Lab meeting update

Samson Phan Sept 24, 2010

In the beginning…

Conclusions

• HIC numbers associated with collisions are insufficient to cause concussions– HIC & concussions: are they really a good

measure?

• Automotive Laceration scales are too insensitive.

• Automotive based injury indices insufficient for robot human collisions

So we built a model…

02

46

810

0

0.05

0.110

4

106

108

1010

velocityrobot radii

Ma

teri

al p

rop

ert

y fu

nct

ion Wassink et al

µ = 0.4

µ = 0.8

Bruise Volumes

And a sensor…

Sensor ResultsNormal 30 degrees

68.2 68.25 68.3 68.35 68.4 68.45 68.5 68.55

0

50

100

150

200

250

300

350

400

450

data1

data2

data3

data4

146.05 146.1 146.15 146.2 146.25 146.3 146.35

0

200

400

600

800

1000

data1

data2

data3

data4

Why similar patterns?Sensors are spaced too far?Sensors are not being sampled quickly enough?

Capacitance Leakage?

225 230 235 240 245 250

-100

-50

0

50

100

150

200

250

300

Capacitance Leakage?Sensor # No touch

Freq (KHz)Finger TouchFreq (KHz)

Pen TouchFreq (KHz)

Delta between Finger and Pen

1 640 507 480 27

2 663 542 490 52

3

4 809 700 580 120

5 720 600 500 100

6 960 740 730 10

7 760 645 600 45

8 865 680 640 40

Inertia Coupling

Frequency Stiffnes Experimental (by Sami Haddadin)

Theory

High High Ilower Ilower+xIupper

High Low Ilower Ilower

Low High Ilower+Iupper Ilower+Iupper

Low Low Ilower+xIupper Ilower+xIupper

0<x<1

Questions

• Why the difference between theory and experiment (if it really exists)– Zero Order Hold? Backlash?– Is there a response rate threshold that is deleterious?– What happens when reaction time is less than collision

time?• Does the source of stiffness matter?

– Preliminary results suggests so– How do hydraulics/pneumatics (PAMS) behave?

(0<x<1)• Initial operating pressure variations

Future Work

• Conduct Collision Tests with Adept Setup to see varying effects of stiffness on Inertia coupling

• Use HSR arm setup to explore stiffness source effects. – Pneumatics, electromagnetic

motors

Experimental Setup

Adept Setup HSR Setup

How does stiffness affect collision?

Want to know more?HSR meeting @4 pm in Gates

GOOD LUCK SAL!