iii
`UNIVERiii2777 O1
`Current Trends in
`Engineering Practice
`
`* CV Ramakrishnan
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`OF ecitor
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`APPLE 1027
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`Contents
`
`xv
`
`367
`
`379
`
`384
`
`Amit Chatterjee
`
`Prospects for Further Work in the Rotary Wing Field with Alh as the Catalyst
`K. S. Sudheendra
`Military Helicopters
`K. S. Sudheendra
`Quality and Reliability
`K. Sudhakara Rao
`Trajectory and Mission Design of Launch Vehicles
`Ve Adimurthy
`Space Debris: Magnitude of the Problem and Engineering Solutions to Its Mitigation
`Ke Adimurthy
`Re-entry of Objects from Geostationary Transfer Orbits
`Ve Adimurthy
`Advancesin Inertial Sensors and Systems
`Amitava Bose
`Navigation of Launch Vehicles
`Amitava Bose
`Redundancy ManagementofInertial Systems
`Amitava Bose
`Modeling, Analysis & Design of Control for Launch Vehicles (Part-I)
`S. Dasgupta
`
`Photovoltaic UPS
`S. Jayasimha and TP. Kumar
`Inertial Systems
`S.N. Puri
`Access Technologies
`S. S. Shekhawat
`
`AEROSPACE ENGINEERIN
`
`METALLURGY, MINING AND MATERIALS SCIENCE
`
`Underground Coal Mining Technology in Coal India Limited Present and Future
`N.K. Sharma
`Selective Mining by Continuous Miner in Opencast Mines
`N.K. Sharma
`:
`Prospects of Smelting Reduction Processes
`Amit Chatterjee
`SomeFeatures of Iron-andSteel makingin Integrated Steel Plants
`Amit Chatterjee
`Trendsin Production of Direct Reduced Iron with Particular Reference to India
`
`6
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`7
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`ustry and uses materials like
`
`ELECTROE PATTERN
`FIG. 20 TWO TINE QUARTZ BEAM WITH E
`|
`|
`UND
`LECTR
`(UNDER DEVELOPMENT IN ISRO)
`ly material for resonator, subsequent developmentat Sunstrand during 1995
`iti
`Capacitive excitat
`xcitation andfal
`oes
`‘
`‘
`“rometerreachedperformancerequirednsaeotmiceSeae
`INS.
`6. MICROMACHINED INERTIALSENSORS
`Micromachinedinerti
`:
`Inertial sensors
`micromachining’ de
`USE process technology
`opedbyintegratedcircuitmameaeRati:sions = pee
`vel,
`.
`Ology
`
`:
`
`eee
`
`‘
`
`ndsin Engineering Practice
`484 Current Tre
`strand design had metallic as well as fused quartz flexure er
`d broughtout resonant beam accelerometer, typed Proog
`ine
`concept. Further, Sun
`aaa performance. Sees
`arket and at a considerable low cost. RBA 509 as RBm
`powerinput Of0.1 watt, weighs 9 gm, operates: a bias
`500 during 1991 for a larger application
`errorof<Img, scale factorerrorof<360 ppm,
`ta cost ofonly Rs.0.4 lakh. A moreaccurate enSlon
`e of 70g andall a
`artz flexure cum proof mass has a performanes
`harang
`C_55°C to +80°C wit
`Jerometer which uses quare
`)
`arfottreportedthe qualification ofone VBA with a range of500gforthestess
`called Superflex acce
`orderbetter. Singer Ke
`:
`£20 micro g and a scale factor error of 10 ppm, weighs em
`application.It has a bias error 0
`
`Bic
`
`.
`
`ae ee tae FO Foe eK ON er wt
`et 4 ho 4 et ee
`t+ + + + t+ 4 4 4 4%
`
`Bottom view of tuning fork
`
`FIG. 19 TUNING FORK USED IN DIGITAL WATCH INDUSTRY WITH ELECTRODE PATTERN
`
`Fig.20 showselectrode pattern ofa dualtine resonator under development in ISRO
`
`main
`
`Section AA
`Scale NTS
`
`;
`
`mph
`
`Quartz is not the on
`usedsilicon beam with
`;
`This accel
`
`su
`
`‘
`
`8
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`

`

`d
`
`A van
`
`ces in Inertial §
`
`€nsors and Systems 485
`
`are
`;area
`
`all
`
`’
`
`i
`
`i
`
`erformance.
`
`D:
`
`be
`
`meter, a very small
`
`ast 30 years
`oes
`the |
`erometer and vibrating gyrosofsuitable shapes,
`accel
`Frolution
`e first developmentofan openloopsilicon a
`:
`SB
`y
`ccelerometer
`wasreported in 1979 b
`Angell. Apartial applicationofthis technology in
`ry Roylance and
`‘chti
`ingi
`’
`gyro wasr
`lateneaotNsTuningforkgyro, BikebySystronDonner,USAduring
`broug t out q
`in'w ich the quartzbeam alone was mi y partofninety, Sunstrand, USA
`signal, USAreportedall siliconVBAwithnavigationclass
`icromachined. During 1995, Allied
`(8] researchonmicromechanicalsensors during 1985 and P
`ce. Draperlab, USAinitiated
`:
`:
`stillcontinui
`,
`ad
`in gyro and 100 ug in accelerometer by now. Using these SETCie,ae. 10°/hrclass
`(micro) IMU wasrealised which wasinte
`i
`from an artillery. Entire system was Suesaoe$peteemapares =roiectilefred
`Fig.21.By2005, anorderimprovementinperformance ee satoe ernie
`eh ee targetted forUS $500.
`istargettedwithsizereducedto 5 cmx2.cm
`applicationwhichcouldnotbeearlieraereBemenatic tsie
`cost and power. Diverse application such as Automotive, guided acillinSuaoresae
`personalnavigatoronsoldier,spacecraftandunmannedmicroairNENeeica ‘ ie
`existingareasexceptingwherestandalonehighaccuracyis‘required.Intheaeraet=
`gyrosandaccelerometersareplannedtoasistapersonwhohaslosthisbalanceduetoaeei
`theinsideoftheearsothathecanwalkwithoutfalling.Duetosuchmultifariousapplications, 1 ah
`onMEMStechnologyisgrowingallovertheindustrialisedworld.
`eye
`
`ing sensors like HRGwere developed and qualified. However,
`
`Micromachined gyros and accelerom
`
`i
`
`2
`
`6.1 Multisensors
`Considerable developmenteffort is also going inthe developmentofmultisensorswhichcombinerate
`and acceleration information in one sensor. SCIRASis one such sensorreportedin [7].
`
`7. CONCLUSION
`the the last 50 years reveal fascinating pictures.
`Advances in inertial sensors and systems during
`high specific investment in materials,fabrication,
`Initially, it was highly electromechanical requiring
`at continued even whenlater
`assembly and integration. The specific investment scenario somewh
`rgence oftechnology cosharing with
`qwene
`generation sensorslike RLG or vibrat
`the advance ofIFOG andits consequent development saw eme
`rating beam accelerometerwhere
`fiberopticcommunication. Asimilarobservationwasnoticedinvib:
`nete
`watch industry. Reduction ofcost andviewing fora
`oan
`Th
`it co-shared with frequency standard and digital
`.
`the technology
`largerapplicationmarketwerethemaindrivingforcesbehindthetransition,Finally,
`:
`hinin
`furthertookaturnwithaviewforsubstantialreductionincostandweightaeeiets Be
`fabricati
`i
`it is seen that each
`techno ogy had
`its sp
`brication route to enable batch production. Also,1
`formance andreliability.
`problems
`whi
`i
`butultimatelyachievedveryhighperton
`whichtoklongtime099°
`tingthedecisionmakingprocessonhighaccuracysensors.
`The adventofGPS orGLONASSis reorien
`:
`es
`Overallitcanbeseenthattheresearchgoaloncost,size,powerandweightreductioninassociat
`;
`jon:
`tion
`:
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`9
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`

`486 Current Trends in Engineering Practice
`lity have been achievedin each ofthe new techn,Ologies
`rmanceand reliabi
`with the improvement in perfo d systemsare pene
`trating large application areas unthinkable;n Other
`achined sensors an
`The microm
`technologies.
`Power Conversion
`
`Nav. Processor
`
`MMISA
`(burled)
`
`'
`
`
`
`GPS
`Receiver
`
`3 axis
`accel assy
`
`sia
`gyro assy
`
`MMISA
`
`FIG. 21 MICRO-MINIA’TURE INS WITH MEMS TECHNOLOGY
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