A NEW APPROACH TO SUPPRESSING ABNORMAL TREMOR THROUGH SIGNAL EQUALIZATION

SystemHuman-Joystick

Display

TrackingSignal

Target Signal

Response or

Tracking Signal

0.80.60.40.20−0.2−0.400.8204060801001201401600.60.40.20−0.2−0.4020406080100120140160APPROACHDRUGS

PROBLEMS-Trial and error

-Eventual adiction-Side effects

-Dangerous

-Not always successful-Fatigue

-Only for one joint-Fatigue

-Uncomfortable-Intermediate signalmust be available-Delay added

SURGERYELECTRICAL

STIMULATIONMECHANICALLOADING

**

SIGNAL

PROCESSING

PSDPSD

1

f (Hz)

15

f (Hz)

Desired movementReal (tremorous) movement

Human-MasterMovementLow-PassFilterComputer

Position signal

to the controlled subsystem

Used onlyfor designMechanical Filter DesignMain criterion: User comfortEqualizer DesignMain criterion: Whole system performanceTargetSignalGeneratorDesiredMovementHuman-MasterActiveMechanicalLoadDampedMovementEqualizerEqualizedDesiredMovementSlaveF =F ( x,f )llComputerThis signal is only

\"seen\" in the design stageThis is the real movementof the Human-MasterThis is the (smoother) control

signal sent to the slave

STNENOPMOCno iErsRosreeUmryaTerpCTpLUuSRTlSorrtenyoaCLSNOITCNUFUser

Master RobotComputerSlave RobotEnvironment

EQUALIZER SUBL.

MECHANICAL FILTER SUBLAYER

C O N T R O L L A Y E R

MASTER ROBOT

COMPUTER

SLAVE ROBOT

Interacts with the human, receiving control Communicates with master and slave robots.Performs the desired (smothed) movementssignals and giving proprioceptive sensoryPerforms all the Signal Processing and and senses the signals from the interactionfeedback. Offers a resistive force controlledControl algorithms.

with the environment.

by the computer in order to mechanicallyfilter the tremor.

Transducer

+

Master

Scaling

Human

Environm.Slave

--

Man-Mach.x-channel

Man-Mach.y-channel

Man-Machine

System

x-smoothedx-Equalizer

movement

y-Equalizer

y-smoothedmovement

TremorousMovement

x desiredmovement

y desiredmovement

TRIAL TIME0:13TASK GOAL:To track the UFOas close as possibleJoystickSubject

Computer ScreenReal TremorousMovement

TargetSignal

t(n)

Man-Machine System

r(n)

Equalizer

s(n)

SmoothedMovement

(shown on the screen)

VisualFeedback

Zero meanWhiteButterworthGaussianLow PassNoise

Filter (N=8)

KOne-dimensionalTarget Signal

White Noise

T(t)Target

Signal

Linear

Time-invariantSystem

+Tracking R(t)Signal

TargetSignalMan-machine

system

Tracking

Mvmnt.

Adaptive Delay Correction

-++

Delay-corrected

error

TargetSignal

Man-MachineSystemAdaptiveDelayCorrection

-++C(f)Performance

Filter

PowerEstimation

F-MSEd

TRIAL TIMEUFO

(Random movement)0:13TASK GOAL:CROSS

(Controlled by subject)To track the UFOas close as possibleInitialPosition

Space Square(Is the actual range ofmovement for both, theUFO and the CROSS)Computer Screen

Tracking

(No equalization)MSE = 0.072d

F-MSE = 0.02011d

MSE = 0.056d

F-MSE = 0.00031d

MSE = 0.049d

F-MSE = 0.00062d

a )0.50.40.30.20.10−0.1−0.2−0.3−0.4−0.58008509009501000105011001150120012501300(Sampling time = 62.5 ms)1c )0.80.60.40.20−0.2−0.4−0.6−0.8−1400450500550600650700750800850(Sampling time = 62.5 ms)10−2b )10−410−610−810−1010−1210−14012345678(Hz)10−2d )10−410−610−810−1010−1210−14012345678(Hz) Off-line equalizationOn-line equalization No

EqualizationOff-lineOperationOn-lineOperation

F-MSEdMSEd

0.000870.00917

0.000090.00500

0.000230.01100

a )Pulled Equalizer0.14MSE = 0.0560.12d

F-MSE = 0.00031d

0.10.080.060.040.020024681012141618(Sampling time = 62.5 ms)c )Non-pulled Equalizer0.14MSE = 0.056d

0.12F-MSE = 0.00024d

0.10.080.060.040.020024681012141618(Sampling time = 62.5 ms)b )(db)0−10−20−30−40−50−60−70012345678(Hz)d )(db)0−10−20−30−40−50−60−70012345678(Hz)Display+

ManMachine

Gain

AdaptiveFIR FilterDelayT ~ 360 msec

Ecd