Agnello Davide 201106 MASc Thesis

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NEW-GENERATION FULLY PROGRAMMABLE CONTROLLER FOR FUNCTIONAL ELECTRICAL STIMULATION APPLICATIONS

by

Davide Agnello

A thesis submitted in conformity with the requirements for the degree of Master of Applied Science Graduate Department of the Institute of Biomaterials and Biomedical Engineering University of Toronto

Copyright by Davide Agnello 2011

New-Generation Fully Programmable Controller for Functional Electrical Stimulation ApplicationsDavide Agnello Master of Applied Science Graduate Department of the Institute of Biomaterials and Biomedical Engineering University of Toronto 2011

AbstractFunctional electrical stimulation (FES) systems have been developed to help restore various neuromuscular functions in individuals with neurological disorders leading to paralysis. Most of the current FES systems are designed for specific neuroprosthesis applications (i.e., walking, grasping, bladder voiding, coughing, etc.) and when one intends to use them in other custom made applications they are very limited due to a lack of functionality and flexibility in hardware and programmability. This prevents effective and efficient development of customized neuroprostheses. Research and development efforts at the Rehabilitation Engineering Laboratory at the University of Toronto were being carried out with an objective to produce a new, fully programmable and portable FES system. This thesis presents a novel proof-ofconcept prototype controller for use in the new FES system. The controller subsystem manages and controls the overall FES system including the real-time decoding and execution of stimulation, data acquisition, external systems interfaces and user interface.

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Acknowledgements

First of all, my most sincere thanks goes out to my supervisor, Professor Milos R. Popovic, for his guidance and support. His passion towards his work and dedication to his students are truly remarkable.

I would also like to express my gratitude to the members of the Rehabilitation Engineering Laboratory for their support and making this laboratory a great place to work.

Finally, I would like to thank my family, particularly my parents for making this possible with their encouragement and support.

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Table of Contents

Abstract ........................................................................................................................................... ii Acknowledgements ........................................................................................................................ iii List of Tables ............................................................................................................................... viii List of Figures ................................................................................................................................ xi List of Acronyms .......................................................................................................................... xv 1 Introduction ............................................................................................................................. 1 1.1 1.2 2 Motivation ........................................................................................................................ 2 Thesis Overview ............................................................................................................... 3

Background ............................................................................................................................. 5 2.1 2.2 2.3 Physiological Overview ................................................................................................... 5 Brief History ..................................................................................................................... 7 Stimulation Characteristics .............................................................................................. 8 Stimulation Waveforms ............................................................................................ 8 Stimulation Waveform Parameters ......................................................................... 11 Stimulation Programmability .................................................................................. 13

2.3.1 2.3.2 2.3.3 2.4 2.5

FES Applications............................................................................................................ 18 Past and Current FES Systems ....................................................................................... 19 Surface FES Systems .............................................................................................. 19 Implantable/Percutaneous FES Systems ................................................................. 25 Summary ................................................................................................................. 27

2.5.1 2.5.2 2.5.3 3

Proposed System ................................................................................................................... 29 3.1 Compex Motion Stimulator System ............................................................................... 29 iv

3.2 3.3 4

Concept System .............................................................................................................. 30 Objectives ....................................................................................................................... 34

System Requirements and Analysis ...................................................................................... 36 4.1 System Requirements ..................................................................................................... 36 System Requirements and Analysis Tools .............................................................. 36 System Context Analysis ........................................................................................ 37 List of Scenarios ..................................................................................................... 40 Functional and Non-functional Requirements ........................................................ 40 Use Cases ................................................................................................................ 44

4.1.1 4.1.2 4.1.3 4.1.4 4.1.5 4.2

System Analysis ............................................................................................................. 47 Static System Model ............................................................................................... 48 Dynamic System Models ........................................................................................ 48

4.2.1 4.2.2 5

Hardware and Software Platform Overview ......................................................................... 50 5.1 5.2 5.3 Hardware Platform ......................................................................................................... 50 Real-Time Software Platform and Development Toolset .............................................. 57 System Structure Overview ............................................................................................ 58

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PC/hand-held Device Interface ............................................................................................. 61 6.1 6.2 6.3 6.4 Communication Protocol Selection................................................................................ 61 Interface Configuration .................................................................................................. 66 Received Data Processing .............................................................................................. 67 Stimulator Function Requests ........................................................................................ 68 Bidirectional Stimulation Protocol Transfer ........................................................... 69 Stimulation Parameter Change ............................................................................... 71 Stimulation Parameter Retrieve .............................................................................. 73 v

6.4.1 6.4.2 6.4.3

6.4.4 6.4.5 7

Stimulation Protocol Change .................................................................................. 74 Stimulator Control through USB Interface ............................................................. 75

User Interfaces ...................................................................................................................... 76 7.1 Stimulator Interfaces ...................................................................................................... 76 Stimulator Input Interface ....................................................................................... 76 Stimulator Output Interface .................................................................................... 78

7.1.1 7.1.2 7.2

PC Interfaces .................................................................................................................. 81 Stimulation Protocol Interface ................................................................................ 81 Stimulator Control Interface ................................................................................... 83

7.2.1 7.2.2 8

Input Sensor Interface ........................................................................................................... 87 8.1 8.2 8.3 Application ..................................................................................................................... 87 Types of Sensors ............................................................................................................ 88 Interface Design ..............................