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Welcome to

your Digital Edition of

Aerospace & DefenseTechnology

May 2015

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Intro

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Deploying Next-Generation UAS Platforms with 3U VPX

UGVs — On the Cutting Edge of Thermal Management

Controlling the Seas — A New Concept in Autonomous Surface/Underwater Vehicles

Connectivity in Robotic Systems

Supplement to NASA Tech Briefs

May 2015

SPECIAL ISSUE Unmanned Vehicle & Robotics Technology

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www.aerod

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Deploying Next-Generation UAS Platforms with 3U VPX

UGVs — On the Cutting Edge of Thermal Management

Controlling the Seas — A New Concept in Autonomous Surface/Underwater Vehicles

Connectivity in Robotic Systems

Supplement to NASA Tech Briefs

May 2015

SPECIAL ISSUE Unmanned Vehicle & Robotics Technology

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AIntro

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2 Aerospace & Defense Technology, May 2015Free Info at http://info.hotims.com/55589-820

Aerospace & Defense Technology

ContentsFEATURES ________________________________________

6 Unmanned Aerial Systems6 Deploying Next-Generation UAS Platforms with 3U VPX

12 Unmanned Ground Vehicles12 UGVs — On the Cutting Edge of Thermal Management

18 Unmanned Surface/Underwater Vehicles18 Controlling the Seas – Introducing a New Concept in

Autonomous Surface/Underwater Vehicles

26 Robotics26 Connectivity in Robotic Systems

30 Tech Briefs30 Infrared Stereo Calibration for Unmanned Ground Vehicle

Navigation31 Simultaneous Vibration Suppression and Energy Harvesting

for a Multifunctional UAV Spar33 Development and Evaluation of the Stingray Amphibious

Maritime Unmanned Ground Vehicle36 Pushbroom Stereo for High-Speed UAV Navigation in

Cluttered Environments38 Modeling and Simulation of an Unmanned Ground Vehicle

Power System

DEPARTMENTS ___________________________________

40 Application Briefs44 Advertisers Index

ON THE COVER ___________________________________

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(Photo courtesy Liquid Robotics, Inc.)

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TECHNOLOGIES

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6 www.aerodefensetech.com Aerospace & Defense Technology, May 2015

More powerful. Lighter.Cooler. These are the keycriteria for the design ofLine Replaceable Units

(LRUs) in next-generation UnmannedAerial System (UAS) platforms, whichcontinue to grow in importance to mil-itary organizations worldwide. Theability of these platforms to providepersistent surveillance of targets whileeliminating the need to put warfight-ers in harm’s way makes them indis-pensable assets to commanders. The ef-fectiveness of these platforms in thefield is governed by their sensor pay-load and their processing systems.Next-generation UAS designs, such asthe Navy’s Unmanned Combat Air Sys-tem Carrier Demonstration (UCAS-D),require high levels of processing powerfor multiple onboard sensors, and allthat power must be delivered in alighter, cooler configuration that mini-mizes the size, weight and power(SWaP) envelope of onboard electron-ics subsystems.

Unfortunately, designing LRUs thatmeet next-generation UAS program re-quirements is a challenge. Commercialoff-the-shelf (COTS) single board com-puters (SBCs) are available that providekey functionality for everything from fea-ture recognition and video surveillance,to target identification and tracking. Butnot all SBCs are ideal for LRUs destinedfor new UAS platforms. Most do not havethe processing power required. Some thatdo have the processing power require too

much real estate in available chassis con-figurations, while others may offer theright mix of processing power and com-pact size, but cannot be cooled properlyto meet rugged operational requirements.LRUs built on open architecture 3U VPXform factor modules offer the optimalbalance of size, weight and power for avariety of UAS applications.

More Functionality in Less SpaceWhatever the configuration of the

sensor payload, the key to the effective-ness of a UAS once it is deployed is howlong it can remain in the air collecting,processing and delivering sensor infor-mation to operators and commanders.If the payload is too large and tooheavy, it will have an impact on fuelconsumption and how long the UAScan stay in the air. Therefore, the moreinformation processing that can be ac-

complished with smaller, more compactand more capable SBCs, the more valu-able the LRU is to a system integratorand, ultimately, to the commander andoperator in the field.

New LRUs configured with SBCs builton the 3U VPX open standard offer anumber of benefits. Compared to sys-tems built on the 6U VME or even 6UVPX standards, LRUs configured with3U VPX cards offer more processingpower in a smaller form factor. As a re-sult, system integrators need fewer cardsand fewer LRUs in the same system todeliver the same functionality of a 6U-based subsystem. For example, 6U VPXdesigns that may have previously re-quired two LRUs can now be built withone LRU, thereby cutting size, weightand power allocations by as much as 50percent.

Beyond functionality, 3U VPX SBCsare also a more cost effective option.With fewer SBCs needed to deliver therequired functionality, developmentand build costs are lower. Once de-ployed, the open standard architecturemakes life cycle maintenance and man-agement easier, and makes tech inser-tion a less costly operation.

Pre-Validated Reference DesignArchitectures

Despite the benefits, leveraging the3U VPX SBCs for next-generation UASplatforms can be difficult.

One of the biggest challenges that sys-tem integrators face is ensuring COTS-

Curtiss-Wright Defense Solutions has supplied Northrop Grumman with the dual Integrated Mission Management Computer (IMMC) subsys-tems used as the redundant flight control processors aboard the Global Hawk UAS since the program’s inception in 2000.

Deploying Next-Generation UASPlatforms with 3U VPX

The compact 2-slot rugged 3U MPMC-9321 missioncomputer supports up to 2 single board computersor one SBC and one mezzanine card carrier board.(Curtiss-Wright)

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UAV Technology

based SBCs will work as intended in aspecific LRU design configuration. Likeall COTS-based solutions, 3U VPX COTSSBCs are designed and built by COTS so-lution providers to perform a specificfunction, such as network routing,switching, or graphics processing. Themanufacturer rarely knows how theirboard will ultimately be used in a LRU,and integrators can use the board to pro-vide its function in a variety of LRUs des-tined for a variety of platforms. Often,the same board can be used in multipleLRUs to enable different applications.

To speed time to deployment of theirCOTS-based LRU subsystem in next-gen-eration UAS platforms, system integratorscan opt to leverage pre-validated 3U VPXSBC architecture-based reference designs.

Test Processes and ToolsRegardless of the design approach, all

3U VPX SBCs must be tested to ensurethey deliver the required functionality

once integrated into a LRU with theother COTS modules that comprise theparticular subsystem. Although COTSmanufacturers will test a board to en-sure it performs its intended function,testing for capabilities beyond the basicfunction is not a requirement and isusually undefined.

Exacerbating the testing challenge isthe fact that COTS SBCs are not usuallydelivered with system integration sup-port tools that will speed the integra-tion process. As a result, integratorsmust focus significant time and efforton developing and executing test soft-ware and processes.

To minimize the cost and time associ-ated with testing and integration of anyCOTS SBC into a UAS platform, integra-tors should opt for 3U VPX SBCs fromsuppliers who offer solutions that en-able testing of:• The hardware: for specific perform-

ance parameters;

Curtiss-Wright's MPMC-9351 rugged 3U 5-slot sys-tem is an example of an LRU designed to reducespace, weight, power and cost for UAS subsystems.(Curtiss-Wright)

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• The software: to ensure it provides theproper commands to the LRU for aspecific function;

• Both hardware and software: to en-sure that they operate together toprovide reliable, predictable resultsevery time.

Getting 3U VPX Designs toDeployment Faster

Ultimately, although next-generationUAS applications can best be addressedusing rugged, high performance, size,weight and power (SWaP)-optimizedprocessing systems built with open ar-

chitecture 3U VPX modules, system in-tegrators should choose the shortestroute to deployment. Some COTS com-ponent manufacturers provide thatpath with a complete pre-validated sub-system solution approach that offersthe pre-packaged boards and test sup-port tools integrators need to reduceprogram risks and development cycleswith new 3U VPX designs. The COTSboard and subsystem vendor knows thecomponents they produce best. There-fore, they are better able to select andpackage the right COTS componentsthat will work together in an LRU to de-liver the required functionality with theoptimal balance of size, weight andpower for a variety of UAS applications.This makes it easier to design advancedLRUs for next-generation UAS platformsthat can carry multiple onboard sen-sors, stay in the field longer, and processmore information faster.

Examples of pre-validated rugged,SWaP-optimized VPX systems are pro-vided by Curtiss-Wright’s family of openarchitecture Pre-Qualified Multi-PlatformMission Computer (MPMC) Subsystems.These fully integrated mission computersare certified to meet the demanding MIL-STD-810, MIL-STD-461 and RTCA/DO-160 military and aviation environmentalengineering standards. They eliminatethe need for customers to undertake theirown time-consuming, costly, and risk-fraught process of building new systemsfrom the ground up in order to meet de-manding performance requirements. Pre-validated systems can save customerstens of thousands of dollars and multipleweeks (typically 8-12 weeks) of develop-ment time that would otherwise be re-quired to meet MIL-STD-810/MIL-STD-461/ RTCA/DO-160 testing requirements.They also save significant amounts oftime before environmental testing evenbegins, because the lead-time to deliveryof the first testable system can shrinkfrom the typical 10 months-to-2 yearsfrequently seen for a customer’s internalhardware development phase, to a matterof several months.

This article was written by Jacob Sealan-der, Chief Architect, Integrated Systems,Curtiss-Wright Defense Solutions (Ash-burn, VA). For more information, visithttp://info.hotims.com/55589-500.


UAV Technology

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Thermal management of un-manned ground vehicles(UGVs) is more complex thanother electronic equipment be-

cause they have to operate in harsh en-vironments such as humid tropical rain-forests or sandy deserts where moistureas well as dust and sand can compro-mise the reliability of the control elec-tronics. Regular open enclosures are cer-tainly not an option; instead they needsealed and ruggedized enclosures to alsowithstand hard shocks and vibrations.

Thus certain cooling methods are ei-ther out of the question or only possiblewith limitations. For example, in gen-eral liquid cooling it is possible to trans-port heat away from the componentand cool it at another location with alarger surface and a better convectioninto the environment. Unmanned aer-ial vehicles (UAVs) and unmanned un-derwater vehicles (UUVs) have the ad-vantage of a good coolant flow of eitherair or water. UGVs in hot desert envi-ronments drive over hot sand with thesun shining on their top side—not thebest conditions for any cooling systems.

Efficient cooling methods range fromthe basic principles of heat transfer tosome more costly and more complexphysics that can be simulated usingcomputational fluid dynamics (CFD)software. There are three basic coolingmechanisms: conduction, convection,and radiation. Two other methods can

be considered too but are more of a hy-brid or model more complex physics:advection and phase transition.

Advection is the movement of heatfrom one point to another, such asheated water run to a heat exchanger,and requires a velocity that is usually

provided with the help of a waterpump. But it works on the same basicprinciples, to conduct the heat into thefluid and back out of it.

Phase transition is actually a very effi-cient method that even our body applieswhen we get hot, either from the envi-

Figure 1. The boiling curve shows qualitatively the dependency of the heat flux on the temperatureΔT on a logarithmic scale. The graph is split in the various regions of the boiling states I‒V and theirtransition points A‒E.

UGVs — On the Cutting Edge ofThermal Management

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UGV Technology

ronment or if under high load in a work-out at a gym. Our body starts to perspireand the sweat evaporates, and this cre-ates a cooling effect from the energytaken to evaporate the sweat. UGVscan’t sweat, but there are methods ap-plied in various applications where thephase change can be used to cool or con-trol the temperature of a component.

For example, phase-change material(PCM) is used in modern electric vehi-cles (EVs) that reduce the critical tem-perature with the help of this bufferingeffect. Of course, phase-change materi-als only work for a certain time andrange. We all know that water whenmelting stays at exactly the freezingtemperature and doesn’t get hotter untilthe ice is molten but, after that, thetemperature increases again. This is thesame principle for phase-change mate-rial, but instead of water, some gels areused that are solid up to a certain tem-perature where they keep the tempera-ture constant—up to the point wherethe gel is molten and then increases alsoin temperature. This technology appliesmostly as a peak load buffer.

Another phase change is the boilingof the coolant (Figure 1). This requires aspecial coolant or mixture to meet a cer-tain boiling range or temperature thatsuits the desired maximum design tem-perature of the component. The boilingeffect is a sensitive state because as thecoolant temperature reaches the transi-tion from single-phase convection topartial nucleate, boiling the coolant willstart to form small bubbles that then de-tach from the surface and rise up. Thebubble doesn’t transport the heat, ratherit’s the coolant flow that is generatednear the wall from the bubble detachingand moving away from the wall. Thefurther the temperature increases, thestronger the boiling gets until it reachesa point where the slope of the increasingheat flux decreases again.

From this point on, we are in the fullydeveloped nucleate boiling range. Thisranges up to the maximum heat fluxwhere it then flips and the heat flux de-creases again. We would not want to getover that point because suddenly theheat flux decreases again as the temper-ature increases and that’s not good forthe cooling of our device. The zone

above the critical heat flux is the transi-tion boiling zone which then enters thefilm boiling; however that zone is ineven higher temperature ranges. Thismethod is used in modern cars’ internalcombustion engine water jackets thatcool the cylinder block and head.

The third phase-change method thatcan be used for cooling is evaporation, aswe mentioned already. Now, I said thatevaporation is something our UGVs can-not use as many living creatures do, butthen, humans are creative. We find waysto use this effect even for machines. Theapplication of spray cooling is exactlywhat most resembles the sweating of ahuman. In spray cooling, the coolant issprayed with a nozzle onto the hot sur-face that wets the surface which is thenevaporated and cooled down, until itchanges phase back to liquid (again else-

where in the cooling loop). This coolingcycle is similar to regular liquid cooling

but with a phase change. This type ofphase change is already applied insome electronics cooling applica-tions. In some ways, it is similar toa heat pipe, where the coolant

evaporates at the hot end and con-denses at the cold end. As the coolanteither flows back because of gravity orwhen a wick is used, the coolant issucked back as a result of the capillaryeffect.

So besides the basic principles of fansand conduction and natural convec-tion, higher more complex coolingmethods find increased interest in ap-plications that were not used even sev-eral years ago. Advanced cooling isneeded with the increased heat gener-ated by complex military designs wherecooling is often not that simple, espe-cially when harsh environments pro-hibit certain mechanisms, making themoperate less effectively.

Case StudyThe following example illustrates the

types of challenges faced when designingelectronic equipment for the types of en-vironments that UGVs operate in. Engi-neers at Azonix, a division of Crane Co.,used the Mentor Graphics® FloEFD®computational fluid dynamics (CFD)thermal simulation software when de-signing the Terra embedded computer.The Terra computer is designed to becompletely sealed from the extreme (orharsh) elements and for use in very hot

Figure 3. The CFD thermal simulation shows the air temperature distribution (left), and the velocity mag-nitude and field in the Azonix model (right).

Figure 2. An example of an Azonix rugged embed-ded computer.

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environments (Figure 2). The simula-tions enabled them to reduce the num-ber of thermal prototypes they had tomake from 12 to 1.

The engineers used their CAD geome-try with the CFD software and definedthe heat dissipation sources, material

properties, and the ambient temperatureoutside the enclosure at the product’sdesign limit of 60 °C. They then definedthe goals and performed thermal simu-lation. The CFD software analyzed theCAD model, automatically identifiedfluid and solid regions, and defined the

entire flow space without interactionand without adding extra objects to theCAD model. The software generatedsimulation results in roughly five min-utes. The results revealed that tempera-tures on the surfaces of key componentsexceeded the allowable limit of 90 °C.

The conduction paths from the heatdissipating components to the heatsinkand heatsink geometry were the pri-mary design parameters that offered anopportunity to improve thermal per-formance. The cross-section of the heatspreader was increased and changedfrom aluminum to copper. Gap-typethermal interface material was insertedat the interfaces between the compo-nents and the heat spreader. The ther-mal interface material was modeled as acontact resistance, reducing the numberof cells, rather than conductionthrough material.

These changes substantially reducedthe surface temperatures on the dissi-pating components, though still notenough to meet the thermal require-ments. They then optimized the designof the heatsink. After roughly six itera-tions, in each case changing the spacingand height of the fins, the heatsink wasoptimized and the internal componenttemperatures held to a minimum.

This is just one example of engineersovercoming, in little time and using so-phisticated simulation tools, the designchallenges in military and aerospace ap-plications.

This article was written by Boris Marovic,Industry Manager for Aerospace and De-fense, Mentor Graphics Mechanical AnalysisDivision (Frankfurt, Germany). For more in-formation, visit http://info.hotims.com/55589-501.

16 Aerospace & Defense Technology, May 2015

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UGV Technology

This is just one example ofengineers overcoming, inlittle time and usingsophisticated simulationtools, the design challengesin military and aerospaceapplications.

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The boundary between the seaand sky is an important place tobe. It’s the critical connectinglayer for commercial and mili-

tary information exchange between theundersea world to aerial, space and shore.Being present at this boundary betweensea and sky, with cost-effective endurancein challenging conditions, requires theuse of autonomous surface vehicles.

Designing long duration autonomoussurface vehicles requires access to inex-pensive, low-power computing; a persist-ent source of power; and durable me-chanical engineering. The volumemarkets created by cellular telephonesand video gaming has totally trans-formed the economics of computing.Coupled with creative mechanical de-signs that harness energy from the oceanfor vehicle propulsion, and new genera-

tions of solar cells for electricity, the per-vasive application of Autonomous Sur-face Vehicles (ASVs) is more practical.New advancements in communications,and sensor technologies are also en-abling developments in ASV and Au-tonomous Underwater Vehicles (AUVs)while paving the way for increased cov-erage, rapid information delivery, in-creased safety and, lower cost.

Tying these all together is what LiquidRobotics has done with their WaveGlider®. They’ve developed the world’sfirst wave and solar powered au-tonomous surface vehicle that providessustainable ocean operations and makesit possible for real time data collectionand information for commercial mis-sions such as conducting seismic sur-veys, environmental and water qualitymonitoring for oil & gas companies;

measuring weather conditions and cli-mate change; and tracking great whitesharks. Leveraging these commercialtechnologies, Wave Gliders are used indefense missions for Anti-SubmarineWarfare (ASW); Intelligence, Surveillanceand Reconnaissance (ISR); and securityof national resources in Marine ProtectedAreas (MPAs), marine sanctuaries, andExclusive Economic Zones (EEZ). Eachone of these operations requires a persist-ent, 24 7, monitoring and surveillancepresence that is not economically or op-erationally feasible with manned assets.

Designing an autonomous vehicle likethe Wave Glider, poses a mixture of com-plex technological challenges such aspersistence, scale, reliability, and cost, toname a few. Add to this the challenge ofoperating a floating computer centerwith sophisticated communications andsensors in salt water, during hurricanes,and at sea for a year at a time.

So how do you provide seafloor tospace surveillance across the vast, haz-ardous oceans? What challenges andtechnological advancements make thedeployment of fleets of networkedASVs/AUVs, interoperating with mannedsystems, a reality in the maritime theater?

Creative Mechanical Design Persistence at sea requires solving the

energy re-supply challenge. A techniqueto harvest energy from wave motionwas the key insight that made long du-ration missions possible. This basicallygives the vehicle unending thrust forfree. The vehicle can endure severeconditions through a combination of

Controlling the Seas

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How a Wave Glider’s unique propulsion system works.

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UUV Technology

mechanical design and sophisticatedmaterials. This gives it the ability tomaintain presence for many months ata time, where most other autonomousvehicles are limited to hours or days.The Wave Glider is the only surface ves-sel that does not retreat when a hurri-cane approaches

The Wave Glider generates thrust bybeing built in two parts: one part floatson the surface and the second part isbelow the surface where it is calm. Itlooks roughly like a surfboard that is cov-ered in solar cells and antennas. It isconnected by an umbilical cord to a sub-mersed component that is a rack ofwings and a rudder. As the float movesup and down in the surface waves, thewing rack, which is down where the seais calm, moves up and down too. But itswings are mounted on hinges in such away that the vertical oscillation is con-verted into forward thrust. While theWave Glider picks up free forward thrustfrom the waves, it gets free electrical en-ergy from solar panels stored in batteriesand distributed through a sophisticatedpower subsystem. There are no fuels ofany kind on the vessel. No emissions areproduced. (To see a video explaininghow the Wave Glider works, go towww.techbriefs.com/tv/Wave-Glider)

The selection of materials for a vesselthat has to survive salt water and hurri-

canes for extended periods required sig-nificant engineering work. The hull isprimarily made of composites. Tita-nium is used for many components, as iscarefully selected grades of stainlesssteel. All of the external electrical con-nections are designed to be wet-mate-able. The umbilical between the float-ing and submersed halves of the vehicleis particularly sophisticated – not onlyare there strength members that have tosurvive significant shock loads, the elec-trical wires that are embedded in theumbilical need to maintain continuousconnectivity through arbitrary flexingand shocks. Even the paint is involvedin durability through the reduction inbio-fouling.

A testament to this innovative engi-neering design is proven through thesuccess and experience with long dis-tance missions such as the journey ofmultiple Wave Gliders across the Pacificocean from San Francisco, CA to Bund-aberg, Australia. This scientific initia-tive, named PacX (Pacific Crossing),spanned approximately 400 days whiletraveling through a Category 5 Ty-phoon and overcoming the East Aus-tralian Current before arriving in Aus-tralia. This achievement was awardedthe Guinness World Record for “thelongest distance traveled by an un-manned, autonomous surface vehicle”.

Compute Capability vs. PowerConsumption

This is an issue that is being helped bythe cellular phone and tablet industry.ARM-based multicore CPU chips fromvendors such as NVIDIA and Qualcommcan scale available compute resourcesbased on workload, thus reducing powerconsumption to minimal levels. Thistype of dynamic CPU technology can beutilized to run basic vehicle navigationon minimal CPU power, but allow theCPU to scale up when data needs to betransformed into information to reducecommunications overhead or on-de-mand onboard computational analysis.The concept of having the ASV’s controlapplication adjust the number of onlineCPU cores and maximum CPU fre-quency to limit power consumption is aviable solution today.

Open Software OperatingEnvironment

The ASV and/or AUV’s operating en-vironment is becoming more sophisti-cated in order to satisfy increasing mis-sion complexities. In the past, onemight elect to use a real-time operatingsystem (or develop one from scratch)and custom application. However,today there are more options includingLinux and Java, both of which offer arich set of capabilities, security, and reli-ability. The use of readily availableopen software platforms, tools, and lan-guages aid the development of applica-tions and sensor integration. Addition-ally, utilizing Linux and Java eases thetask of finding qualified engineering re-sources, as the talent pool is larger andmore current.

The ability for the autonomous vehi-cles to easily adapt to specific mission re-quirements drives the need for flexibil-ity in the operating environment thatcan be custom tailored without majormodification. A pluggable architectureallows new network interfaces, sensors,and navigation methods to be devel-oped while leaving the core of the oper-ating environment intact. Pluggablecomponents tend to be smaller in size,which makes on-mission modificationspossible without the need to recover andservice the ASV/AUV. One of the specialfeatures of the plugin facilities in Java isA Wave Glider Autonomous Surface Vehicle (ASV) awaiting deployment.

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UUV Technology

that it allows for dynamically loadingnew software on-the-fly in the midst of amission, while protecting the integrityof the core system software from bugs inplugins. Liquid Robotics’ Regulus, thecontrol software on the Wave Glider,makes extensive use of these facilities.

These dynamic & flexible softwareenvironments aren’t just for adapting to

mission changes. When an au-tonomous vehicle is on a mission last-ing months, far away from human assis-tance, software updates to fix recentlydiscovered bugs or adapt to failures canhelp dramatically. For example, on a re-cent mission a Wave Glider’s compassfailed because it got too close to theNorth Magnetic Pole. Specialized soft-

ware was written to “fake” the existenceof a compass using the onboard GPS,and this was uploaded over a satellitelink, saving the mission.

AutonomyToday's missions require autonomy,

not only at the single vehicle level, butalso vehicle-to-vehicle. Imagine 100 to500 vehicles working together as a set tocollect data and/or to cover large swathsof the ocean. With good onboard au-tonomy, humans can concentrate onthe strategic mission of the fleet, ratherthan the moment-by-moment tactics ofeach individual vessel.

How do we keep autonomous vehi-cles out of harm’s way? Today's oceangoing vessels employ devices such asAutomatic Identification System (AIS)to transmit current location allowingother vessels to receive this informa-tion. Radar and acoustic informationcan be fused in the system’s situation

The SHARC (Sensor Hosting Autonomous Remote Craft) is a special version of the Wave Glider designedfor the defense industry.

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AIntro

awareness where AIS is not available.Autonomous navigation can be verycomplex and require solutions thatenter into the territory of artificial intel-ligence. One of the big advantages ofusing Java is that it spans the widerange of use cases demanded from an

autonomous vehicle – it works well allthe way from artificial intelligencethrough sophisticated networkingdown to device drivers.

Behaviors can be much more com-plex, fusing many kinds of sensors. Forexample, chemical sensors and cameras

can be integrated to follow the edge ofan oil slick.

Perhaps even more complex than au-tonomous navigation is autonomous ve-hicle health management. A persistentautonomous vehicle has to take care ofitself. It has to detect failures, reportthem, fail-over when redundant systemsare available, and sometimes, even at-tempt to recover the function of the de-vice. It’s remarkable how often powercycling revives an ailing sensor or sweep-ing a rudder back-and-forth can cleanobstructions from bio-fouling. Handlingthese issues is a significant part of theRegulus operating software.

InteroperabilityAs unmanned systems become more

pervasive, interoperability betweenmanned and unmanned systems is acritical capability. A fleet of AUVs doesnot necessarily have to be homoge-neous. It should be an interconnectedcollection of ASVs, UAVs, and mannedsurface vehicles using the best of breedin each area. The utilization of stan-dardized software interfaces make com-munications and integration of hetero-geneous systems much morecost-effective and offer reduced powerconsumption, increased reliability, andmission agility.

Imagine a fleet of ASVs monitoringan area of ocean, searching for targetsof interest and then sending target lo-cation, target type, pictures, and videoof the target back to shore for analysisas they are acquired. Now add the abil-ity for ASVs to coordinate with un-manned and manned assets to collect,analyze, and report a more complete,real time situational awareness to com-mand headquarters.

And let’s not forget that stealth capa-bilities are sometimes necessary whenpatrolling for hostile or illegal activities.A small, mobile ASV with a low profile,acoustically silent and with a small sur-face footprint can be extremely difficultto spot in the ocean whereas a 120-footpatrol boat is not. The SHARC (SensorHosting Autonomous Remote Craft, theWave Glider brand for the defense mar-ket) with low observability, navy bluecolor and lack of thermal or acoustic sig-natures is well suited for maritime patrol


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UUV Technology

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UUV Technology

and detection. And when it comes torisk, the ASV is expendable – as it has noonboard crew – and is lower cost.

As the design and use of ASVs/AUVsadvances, the industry must drive for-ward with open standards to reduce thecomplexities of software developmentacross multiple interoperating plat-forms. The use of standard operatingsystems and development languages is amove in the proper direction to fostermore inter-company cooperation.

Sensor TechnologyASVs and AUVs require smaller, lower

power sensors to achieve long missiondurations. There are many good sensorsavailable now, but some have too high acost in power consumption and space.Not many radar units will fit in thepalm of your hand and only draw onewatt of power. Further advancement inthe miniaturization of sensors is stillneeded. Advancements in sensor tech-nology coupled to implementation ofstandards based operating environmentwith open APIs is needed to propel sen-sor integration and application develop-ment for ASVs/AUVs.

Inter-Vehicle CommunicationsA mixture of communications devices

is required to manage telemetry, com-mand, and inter-vehicle communica-tions. Global satellite coverage is attrac-tive but comes at a high cost and can bebandwidth limited. Cellular communi-cations is fast and available close toshore in some areas. Multiple commu-nication channels are required to servethe needs of autonomous vehicles.

One of the distinguishing characteris-tics of the Wave Glider is its flexibility inaccepting a wide variety of communica-tions technologies such as Iridium,BGAN, Wi-Fi and cellular, and automaticswitching from one device to another ascircumstances change. For example,when a Wave Glider is close to shore itautomatically switches from expensiveand slow satellite communication tofaster and cheaper cellular communica-tion. As with the other electronics andsensor payloads, these are protectedfrom the harsh environments by beingplaced inside watertight compartmentswith wet-mateable connectors leading

to antennas on one of the masts.There are hybrid solutions that em-

ploy several communication techniquesat once: acoustic to communicate tosubsurface assets, radios to aircraft andsatellites, and cellular telephones toshore. By doing this, Wave Gliders canfunction as bridges that connect the seafloor to the shore or to aerial assets.

Navigation for Subsurface VesselsSafe vehicle navigation is another

challenge. Vehicles on the surface canuse GPS to determine position, but forunderwater vehicles, other methodssuch as a magnetic compass and/or Atti-tude and Heading Reference System(AHRS), are all that are available. Butthese dead-reckoning techniques arenotoriously error-prone. By couplingwith a persistent surface vessel carryingan acoustic modem and underwater po-sition sensor, underwater assets can begiven a firm frame of reference andcommunication path.

Conclusion:The boundary between the sea and

the sky is an important place to be. Byemploying modern technologies,ocean-going autonomous vehicles likethe Wave Glider can provide critical in-formation exchange from subsea tospace, adding an important extensionto modern national security operations.

This article was written by Dr. JamesGosling, Chief Software Architect, and Mr.John Weeks, Distinguished Member of theTechnical Staff, Liquid Robotics, Inc. (Sun-nyvale, CA). For more information, visithttp://info.hotims.com/55589-502.

Small, unobtrusive, and capable of collecting andcommunicating large amounts of data inconspicu-ously, the Wave Glider ASV could have numerousdefense applications.

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Connectivity inRobotic Systems

While many think of un-manned aerial vehicles(UAVs) or space probesand planet rovers when

they think of unmanned systems, thefield of robotics covers every environ-ment known to man: sea, ground, air,and space. Beyond UAVs, unmannedunderwater vehicles (UUVs) and un-manned surface vessels (USVs) havebegun to capture headlines, primarilyin the role of security and defense.Likewise, terrestrial unmanned groundvehicles (UGVs) are now gaining theirshare of the limelight. The U.S. Navy iseven experimenting with a humanoidrobot (SAFFiR) to help fight shipboardfires as a first responder.

Each of these unmanned systems ismeant to operate in an environmentand ecosystem where a machine can ei-ther augment or replace a human. Rea-sons include safety, environmental con-cerns, technological superiority, orcosts. Sending an unmanned vehiclecan be less dangerous and less expen-sive than sending a human. Applica-tion requirements drive the technologyof the electromechanical buildingblocks used to create the robot, andthese solutions can range from themundane to the extreme. There are re-markable technological and economicparadigms associated with each missionthat lead engineers to select specificconnectivity solutions.

UAVs – SwaP and BandwidthWhether shoulder launched or carrier

launched, UAVs are all about SWaP (size,weight, and power) and bandwidth.Lightweight construction, includingconnectivity solutions, is paramount toenable maximum payload, range, andtime on station. While high-speed signalprocessing is important in surveillanceand similar applications, communica-tion bandwidth is more convenientlyhandled in UAVs than in other un-manned vehicles. Most UAVs use light-weight datalinks and typically have anunobstructed environment to conversereal time with receiving stations.

As a result of their environment,UAVs benefit from lightweight, high-ca-pacity power distribution equipment.Cables and harnessing componentshave become lighter over the years.Cross-linked insulation and jacketingmaterials allow significantly thinnerwall thicknesses, saving both space andweight. Since every gram counts, TEConnectivity (TE) recently introducedlightweight heat-shrink boots that areup to 20 percent lighter than the partsthey can replace. In many instances,fiber optic connectivity has been imple-mented as the exemplification of lowweight, high bandwidth and EMI im-munity.

Local processing of images and sig-nals intelligence allows the UAV to siftand prioritize data to be transmitted tothe receiving station. With sophisti-cated processing comes the need forhigh-speed embedded computing. TE’sVITA 46 VPX standard MULTIGIG RT 2-Rbackplane connector (Figure 1) is suit-

This small selection of terrestrialrobots illustrates the different

configurations and missionsdesigners must take into

consideration when specifyingconnectors. (David Vergun)

Figure 1. For weight-savings embedded computing, MULTIGIG RT 2 connectors use a design that minimizesweight while supporting high-speed data rates. (TE Connectivity)

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Rick Harrington, team member and Vice President of Engineering for RTC Electronics, Inc. (formerly College Park

Industries), was the Electronics Category Winner in the 2011 and the 2013 Create the Future Design Contest.

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Robotics Technology

able for this role. The open architec-ture VPX connector is modular andscalable for application flexibility,and has been demonstrated in excessof 10 Gb/s for excellent functionaldensity. UAV designers are also bene-fiting from advances in compositeand selective metallization to createintegrated composite enclosures andantennas.

UGVs – Rugged and Cost DrivenUGV design has traditionally

targeted lower costs as a high pri-ority. Reasons include the poten-tially high number of units pro-duced, the less challenging natureof the ground environment, andthe fact that UGVs are often con-sidered expendable. Nevertheless,UGVs are expected to be ruggedand perform when needed, drivingdesigners to tread a fine line be-tween cost and performance.

UGVs range from small, inex-pensive rovers that might have acamera or other sensor to high-ca-pability, multifunction systems.Given the wide range of these plat-forms, connectivity solutions rangefrom commercial, industrial or auto-motive connectors to mil-spec con-nectors. In each instance, connectiv-ity solutions must be appropriatelyengineered to suit the application.

At one end are relatively basic, lowcost, potentially expendable systems.Vehicles like Humvees and trucks tosupport logistics are being designed tooperate in either a manned or un-manned mode. They can use weather-resistant automotive connectors, IP67input/output connectors, and militaryor military-style circular connectors.

MIL-DTL-38999 connectors and theirclose relatives remain one of the mostpopular choices for rugged interconnect.Beyond a full mil-qualified connector, agreat variety of connectors use the famil-iar 38999 shell as the basic form factor.The new generation of military-styleCOTS circular connectors are ideal forUGVs. For example, TE’s Wildcat Microand 38999 connectors are based on mili-tary circular connector design practice.With between 3 and 9 contacts, theWildcat Micro bayonet latching mecha-

nism is very robust and enables quickand positive coupling. An anti-vibrationtriple-start threaded coupling option isalso available, as well as various mount-ing options and rear accessory features.

Based on Mil-DTL-38999, Wildcat38999 connectors are available in fourhousing sizes with between 11 and 64contacts and offer almost double thecontact density of traditional 38999connectors. The triple start couplingthread provides robust and high-relia-bility engagement to help withstand se-vere shock and vibration, and the con-nectors are fully sealed, a vital featurefor all-weather operation or potentialsubmersion during a mission.

Beyond ruggedness and high density,many sensor systems found on un-manned systems demand bandwidth.TE’s CeeLok FAS-X connector (Figure 2)supports 10 Gb/s Ethernet in a 38999shell—accommodating a single Ether-net channel in a size 11 shell or fourchannels in a size 25 shell. One advan-tage of 38999-derived connectors is thatthey can use the same, readily availablebackshells and other accessories.

UUVs – Challenging the NavalEnvironment

The naval environment bringsunique challenges, particularly interms of withstanding the underseapressures, operating in a flooded en-vironment, and protecting againstsalt-induced corrosion. Electronicsare often housed in containmentvessels or line-replaceable units(LRUs). Subject to the effects of hy-drodynamics, UUVs that are ex-pected to operate at any significantforward speed most often have min-imal frontal cross-section or are tor-pedo shaped and space is very muchat a premium. The need for under-water performance as well as spaceand weight-saving higher densitiesare often in conflict.

Given the resulting packagingchallenges, small-form-factor, ruggedconnectors, such as the dry-mateSEACON MINI-CON connectors,work well in the UUV environment.MINI-CON connectors were devel-oped as a small-diameter, high-den-sity, high-pressure system, availablein 13 shell sizes and up to 203 con-

tacts. The standard connector with-stands 16,000 psi, although higher pres-sure versions are available.

Wet-mate connectors tend to belarger since they need both pressure bal-ancing and a mechanism to seal the un-mated connector contacts. They alsoneed generous lead-in to allow propermating of connector halves roboticallyby a UUV in an underwater environ-ment. While wet-mate connectors havelong been used in subsea petroleumproduction, they may also find use innaval applications such as an underwa-ter docking system for UUVs.

There remains a need to create au-tonomous underwater vehicles. Theremotely operated vehicles used in oiland gas applications are controlleddirectly through a long umbilicalcable for power, control, and data.Power lines and fiber optic cables inthe umbilical cable provide adequatepower and bandwidth. However, therange, freedom and stealth of teth-ered remotely operated vehicles(ROVs) can be problematic in defenseapplications.

Figure 2. 10G Ethernet is supported in a rugged format bythe CeeLok FAS-X connector. (TE Connectivity)

Figure 3. SEACON MINI-CON connectors provide a high-den-sity dry-mate interconnection that can withstand 16,000 psi.(TE Connectivity)

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Aerospace & Defense Technology, May 2015 29

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Robotics Technology


Untethered autonomous operationcan create its own set of issues, includ-ing means of communication andpower supply. A vehicle underwaterdoes not have the same convenientwireless communication capabilitiesof a UAV or UGV. Water does nottransmit RF signals well. Whileacoustic communications or low-fre-quency towed antennas allow somedegree of communications, they arenot efficient for higher data payloads.A common use for acoustic signals issimply to tell the UUV to surface tosend or receive communications. Oncesurfaced, the UUV has clear communi-cation capabilities either with nearbyvessels or with satellites.

As a consequence of the communica-tions issues, many UUVs do not per-form intense on-board signal process-ing. Unlike the heavy signal processingperformed by a UAV to obtain high-res-olution photos and video, a UUV’s

needs tend to be more humble. If theembedded computer is well protectedfrom water and pressure, its operatingenvironment is relatively benign—with-out the shock and vibration that UAVsand UGVs experience. COTS embeddedcomputing systems will provide the re-quired processing power mechanicaland environmental robustness required.Sealed connectors are required betweenthe protected environment and the restof the UUV.

Power supply on UUVs is typically bybattery. The latest in battery technol-ogy, as well as efficient power distribu-tion and low power consumption sys-tems are vital to range and missionsuccess. Minimizing SWaP is a commontheme in unmanned system design.

The Unmanned WorldAs sensor, software and processing

technologies evolve, so will the effec-tiveness and presence of unmanned ro-

botic systems. One thing that is notgoing to change is the environmentalchallenges facing robotic systems. Eachenvironment – sea, land, air and space –poses its own hurdles and has a pro-found effect on the unmanned system’sdesign. These challenges range fromthe most basic, for example, material se-lection, to the highest level, such as thelevel of autonomy required. Similarly,the role of connectivity and range of so-lutions available to the designer is af-fected by the unmanned system’s envi-ronment. As interconnect sciencemerges form and function, the role ofconnectivity will continue to rise in im-portance in the future of unmannedsystem design.

This article was written by Gregory Pow-ers, Market Development Manager, GlobalAerospace, Defense and Marine, TE Con-nectivity (Berwyn, PA). For more informa-tion, visit http://info.hotims.com/55589-503.

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www.aerodefensetech.com Aerospace & Defense Technology, May 2015

Tech Briefs

Infrared Stereo Calibration for Unmanned Ground VehicleNavigationThis method enables detection and classification of obstacles for avoidance and path planning.

Space and Naval Warfare Systems Center Pacific, San Diego, California

Many challenges still persist in thearea of autonomous (and even

semi-autonomous) vehicle navigationfor unmanned ground vehicles (UGVs).One challenge is in detecting and classi-fying obstacles for avoidance and pathplanning. The use of laser-based sensors,such as lidar, has become quite commonfor assisting in such a task; however, lidarsystems may be too expensive for certainapplications, and are active, not passivesensors, so they may not be desirable insome missions. Lidar is adversely affectedby smoke, dust, fog, and rain. Therefore,the use of passive camera sensors, such astypical color and infrared (IR) cameras,has become an important research topicin UGV navigation.

One of the greatest challenges ofusing a stereo pair of color and/or IRcameras is to accurately determine theextrinsic calibration parameters be-tween the cameras. For color cameras,this has historically been solved using acheckerboard pattern of black andwhite squares. This does not necessarilywork out-of-the-box for IR stereo cam-eras, due to thermal radiation required

for high- and low-intensity pixels in anIR sensor. For instance, on a cold andcloudy day, there will be very little dif-ference registered in an IR sensor be-tween the black and white squares on apiece of paper. Therefore, more care andpreparation is required in order to cali-brate stereo IR cameras.

The first challenge is the calibrationboard itself. Unlike the calibration pat-tern for color stereo cameras, whichcan utilize simple black and whitecheckerboard patterns for highly accu-rate calibration, the calibration patternfor two IR stereo cameras must be care-fully selected, designed, and/or manu-factured.

The second challenge was the calibra-tion pattern itself. Starting with theclassic black and white checkerboardpattern, the dynamic range between thewhite and black squares was not suffi-cient for the calibration routine to de-tect the pattern. Even when the size ofthe calibration board was increased, thedetection algorithm was unsuccessful.

The successful methodology used tocalibrate the IR stereo cameras incorpo-rated a calibration board made from di-bond, a lightweight, rigid, and durablealuminum composite material. The pat-tern printed onto the boards was a 3 x 5pattern of asymmetric circles with a 17-cm diameter with a spacing of 17 cm be-tween the circles. By using this large

asymmetric circle pattern on a warmday with little to no wind (with theboard left in direct sunlight), the detec-tion results improved dramatically. Ad-ditionally, simple pre-processing tech-niques were used to increase theaccuracy of IR stereo calibration.

In the first method, a median blur fil-ter was applied to each IR image with awindow of 5 pixels. For the secondmethod, a thresholding function wasused to truncate the pixel values abovean intensity of 50. The third methodcombines the first two methods.

For experiments with the color camerasin the system, checkerboard patterns,symmetric circle patterns, and asymmet-ric circle patterns were all successfullyused in the calibration routine. For exper-iments with the IR stereo cameras, onlythe asymmetric circle patterns were suc-cessfully used in calibrating the cameras.

To evaluate the stereo calibration re-sults numerically, OpenCV was used tocalculate the stereo re-projection errorfor each of the calibration patterns usedfor both the color stereo cameras and theIR stereo cameras.

This work was done by Josh Harguess ofthe Space and Naval Warfare Systems CenterPacific and Shawn Strange of Leidos. Formore information, download the Tech-nical Support Package (free white paper)at www.aerodefensetech.com/tsp underthe Sensors category. SPAWAR-0002


(a) The TORC ByWire XGV unmanned vehicle, and (b) mounted camera sensors.

(a) (b)

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Aerospace & Defense Technology, May 2015 31Free Info at http://info.hotims.com/55589-849

Tech Briefs

The goal of this work was to investi-gate using harvested energy to di-

rectly control the vibration response offlexible aerospace systems. Small, light-weight, flexible Micro Air Vehicles(MAVs) operate near flutter, providingboth harvesting opportunities and vi-bration suppression requirements. Thepossibility that ambient energy mightbe harnessed and recycled to provideenergy to mitigate the vibrationsthrough various control laws was inves-tigated. The goal was to integrate har-vesting, storage, control, and computa-tion into one multifunctional structure,and illustrate its benefits.

The first task was to discover ways tominimize control effort for vibrationsuppression. Basic control laws weretuned to achieve the same perform-ance. The required amount of energy ineach case was calculated and com-pared. A saturation function was insti-tuted over the top of each controller tolimit the amount of energy called for inthe early part of the control law. Thesebang-bang, or saturation, controllersclearly used the least amount of energyto produce the same performance. Asmuch as two-thirds of the required en-ergy can be saved by using a saturationcontrol. This reduction makes running

a control law off of harvested energypossible.

In implementing these control laws, itwas discovered that the high voltagescommanded by the control laws result inthe piezoelectric coupling coefficientbeing non-constant. An adaptive controllaw had to be implemented to accountfor the change in coupling coefficient asthe control voltage demand increased.

The next task was to integrate har-vesting and storage into the same pack-age with a control actuator and a con-trol law (i.e. the circuitry) embedded ina multifunctional composite structure.The goal was to integrate all of these

Simultaneous Vibration Suppression and EnergyHarvesting for a Multifunctional UAV SparResults show how long a UAV must fly before enough energy is harvested to be able to suppress a wind gust.

Virginia Tech, Blacksburg, Virginia

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Tech Briefs

components in order to provide a mul-tifunctional system capable of the fol-lowing functions:1. Energy harvesting2. Sensing3. Energy storage4. Vibration suppression using active

control5. Embedded computing (providing en-

ergy management and control laws)6. Structural integrity

This was all fabricated, modeled, andtested. Before proceeding, the harvesting,sensing, and control authority of severaldifferent types of piezoelectric materialwere considered, in order to choose thebest components for each task. Macrofiber composites form the best control ac-tuation devices, and monolithic piezoce-ramic forms the best sensing and harvest-ing device. These results were validatedwith extensive experiments.

The concept of a multifunctionalcomposite beam was applied to a prob-lem prevalent in UAVs: they tend to belight and travel near their flutter speed,which means that they are susceptibleto instabilities caused by gusts. Whilethe UAV is in normal flight, its wing vi-brates. The multifunctional wing sparwould transfer the wing vibration intoelectrical energy and store it in the em-bedded battery. When the UAV hits agust, the sensor function of the multi-functional spar would then see the in-creased strain and turn on the activecontrol system embedded in the PCBpart of the spar. The resulting feedbackcontrol law would then quiet the gustresponse and keep the vibration sup-pressed during the period of the gust.Laboratory results show great agree-ment with the theoretical models andnumerical simulations.

Two different controllers are used. Apositive position feedback controller(basically a second order filter) and thereduced energy controller illustratethat the settling time is about thesame, while the energy consumed ismuch less.

With validation of the model, simula-tions were used to predict how the sys-tem would behave as a gust suppressionsystem for a small UAV. The gust andclear sky condition (the condition of vi-bration induced during normal flight)were simulated using the Dryden PSDsignal for both clear sky and gust. Thesimulations were fed into the model ofthe multifunctional wing spar. The re-sponse of the wing to a gust shows alarge tip deflection. The response of thewing tip with the controller turned onand the gust as input shows substantialvibration reduction.

Other results that spun off of the pro-posed research include a MEMs-basedenergy-harvesting device, the use ofnonlinearity to improve the amount ofenergy captured by improving the me-chanical efficiency, and a look at har-vesting impacts. The main contributionhere is to show that closed-loop controlcan be accomplished with harvestedenergy.

This work was done by Daniel J. Inmanand Pablo Tarazaga of Virginia Tech for theAir Force Office of Scientific Research. Formore information, download the Tech-nical Support Package (free whitepaper) at www.aerodefensetech.com/tspunder the Aerospace category. AFOSR-0008The experimental validation of the multifunctional structure capable of performing harvesting and control

based on harvested energy.

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Tech Briefs

Development and Evaluation of the Stingray AmphibiousMaritime Unmanned Ground VehicleThis small tactical robot can be deployed ahead of the team to provide enhanced situational awareness inboarding, breaching, and clearing operations.

SPAWAR Systems Center Pacific, San Diego, California

Every year, the U.S. Navy and MarineCorps conduct thousands of Mar-

itime Interdiction Operations (MIOs) toenforce embargoes, intercept contra-band, prevent drug and human smug-gling, and fight piracy. These operationsare usually conducted by Visit, Board,Search, and Seizure (VBSS) teams usingrigid-hull inflatable boats (RHIBs) orhelicopters. Key performance parame-ters were developed for a portable,throwable robot that can best supporttheir missions. This robot can be usedfor advanced reconnaissance as theteam is about to board a target vessel, to

assist in compartment clearing, and forinspection of flooded compartmentsand bilges.

Subsequent user tests and demonstra-tions have revealed that its applicabilityis much wider than originally thought.The same characteristics critical to VBSSoperations also make the system a use-ful tool for land-based tactical opera-tions, especially for missions involvingstreams and culverts.

Design guidelines for a VBSS tacticalrobot were converted to explicit per-formance thresholds and objectives thatrequired considerable research and de-

velopment. Two prototype systems,each consisting of an operator controlunit (OCU) and two amphibiousStingray robots, were developed. Theareas that were the most challenging inthe design of these robots include:1. Weight threshold2. Maximum volumetric envelope3. Flotation in seawater4. Mobility in water5. Traction on wet, oily surfaces6. Impact resistance

The maximum weight ceiling of 1.8kg, when coupled to the other perform-ance requirements, was a major chal-

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Tech Briefs


lenge. The resulting design was a woven carbon-fiber mono-lithic chassis coupled to aircraft-grade aluminum sides andhardware, woven carbon-fiber wheels and internal brackets,and closed-cell foam for flotation purposes.

The 4500-cm3 maximum volumetric envelope for theStingray was determined by the requirement to fit in a Modu-lar Lightweight Load-carrying Equipment (MOLLE) pouch. Ithad repercussions in terms of the wheelbase, width, andwheel diameter for the UGV, given that the wheels are themost prominent physical features of the robot. For practicalpurposes, the wheel diameter was dictated by the requirementto be able to cross a 5-cm-tall obstacle (i.e. the wheel diameterhad to be approximately 10 cm to allow the wheel to climbover the 5-cm obstacle), and the width was mandated by thedimensions of the largest non-modifiable electronic compo-nent, which was the battery pack. As a result, the only free di-mension was the overall length, which was set at 10 inches toprovide an adequate amount of air inside the sealed UGVchassis for flotation, as well as to provide extra stability andbetter obstacle-climbing capabilities.

The Stingray had to float when immersed in seawater, bothfor recovery options and for operational reasons (capability ofcrossing standing water). Therefore, a passive, positivelybuoyant robot design was selected to accomplish both objec-tives. Instead of driving on the floor of a flooded space, therobot became a hybrid vehicle that can drive on the water sur-face as well as on land.

In order to achieve the desired results, the design team useda two-pronged approach where the UGV itself would be asbuoyant as possible through the integration of custom-de-signed floats in the wheels, and the maximization of the inter-nal volume of the UGV chassis (without sacrificing groundclearance), coupled with the custom development of a high-visibility Sling Flotation Device (SFD ) that would be wrappedaround the UGV when an in-water operating environment

Figure 1. The Stingray prototype wearing a high-visibility Sling Flotation Device(SFD). The SFD is similar to a personal flotation device in color (fluorescentyellow) and material (closed-cell foam).

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was expected, but would not impedeground operation. The SFD would besimilar to a personal flotation device incolor (fluorescent yellow) and material(closed-cell foam), with openings to ac-commodate the camera and the multi-purpose high-intensity LEDs. Initial cal-culations showed that the system wouldhave a density of 0.85 in saltwater,yielding a positive buoyancy of approx-imately 15%.

Once the UGV design had achievedthe required goals of weight andbuoyancy, the next challenge was todesign a system that would be capa-ble of mobility in the water. The orig-inal wheel design was a good startingpoint since the horizontal deeptreads, initially designed mainly fortraction and impact absorbance, hadshown the ability to perform as rudi-mentary paddle wheels.

The requirement for Stingray tractionspecified that the UGV should be ableto achieve sufficient traction on wet,oily metal surfaces up to sea states 5(rough). To determine the performanceof the Stingray in the operational envi-ronment, a test rig was created where asteel surface was left bare on one sideand painted on the other (to simulateboth scenarios) and wetted with oilywater (to simulate conditions oftenfound on a ship deck). The tread thatperformed the best overall was a micro-knobby design, which was chosen asthe final Stingray tread design and im-plemented in the prototype units.

The capability of surviving 5-meter(threshold) and 10-meter (objective)drops onto a steel deck was one of the

key requirements for the Stingray. Finiteelement analysis (FEA) was performedon all components and on the overallsystem, with safety factors always in ex-cess of 10, which allowed the system topass both the threshold and objectiverequirements once built.

This work was done by Hoa G. Nguyenof SPAWAR Systems Center Pacific andCino Robin Castelli of Macro USA Corp.For more information, download theTechnical Support Package (free whitepaper) under the Manufacturing &Prototyping category. SPAWAR-0003


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Tech Briefs

Pushbroom Stereo for High-Speed UAV Navigation inCluttered EnvironmentsThe high-frame-rate stereo detection systemrequires no external sensing.

Massachusetts Institute of Technology, Cambridge,Massachusetts

Unmanned aerial vehicles (UAVs) rely on an external motion-capture apparatus that gives the vehicles almost perfect state

information at high rates. Major challenges in gathering sensingdata necessary for flight are the limited payload, computation,and battery life of the vehicles. Lightweight cameras are a goodsolution, but require computationally efficient machine visionalgorithms that can run within the limits of these vehicles.

A novel method for stereo vision computation was developedthat is dramatically faster than the state of the art. The methodperforms a subset of the processing traditionally required forstereo vision, but is able to recover obstacles in real time at 120frames per second (fps) on a conventional CPU. The system islightweight and accurate enough to run in real time on aircraft,allowing for true, self-contained obstacle detection.

A standard block-matching stereo system produces depthestimates by finding pixel-block matches between two images.Given a pixel block in the left image, for example, the systemwill search through the epipolar line to find the best match.The position of the match relative to its coordinate on the leftimage, or the disparity, allows the user to compute the 3D po-sition of the object in that pixel block.

One can think of a standard block-matching stereo visionsystem as a search through depth. As one searches along theepipolar line for a pixel group that matches the candidateblock, the space of distance away from the cameras is explored.For example, given a pixel block in a left image, one might startsearching through the right image with a large disparity, corre-sponding to an object close to the cameras. As one decreasesdisparity, pixel blocks that correspond to objects further andfurther away are examined until reaching zero disparity, wherethe stereo base distance is insignificant compared to the dis-

tance away andthe obtstacle’s lo-cation can nolonger be deter-mined.

The algorithm iscalled “pushbroomstereo” because thedetection region ispushed forward,sweeping up obsta-cles like a broomon a floor (andsimilar to pushb-room LIDAR sys-

By detecting at a single depth (dark blue) and inte-grating the aircraft’s odometry and past detections(lighter blue), a full map of obstacles in front of thevehicle can be built quickly.

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Tech Briefs

tems). This is distinct from a “pushbroomcamera,” which is a one-dimensionalarray of pixels arranged perpendicular tothe camera’s motion. These cameras areoften found on satellites and can be usedfor stereo vision.

The system requires relatively accu-rate odometry over short time horizons.This requirement is not particularlyonerous because long-term accuracy isnot required like many map-making al-gorithms. In this case, the odometry isonly used until the aircraft catches upto its detection horizon, which onmany platforms is 5-10 meters away. Onaircraft, a wind-corrected airspeed meas-urement is sufficient.

A design and parameters were chosento cause sparse detections with few falsepositives. For obstacle avoidance, notevery point on an obstacle needs to beseen, but a false positive might causethe aircraft to take unnecessary risks toavoid a phantom obstacle.

To test the full system with an inte-grated state-estimator, the platform wasflown close to obstacles on three differ-ent flights, with control inputs, sensordata, camera images, and onboard stereo

processing results recorded. During eachflight, points on every obstacle wererecorded in real time. The state estimatewas robust enough to provide online es-timation of how the location of the ob-stacles evolved relative to the aircraft.While these flights were manually pi-loted, the system could autonomouslyavoid the obstacles with these data.

Metrics demonstrate that the pushb-room stereo system sacrificies a limitedamount of performance for a substan-tial reduction in computational cost,and thus a gain in speed. Finally, alldata used identical threshold, scoring,and camera calibration parameters.

This work was done by Andrew J. Barryand Russ Tedrake of Massachusetts Insti-tute of Technology. For more informa-tion, download the Technical SupportPackage (free white paper) atwww.aerodefensetech.com/tsp underthe Information Technology & Soft-ware category. MIT-0004

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Tech Briefs

Modeling and Simulation ofan Unmanned GroundVehicle Power SystemThese models can be used to plan missions orroughly estimate power system operation for anunmanned ground vehicle.

Army RDECOM-TARDEC, Warren, Michigan

Robotic vehicles such as unmanned ground vehicles (UGVs)have multiple sources of power, including batteries, fuel cells,

combustion engines, ultracapacitors, and solar cells to allow forextended periods of operation. Fuel-based power sources have ahigher specific energy than batteries, which is why most currentautomobiles are gasoline-powered. Batteries have many other ad-vantages in terms of low noise profile, easy replacement, and di-rect energy conversion. Solar charging allows for harvesting ofnatural resources to increase total energy reserves. Mission dura-tion may be maximized using a combination of power systems.

To effectively integrate multiple power system components, amodeling framework was developed to simulate and plan opera-tion of UGV power systems. First, each component is individuallymodeled using either empirical or theoretical techniques. Thesemodels consider power component states such as time of opera-tion, state of charge, and temperature. For a given mission, thepower demand is estimated and the power system models arecombined to compute total energy use. As a part of the model, en-ergy losses due to the operation of power system components areaccounted for. Losses include resistive heating in batteries, andstartup or shutdown power demands. In addition to full, nonlin-ear models for the UGV power system, a simplification processwas demonstrated that can be used to reduce the models to lineardynamics. These simplified models can be used to plan missionsor roughly estimate power system operation for a desired mission.

The fuel cell used in this work can only be turned on or off,with no variation in the power produced when on, and re-quires several minutes and nontrivial power input to transi-tion between on and off. These limitations on the fuel celllead naturally to the proposed hybrid systems framework.

The power system model consists of the 200W fuel cell anda Li-ion battery. The fuel cell is fueled by commercial propanecanisters and consists of a 200W solid oxide fuel cell, a fuel re-former, and a DC/DC converter. The propane gas is first desul-furized and then reformed via partial oxidation into a hydro-gen-rich fuel stream to feed the fuel cell. The fuel cell wasdesigned to be integrated with existing batteries on smallUGVs such as the TALON robot. This combined power systemsignificantly increases the possible mission duration, espe-cially under low-power loads such as persistent stare missions.

One of the challenges of integrating this power source is to de-velop an optimal duty cycle for using the fuel cell to recharge thebatteries. The fuel cell was connected to a TALON battery packwith a moderate state-of-charge (SOC) and issued a startup com-mand. The current draw from the batteries was logged every 10seconds until the fuel cell completed the startup procedure and

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Tech Briefs

began charging the batteries. Likewise,the fuel cell was then issued a shutdowncommand, and the current draw waslogged every 10 seconds until the fuel cellshut down. Power and energy values werecalculated using the average voltage of thebattery back (35 Volts) throughout thetests. The fuel cell consumed approxi-mately 6.5 Watt-hours over 16 minutes tostart up, and approximately 5.3 Watt-hours over 18 minutes to shut down.

To determine the power requirementsfor the mission, a simulation model wasused for the UGV operating in a knownenvironment. This model includesmotor models and track-terrain interac-tion models. From this model, one cansimulate the desired mission and obtainthe power demand over time for a givenmission. The driving loads can be de-composed into resistance due to terrainand changes in kinetic energy.

To provide appropriate torque inputs tothe terrain model, a motor model was ob-

tained experimentally by testing iRobotPackbot motors. The model takes in thecurrent shaft speed and the power beingdelivered to the motors, and calculatesthe torque output. Together with a simplerigid body model of the UGV, one cansimulate the UGV completing a missionand record the power used. In addition tovariable power demands due to locomo-tion, electronic components onboard re-quire power for operation. It is assumedthat these loads are known and constantover the entire mission.

Studying a simple fuel cell/battery hy-brid, this framework can be used to eval-uate the performance of different con-trol laws for desired criteria. Inparticular, energy losses of the entirepower system and thermal response ofthe battery for an extended UGV mis-sion were investigated. Future work in-cludes using this combined model toplan and optimize energy efficiency fora mission. These models can be vali-

dated by running physical experimentswith a UGV carrying a fuel cell and bat-teries running the controllers described.

This work was done by Jack Hartner ofArmy RDECOM-TARDEC; and John Brod-erick, Dawn Tilbury, and Ella Atlkins ofthe University of Michigan. For more in-formation, download the TechnicalSupport Package (free white paper) atwww.aerodefensetech.com/tsp underthe Information Technology & Soft-ware category. ARL-0176

The fuel cell connected to a TALON robot battery pack.

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Application Briefs

Anti-Hacking Software for UAVsGaloisPortland, OR503-626-6616http://galois.com

To address growing evidence that commercial UnmannedAerial Vehicles (UAV), automobiles and other vehicles are

vulnerable to hacking and sophisticated cyber security attacks,Galois developed and successfully demonstrated what has beencalled “the world’s most secure UAV software.” Galois, a com-pany that specializes in protecting information, devices, net-works, and vehicles, recently conducted a successful demon-stration for the U.S. Defense Advanced Research ProjectsAgency’s High-Assurance Cyber Military Systems (HACMS) pro-gram. Galois is part of a team that produced provably correctand secure software that runs on commercial UAVs.

For a February 2015 CBS ’60 Minutes’ segment profiling theU.S. Defense Advanced Research Projects Agency (DARPA),Galois demonstrated an exploit that allows an attacker tocompletely take over a commercial, off-the-shelf UAV inflight. Galois then showed the same UAV running its high-as-surance UAV software that is guaranteed to be invulnerable tolarge classes of attack. The technology addresses the same se-

curity vulnerabilities in many systems, including modern au-tomobiles and the Internet of Things (IoT).

“As unmanned drones – particularly those used for civilianand commercial purposes – grow in number and usage, current

During the HACMS demonstration, red lights indicate that an unprotecteddrone is being hacked. A similar drone, with Galois software installed, could notbe hacked.

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Application Briefs

Unmanned Naval HelicopterNorthrop Grumman CorporationRedondo Beach, CA310-812-4321www.northropgrumman.com

The U.S. Navy has been conducting ship-board flight test-ing of the first operational MQ-8C Fire Scout unmanned

helicopter delivered by the Northrop Grumman Corporation. After more than a year of land-based testing conducted at

Point Mugu, California, the MQ-8C took its first flight off thedeck of the guided-missile destroyer, USS Jason Dunham(DDG 109), off the coast of Virginia in mid-December lastyear. It marked the first time an unmanned helicopter hadever operated from the deck of a U.S. Navy destroyer. All told,the new Fire Scout made 22 takeoffs and precision landingsduring its first sea trials, all while being controlled from theship’s ground control station. According to George Var-doulakis, Northrop Grumman’s vice president for mediumrange tactical systems, the test program will run throughoutthe summer of 2015 and if all goes well, the aircraft should beoperational by the end of the year.

The MQ-8C is an upgraded version of the MQ-8B Fire Scout,which has logged more than 14,000 flight hours and 5,300

software vulnerabilities pose a national security risk,” said Kath-leen Fisher, former DARPA HACMS program manager. “Galois’demonstration offers evidence that software built the right waydramatically reduces vulnerabilities, not just for drones, but forcars, information systems and the Internet itself.”

For the DARPA HACMS program, Galois demonstrated itsability to prevent both UAV drone hacking and automobilehacking. Galois’ secure UAV software provides an alternativeto currently available software that’s open to remote takeoverand other vulnerabilities. One of the tests Galois performedwas having its software evaluated by independent, world-classpenetration testing teams that were unable to gain remote ac-cess to the vehicle. The software has also been demonstratedto prevent the types of wireless automotive control system at-tacks exposed in a February 2015 report released by SenatorEdward J. Markey (D-Mas) called “Tracking & Hacking: Secu-rity & Privacy Gaps Put American Drivers at Risk.”

“The message for organizations building connected vehi-cles, systems and products is that vulnerabilities are not a fore-gone conclusion if secure and reliable software is designedinto their products up front,” said Rob Wiltbank, CEO, Galois.“The same way an automaker would not design a vehicle bytrial and error, you can’t develop a secure system on the fly, asthe product is being released. Systems can be made correct bydesign, which presents an opportunity for organizations todramatically reduce the hacking threat.”

In the HACMS program, Galois is part of a team led byRockwell Collins, and also includes University of Minnesota,National ICT Australia, and Boeing.

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INTRODUCINGCOMSOL 5.1COMSOL redefined theengineering simulation mar-ket with the release of COM-SOL Multiphysics® softwareversion 5.1, featuring thenew and revolutionaryApplication Builder. COM-SOL users can now buildapplications for use by engi-neering and manufacturing

departments, expanding accessibility to their expert-ise and to cutting edge simulation solutions. See howat comsol.com/release/5.1

COMSOL, Inc.

Application Briefs

sorties while being deployed on the Navy’s frigates and littoral combat ships. TheMQ-8C, which is based on the FAA-certified Bell 407 commercial helicopter, featuresa larger airframe than the MQ-8B and it can fly twice as long and carry three timesmore intelligence, surveillance, and reconnaissance payloads. Powered by a Rolls-Royce 250-C47E engine with dual channel full authority digital engine control, theMQ-8C has a top speed of 135 knots, a maximum ceiling of 16,000 feet, an internalpayload capacity of 500 lbs., a maximum sling load of 2,650 lbs., maximum en-durance of 12 hrs., and a maximum range of 1,227 nautical miles.

Northrop Grumman is under contract with the Navy to build a total of 19 MQ-8CFire Scout helicopters, including two for testing purposes. All told, the Navy hopes toacquire 70 units.


UAV Circuit BoardsSunstone CircuitsMulino, OR503-829-9108www.sunstone.com

Miki Szmuk is an aerospace engineer with big ideas for building better unmannedaerial vehicles (UAVs). As a doctoral student from the Controls Lab for Distributed

and Uncertain Systems (C-DUS) of the Department of Aerospace Engineering at the Uni-versity of Texas (UT) in Austin, Szmuk specializes in the engineering of small, sophisti-cated UAVs.

Szmuk and the rest of the C-DUS research group, who are advised by Dr.Maruthi Akella, focus on addressing fundamental engineering problems in non-linear dynamical systems, measurements, and control. This includes the coordi-nated operation of distributed multi-vehicle swarms. Consequently, the C-DUS re-search group employs UAVs in demonstrating various control and estimationalgorithms that it develops.

These crafts are not easy to build. Weighing only a few pounds, UAVs musttravel long distances, reliably collecting and processing data along the way. Inorder to meet the always evolving needs of the UAV industry, Szmuk recognizedthe need to develop PCB design skills. Without them, it would be difficult to cost-effectively improve functionality of his department’s drones and get in front of in-dustry expansion.



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Application Briefs

Szmuk first reached out to Sunstone as an undergrad at UT.“I was working on a UAV with a two and a half pound autopi-lot system,” said Szmuk. The vehicle’s overall size is a functionof the payload it must carry and it took a twenty-five to thirtypound UAV just to accommodate the oversized autopilot.“That was simply too big for what we needed this plane todo,” said Szmuk.

Issues with size compound quickly when building a UAV.If the autopilot is too big, that impacts the wing area andfuselage size. The result is an oversized craft with less func-tionality and a higher cost. The cumbersome, original UAVdesign was done component by component, thus the over-sized end product. Szmuk took it upon himself to look at thebigger picture.

Szmuk called Sunstone, looking not just for someone tomanufacture boards but for a way to design them himself.With their help, he designed his first PCB—a small board thatrouted the plane’s wiring in a more organized and efficientway. The board helped reduce the size of the autopilot and en-abled other refinements such as the replacement of a baseball-size sensor with a small chip. As the autopilot design evolved,the system shrank from its original weight of over two poundsdown to just thirteen grams. As a result, the next version ofthe craft weighed just 20% of its predecessor.

Szmuk continues to develop smaller, higher performanceUAVs. Using PCB123 and Sunstone, he has made increasinglycomplex circuits to trim bulk and increase capabilities. Aproject funded through NASA required Szmuk to demon-strate novel guidance algorithms and build his smallest UAVto that point. These algorithms were geared towards improv-ing the autonomy of unmanned climate science missions inthe Arctic.


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Ad IndexFor free product literature, enter advertisers’ reader service num-bers at www.techbriefs.com/rs, or visit the Web site beneath theirad in this issue.

Reader ServiceCompany Number Page

Abbott Technologies, Inc. . . . . . . . . . . . . . .831 . . . . . . . . . . . .17

Aero Tec Laboratories Inc. . . . . . . . . . . . .856 . . . . . . . . . . . .43

Aurora Bearing Co. . . . . . . . . . . . . . . . . . .846 . . . . . . . . . . . .38

C.R. Onsrud, Inc. . . . . . . . . . . . . . . . . . . . . .829 . . . . . . . . . . . .15

Cobham Semiconductor Solutions .818, 852 . . . . .COV II, 42

Coilcraft CPS . . . . . . . . . . . . . . . . . . . . . . . .821 . . . . . . . . . . . . .3

COMSOL, Inc. . . . . . . . . . . . . . . . . . . .853, 858 . . . .42, COV IV

Cornell Dubilier . . . . . . . . . . . . . . . . . . . . . .835 . . . . . . . . . . . .23

Crane Aerospace & Electronics . . . . . . . .820 . . . . . . . . . . . . .2

Create The Future Design Contest . . . . . . . . . . . . . . . . . . . . .27

CST of America, Inc. . . . . . . . . . . . . . . . . . .857 . . . . . . . .COV III

DARcorporation . . . . . . . . . . . . . . . . . . . . .838 . . . . . . . . . . . .30

Dawn VME Products . . . . . . . . . . . . . . . . .843 . . . . . . . . . . . .35

Designatronics Inc. . . . . . . . . . . . . . . . . . .830 . . . . . . . . . . . .16

EMCO High Voltage Corporation . . . . . . .851 . . . . . . . . . . . .41

EPIX, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . .854 . . . . . . . . . . . .42

Gage Bilt Inc. . . . . . . . . . . . . . . . . . . . . . . . .834 . . . . . . . . . . . .22

HARTING, Inc. of North America . . . . . . .839 . . . . . . . . . . . .29

John Evans' Sons, Inc. . . . . . . . . . . . . . . . .842 . . . . . . . . . . . .34

Lemo USA, Inc. . . . . . . . . . . . . . . . . . . . . . .844 . . . . . . . . . . . .36

Lumenera Corporation . . . . . . . . . . . . . . .833 . . . . . . . . . . . .21

Lyons Tool & Die Co. . . . . . . . . . . . . . . . . . .837 . . . . . . . . . . . .25

M.S. Kennedy Corporation . . . . . . . . . . . .824 . . . . . . . . . . . . .8

Master Bond Inc. . . . . . . . . . . . . . . . .847, 855 . . . . . . . .38, 42

Maxon Precision Motors, Inc. . . . . . . . . . .836 . . . . . . . . . . . .24

MPL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .850 . . . . . . . . . . . .41

New England Wire . . . . . . . . . . . . . . . . . . .849 . . . . . . . . . . . .31

OFS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .832 . . . . . . . . . . . .19

Photonis USA . . . . . . . . . . . . . . . . . . . . . . . .841 . . . . . . . . . . . .33

PI (Physik Instrumente) LP . . . . . . . . . . . .840 . . . . . . . . . . . .32

Positronic Industries, Inc. . . . . . . . . . . . . .825 . . . . . . . . . . . . .9

Proto Labs, Inc. . . . . . . . . . . . . . . . . . . . . . .827 . . . . . . . . . . . . .11

PTI Engineered Plastics, Inc. . . . . . . . . . . .819 . . . . . . . . . . . . .1

Remcom . . . . . . . . . . . . . . . . . . . . . . . . . . . .828 . . . . . . . . . . . .13

Renishaw Inc. . . . . . . . . . . . . . . . . . . . . . . .845 . . . . . . . . . . . .37

RTD Embedded Technologies, Inc. . . . . . .823 . . . . . . . . . . . . .7

SAE International . . . . . . . . . . . . . . . . . . . .859 . . . . . . . . . . .40

Specialty Coating Systems . . . . . . . . . . . .848 . . . . . . . . . . . .39

Stratasys Direct Manufacturing . . . . . . . .822 . . . . . . . . . .4, 5

W.L. Gore & Associates . . . . . . . . . . . . . . .826 . . . . . . . . . . . .10

Publisher . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Joseph T. PrambergerEditorial Director – TBMG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Linda L. BellEditorial Director – SAE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Kevin JostEditor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bruce A. BennettManaging Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Jean L. BrogeManaging Editor, Tech Briefs TV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Kendra SmithAssociate Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Billy HurleyAssociate Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Ryan GehmProduction Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Adam SantiagoAssistant Production Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Kevin ColtrinariCreative Director . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Lois ErlacherDesigner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bernadette TorresGlobal Field Sales Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Marcie L. HinemanMarketing Director . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Debora RothwellMarketing Communications Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Monica BondDigital Marketing Coordinator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Kaitlyn SommerAudience Development Director . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Marilyn SamuelsenAudience Development Coordinator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Stacey NelsonSubscription Changes/Cancellations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]

TECH BRIEFS MEDIA GROUP, AN SAE INTERNATIONAL COMPANY261 Fifth Avenue, Suite 1901, New York, NY 10016(212) 490-3999 FAX (212) 986-7864Chief Executive Officer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Domenic A. MucchettiExecutive Vice-President . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Luke SchnirringTechnology Director . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Oliver RockwellSystems Administrator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Vlad GladounWeb Developer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Karina CarterDigital Media Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Peter BonavitaDigital Media Assistants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Keith McKellar, Peter Weiland, Anel GuerreroDigital Media Audience Coordinator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Jamil BarrettCredit/Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Felecia LaheyAccounting/Human Resources Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Sylvia BonillaAccounting Assistant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Martha SaundersOffice Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Alfredo VasquezReceptionist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Elizabeth Brache-Torres

ADVERTISING ACCOUNT EXECUTIVESMA, NH, ME, VT, RI, Eastern Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Ed Marecki . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Tatiana Marshall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .(401) 351-0274CT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Stan Greenfield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .(203) 938-2418

NJ, PA, DE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .John Murray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (973) 409-4685Southeast, TX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Ray Tompkins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .(281) 313-1004NY, OH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Ryan Beckman . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .(973) 409-4687

MI, IN, WI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Chris Kennedy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .(847) 498-4520 ext. 3008MN, ND, SD, IL, KY, MO, KS, IA, NE, Central Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bob Casey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .(847) 223-5225Northwest, N. Calif., Western Canada Craig Pitcher (408) 778-0300

CO, UT, MT, WY, ID, NM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Tim Powers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .(973) 409-4762S. Calif., AZ, NV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Tom Boris . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (949) 715-7779S.

Europe — Central & Eastern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Sven Anacker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49-202-27169-11Europe — Western . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Chris Shaw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44-1270-522130Hong Kong . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Mike Hay

852-2369-8788 ext. 11China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Marco Chang . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86-21-6289-5533 ext.101Taiwan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Howard Lu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .886-4-2329-7318Integrated Media Consultants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Patrick Harvey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (973) 409-4686 Angelo Danza (973) 874-0271 Scott Williams (973) 545-2464 Rick Rosenberg (973) 545-2565 Todd Holtz (973) 545-2566Corporate Accounts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Terri Stange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (847) 304-8151Reprints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Jill Kaletha . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .(866) 879-9144, x168

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