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METR3100: Course Overview

Sensor Part: Course Overview

Lecturer: Han Huang

Room 45-212; Phone: 3365 [email protected]

Sensor Part Website:

http://www.mech.uq.edu.au/courses/metr3100/

METR3100: Sensors and Actuators


Text Reference

Experimental Methods forEngineers, J. P. Holman, 6or 7th Edition, McGraw-Hill,2001.


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Course Overview

Lecture 1: Course overview

Lecture 2: Introduction to sensors

Lecture 3:Guest lecture (Sensor application)

Lecture 4-12:

Project (group presentation)

Tutorial (group project discussion)

Practical (experiment and report) strain gauge measurement and data acquisition

Final examination (theory and practice)


Assessment

Sensor Presentations (group project).Assessment 20%

Strain Gauge Experiment (practical).Assessment 15%

Final Examination (including both sensor and actuator).Assessment 15% for sensor part


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Group Projects

There are nine topics for students projects.Detailed grouping method, project informationwill be announced on the web.

http://www.mech.uq.edu.au/courses/metr3100/

Each group member must present a part of theproject. The presentation time is 42-45 minutes,followed by about 5 minutes questionnaire.Keeping the time frame is important for your

team to receive a good mark.



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Project Assessment

Student mark on presentation: 10%

Lecturer mark on presentation: 90%

Project discussion in tutorial and overallperformance will be considered (by the lecturer)

Your attendance to all presentations can

gain extra bonus points


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Assessment form for Student Presentation

Overall Rating

Question Answer(Are the answers clear or meaningful to you?)

Presentation Skill(Is the PowerPoint document well prepared? How doyou think the speakers presentation skills?Do they handle the presentation time well?)

Coherence of Team(Is this a continuous thread of thought through thewhole presentation?)

Clarity(Do you understand the contents presented? Do youthink the speaker understand their presented topics?)

Content(Are all the r equired topics covered in the group

presentation?)

654321Speaker Order

Mark (0-5)*


Please write down your name andstudent no. as this is an evidence ofyour attendance for bonus points.

Instructions for grading:

5 Excellent. Demonstrates excellent understanding of deeperand subtler aspects of the learning topics. Excellent team work,excellent presentation documents and oral presentation skills.4 Good. Demonstrates awareness and understanding of deeperand subtler aspects of the learning topics. Well organized

presentation documents. Good team work and presentation skills3 Pass. Satisfies all of the basic requirements for the project.2 Fail to satisfy some of the basic requirements of the project.Clear deficiencies in performance, but evidence that some basicrequirements have been met.

1 Fail to satisfy most of the basic requirements of the project.0 unable to make the presentation and unable to attend theother group activities.


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Grouping

Rhys ColinCampbell

Jeremy IanBidgood

David GraemeBell

Geoffrey BruceBeck

SurjeetAtwal

ChristopherAndrews

Each member has 7 min. and then 8 min. for questioningEach member has 7 min. and then 8 min. for questioning

Basic Concepts in Measurements and Data Analysis


WarnerZhangNortonSilverwoodHarrisLindenberg

WareC. WalshMillenRobsonGloverKapelj

D. WalshUnwinMcLeodPaulingGiermanskiJensen

TilleyTrimbornMcInnesPalmerFreakleyJenkins

XuTaylorMissinghamMaddernNakkaCarmichaelJames

WuStannardLehnertKhengMcBrideCampbellHayden

WilsonSokolichKlimenkoHillhouseMarleyBidgoodBell

WhiteOsborneAtwalHasenkamMahadevwalaAndrewsBeck

12pm-1:50pm2pm-3:50pm

12pm-1:50pm2pm-3:50pm

12pm-1:50pm2pm-3:50pm

12pm-1:50pm2pm-3:50pm

12Week11Week10Week9Week

Prac. Grouping (Monday)

Each session has 8 students, who will form 4 groups.Each session has 8 students, who will form 4 groups.


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straingauge

amplifier

PC based dataacquisition

system

Fl

straingauge

voltage read-out

graphic display

Strain Measurement

F = gauge factor = axial strainR = change in gauge resistance due to deformationR = undeformed gauge resistance


Basics of Wheatstone bridge

Using the current defined in the plot, wehave:

i2R2=i1R1i2=i3=E/(R2+R3)

i1=ix=E/(R1+Rx)

Eliminating the current, the result is

Rx=R1R3/R2


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( )

+

+

=

4

4

3

3

2

2

1

1

2

21

21

1

0

R

R

R

R

R

R

R

R

RR

RR

V

V

Wheatstone Bridge Sensitivity


A

LR =

1 11 2

RF and

F R

= + + =

How to computer strain(From: Laboratory Exercises to accompany Introduction to Mechatronic and Measurement Systems)

The basic principle under which a strain gauge operates is the fact that the electrical resistance of a

conductor changes in response to a mechanical deformation:

R = resistance of conductor

= resistivity of material

L = length of conductor

A = cross sectional area of conductor

F = gauge facto, = Poissons ratio, = axial strain

R = change in gauge resistance due to deformation

R = undeformed gauge resistance

Relating the above definition to Poissons ratio and strain yields the following:

The change in resistance in a strain gauge is usually read off as a change in voltage across

a Wheatstone bridge. The concept of the bridge is thoroughly explained in the text:

Experimental Methods for Engineers and further strain gauge information can be found on

the National Instruments website under the developer zone

(http://zone.ni.com/devzone/devzone.nsf/webcategories/ see the general list, then sensors)


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Beam Bending Theory

Cantilever beam bending

End load

Top under tensile stress, and bottom under compression

Maximum stress

Stress-strain relationship


From beam theory: M = Bending Moment,

y = distance from neutralaxis to strain gaugelocation

I = Area Moment of Inertia

From Hookes law: E = Youngs modulus of

material

= Strain

= Stress

I

My=

E=

Arrange to find strain!Arrange to find strain!


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Load

Cross-Section

12

3bdIxx =

XX

b

d

Moment Arm

http://www.efunda.com/formulae/solid_mechanics/beams/casestudy_

display.cfm?case=cantilever_endload#target


Practical Details


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Practical Assessment

You must attend the practical for getting score on thispart.

Your mark on practical will be given based on youroverall performance in the experiment and the report.

Experimental report must be submitted 2 weeks afteryour experiments

A hard copy is required and submitted to the School of

Engineering Office in Hawken Building


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Safety Issues on Prac.

Complete the one-page standard Safety Declaration onPage 8 at the end of the OH&S Safety in the Laboratory(U/Grad edition) found herehttp://www.uq.edu.au/ohs/pdfs/studentind.pdf

Familiarize yourselves with the Lab Rules (copyattached). You must read these and be aware that you

need covered footwear (along with other

requirements) or you will not be admitted to the Lab.


http://www.uq.edu.au/ohs/pdfs/studentind.pdf

Documents

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