Table Of ContentIntroduction to Biomechatronics
This text/reference provides fundamental knowledge of mechanical and electronic
(mechatronic) components and systems and their interaction with human biology to assist
or replace limbs, senses, and even organs damaged by trauma, birth defects, or disease.
The first half of the book provides the engineering background to understand all the
components of a biomechatronic system: the human subject, stimulus or actuation,
transducers and sensors, signal conditioning elements, recording and display, and feedback
elements. It also includes the major functional systems of the body to which biomechatronics
can be applied including:
• Biomechanical
• Nervous
• Cardiovascular
• Respiratory
• Musculoskeletal
The second half discusses five broadly based devices from a historical perspective and
supported by the relevant technical detail and engineering analysis. These devices include
hearing prostheses, sensory substitution and visual prostheses, artificial hearts, respiratory
aids, and artificial limbs.
Introduction to Biomechatronics provides readers with the fundamental engineering
(biomedical, mechanical, electronic) background to analyze and design biomechatronic
devices and will inspire greater designs by discussing successful inventions that have done
the most to improve our lives.
ABOUT THE AUTHOR
Graham Brooker is a Senior Lecturer at the Australian Centre for Field Robotics at the University
of Sydney. While completing his baccalaureate in electrical engineering, he developed a
myoelectric controlled rehabilitative exercise device using an early microprocessor. During
his two years of compulsory national service, his passion turned toward radar, which he
continued in for 20 years until he left industry for academia in 1999. While completing his
Ph.D. at the Centre for Field Robotics, he conducted research and lectured in sensors to
reestablish his biomedical credentials. In 2007, he developed a course in Biomechatronics
which has been offered as a final year elective for mechatronic and biomedical engineering
students. This book has evolved from that course.
Raleigh, NC
www.scitechpub.com
Brooker-7200029 brook7200029˙fm ISBN:978-1-891121-27-2 January25,2012 14:25 iii
Contents
Preface xi
Acknowledgments xiii
1 Introduction to Biomechatronics 1
1.1 Introduction 1
1.2 BiomechatronicSystems 2
1.2.1 TheHumanSubject 2
1.2.2 StimulusorActuation 3
1.2.3 TransducersandSensors 3
1.2.4 SignalProcessingElements 3
1.2.5 RecordingandDisplay 3
1.2.6 FeedbackElements 4
1.3 PhysiologicalSystems 4
1.3.1 BiochemicalSystem 4
1.3.2 NervousSystem 5
1.3.3 CardiovascularSystem 5
1.3.4 RespiratorySystem 5
1.3.5 MusculoskeletalSystem 5
1.4 SummaryofContents 6
1.5 TheFutureofBiomechatronicSystems 6
1.6 References 7
2 Sensors and Transducers 9
2.1 Introduction 9
2.2 Switches 9
2.2.1 ToggleSwitches 10
2.2.2 Push-ButtonSwitches 10
2.2.3 LimitSwitches 10
2.2.4 RotarySwitches 11
2.2.5 OpticalSwitches 11
2.2.6 OtherSwitches 11
2.2.7 Relays 12
2.3 PowerSupplies 13
2.3.1 LinearPowerSupplies 13
2.3.2 Switch-ModePowerSupplies 15
2.3.3 Batteries 16
2.3.4 EnergyScavenging 19
iii
Brooker-7200029 brook7200029˙fm ISBN:978-1-891121-27-2 January18,2012 13:4 iv
iv Contents
2.4 SensorsandTransducers 22
2.4.1 ResistiveDisplacementSensors 22
2.4.2 InductiveDisplacementSensors 28
2.4.3 MagneticDisplacementSensors 31
2.4.4 CapacitiveDisplacementSensors 34
2.4.5 OpticalDisplacementSensors 34
2.4.6 RangingSensors 38
2.4.7 Time-of-FlightRanging 41
2.4.8 MeasuringRateandAngularRate 43
2.4.9 Accelerometers 50
2.4.10 TiltSensors 55
2.4.11 PressureMeasurement 56
2.4.12 SoundPressure 60
2.4.13 Flow 61
2.4.14 TemperatureSensors 67
2.4.15 TactileSensing 73
2.4.16 ChemicalSensors 77
2.4.17 OpticalChemicalSensors 80
2.5 Electrodes 83
2.5.1 Body–SurfaceBiopotentialElectrodes 84
2.6 References 88
3 Actuators 91
3.1 Introduction 91
3.2 ElectromechanicalActuators 91
3.2.1 SolenoidsandVoiceCoils 94
3.2.2 DirectCurrentMotors 99
3.2.3 BrushlessDCMotors 113
3.2.4 StepperMotors 117
3.2.5 LinearActuators 124
3.2.6 ServoMotors 130
3.2.7 ACMotors 134
3.3 HydraulicActuators 137
3.4 PneumaticActuators 139
3.4.1 PneumaticMuscles 140
3.5 ShapeMemoryAlloy 142
3.5.1 PrincipleofOperation 142
3.5.2 BiomechatronicApplications 145
3.6 MechanicalAmplification 145
3.6.1 LinkagesandLevers 145
3.6.2 Cams 148
3.6.3 GearsandBeltDrives 149
3.6.4 TranslationScrewDevices 153
3.7 ProstheticHandActuation 154
3.7.1 ShapeMemoryAlloys 155
3.7.2 ElectricMotors 155
Brooker-7200029 brook7200029˙fm ISBN:978-1-891121-27-2 January18,2012 13:4 v
Contents v
3.7.3 PneumaticArtificialMuscles 156
3.8 References 157
4 Feedback and Control Systems 159
4.1 Introduction 159
4.2 BiologicalFeedbackMechanisms 160
4.3 BiomechatronicFeedbackMechanisms 160
4.3.1 LimitSwitches 161
4.3.2 ProportionalandHigher-OrderControllers 161
4.4 SystemRepresentation 162
4.5 SystemModels 164
4.5.1 MechanicalElements 164
4.5.2 MechanicalModel 166
4.5.3 ElectricalElements 168
4.5.4 ElectricalModel 169
4.5.5 SimilaritiesoftheTwoModels 171
4.5.6 FluidFlowElements 171
4.6 SystemResponse 174
4.6.1 PartialFractionExpansion 178
4.6.2 AnalyzingComplexModels 179
4.7 SystemStability 181
4.7.1 RootLocus 184
4.7.2 Steady-StateError 188
4.8 Controllers 188
4.8.1 ProportionalController 188
4.8.2 IntegralController 198
4.8.3 ProportionalPlusIntegralController 198
4.8.4 Proportional–Integral–DerivativeController 200
4.9 ControllerImplementation 201
4.9.1 SelectionofControllerGains 201
4.9.2 ControllerHardware 202
4.10 References 205
5 Signal Processing 207
5.1 Introduction 207
5.2 BiomedicalSignals 207
5.2.1 BioelectricSignals 208
5.2.2 SignalsCharacterizedbySource 210
5.2.3 SignalsCharacterizedbyType 210
5.3 SignalAcquisition 211
5.3.1 Noise 212
5.3.2 Amplifiers 216
5.3.3 PracticalConsiderations 222
5.3.4 OpAmpSpecifications 223
Brooker-7200029 brook7200029˙fm ISBN:978-1-891121-27-2 January18,2012 13:4 vi
vi Contents
5.4 AnalogSignalProcessing 224
5.4.1 FrequencyContentofaSignal 224
5.4.2 AnalogFilters 225
5.4.3 OtherAnalogCircuits 234
5.5 DigitalSignalProcessing 241
5.5.1 TheComparator 241
5.5.2 SignalAcquisitionandProcessingOverview 241
5.5.3 ADCsandDACs 243
5.5.4 SignalAliasing 245
5.5.5 DigitalFilters 248
5.5.6 FilterTime-DomainResponse 258
5.5.7 EnvelopeDetection 259
5.5.8 SpectralEstimation 260
5.6 StatisticalTechniquesandMachineLearning 264
5.6.1 StatisticalTechniques 264
5.6.2 DataMining 267
5.6.3 MachineLearning 267
5.7 IsolationBarriers 270
5.7.1 ImplantSystems 270
5.7.2 IsolationAmplifiers 272
5.8 References 274
6 Hearing Aids and Implants 277
6.1 Introduction 277
6.2 WhatIsSound? 278
6.2.1 CharacteristicImpedance(Z)andSoundPressure 278
6.2.2 SoundIntensity(I) 279
6.3 HowHearingWorks 281
6.3.1 TheOuterEar 281
6.3.2 TheMiddleEar 281
6.3.3 TheInnerEar 283
6.3.4 HearingStatistics 283
6.4 HearingLoss 285
6.4.1 Causes 285
6.4.2 Diagnosis 286
6.4.3 Treatment 288
6.5 HearingAids 289
6.5.1 History 289
6.5.2 HearingAidOperation 292
6.6 BoneConductionDevices 300
6.7 MiddleEarImplants 302
6.7.1 PiezoelectricDevices 303
6.7.2 ElectromagneticHearingDevices 307
6.7.3 IssueswithImplantableMiddleEarDevices 311
6.8 DirectAcousticCochlearStimulatoryDevices 312
6.8.1 ActuatorDesign 312
Brooker-7200029 brook7200029˙fm ISBN:978-1-891121-27-2 January18,2012 13:4 vii
Contents vii
6.9 CochlearImplants 314
6.9.1 HistoricalBackground 314
6.9.2 HowCochlearImplantsWork 315
6.9.3 InstallationoftheElectrode 320
6.9.4 SignalProcessingandCochlearStimulation 320
6.9.5 SpectralMaximaStrategies 326
6.9.6 StrategiestoEnhanceVocalPitch 326
6.10 AuditoryBrainstemImplants 328
6.10.1 Electrodes 329
6.10.2 StimulusMapping 330
6.11 References 330
7 Sensory Substitution and Visual Prostheses 333
7.1 Introduction 334
7.2 AnatomyandPhysiologyoftheVisualPathway 335
7.3 MainCausesofBlindness 339
7.4 OpticalProsthetics—Glasses,ThermalImagers,NightVision 339
7.5 Sonar-BasedSystems 341
7.5.1 SomeExistingSystems 344
7.5.2 IssueswithSonar-BasedSystems 350
7.6 Laser-BasedSystems 350
7.7 SensorySubstitution 350
7.7.1 AuditorySubstitution 351
7.7.2 ElectrotactileandVibrotactileTransducers 356
7.8 GPS-BasedSystems 370
7.9 VisualNeuroprostheses 371
7.9.1 HistoricalPerspective 371
7.9.2 PotentialSitesforVisualNeuroprostheses 371
7.9.3 Components 372
7.9.4 WorldwideResearchActivity 375
7.9.5 SubretinalImplants 375
7.9.6 EpiretinalImplants 381
7.9.7 AlternativeImplants 386
7.9.8 OpticNerveStimulation 387
7.9.9 VisualCortexImplants 388
7.10 TheFuture 391
7.11 References 392
8 Heart Replacement 395
8.1 Introduction 396
8.2 TheHeartasaPump 397
8.2.1 HeartValves 398
8.2.2 ThePumpCycle 399
8.2.3 TheCardiacOutput 401
Brooker-7200029 brook7200029˙fm ISBN:978-1-891121-27-2 January18,2012 13:4 viii
viii Contents
8.2.4 PressureRegulation 401
8.2.5 HeartDisease 402
8.2.6 BiomechatronicPerspective 402
8.3 Heart–LungMachines 403
8.3.1 History 403
8.3.2 ModernHeart–LungMachines 404
8.4 ArtificialHearts 408
8.4.1 History 409
8.4.2 ImplantinganArtificialHeart 417
8.5 VentricularAssistDevices 417
8.5.1 History 419
8.5.2 ExtracorporealVentricularAssistDevices 420
8.5.3 IntracorporealLeftVentricularAssistDevices 421
8.5.4 Generation1LVADs 421
8.5.5 PulsatilePumpTechnology 429
8.5.6 Generation2VADs 433
8.5.7 Generation3VADs 435
8.5.8 Generation4VADs 439
8.5.9 TowardanIdealReplacementHeart 443
8.5.10 OtherPumpTypes 443
8.6 EngineeringinHeartAssistDevices 446
8.6.1 FluidDynamicsinPulsatileLVADs 446
8.6.2 FluidDynamicsinCentrifugalandAxialLVADs 448
8.6.3 EstimationandControlofBloodFlow 450
8.6.4 TranscutaneousEnergyTransfer 452
8.7 PumpTypes 455
8.7.1 CentrifugalandAxialPumpCharacteristics 456
8.7.2 RotaryPumpCharacteristics 460
8.7.3 ReciprocatingPumpCharacteristics 462
8.7.4 Bearings 466
8.8 References 466
9 Respiratory Aids 471
9.1 Introduction 472
9.2 Construction 473
9.3 TheMechanicsofRespiration 476
9.3.1 PhysicalProperties 477
9.3.2 LungElasticity 480
9.3.3 FrictionalForces 481
9.3.4 Inertia 485
9.4 EnergyRequiredforBreathing 485
9.5 MeasuringLungCharacteristics 488
9.5.1 Spirometry 488
9.5.2 Pneumotachography 492
Brooker-7200029 brook7200029˙fm ISBN:978-1-891121-27-2 January18,2012 13:4 ix
Contents ix
9.6 MechanicalVentilation 494
9.6.1 EarlyHistory 494
9.6.2 Polio 495
9.6.3 ExternalNegative-PressureVentilators 497
9.6.4 TheDrinkerRespirator 499
9.6.5 TheBothRespirator 501
9.6.6 HomemadeIronLungs 501
9.6.7 TheEmersonRespirator 504
9.6.8 TheAlligatorCabinetRespirator 505
9.6.9 PortableRespirators 506
9.6.10 OtherUsesforNegative-PressureVentilation 507
9.7 ThePhysicsofExternalNegative-PressureVentilation 508
9.8 Positive-PressureVentilators 511
9.8.1 HistoricalBackground 511
9.8.2 TheNeedforPositive-PressureVentilation 512
9.8.3 VentilationModes 513
9.8.4 ControlledMandatoryVentilation 514
9.8.5 Volume-ControlledMandatoryVentilation 514
9.8.6 Pressure-ControlledMandatoryVentilation 516
9.8.7 SpontaneousVentilation 517
9.8.8 ContinuousPositiveAirwayPressure 517
9.8.9 PortableVentilators 517
9.8.10 SleepApnea 519
9.9 References 520
10 Active and Passive Prosthetic Limbs 523
10.1 Introduction 524
10.1.1 ABriefHistoryofProsthetics 524
10.2 StructureoftheArm 529
10.2.1 Wrist 529
10.2.2 Elbow 530
10.2.3 Shoulder 530
10.3 KinematicModeloftheArm 531
10.4 StructureoftheLeg 532
10.4.1 TheHipJoint 532
10.4.2 TheKneeJoint 533
10.4.3 TheAnkleJointandtheFoot 533
10.5 KinematicModeloftheLeg 534
10.5.1 Walking 534
10.5.2 NormalWalkingDynamics 535
10.6 KinematicsofLimbMovement 536
10.6.1 CenterofMassandMomentofInertiaofaLimbSegment 536
10.6.2 AngularAcceleration 538
10.6.3 CenterofMassandMomentofInertiaofaCompleteLimb 538
10.7 Sensing 538
