Practical Structural Design and Control for Digital Clay Haihong Zhu Woodruff School of Mechanical Engineering Georgia Institute

Practical Structural Practical Structural Design and Control for Design and Control for Digital ClayDigital Clay

Haihong Zhu

www.imdl.gatech.edu/haihong

PhD Defense PhD Defense PresentationPresentation

Woodruff School of Mechanical EngineeringGeorgia Institute of Technology

PhD Reading Committee Members

Dr. Wayne J. Book, Chair, Advisor, ME Dr. Imme Ebert-Uphoff, ME Dr. Mark Allen, ECE Dr. David Rosen, ME Dr. Jarek Rossignac, COC

Outline of This Presentation

Introduction to Digital Clay Cell of Digital Clay Cell array of Digital Clay Implementations of the multi-cell system Conclusions and recommendations

Basic idea Background & context Hardware of Digital Clay Control of Digital Clay Advantages and potential applications

Overview & objectives Cell level control

Control methods Control states, switching logic and user gesture

interpretation Experimental system & results

Displacement measurement PWM speed control and displacement estimation Non-contacting resistance displacement sensor Displacement sensor embedded micro actuator

1x5 prototype Summary

Overview & objectives “N2 by 2N” fluidic matrix drive Surface refresh methods for the fluidic matrix drive Control architecture based on fluidic matrix drive Summary

Overview & objectives Mechanical structure design

Functional modules Realization of “N2 by 2N” fluidic matrix drive Displacement sensor embedded actuator array

assembly Pressure sensor array mounting base

Electronic system Functional block diagram of the electronic system Displacement sensor array multiplexing

5x5 cell array prototype Summary

Outline of Current Section

Basic idea Background & context Hardware of Digital Clay Control of Digital Clay Advantages and potential

applications

Surface Level

ControllerFeedback Processor

APIInterface

Cell-Level Controller

Cell L

evel Control

Feedback Bus

Command Bus



User API

Surface L

evel Control

User A

P I

Cell System

Sensor Actuator

Cell System

Sensor Actuator

Cell System

Sensor Actuator

Surface Level


APIInterface


Cell L

evel Control

Feedback Bus

Command Bus



User API

Surface L

evel Control

User A

P I

Cell System

Sensor Actuator

Cell System

Sensor Actuator

Cell System

Sensor Actuator

Cell System

Sensor Actuator

Cell System

Sensor Actuator

Cell System

Sensor Actuator

Surface Level


APIInterface


Cell L

evel Control

Feedback Bus

Command Bus



User APIS

urface Level C

ontrolU

ser AP

I

Cell System

Sensor Actuator

Cell System

Sensor Actuator

Cell System

Sensor Actuator

Surface Level


APIInterface


Cell L

evel Control

Feedback Bus

Command Bus



User APIS

urface Level C

ontrolU

ser AP

I

Cell System

Sensor Actuator

Cell System

Sensor Actuator

Cell System

Sensor Actuator

Cell System

Sensor Actuator

Cell System

Sensor Actuator

Cell System

Sensor Actuator

Introduction to Digital ClayIntroduction to Digital ClayIntroduction to Digital ClayIntroduction to Digital Clay

Basic Idea

3D human-machine haptic interface Input / output using tangible 3D shape/surface Computer controlled Haptic/semi-haptic style Can be edited / transferred digitally

Video

Introduction to Digital Introduction to Digital ClayClay

Haptic?

Sense of touch

Haptic?

Sense of touch

Background & Context

Haptic manipulators Tactile array Haptic display interfaces


Hardware of Digital Clay General structure

Formable crust Formable body

Planar pin-rod array

Composition Actuator array Sensors array Fluidics system Control system

Actuator Array

Fluidics System

On-board

Controller


Video

Control Structure

Cell Level Control Surface Level Control User API

Surface Level


APIInterface


Cell L

evel Control

Feedback Bus

Command Bus



User API

Surface Level C

ontrolU

ser AP I

Cell System

Sensor Actuator

Cell System

Sensor Actuator

Cell System

Sensor Actuator


Advantages and Applications

Advantages Natural, direct, fast and efficient

communication Unleash the mind power of creation,

perception and intuition Applications

Engineering design & science research

Medical diagnosis Vision Impaired assistance Military & civil map Art Communication Education, Entertainment, etc.

Model of a patient’s stomachModel of a patient’s stomach

Video



Cell of Digital ClayCell of Digital ClayCell of Digital ClayCell of Digital Clay

Overview & objectives Cell level control

Control for solenoid valve based system Control states, switching logic and user gesture

interpretation Experimental system & results

Displacement measurement PWM speed control and displacement estimation Non-contacting resistance displacement sensor Displacement sensor embedded micro actuator


Overview and Objectives Overview

Elementary unit of Digital Clay Mimics a point on a material surface One dimensional actuation type

Challenges Control:

Haptic effect compromised by on-off valves User gesture interpretation without other

help Volume change using unidirectional force

(push) No suitable displacement sensor Micro actuator suitable for massive

production Objectives

Control algorithm to mimic a point on a material surface

Sensing methods Actuator

K

b

x

F

Skin

Cell of Digital Cell of Digital ClayClay

650 700 750 800 850 900

8

10

12

Time (milliseconds)

Pressure (PSI)

6

Cell Level Control (I) Control for solenoid valve based hydraulic system

Testing system setup Pressure surge caused by solenoid valve Pressure signal filtering Position control vs. pressure control


Pre

ssur

e

Displacement

Position Control

Pressure Displacement

Pressure Control

PressureDisplacement

Pressure Sensor

Cell Level Control (II) Control states, switching logic and user

gesture interpretation

Elastic state Plastic state

Shaping state

Ff > Fy

Ff < Fy

Display mode

Edit mode

Holding finger for 2 second

while the toggle switch is on

Quickly remove finger or turn off the toggle switch

Ff -- External Force Acting on the Actuator Fy -- The Virtual Yielding Force Limit

Control state selection

PI control

Control Law

Control law generation

Plant

Timer/ Trigger

Feedback

External F

orce Ff

Fy

X0 X1

a

b c

dActuator’s Displacement

Fp

Fl

ab

cd

e

External F

orce Ff

Actuator’s Displacement


Cell Level Control (III)

Elastic state

-5 0 5 10 15 20 25 301

2

3

4

5

7

9

10

11

12

Actuation Displacement (mm)

a

b c

d

f

e

g

h

i

j k

l

Fy

Fl

Inp

ut F

orce (Pressu

re PS

I)

Plastic state Keep

stationary Shaping state Exit shaping

state

Experimental system & results


Where are we?

Overview & objectives Cell level control Displacement measurement

PWM speed control and displacement estimation Non-contacting resistance displacement sensor Displacement sensor embedded micro actuator



Why is this topic important?

1. Sensor and actuator are critical

2. Huge number of sensors and actuators are needed

3. No suitable existing products are found

Why is this topic important?

1. Sensor and actuator are critical

2. Huge number of sensors and actuators are needed

3. No suitable existing products are found

Displacement Measurement (I) PWM Speed Control and Displacement Estimation

Experimental system & preliminary test results PWM Frequency <100 Hz: High Linearity; Bad haptic sense PWM Frequency >150 Hz: Low linearity; Good haptic sense

Measuring System

Cylinder

Pressure Sensors

Solenoid Valves

High Pressure Source

Drain Tank

Low Pressure Source

Linear Actuator

Potentiometer

0 10 20 30 40 50 60 70 80 90 100 0

10

20

30

40

50

60 PWM Testing Results (200Hz)

Cylin

der

Dis

pla

cem

ent

(mm

)

PWM Duty Cycle (%)

13 PSI11 PSI

1 PSI


PWM Speed Control and Displacement Estimation Analytic model used for curve fitting

0 10 20 30 40 50 60 70 80 90 100 0

10

20

30

40

50 Valve Working Phases

Cyl

ind

er

Ro

d D

isp

lace

me

nt (m

m)

PWM Duty Cycle (%) 0 10 20 30 40 50 60 70 80 90 100

0.5 1 1.5 2

2.5 3 3.5

Co

rre

spon

din

g F

low

Ra

te (

ml/s

ec)

Phase I Phase II Phase III Phase IV

2)( acII ttCFlow

)]()[( bcbcII ttfttKCFlow

)( 'bcII ttKCFlowFinal

2)( mcIVIII ctpCCFlow


Displacement Measurement (II)

Phase I

Flow = 0 Phase II

Phase III

Phase IV

! Definitions of terms can be found in the thesis

Potentiometer

External Force

Cylinder

Pressure Sensors

Solenoid Valves

High Pressure Source

Drain Tank

Low Pressure Source

PWM speed control and position estimation test Test setup Control structure Test result

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000 0

10

20

30

40

50

60

70

Spe

ed a

nd P

ositi

on C

ontr

ol U

sing

PW

M

Cylinder Rod Displacement (mm)

Tim

e (m

illis

econ

d)

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000 0

2

4

6

8

10

12

14

Pressure across the Valve (PSI)

Pressure across the Valve (Caused by Input Force)

Measured Displacement

Ideal Displacement (Dashed Line)

Duty Generation

Position Estimation

One Step Delay

PWM Generation

Driver

PressureSampling

PositionSamplingRecording

Duty

Stop Signal

RequiredSpeed

RequiredPosition

Plotting

Displacement Measurement (III)


Video

Displacement Sensor Embedded Micro Actuator

Displacement Measurement (IV)

Piston (graphite)

Resistance Film

Signal Out

Cylinder Rod

C1

Uout

Uin

Cylinder Bore


25 30 35 40 45 50 55 60 65 70 75

20

25

30

35

40

45

50

55

60

65

70

Sensor D

AT

A (m

m)

REFERENCE DATA (LVDT) (mm)

y vs. xFitted curve

Goodness of fit: SSE: 1.297 R-square: 0.9999

LVDTProposed Sensor

Non-contacting Resistance Sensor Resistance to displacement

signal Capacitor picks up the signal

Structure Micro glass tube + graphite

piston Uniform thin film deposited

Advantages Ultra-compact size Low cost Interchangeable with LVDT Nonlinearity < 0.5% Resolution Theoretically Infinity

Where are we?

Overview & objectives Cell level control Displacement measurement 1x5 prototype Summary


1 x 5 Cell Array Prototype of Digital Clay

A line on a material surface Structure Features

Micro Solenoid Valve No Displacement Sensor SLA10120 Base

Control Direct control on each cell using

proposed PWM methodReturn Pressure

HighPressure

LowPressure

PressureSignal

Valves


Video

Summary


Position control method is suitable for solenoid valve based hydraulic system

Proposed control states, switching logic and user gesture interpretation are effective for hydraulic system to mimic material mechanics properties with haptic senses

Novel displacement measurement methods suitable for large number and micro size hydraulic system are presented PWM speed control and displacement estimation Non-contacting resistance displacement sensor Displacement sensor embedded micro actuator (patent

in application) 1x5 prototype gives one solution to realize the Digital

Clay Good experimental system & results are shown


Cell Array of Digital ClayCell Array of Digital ClayCell Array of Digital ClayCell Array of Digital Clay

Overview & objectives “N2 by 2N” fluidic matrix drive Surface refresh methods for fluidic matrix drive Control architecture based on fluidic matrix

drive Summary

Cell Array of Digital Cell Array of Digital ClayClay

Overview and objectives

Overview Forms the human-machine interactive tangible

surface Planar pin-rod array (bed of nails) Huge number of identical components involved Challenges and solutions

Objectives Conceptual design of practical structure suitable

to realize cell array that has huge number of cells Control architecture suitable for large scale

subsystem array

Practical structure at current stage of technology One dimensional actuation 2.5 D

Hardware Raw material cost Manufacturing Structural simplicity Fluidic Matrix Drive

Control Control resource Dynamic control resource allocation

2N (+ 1 or 2) control valves control an N by N actuator array (needs 2N2 valves usually )

Column and row matching style Independently addresses every actuator Greatly reduced the amount of valves

and control resourse example. N=100, 2*1002 =20,000 >> 201

Relatively slow

“N2 by 2N” Fluidic Matrix Drive (FMD) (I)Actuator

Row Control Valve Array

Control Adaptor

Column Valve Array

Pressure Source Selection Valve

High PressureLow Pressure

High P

ressure

Low

Pressure

Hydraulic Actuator

Row Control Valve Array

Column Control Valve Array

Pressure Source Selection Valve

High PressureLow Pressure

High P

ressure

Low

Pressure


“N2 by 2N” Fluidic Matrix Drive (FMD) (II) Working principle of the control adapter

Row Control Valve

High LowControl Pressure

Column Control Valve

Control Adapter

Pressure Selection

Valve


Surface Refresh Methods for FMD (I) Model of the FMD Node

Column Control Valve

Row Control Valve

Control Adapter

);,( 21 fq

),g(),( 2121 fkqkc

Flow rate:

Actuator displacement:

• δ1 and δ2 are the PWM duty cycles applied to the valves

• k is a constant• PWM waves are of the same

phase


Surface Refresh Methods for FMD (II)

Reducing the FMD node model Keep row control valve only on or off (PWM

duty cycle = 0% or 100%)


0c or )g(δc 1

Surface Refresh Methods for FMD (III) Matrix representation of surface refresh

Working surface matrix representation Surface refresh

),

),

),),

;;

12

2111

1

1

ji

nj

n

i

bag(

bag(

bag(bag(

Then

bbb and

a

a

a

;]''[];[

10000

01000

00100

00010

00001

8.0

6.0

4.0

2.0

2121 nn ... ' 'B ... A

*

0.60.50.70.50.6

0.30.60.40.5

0.70.50.30.4

0.50.40.20.3

0.30.30.10.2

B* A C

1st RRC

1st RR

C

2nd R

RC

2nd RRC


α and β are the PWM duty cycle vectors applied on the column and row control valve arrays

Surface Refresh Methods for FMD (IV)


One-time refresh method Process

1. Fully open one row valve; 2. Control the column valve array until the actuators

in that row reach the desired final position;3. Close that row valve;4. Open the next row valve and repeat step 2.

Advantage and disadvantages Simple Slow Bad visual effect and haptic effect

In this example, actual total time taken is around 3.5 seconds


Surface Refresh Methods for FMD (V)


Gradual refresh method Process

1. Divide the desired final surface into several intermediate surfaces;

2. Use one-time refresh method to achieve each intermediate surfaces.

Advantage and disadvantages Good visual effect and haptic effect Relatively complicated Slower



Surface Refresh Methods for FMD (VI)


Gradual approximation refresh method Process

1. Divide the desired final surface into several intermediate surfaces;

2. Decompose and translate intermediate surfaces into certain sub-surfaces;

3. Realize each sub-surface once a time;4. When realizing each sub surface all the valves

are activated at certain PWM duty cycle. Advantage and disadvantages

Good visual effect and haptic effect Most complicated Very fast Need further researchIn this example, total time taken is around 1 second

In this example, total time taken is around 1 second

Cell level control Surface refresh coordinator Dynamic control resource allocation Hot area processor

Cell Level Control

Valv

e

Con

trolle

rV

alv

e

Con

trolle

r

Valve ControllerValve Controller

Valv

e

Con

trolle

rV

alv

e

Con

trolle

r

Control Valves

Actuator & Sensor

Mu

ltiple

xers &

Feed

back

Pro

cesso

rM

ultip

lexers &

Feed

back

Pro

cesso

r

Surface Refresh Coordinator

PWM Vector

PW

M

Vecto

r

Hot Area Processor Memory

Valve ControllerValve Controller

Control Architecture Based on FMD (I)


ID Recognition

ID Recognition

PWM Wave GenerationPWM Wave Generation

Valve DriverValve DriverValve DriverValve Driver

ID1+ PWM Duty1; ID2+ PWM Duty2; …

Cell Level ControlCell Level Control

Valve ArrayValve Array

Valve Controller

Control Architecture Based on FMD

CAD Model

Other User Inputs

User APIUser APIDesired [MP]

Current [ X ], [ P ][User Motion] Desired [X] &[V]

Surface Level Control1. Position matrix decomposition2. Contact detection3. Control source allocation4. Aftermath compensation

Surface Level Control1. Position matrix decomposition2. Contact detection3. Control source allocation4. Aftermath compensation

Current [ X ] & [ P ]

Surface Refresh Coordinator1. PWM vector generation2. Compensate structural

variation

Surface Refresh Coordinator1. PWM vector generation2. Compensate structural

variation

Desired [ X ]

Current [ X ]

PWM Vector

Com

pen

satio

n m

atrix

Con

tact P

roce

ss Sig

nal

Hot Area Processor1. Haptic reaction2. PWM vector generation3. Aftermath compensation

Hot Area Processor1. Haptic reaction2. PWM vector generation3. Aftermath compensation

Current [ X ] & [ P ]

Con

tact P

roce

ss info

rmatio

n

PWM Vector

Valve ControllersValve Controllers

GUI

Valve ControllersValve Controllers

[Use

r Motio

n]


Mu

ltiple

xers &

Feed

back

Pro

cesso

rM

ultip

lexers &

Feed

back

Pro

cesso

r

Current actuator array’s displacement matrix and pressure matrix

The matrix contains the information of user actions and intentions for each cell in the hot area

Desired actuator array’s displacement matrix and the speed to achieve the displacement

Desired actuator array’s displacement matrix in the next surface refresh cycle

Signal to tell surface refresh coordinator lower down its priority, and tell Hot area processor to work

Hot areas’ locations, sizes, etc.

To compensate the surface discrepancy caused by the delayed refresh on the surface other than the hot area

Desired material property for each cell to simulate

Summary “ N2 by 2N” fluidic matrix drive is novel and

has great benefits for large scale fluidic subsystem array. (Patent application) Greatly reduces the control valves and control

channels needed Makes the cell array (with huge number of units)

practical Relatively slow speed maybe compensated using

proper surface refresh method Suitable surface refresh methods for fluidic

matrix drive make it possible for the system using FMD to achieve smooth and fast surface refresh.

Carefully designed control architecture for FMD can both reduced hardware cost and computing resource.



Implementations of the Implementations of the Multi-cell SystemMulti-cell System

Implementations of the Implementations of the Multi-cell SystemMulti-cell System

Overview & objectives Mechanical structure design

Functional modules Realization of “N2 by 2N” fluidic matrix drive Displacement sensor embedded actuator array

assembly Pressure sensor array mounting base

Electronic system Functional block diagram of the electronic

system Displacement sensor array multiplexing

5x5 cell array prototype Summary

Overview & objectives

Practical structural implementation Aims at N by N cell array Challenges Objectives

Design for manufacturing Modular design Structural simplicity Design for mass production

Design for scalability Structural expandable Size and resolution scalable

Vertically modular

Implementations of Implementations of the Multi-cell Systemthe Multi-cell System

Large number of identical components Material cost, fabrication cost, assemble cost Manufacture and assemble difficulty

Large number of feedback measurements Hardware cost DAQ resource limitation

Mechanical Structure Design (I) Functional Modules

Row control hydraulic board Column control hydraulic board Pressure sensor array assembly Fluidic channel concentrating block Actuator-sensor array assembly

Actuator-sensor Array Assembly

Row Control Valves

Pressure Sensor Array Assembly

Column Control Hydraulic Board

Row Control Hydraulic Board

Fluidic Channel Concentrating Block

Column Control Valves


Mechanical Structure Design (II)

Column control valveColumn control valve

Row control valveRow control valve Control chamber

Working chamber

Residue volume

Input channel Output channel Input channelOutput channel

Membrane


Realization of “N2 by 2N” fluidic matrix drive Design of the control adapter

Mechanical Structure Design (III) Displacement sensor embedded actuator

array assembly


Retracting Pressure

To Control Valves

Displacement Sensor

Plugs prevent graphite paste from getting into the tubes

Glass Tubes

Graphite Paste

Tube Racks

Sensor Embedded Cylinder

Conductive Epoxy

Bottom Plate

Conductive Epoxy

Top Pressure Chamber

Return Pressure

Sealing Board

Multiplexer

Digital Switch

Mechanical Structure Design (IV) Pressure sensor array mounting base


Pressure Sensor Leads

Printed Circuit Board

Top Metal Plate

Bottom Metal Plate

Main Channel

Branch Channel

Pressure Sensor Leads

Printed Circuit Board SLA Base

Main Channel

Branch Channel

Electronic System (I)


Functional block diagram of the electronic system

Multiplexer

Multiplexer

Multiplexer

Multiplexer

Signal Conditioners

Signal Conditioners

Valve Driver Array

Valve Driver Array

Multiplexer Driving Circuit




Inte

rfaces

Inte

rfaces

To C

ell Le

vel C

ontro

l

Position Sensor Array

Position Sensor Array

Pressure Sensor Array

Pressure Sensor Array

Filter Array

Filter Array

Control Valve ArrayControl Valve Array

Electronic System (II)

Signal ConditionerR

Resistive Film

CiCgi

Cs

Vi IiV’

Vk Ik

U To A

/D

Converter

Excitation Voltage

sCUVI

IsCgVsCVV

si

iiii

)'(

')'( sCUVI

IsCgVsCVV

si

iiii

)'(

')'(

Displacement sensor array multiplexing Simple multiplexing scheme


Electronic System (III)

22 db

VaVU ik

22 db

VaVU ik

involved sensorsthe of number the is n

C Cg Cg ; C C C

CCCC

CCnCCCd

RC

b CCC

Ca

:Where

2ki 1ki

s

s

s

s

)(

))((

;1

;

211

2121

121

Displacement sensor array multiplexing Simple multiplexing scheme results


||U|| (V

)

||Vk|| (V)

1000 Sensors

0 1 2 3 4 5 6 7 8 90

0.5

1

1.5

2

2.5

3

3.5

4

10 Sensors

100 Sensors

Without Crosstalk

C1 = 18pf, C2 = 30pf, Cs = 0.3 pf, R = 1M Active sensor output: 0 - 10 voltInactive channels’ outputs: 10 volt

C1 = 18pf, C2 = 30pf, Cs = 0.3 pf, R = 1M Active sensor output: 0 - 10 voltInactive channels’ outputs: 10 volt

Electronic System (IV)

Signal

ConditionerR

Resistive Film

CiCgi

Cs

Vi IiV’

Vk Ik

U To A

/D

Converter

Rg

Excitation Voltage

is

i

gi

gii

IsCUV

I

sRCg

RV

sCVV

)(

1

)(

is

i

gi

gii

IsCUV

I

sRCg

RV

sCVV

)(

1

)(


Displacement sensor array multiplexing Multiplexing scheme using grounding resistor

Electronic System (V)

222

222

)()(

)()(

acb

deU

222

222

)()(

)()(

acb

deU

k

ksisg

g

sgg

sg

VCe

VCCCVCCRd

RRc

CnR

RCC

R

Rb

nCCCCCRa

1

211

21

2121

))((

11

)())(2(

))((

Displacement sensor array multiplexing Results of multiplexing scheme using grounding resistor


||U|| (m

illivolt)

||Vk|| (Volt)

100 1 2 3 4 5 6 7 8 90

5

10

15

20

25

30

35

40

1000 Sensors

10 Sensors

100 Sensors

Without Crosstalk

Working Range

Rg = 20K Active sensor output: 0 - 10 voltInactive channels’ outputs: 10 volt

Rg = 20K Active sensor output: 0 - 10 voltInactive channels’ outputs: 10 volt

Electronic System (VI)

Displacement sensor array multiplexingOther multiplexing schemes

Numerically compensate Two Digital Switches

To A

/D

Converter

Signal Conditioner


5x5 Cell Array Prototype Designed and controlled using proposed

solutions Key Features

Stereolithography Technology 5 x 5 actuators in a linear pattern Grid size (center to center) is 5mm Hydraulic Matrix Drive Non contacting resistive sensors and modified

pressure sensors Reduced control signals for multiplexers Controlled by RT Linux on a host PC

Column Control

To ADC

Row

Con

trol

Sig

nal

Con

ditio

ner

Sig

nal

Con

ditio

ner

Sig

nal

Con

ditio

ner


Summary


Vertically modular design reduces the complexity of fabrication and assembly, improves the reliability and convenience for maintain, and suitable for mass production.

Successfully Designed FMD control adapter realized the concept of FMD

Displacement sensor embedded actuator array assembly makes fabrication of large number actuator-sensor array become simple and fast.

Pressure sensor array mounting technology reduces the cost and makes the multi-cell system expandable.

Carefully design electronic system can reduce the complexity of the control hardware, amount of components and improve the feasibility of realizing the Digital Clay.

Displacement sensor array multiplexing using grounding resistor is a simple but effective way to realize the large scale multiplexing.

5x5 cell array prototype is designed under the guidelines suitable for N by N cell array, and can be expanded to larger size array. Test results preliminarily validated the design and control methods presented.

Conclusions (I) System development

Cell level control architecture and realization Haptic control for solenoid valve based hydraulic

system (Position control, shaping state, user gesture interpretation)

Surface refresh methods for FMD Surface level control architecture based on the

FMD Vertical modular design for multi-cell system

Key components design Displacement sensor embedded micro actuator Fluidic matrix drive for multi-cell system with

huge number of cells Pressure sensor array assembly

Conclusions (II) Measurement technology

PWM displacement estimation Non-contacting displacement sensing Multiplexing technology for huge amount AC signals Control signal reducing for sensor arrays

Conclusions (III) Prototype development and manufacturing

process Single cell system prototype validates the cell

level control for single cell system 1x5 cell array prototype validates the PWM

control method and the horizontal modular design

10x10 cell array prototype validates the concept of FMD

5x5 cell array prototype validates the N x N planar pin-rod Digital Clay structure and control

Micro displacement sensor – actuator array mass production process Key step to the success of Digital Clay realization

Pressure sensor array assemble process Key step to the success of Digital Clay realization

FMD realization using SLA technology Key step to the success of Digital Clay realization

Recommendations on Future Work Actuator and sensors

Current displacement sensor needs further comprehensive test

Further investigations on the assembly of the pressure sensors array

Micro valve for the Fluidic Matrix Drive Embed MEMS valve into the cell array system using

fluidic matrix drive Refresh method for Fluidic Matrix Drive

Gradual approximation refresh method shows promising merits, but the matrix decomposition needs to be solved before implementation

Other general topics Control architecture for “2 valves per cell” driving

scheme The manufacturing process to realize multi-cell array

system

Questions & Questions & AnswersAnswers

Documents

Practical Structural Design and Control for Digital Clay Haihong Zhu Woodruff School of Mechanical Engineering Georgia Institute