the LEDs should function had not been totally thought through, and the light from the

LEDs was not strong enough to be detected in the video, which resulted in it not being

possible to sync the EMG data to the videos. The test nevertheless gave promising

EMG data.

Before the next testing, the control and the strength of the LEDs was improved.

Those tests gave usable EMG data and videos, but the system could still be improved.

The blinking LED had a strong light which dominated the LED indicating the sampling

of the data (see chapter 3.3.1 for explanation). Nevertheless it was possible to use that

data for matching video and EMG data.

Since the EMG data comes processed from the IMES and the PCI, no signal process-

ing was required. The data from the test were plotted and analysed using MATLAB. By

30

using the video and the EMG data it was possible to match the signals to the gait cycle.

Those results were what had been hoped for and tests had indicated. Figure 27 shows

the EMG activity during the 20 m walking on flat surface. Toe-off events, according to

the videos, have been marked into the graphs in order to define the gait cycles.

Figure 27: The EMG data from the IMES devices in the Hamstring muscle and the Quadricepmuscle. The data was sampled while the amputee walked 20 meters on flat surface. Toe-off foreach step is indicated with a vertical line.

As mentioned in chapter 3.2.3 there is always some variance in the amplitude of the

EMG signal. For the three test the highest peak varies from 133 to 77 values for the

Hamstring muscle and from 152 to 79 values for the Quadricep muscle. See figures 28

and 29. This is up to 40 % changes between steps which needs to be considered when

the threshold values for the control are chosen. All of the peak values can be seen in

appendix D

31

Figure 28: The EMG data from the Hamstring from all of the three tests. This comparison ismade in order to see the variance of the peak values during the testing.

Figure 29: The EMG data from the Quadricep from all of the three tests. This comparison ismade in order to see the variance of the peak values during the testing.

For more detailed analyses, one gait cycle was picked out and the activity of each

muscle plotted separately. The toe-off event, which divides the gait into stance and

swing phase, is shown on the graphs in figure 30. Events from the video were picked out

and put together in order to match the gait cycle.

32

Figure 30: The EMG data from the IMES devices in the Hamstring and the Quadricep muscles.The gait cycle is divided into stance and swing phase and captures from the videos are usedfor visual presentation of the gait.

It is interesting to see that the activation of the Hamstring muscle and the Quadricep

muscle is during the midstance and not the initial contact as it is in a normal gait (see

chapter 2.2.2 ). That can be explained by that those muscles are not connected over the

knee joint, as it is for a natural limb, but only the hip, which changes the activation.

The amputee uses the muscles in order to move the body forward over the prosthetic

leg since the amputee does not have the power from the ground pushing it forward as

is normal. Small activation can again be noticed after the toe off. Again the amputee

needs to use the muscle instead of the ground reaction force, this time in order to swing

the leg forward.

It is very positive for the control potential that detectable, stable pulses from the

muscles come in the preparation for the swing phase. Just at the moment when the user

goes into swing phase, and takes the weight of the leg, the prosthetic knee needs to be

totally loosened up to allow the forward swing. Up to now, this has been the most vital

moment of prosthetic control during the gait cycle. If the knee is loosened up to soon,

33

when the user still has weight on the leg, he would fall down. These EMG data make

it possible to predict the start of the swing phase in advance. That means a lot for the

confidence, security and stability of the user and efficiency of the gait cycle.

4.2.2 Transtibial User

Pretesting had shown that the data from the transtibial amputee would not be suitable

for event detection. Therefore the test described in chapter 3.3.1 was not carried out

for this user. The results from the pretesting can be seen in figure 31. The muscle signal

was sampled during 20 m of walking on flat surface.

Figure 31: The EMG data from the IMES devices in the Tibialis anterior and Gastrocnemiusfrom the transtibial user. This is data from 20 m on flat surface.

The results from the sensors in the transtibial amputee were not good, they did

not show any usable events. It is interesting to see how weak the signal is from the

Gastrocnemius muscle. It could be that the sensors are not positioned well enough

or that the muscles in this user are not strong enough. Then there is a question if it

would be better to use the Soleus muscle than to use the Gastrocnemius muscle. The

Solues muscle is a plantarflexor like the Gastrocnemius muscle but it is not controlling

the knee flexion like the Gastrocnemius muscle, which could be affecting utility of the

muscle signal. It is hard to make any statements about the data since there is only one

user.

34

4.3 Current Consumption

Calculations were carried out in order to see if it would be possible to power up the PCI

with the same battery as the Bionic devices are powered with. The details needed for

those calculations can be seen in table 2.

Table 2: Battery size and average current consumption for the PCI, RHEO KNEE and PRO-PRIO FOOT.

Device Battery size Average current consumption

PCI 2200 mAh 275 mA

RHEO KNEE 1880 mAh 40 mA

PROPRIO FOOT 1800 mAh 75 mA

The current consumption and the batteries are different for different Bionic devices.

If the PCI would share power with RHEO KNEE the battery would last around 6 hours

since we have a 1880 mAh battery and current consumption of 315 mA. It would last

even shorter with the PROPRIO FOOT or only 5 hours. There the battery is only

1800mAh and the current consumption 350 mA. This extra load on the Bionic device

battery would cause the battery to empty up to around 75% faster than before.

35

36

5 Discussion

5.1 The Design Process of BSMB

The design process of the BSMB took more time than had been expected. Because

of delays in the routing and difficulties with the manufacturing company it took nine

weeks instead of five as had been assumed for in the time-plan. The use of a BGA

microprocessor meant more complicated routing and more challenging manufacturing

standards. After 3 weeks of discussion and changes in co-operation with the manufac-

turing company, Advanced Circuit, the circuit finally got through for manufacturing.

This delay caused there being not much time for testing and in order to carry out the

event detection a replacement system had to be used.

The prototype of the BSMB fulfilled all of the design criteria, see chapter 3.2.1. It

was possible to communicate with the IMES and the Bionic device, and connect to the

module with Bluetooth. The design allowed the PCB to be fitted inside the Bionic

device and to be powered with the battery in the Bionic device. It was also possible to

power the PCI by using power from the BSMB module.

In the future version it would be convenient to place an accelerometer on the BSMB

module for better event detection. Together the IMES and the accelerometer should

give data good enough for sufficient control of the prosthetic device.

5.2 The System

Today all the external parts of the system are located on the prosthetic socket, except

for the PCI module. The user has to wear the PCI module around his waist which is

rather uncomfortable for the user. The PCI is connected via cable to the CDM on the

prosthetic socket. That can be uncomfortable for the user and it also increases the risk

of broken connectors and malfunction of the devices.

The cables connecting the modules together caused some trouble during the testing

period. The cables are attached on the outside of the socket, and little pulling on the

cables caused the soldering to brake. For this version of the system it was important

to have the cables on the outside since it had to be possible to disconnect the parts

easily. In future version it would be best that those cables will somehow be covered to

minimize the risk of pulling the cables.

The next step in the development of the system would be to place the PCI module

and the BSMB inside the Bionic device, sharing the battery. That would mean fewer

cables and no extra device for the user as it is now with the PCI. It is not possible to

move the CDM away from the coil so it would still need to be located on the prosthetic

socket. For this to be possible the current consumption of the implant system has to be

37

minimized somehow. Today the PCIs max current consumption is 275 mA. The RHEO

KNEEs max power consumption is 40 mA and the max power consumption for the

PROPRIO FOOT is 75 mA. The system powered with the battery in the bionic device

would only last for 5-6 hours, assuming maximum consumption, before it would need

to be re-charged. That is a short time compared to the 24-72 hours the Bionic devices

last today. It would be best that the device would last through the day, around 16-18

hours, and then be charged during the night. That requires a battery with 6300 mAh.

For future testing it is recommended to improve the LED system used for the event

detection, by separating the diodes and to make sure that the blinking diode is turned

off when data sampling starts. The system could also be improved by using a LED band

that would be attached all around the prosthetic socket, allowing a better view from all

angles.

5.3 Ethical Perspectives

The use of implantable electrodes, the IMES, has advantages for the user and the en-

vironment. Not only does it give a more stable and better signal for controlling the

prosthetic device, but it is also more comfortable for daily use. The user does not have

to think about the implant, after they are implanted they stay in place and work with-

out maintenance. The surface electrodes on the other hand need to be changed out,

and can cause discomfort and irritation of the skin. It can also be problematic to locate

the surface electrodes on the residual limb because of the prosthetic socket. The use of

implanted electrodes is also better for the environment since the surface electrodes need

to be changed out rapidly.

There are clearly some disadvantages with the implanted electrodes. The system has

a high starting cost because of expensive electrodes, and furthermore the user has to

undergo surgery, which is always risky and expensive. Tests indicate that the implants

should tolerate being inside the body and function for dozens of years, but since this

is new technology no one can say for certain how it will perform over a longer time

period. It is vitally important that the system shall be of benefit to the user since it is

hard to remove the electrodes again without damaging muscle tissue. To prevent this,

a pretest can be carried out using fine-needle electrodes, inserted through the skin. As

the tests show this system will give the user more control and security which will change

the experience and improve the quality of life. It is impossible to put a price on such

things.

38

5.4 Future Considerations

The work delivered in this report is only one part of building a fully functioning myo-

electrically controlled prosthetic leg. There are many things which have to be considered

before this system can be delivered as a fully functioning product. These are the first

test that have been carried out employing such a system. The most important thing at

this stage is to implant electrodes into more users, in order to get reliable results. To

do so it would be convenient to create a system that works with surface or fine needle

electrodes, so that the users can get some idea as to how the system will work before

undergoing the full implantation surgery.

The results of this report indicate that minor modifications can be carried out in order

to make the system better and more user-friendly. These would involve implementing

the event detection into the control scheme of the Bionic devices, as well as making the

system smaller and more manageable for the user by combining everything in the Bionic

device. For this to function the power consumption has to be minimized, so the charge

of the leg will last throughout the day.

39

40

6 Conclusions

A Bionic Signal Message Broker (BSMB) was designed and a functioning prototype

manufactured. It was possible to connect to the implanted electrodes and the Bionic

device through the BSMB module. The design of the module was in right size in order

to fit inside the Bionic device and has extra space for further development of the module.

Adding the PCI and the BSMB into the Bionic device will improve the whole system,

making it more user-friendly and more comfortable for the user. In order to be able to

implement the whole system into the Bionic device, the power consumption has to be

considered as well as the battery size.

The testing carried out in this project indicates that implementing event detection,

from the EMG data from the implanted device, is possible and should have good effects

on the control of the prosthetic leg. That will improve the users security, efficiency

and experience of life. Even though the testing shows promising results it has to be

kept in mind that there was only one user for each of the tests which does not give

reliable results. These users are only number two and three in the world as users of the

implanted electrodes, IMES. A lot of testing and analyses with a wider group of users

have to be carried out before this will be available as a product on the market.

41

42

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COR1

06

PIR10701

PIR10702CO

R107PIR10801PIR10802 COR108

PIR10901

PIR10902

COR1

09

PIR11001

PIR11002

COR1

10

PIR11101

PIR11102

COR1

11

PIR11201

PIR11202

COR1

12

PIR11301

PIR11302

COR1

13

PIS20001

PIS20002

COS2

00

PIU1

000A

1

PIU1000A2PIU1000A3

PIU1000A4PIU1000A5PIU1

000A6PIU1000A7

PIU1000A8PIU1000A9

PIU1000A10PIU1000A11

PIU1000A12

PIU1

000B

1

PIU1000B2PIU1000B3

PIU1000B4PIU1000B5

PIU1000B6PIU1000B7

PIU1000B8PIU1000B9

PIU1000B10

PIU1000B11

PIU1000B12

PIU1

000C

1

PIU1

000C

2PIU1000C11

PIU1000C12

PIU1

000D

1

PIU1

000D

2

PIU1000D4PIU1000D5

PIU1000D6PIU1000D7

PIU1000D8PIU1000D9

PIU1000D11

PIU1000D12

PIU1

000E

1

PIU1

000E

2

PIU1

000E

4

PIU1000E9

PIU1000E11

PIU1000E12

PIU1

000F

1

PIU1

000F

2

PIU1

000F

4

PIU1000F9

PIU1000F11

PIU1000F12

PIU1

000G

1

PIU1

000G

2

PIU1

000G

4

PIU1000G9

PIU1000G11

PIU1000G12

PIU1

000H

1

PIU1

000H

2

PIU1

000H

4

PIU1000H9

PIU1000H11

PIU1000H12

PIU1

000J

1PI

U100

0J2

PIU1

000J

4

PIU1000J5PIU1000J6

PIU1000J7PIU1000J8

PIU1000J9

PIU1000J11

PIU1000J12

PIU1

000K

1

PIU1

000K

2PIU1000K11

PIU1000K12

PIU1

000L

1

PIU1000L2PIU1000L3

PIU1000L4PIU1000L5

PIU1000L6PIU1000L7

PIU1000L8PIU1000L9PIU10

00L10PIU1000L11

PIU1000L12

PIU1

000M

1

PIU1000M2PIU1000M3

PIU1000M4PIU1000M5

PIU1000M6PIU1000M7

PIU1000M8PIU1000M9

PIU1000M10PIU1000M11PIU10

00M12

COU1

00A

PIU10101

PIU10102

PIU10103

PIU10104

PIU1

0105

PIU1

0106

PIU1

0107

PIU1

0108

COU101

PIY1

0001

PIY1

0002

COY100

PIC10001PIC10401

PIC10101PIC10201PIC10301

PIC10501PIC10601PIC10701

PIC10901PIJ1

0101

PIR10001

PIR10702

PIR10802

PIU1000B7

PIU1

0106

PIC10002 PIC10102PIC10202PIC10302

PIC10402 PIC10502PIC10602PIC10702

PIC1

0802

PIC10902

PIC11001PI

J101

05

PIJ10207

PIJ10308

PIS20001

PIU1000B6

PIU1000C3 PIU10

00E5 PIU1000E

6 PIU1000E7 PIU10

00E8 PIU1000F5 PIU10

00F8 PIU1000G5 PIU10

00G8 PIU1000H5 PIU100

0H6 PIU1000H7 PIU10

00H8

PIU1

0107

PIU1

0108

PIU10104

PIU10103

PIU10102

PIU10101

PIU1000M12PIU1000M11PIU1000M10

PIU1000M9PIU1000M8

PIU1000M7PIU1000M6PIU1000M5

PIU1000M4PIU1000M3

PIU1000M2

PIU1

000M

1PIU1000L12

PIU1000L11PIU1000L10PIU1000L9

PIU1000L8PIU1000L7

PIU1000L6PIU1000L5

PIU1000L4PIU1000L3

PIU1000L2

PIU1

000L

1

PIU1000K12

PIU1000K11

PIU1

000K

2

PIU1

000K

1

PIU1000J12

PIU1000J11

PIU1000J9

PIU1000J8PIU1000J7

PIU1000J6PIU1000J5

PIU1

000J

4

PIU1

000J

2

PIU1

000J

1

PIU1000H12

PIU1000H11

PIU1000H9

PIU1

000H

4

PIU1

000H

2

PIU1

000H

1

PIU1000G12

PIU1000G11

PIU1000G9

PIU1

000G

4

PIU1

000G

2

PIU1

000G

1

PIU1000F12

PIU1000F11

PIU1000F9

PIU1

000F

4

PIU1

000F

2

PIU1

000F

1

PIU1000E12

PIU1000E11

PIU1000E9

PIU1

000E

4

PIU1

000E

2

PIU1

000E

1

PIU1000D12

PIU1000D11

PIU1000D8PIU1000D7

PIU1000D5PIU1000D4

PIU1

000D

2

PIU1

000D

1

PIU1000C12

PIU1000C11

PIU1

000C

2

PIU1

000C

1

PIU1000B11

PIU1000B8PIU1000B5

PIU1000B4PIU1000B3

PIU1000B2

PIU1

000B

1

PIU1000A12

PIU1000A11PIU1000A9

PIU1000A8PIU1000A7

PIU1000A6PIU1000A5PIU1000A4

PIU1

0105

POW\P\

PIU1000A3PIU1000A2

PIU1

000A

1

PIS20002

PIR11301

PIR11201

PIR11101

PIR11001

PIR10901

PIU1000B12

PIR10801

PIR10601

PIU1000D9

PIR10501

PIU1000B10

PIR10402

PIU1000A10

PIR10301

PIU1000B9

PIR10002

PIJ10306

PIR11302

PIJ10305

PIR11202

PIJ10304

PIR11102

PIJ10303

PIR11002

PIJ10302

PIR10902

PIJ10206

PIR10602PIJ10205

PIR10502PIJ10204

PIR10401PIJ10203

PIR10302PIJ10202

PIR1

0202

PIJ10201

PIR10102

PIJ1

0104

PIJ1

0103

PIJ1

0102

PIU1000D6

PID10102

PID10101

PIR10701

PIC11002

PIC1

0801

PIY1

0001

POXINPI

Y100

02

POXOUT

POBT0CTSPOBT0RTS

PIJ10307

POBSMB0INT

POBT0RXD POBT0TXD POBT0RESET

NLTP

ACLK

2

NLTP

MCLK

1

PIJ10301

PIR10101

PIR1

0201

POBSMB0INTPOBT0CTS

POBT0RESETPOBT0RTS

POBT0RXD POBT0TXD

POW\P\

POXIN

POXOUT

Appendix A - Technical Drawings

11

22

33

44

DD

CC

BB

AA

Össur

Grj

óthá

ls 1

- 511

0 Re

ykja

vík

ICEL

AND

6082

401

O_R

evis

ion

20.5

.201

416

:19:

33C

omm

unic

atio

n.Sc

hDoc

Size

:N

umbe

r:

Dat

e:Fi

le:

Rev

.:

Tim

e:A

4

ÖSS

UR

CO

NFI

DEN

TIA

LITY

AG

REE

MEN

T N

OTI

CE:

INS

OFA

R A

S T

HIS

DR

AW

ING

EM

BO

DIE

S A

CO

NFI

DE

NTI

AL

PR

OP

RIE

TAR

Y D

ES

IGN

OW

NE

D B

Y Ö

SS

UR

, N

OTI

CE

IS H

ER

EB

Y G

IVE

N T

HA

T A

LL D

ES

IGN

, MA

NU

FAC

TUR

ING

, RE

PR

OD

UC

TIO

N U

SE

AN

D S

ALE

S R

IGH

TS

RE

GA

RD

ING

TH

E S

AM

E A

RE

EX

PR

ES

SLY

RE

SE

RV

ED

TO

ÖS

SU

R.

THIS

DR

AW

ING

IS S

UB

MIT

TED

UN

DE

R A

CO

NFI

DE

NTI

AL

RE

LATI

ON

SH

IP F

OR

A S

PE

CIF

IC P

UR

PO

SE

AN

D T

HE

RE

CIP

IEN

T H

ER

ETO

AG

RE

ES

NO

T TO

DIS

CLO

SE

THIS

DR

AW

ING

OR

AN

Y P

RO

TIO

N O

F IT

'S C

ON

TEN

TS T

O A

NY

UN

AU

THO

RIZ

ED

PE

RS

ON

, OR

TO

INC

OR

PO

RA

TE T

HIS

PR

OP

RIE

TAR

Y D

ES

IGN

OR

TH

E S

UB

STA

NC

E O

F IT

EIT

HE

R IN

WH

OLE

OR

IN P

AR

T IN

AN

Y O

THE

R P

RO

JEC

TS.

BPC

B C

PUTi

tle

37

Shee

tof

Dra

wn

by

Che

cked

by

Eng.

App

r.

App

rove

d by

SIG

NA

TUR

ESD

ATE

S

Stef

anía

Hák

onar

dótti

r

O_C

heck

edB

y

Óla

fur H

auku

r Sve

rris

son

O_C

heck

edD

ate

25.0

3.20

14

25.0

3.20

14

O_E

ngA

pprD

ate

O_E

ngA

ppr

NC

1

RES

ET2

GN

D3

GN

D4

NC

5

MV

cc6

PG6

7

XO

SCEN

8

Vcc

_CO

RE

9

Vcc

10

Vcc

_IO

11

RX

D12

TXD

13

RTS

#14

CTS

#15

OP3

16

GN

D17

GN

D18

PG7

19

SCLK

20SF

S21

STD

22SR

D23

GN

D24

OP5

25O

P4/P

G4

2632

K+

2732

K-

28G

ND

29G

ND

30G

ND

31G

ND

32N

C33

NC

34N

C35

NC

36N

C37

NC

38N

C39

NC

40LM

X98

38SB

U30

0

BG

ND

BG

ND

B_D

VC

PU

BG

ND

BT_

RES

ET

BT_

RX

DB

T_TX

D

R30

1

1k 1

% 1

/10W

B_D

VC

PU

B_D

VC

PU

BG

ND

C30

62.

2uF

10%

X5R

10V

Blu

etoo

th M

odul

e

C30

70.

1uF

10%

X7R

50V

B_D

VC

PU

BG

ND

C30

42.

2uF

10%

X5R

10V

C30

50.

1uF

10%

X7R

50V

B_D

VC

PU

BG

ND

C30

12.

2uF

10%

X5R

10V

C30

20.

1uF

10%

X7R

50V

R30

210

k 5%

1/1

0W

B_D

VC

PU

BG

ND

BT_

RTS

BT_

CTS

BG

NDR30

310

k 5%

1/1

0W

R30

01k

1%

1/1

0W(P

opul

ate

for 1

1520

0bps

)

12

Y30

0FC

-135

32.

768K

HZ

C30

012

pF 1

0% X

7R 5

0V

C30

3

12pF

10%

X7R

50V

BG

ND

R30

50o

hmR

304

0ohm

(NP)

PIC30001

PIC30002

COC3

00PIC30101 PIC30102

COC3

01PIC30201 PIC30202

COC302

PIC30301

PIC30302

COC303

PIC30401 PIC30402COC3

04PIC30501 PIC30502

COC305

PIC30601 PIC30602COC3

06PIC30701 PIC30702

COC307

PIR30001PIR30002 COR3

00

PIR3

0101

PIR3

0102

COR301

PIR3

0201

PIR30202

COR302

PIR30301PIR30302 COR3

03

PIR3

0401

PIR3

0402

COR304

PIR3

0501

PIR3

0502

COR305

PIU30001

PIU30002

PIU30003

PIU30004

PIU30005

PIU30006

PIU30007

PIU30008

PIU30009

PIU3

0001

0

PIU3

0001

1

PIU3

0001

2

PIU3

0001

3

PIU3

0001

4

PIU3

0001

5

PIU3

0001

6PI

U300

017

PIU3

0001

8

PIU3

0001

9

PIU3

0002

0PIU300021

PIU300022

PIU300023

PIU300024

PIU300025

PIU300026

PIU300027

PIU300028

PIU300029

PIU300030

PIU300031

PIU300032

PIU300033

PIU300034

PIU300035

PIU300036

PIU300037

PIU300038

PIU300039

PIU300040

COU300

PIY30001PIY30002 COY300

PIC30101PIC30201

PIC30401PIC30501

PIC30601PIC30701

PIR30002

PIR3

0101

PIU30006

PIU3

0001

0

PIU3

0001

1

PIC30002

PIC30102PIC30202

PIC30302

PIC30402PIC30502

PIC30602PIC30702

PIR30202

PIR30301

PIU30003

PIU30004

PIU3

0001

7

PIU3

0001

8

PIU300024

PIU300029

PIU300030

PIU300031

PIU300032

PIU300040

PIU300039

PIU300038

PIU300037

PIU300036

PIU300035

PIU300034

PIU300033

PIU300023

PIU300022

PIU300021

PIU3

0002

0

PIU3

0001

9

PIU3

0001

5POBT0CTS

PIU3

0001

4POBT0RTS

PIU30009

PIU30008

PIU30007

PIU30005

PIU30002

POBT0RESET

PIU30001

PIR3

0502

PIU3

0001

3PI

R305

01POBT0TXD

PIR3

0402

PIU3

0001

2PI

R304

01POBT0RXD

PIR3

0201

PIU300025

PIR3

0102

PIU3

0001

6

PIR30001 PIR30302PIU300026

PIC30301

PIU300027

PIY30001

PIC30001

PIU300028

PIY30002

POBT0CTS

POBT0RESET

POBT0RTS

POBT0RXD

POBT0TXD

11

22

33

44

DD

CC

BB

AA

Össur

Grj

óthá

ls 1

- 511

0 Re

ykja

vík

ICEL

AND

6082

401

O_R

evis

ion

20.5

.201

416

:19:

34Po

wer

.Sch

Doc

Size

:N

umbe

r:

Dat

e:Fi

le:

Rev

.:

Tim

e:A

4

ÖSS

UR

CO

NFI

DEN

TIA

LITY

AG

REE

MEN

T N

OTI

CE:

INS

OFA

R A

S T

HIS

DR

AW

ING

EM

BO

DIE

S A

CO

NFI

DE

NTI

AL

PR

OP

RIE

TAR

Y D

ES

IGN

OW

NE

D B

Y Ö

SS

UR

, N

OTI

CE

IS H

ER

EB

Y G

IVE

N T

HA

T A

LL D

ES

IGN

, MA

NU

FAC

TUR

ING

, RE

PR

OD

UC

TIO

N U

SE

AN

D S

ALE

S R

IGH

TS

RE

GA

RD

ING

TH

E S

AM

E A

RE

EX

PR

ES

SLY

RE

SE

RV

ED

TO

ÖS

SU

R.

THIS

DR

AW

ING

IS S

UB

MIT

TED

UN

DE

R A

CO

NFI

DE

NTI

AL

RE

LATI

ON

SH

IP F

OR

A S

PE

CIF

IC P

UR

PO

SE

AN

D T

HE

RE

CIP

IEN

T H

ER

ETO

AG

RE

ES

NO

T TO

DIS

CLO

SE

THIS

DR

AW

ING

OR

AN

Y P

RO

TIO

N O

F IT

'S C

ON

TEN

TS T

O A

NY

UN

AU

THO

RIZ

ED

PE

RS

ON

, OR

TO

INC

OR

PO

RA

TE T

HIS

PR

OP

RIE

TAR

Y D

ES

IGN

OR

TH

E S

UB

STA

NC

E O

F IT

EIT

HE

R IN

WH

OLE

OR

IN P

AR

T IN

AN

Y O

THE

R P

RO

JEC

TS.

BPC

B C

PUTi

tle

47

Shee

tof

Dra

wn

by

Che

cked

by

Eng.

App

r.

App

rove

d by

SIG

NA

TUR

ESD

ATE

S

Stef

anía

Hák

onar

dótti

r

O_C

heck

edB

y

Óla

fur H

auku

r Sve

rris

son

O_C

heck

edD

ate

25.0

3.20

14

25.0

3.20

14

O_E

ngA

pprD

ate

O_E

ngA

ppr

AV

CPU

IN1

GND 2

OU

T3

FB4

SHD

N5

POK

6

MA

X88

81EU

T33+

TU

401

C40

50.

1uF

10%

X7R

50V

C40

310

uF 2

0% X

5R 1

0VC

404

10uF

20%

X5R

10V

VC

C

DV

CPU

IN1

GND 2

OU

T3

FB4

SHD

N5

POK

6

MA

X88

81EU

T33+

TU

400

C40

20.

1uF

10%

X7R

50V

C40

010

uF 2

0% X

5R 1

0VC

401

10uF

20%

X5R

10V

VC

C

GN

D

GN

D

Pow

er M

odul

e

GN

DB

GN

D

B_D

VC

PUi

TP1

iTP

5iTP

2 iTP

3

R40

0

0 oh

m

R40

2

0 oh

m

R40

3

0 oh

m

5V 5V

V_D

CD

C_I

N

GN

D

D20

3PM

EG60

10C

EH

VC

C

C20

54.

7uF

10%

X5R

16V

C20

21u

F 10

% X

7R 5

0V

SHD

N4

VIN

5

GN

D2

FB3

SW6

CB

1

U20

0

LM28

41Y

R20

35.

49k

1% 1

/10W

R20

21k

5%

1/1

0W

SW FB

C20

30.

22uF

10%

X7R

50V

C20

110

uF 1

0% X

7S 5

0VC

206

10uF

10%

X7R

10V

SRR

4028

-560

Y

652-

SRR

4028

-560

YL2

00

56uH

C20

7N

P

C20

422

0nF

10%

X7R

50V

CB

PIC20101 PIC20102COC201

PIC20201 PIC20202COC202

PIC20301 PIC20302COC203

PIC20401 PIC20402CO

C204

PIC20501 PIC20502COC205

PIC20601 PIC20602COC206

PIC20701 PIC20702COC207

PIC40001 PIC40002COC400

PIC40101 PIC40102COC401

PIC40201 PIC40202COC402

PIC40301 PIC40302COC403

PIC40401 PIC40402COC404

PIC40501 PIC40502COC405

PID2030APID2030KCOD203

PIL20001

PIL20002

COL2

00

PIR20201 PIR20202COR202

PIR20301 PIR20302COR203

PIR40001

PIR40002CO

R400

PIR40201

PIR40202CO

R402

PIR40301

PIR40302CO

R403

PIU2

0001

PIU2

0002

PIU2

0003

PIU2

0004

PIU2

0005

PIU2

0006

COU200

PIU40001

PIU40002

PIU4

0003

PIU4

0004

PIU40005

PIU4

0006

COU400

PIU40101

PIU40102

PIU40103

PIU40104

PIU40105

PIU40106

COU401

PIC40401PIC40501

PIU40103

PIU40104

PIR40301

PIR40201

PIC20401PI

U200

01NL

CB

PIC40101PIC40201

PIR40302

PIU4

0003

PIU4

0004

PIR20201PIR20302PI

U200

03NL

FB

PIC20102PIC20202

PIC20302PIC20502

PIC20602PIC20702

PIC40002PIC40102

PIC40202

PIC40302PIC40402

PIC40502

PID2030A

PIR20202

PIR40202

PIU2

0002

PIU40002 PIU40102PIU40106

PIU4

0006

PIR40001P

IU40105

PIC20402 PID2030KPIL20001

PIU2

0006

NLSW

PIC20101PIC20201

PIC20301

PIU2

0004

PIU2

0005

PIC20501PIC20601

PIC20701

PIC40001 PIC40301

PIL20002

PIR20301

PIR40002

PIU40001

PIU40005

PIU40101

Pin QFN Pin ZQW MSP430F5438AIPZ BSMB Comment: Primary / Secondary I/O

11 E2 AVCC AVCPU AVCPU +

12 F2 AVSS GND GND -

13 F1 XIN XIN Crystal oscillator Y100 IN

14 G1 XOUT XOUT Crystal oscillator Y100 OUT

15 G2 DVSS1 GND GND -

16 H2 DVCC1 DVCPU DVCPU +17 H1 ACLK TPACLK2 TP10 OUT

20 J1 P1.3 SW1 Switch R108 I/O

24 L1 P1.7 D101 D101 / R107 / GND I/O

25 M1 MCLK TPMCLK1 TP11 OUT

26 L2 P2.2 BT_CTS Clear to send OUT27 M2 P2.3 BT_RTS Request to send IN

31 M4 P2.6 BSMS_INT Interupt BSMB to Bionic IN

32 J5 P2.7 U101 - 4 Chip select OUT

33 L5 P3.0 U101 - 3 Reset OUT

34 M5 P3.1 U101 - 1 Serial Input - Shift device OUT

35 J6 P3.2 U101 - 8 Serial Output IN

36 L6 P3.3 U101 - 2 Serial Clock OUT

37 M6 DVSS3 GND GND -

38 M7 DVCC3 DVCPU DVCPU +

39 L7 UCA0TXD BT_RXD Send out data to BT OUT

40 J7 UCA0RXD BT_TXD Receive data from BT IN41 M8 P3.6 BT_Reset Reset OUT

62 G12 Vcore C108 Capacitor to GND -

63 F12 DVSS2 GND GND -64 E12 DVCC2 DVCPU DVCPU +

69 F9 UCB2SIMO MOSI J103 - 6 Rheo MOSI OUT

70 C12 UCB2SOMI MISO J103 - 5 Rheo MISO OUT

71 E9 UCB2CLK CLK J103 - 4 Rheo clock OUT

72 C11 UCA2TXD TX J103 - 3 TX Proprio OUT 73 B12 UCA2RXD/UCA2SOMI RX/CS J103 - 2 RX Proprio/SSEL OUT

76 D9 UCA3CLK UCA3CLK J102 - 6 SCK IN

79 B10 UCA3STE SSEL J102 - 5 SSEL IN

80 A10 UCA3SIMO MOSI J102 - 4 MOSI IN81 B9 UCA3SOMI MISO J102 - 3 MISO IN

87 B7 DVCC4 DVCPU DVCPU +

88 B6 DVSS4 GND GND -

91 D6 SBWTCK J100 - 2 Spy-Bi-Wire Connection OUT

93 A4 TCLK WP Write Protect OUT96 A3 SBWTDIO J100-3 Spy-Bi-Wire Connection OUT

Appendix B - Pinout list

GND BT

POWER BIONIC

BOTTOM MEMORYTOP CDM

Appendix C - PCB layout in 3D

Quadricep - Peak values

Test 1 Test 2 Test 3

Step 2 127 94 114

Step 4 119 77 94

Step 6 133 95 112

Step 8 126 128 99

Step 10 129 119 108

Step 12 98 103 115

Step 14 90 90 94

MAX 133 128 115

MIN 90 77 94

Diff 43 51 21

Hamstring - Peak values

Test 1 Test 2 Test 3

Step 2 92 79 117

Step 4 134 98 133

Step 6 115 133 141

Step 8 148 152 151

Step 10 131 133 150

Step 12 135 140 113

Step 14 133 128 123

MAX 148 152 151

MIN 92 79 113

Diff 56 73 38

Appendix D - Variance of Peak Values during gait

Documents

Prosthetic Co ntrol using Implanted Electrode Signals