Whitepaper 5G and Mobile Robotics - HMS Networks

Whitepaper

Scaling for the future of robotics. 5G and Mobile Robotics

© 2019 HMS Industrial Networks Inc. All rights reserved. www.hms-networks.com

2

5G and Mobile Robotics

HMS Industrial Networks Inc.All rights reserved.

Introduction

Mobile Robotic Market................................................pg. 4

Understanding the Ecosystem.................................pg. 5

Wireless Networks for Mobile Robots Today.....pg. 7

802.11 Limitations and Considerations................pg. 8

Addressing Challenges with 5G Cellular..............pg. 10

Conclusion....................................................................pg. 14

Table of Contents

3



IntroductionMobile robotic systems such as Unmanned Ground Vehicles, Unmanned Surface Vehicles, Unmanned Aerial Vehicles and Autonomous Underwater Vehicles are becoming increasingly prevalent today with a broad number of applications including defense, medical, logistics, manufacturing support and personal use. With the rise of Artificial Intelligence and Machine Learning, many of these systems can function in autonomous or semi-autonomous states.

For the sake of this paper, the focus will be on mobile robotic uses in the manufacturing space and how communications will need to evolve to account for the specific needs of this use case.

“Our products connect millions of devices around the world and enable our customers to widen their market and improve their business. HMS‘ long expertise, large installed base, and wide market coverage, make us the undisputed market leader of our field. HMS stands for Hardware Meets Software™ . HMS products, solutions and know-how enable industrial hardware to get connected to IoT software. As such, HMS enables the Industrial Internet of Things which is all about Connecting Devices™ “

Staffan Dahlström, CEOHMS Networks

4



Mobile Robotic MarketTogetsomeperspectiveonhowcriticalthiswillbecomeovertime,itisbeneficialtogainsomeperspectiveonhowfastthemarketisgrowing.Iftheentirescopeofapplicationsareconsidered,someestimatessizethemarketat$54.1Bby2024($18.7B2018)whichamountstoa23.71%CAGR,butifthefocusisnarrowedtoAutonomousGuidedVehicles(AGV)thatareusedinlogisticsandmanufacturingsupportthemarketisexpectedtoreacharound$12Bby2025withanestimated15.8%CAGRasshowninFigure1.Thisisbasedonaroughaveragingofmultiplesourcesasdataissomewhatvariable.

The key takeaway when looking at the market growth for these devices is that they are going to continue to be a significant and increasing part of our manufacturing and logistics environment.

Asnumeroushumanworkersoccupythesespaces,itwillbecriticaltoensurethatthesesystemscancoexistsafely.Inthispaper,wewilladdresshowthesesystemsworkintheircurrentecosystems,thechallengesthatarepresentedandhow5Gcommunicationstechnologycouldbeusedtoaddresssomeofthesechallenges.

Figure 1

5



Understanding the EcosystemTounderstandhowcommunicationsmustevolvetomeettheneedsofmobileautomation,ithelpstounderstandtheecosystemwithinawarehouseormanufacturingplanttheyoperatein.WhenoneconsidersAGVs,theyoftendonotsimplyconsistofthebasevehiclebutareoftenintegratedwithotherautomatedcomponentsforassemblingorpositioningmaterial.

Thesesystemsalsointeractwithothermachineryinawarehouseorfactory.Figure2providesasnapshotofthepotentialecosystemthatmobilerobotsworkin.TheAGVitselfmanagesmostofitsinternal controls from the AGV Controller that interacts with control systemsforSteering,Drive,PowerandCollisionAvoidance.

ThesesystemstypicallycommunicateoverdeterministiccontrolnetworksbasedontechnologiessuchasCANorindustrialEthernet(ex.EtherCAT,EtherNet/IP,PROFINet,etc.)asthedataexchangediscriticalforcoordinatedcontrolfunctionsandsafeoperation.Withintheseself-containedsystems,thedevicesaretypicallyoncopper-basednetworkssowirelesscommunicationsisseldomlyrequired.

Figure 2

6



AGVsaremostofteninterconnectedwithsomeformofroboticsystemonthevehicle.Acoupleofexampleapplicationswouldbeoperatingaliftsystemfortransportingmaterialonpalletsorracks,orasamobileloaderplacingmaterialintoorremovingmaterialfromamachinecell.TheseroboticcontroltasksmaynotbeintegratedintotheAGVcontrollerbutoperatedbyaseparatecontroller.Thiscontrolsystemdoeshoweverneed to be interlocked with the AGV controller as their tasksarecooperativeinnatureandwhiletheyareseparatecontrolsystems,theyareoftenintegratedontothesamecopper-basednetwork.

ThenavigationfortheAGVishandledbysomeformoftrafficmanagementsoftwarewhichappliesmapsofthefacilitytheAGVisoperatingintodopathoptimization.Thismaybeastand-aloneapplicationorintegratedintoaWarehouseExecutionSystem.SincetheseapplicationsrunoutsideofthelocalcontrolnetworkoftheAGVtypicallyonPCsorservers,itisnotfeasiblefortheAGVtointeractoveraphysicalmediumsowirelesstechnologiesareusedfortheseinterfaces.

ThisisalsotruefortheplantorwarehousemachinerythattheAGVandroboticsystemneedtointeractwithduringtheperformanceofitstasks.Theseincludebutarenotisolatedtostaticsystemssuchasmanufacturingcells,automatedstorageandretrievalsystems,roboticcellsandautomatedconveyors.Wirelesscommunicationsallowcriticalcontrolandsafetydatatobeexchanged.

Itisimportanttounderstandwhattypeofdataistypicallyexchangedinthesesystemsandhowimportant

networkreliabilityisforcertaintypesofinformation.Slow-movingvariablessuchaspowerlevelsorotherenvironmentalmeasurementscanbemoretolerantofnetworkinconsistencieswhilecontrolandsafetydataneedtopassoverextremelyreliablenetworkswithconsistenttimecycles.Itisdifficultforamanufacturingprocesstobeproductiveiftherearenetworkerrorswhenamobilerobotistryingtointeractwithamachinecellandneithersystemcaneffectivelymoveforwardintheirtaskwithoutthedataexchanged.

Inthispaper,wewilloftenreferbacktosafetydataduringthefollowingtopics.Formerly,safetycircuitryhadtobehard-wiredandcouldnotmoveoveranetwork,butthishasshiftedandtherenowexistsafetynetworkprotocolssuchasCIPSafety,PROFIsafeandFSoE(FunctionalSafetyoverEtherCAT)amongothers.Inadditiontorunningovercopper-basednetworks,thisdatacanmoveoverwirelessnetworksaswell.Thekeywithsafetydataisthatthenetworkandthedataisreliable,notnecessarilyfast.

Mostnetworksmeasurenetworkreliabilityintermsofpacketloss,butthisislessimportantforsafetydata.Thesafetyprotocolscanhandlepacketlossthoughtheminimumsafereactiontimemaybeimpacted.Safetyapplicationsarefarlesstolerantofbiterrorssincethisbringsintoquestiontheintegrityoftheunderlyingdata.

SafetyprotocolsrunningoverEthernettypicallyhavearesidualbiterrortoleranceoflessthan1outof100bits.Unreliablenetworkconnectivitycanleadtoburstsofthesebiterrorssendingthesafetynetworkintoafaultstate.

7



ThemostcommonlyusedtechnologyforwirelessconnectivitytomobileroboticsystemsisbasedontheIEEE802.11xsetofstandardscommonlyknownasWi-Fi™.Thesenetworkstransmitatpubliclyavailablefrequencieswithineitherthe2.4GHzor5GHzspaceandareslicedintochannelsusually20MHzor40MHzwide(adjacentchannelsbonded).

Thesechannelsareessentiallythepipesthatdatacanpassthroughandthewidthofthesechannelssignificantlyimpactsthroughputinthesystem.Overtime,theIEEE802.11xspecificationhasevolvedtoincorporatechangesinareassuchasradiomodulationandantennastructure(MIMO)toimproveoverallsystemthroughputandreliability.Updatedstandardssuchas802.11nand802.11accanrealizenetworksspeedsofseveralhundredbitspersecond

802.11x-basednetworksarebasedonthelowerlayerEthernetprotocolsforitsnetworkstructurewithbothitsuseofMACaddressingforuniquedeviceidentifiersand

Wireless Networks for Mobile Robots-TodayIPprotocolsforlogicalnetworkaddressing.Thisgivesaroughnetworkcapacityof255devices(includingAccessPoint)onasinglesubnetwork

Oneamendmentunder802.11thatisheavilyusedinmobileautomationapplicationsis802.11r,whichisaprovisionforfastroamingbetweenaccesspoints.802.11alreadyhassupportforroamingbutinnormaloperationthisrequiresre-authenticationwhentransitioningbetweenaccesspointswhichcanresultinreconnecttimesamountingtoseveralseconds,whichcanbeunacceptableinautomationapplications,particularlywithcontrolandsafetydata.

With802.11r,theauthenticationkeycanbecachedallowingtransitiontimestobereducedtoafewmilliseconds(30-50mstypically).Figure3showsanexampleof802.11rinaction.Withthehigherthroughputwirelessstandards(802.11nand802.11ac)plus802.11rfastroaming,802.11hasgainedgreateracceptanceinsidethefactory.

Figure 3

8



Wirelessisbeingeffectivelyusedtodayforsomechallengingapplicationsbutlikeanycommunicationstechnology,therearelimitationsinperformancethatmustbeconsideredwhenimplementing.Forthesakeofthispaper,wewillconsiderfactorsthatimpactscalabilityandreliabilityof802.11-basednetworks.

Thereareacoupleoffactorsthataffectthescalabilityof802.11-basednetworks.WhilethetheoreticallimitationofasingleIP-basedsubnetworksegmentis255devices,thepracticallimitationissignificantlyfewerdevices.Thisisduepartiallytothefactthat802.11channelsat2.4or5GHzaretypically20MHzor40MHzwideandthatalldevicesonthenetworkneedtosharethatchannel.Asthenumberofdevicesincrease,smallerslicesofbandwidthareavailableforeachdevicetopassdatathroughwhichcanimpactperformanceoftheoverallsystem.Specifically,forsafetydata,thismaymeanthatlongertimeoutsneedtobeusedandthattheminimumsafereactiontimemaybelongerthandesiredfortheapplicationinquestion.Inthosecases,thenetworkmayneedtobede-scaledtoallowforenoughbandwidthtothedevicesonthenetwork.

Additionally,802.11isbasedonpubliclyavailable,unlicensedfrequencies,whichmeansthatthechannelsmaybesharedbymultiplenetworks,furtherreducingtheamountofavailablebandwidth.Thisisdifficulttoavoidat2.4GHzfrequenciesasthereexistonlyfour(4)non-overlappingchannelsthatcanbeusedfornetworksanditshouldbeexpectedthat2.4GHzchannelswillbeshared.

Higherthroughputchannelsinthe5GHzspectrumaremorereadilyavailablewithfeweroverlappingfrequenciesandarebeingincreasinglyusedforcriticalapplications.Thiswillcomeunderstrainovertimeasmorenetworksareconfiguredinthe5GHzspace.Reliabilitycanalsobeachallengewhenusing802.11-basednetworks.Thebiggestfactorthatimpactsnetworkreliabilityissignalinterference,particularlyat2.4GHzfrequencies.

Aspreviouslymentioned,thesefrequenciesareavailablepubliclyandwhile2.4GHzismostcloselyassociatedwith802.11networks,thisfrequencyisusedbyotherdevicesandcommunicationstechnologiesincludingcordlesshandsets,microwaveovens,BluetoothandZigbeeamongothers.Inadditiontoaccountingforthedensityofnetworksinthespectrum,thenoisegeneratedbytheseotherdevicescanhavesignificantimpactonthequalityofcommunications.

802.11 Limitations and Considerations

9



Figure4belowfeaturesanexamplefromaspectrumanalyzerofamanufacturingfacilityfeaturingbothsignificantcongestiononthe2.4GHzassignedchannelsandsignificantnoisefromothersignalgeneratorsinthespectrum,includingother802.11networksonnearbyfrequencies.ThesumofthesesecondarysignalsisreferredtoasthenoisefloorandthedifferencebetweenthisnoisefloorandtheoverallsignalstrengthisreferredtoastheSignal-to-NoiseRatio(SNR).WhentheSNRistoolow,packetslossandbiterrorscanoccurleadingtofaultstatesorlossofcriticaldata.Thisparticularlyimportantwhenlookingatsafetydata,whichaspreviouslymentionedissensitivetobiterrorsandisacriticalpartofthemobileroboticssystem.

Inadditiontocongestion,thepresenceofphysicalobjectscanimpactthereliabilityofwirelesscommunications.Inaperfectenvironment,wirelesstransceiversconnectwitheachotheroveropenair,butthisisnotpracticalinamanufacturingenvironment,astherewillbemachineryandbuildingstructurestocontendwith.Absorption

orreflectionofwirelesssignalsbystructurescansignificantlyreducetheeffectiverangeofthesenetworksandcreateholeswheresignalsmaybelostcompletely.Materialssuchassolidmetalsandconcreteprovidethebiggestchallengesforwirelesssignals.Lossofsignalcanleadtobiterrorsandtimeouts,whichcannegativelyimpactsafetycommunications.

Thepracticeofroamingbetweenaccesspoints,whichistobeexpectedinmostmanufacturingfacilities,canalsohavenegativeimpactsoncriticalcommunications.802.11rmitigatesthissignificantly,butifthereareanyissuesduringre-authenticationthatextendsthehand-offsignificantlypastthenormal30-50mstimeframe,thiscancreatepacketlossandbiterrorsthatcansignificantlyimpactcontroldataandsafetydata.

Figure 4

10



Addressing Challenges with 5G CellularItisimportanttostatethat5Gcellulartechnologyisstillemergingandcurrentimplementationsarelimited,howeverthereismuchthatisbuiltintothisnetworkthatwilladdressmanyofthechallengescurrentlyposedbyotherwirelessnetworks.Additionally,muchhasbeenwrittenaboutthecorecapabilitiesofeMBB(EnhancedMobileBroadband),uRLLC(Ultra-ReliableLowLatencyCommunications)andmMTC(MassiveMachine-TypeCommunications)andwillhavelimitedmention.

Thefirstchallengetofocusonisthecomplicationsposedbyrunningcriticalcommunicationsformobilerobotsinunlicensedfrequencies.With5G,youhaveamixtureoflicensedandunlicensedbands(5GHzspectrum).Figure5showstherangeoffrequenciesthatwillbepartofthe5Gspectrum.OnesliceofspectrumtomakenoteofinNorthAmericaisthe3.5(3.55-3.7)GHzbandknownasCBRS(CitizensBroadbandRadioService)whichhastraditionallybeenreservedfornavalradarcommunications.

Thishasbeenreleasedtobeusedforsemi-privatenetworks.Insteadofhavingtorequestalicenseforspectrumfromagovernmententityorpurchaseaprivatenetworkfromapublicprovider,manufacturerscanrequestabandfromaSpectrumAllocationServerthatthenassignsthebandbasedonterrainandRFdensitycalculations.Thebenefittothemanufactureristhataslongastheyareusinglowerpowerradiostheycanhavewirelessspectrum

thatisspecificallyallocatedtotheirfacilitywithoutinterferencefromothernetworks.Thisincombinationwiththehighspeed(<20GBPS)andlowlatency(<1ms)characteristicsof5Gmakethisfeasiblefortransmittingthecriticalcontrolandsafetydataassociatedwithmobilerobots.

Anotherchallengethat5Gtechnologyhelpsaddressistheimpactofphysicalstructuresonreliablewirelesscommunications.Whileanywirelesssignalisimpactedbystructures,5Gcanusereflectedsignalsinabeneficialway.5Gsupportstheuseofahigh-densityantennaconstructknownasmassiveMIMO(Multi-InputMulti-Output)andbeamformingtooptimizeconnectionpathways.

Transmitterscanbroadcastsignalsinmultipledirectionswhilethereceiverseesmultiplecopiesofthesamesignalwhichistheneitherdestructivelyaveragedifoutofphaseorconstructivelysummedifinphase.Thisincreasesthereliabilityoftheseconnectionswiththeaddedbenefitofincreasingthroughputaswell.Withmorereliableconnectivity,criticalcommunicationsforcontrolandsafetycanbemaintained.Figure6showsasimplifiedviewofamulti-pathsystemofBaseStations(BS)andenddevices(ex.AGV)inamanufacturingenvironment.

11



Thefinalchallengewewilladdressishandovertimesassociatedwithroaming.While802.11-basednetworkssupporting802.11rminimizehandovertimestoafewmillisecondsthiscanstillimpactcriticalcommunications.5GtechnologyaddressesthisbyallowingdevicestomakeconnectiontootherbasestationsbeforeseparatingfromapreviousbasestationasshowninFigure7.Thisallowsforseamlesscommunicationsonthe5Gnetworkandeliminatesthepossibleissueoftimeoutsandbiterrorsduringhandovers.

Thefinalquestioniswhetherthiscanbescaledtomeetagrowingmarketformobilerobotics.Whileitisnotexpectedthatmobileroboticswillbedeployedtothisscale,withsupportformMTC(MassiveMachineTypeCommunications)serviceon5G,networkdensitycanachieveupto10⁶devices/km².

Figure 6

Figure 7

12



AfterwordWirelesstechnologiesaregainingacceptanceinmanufacturingastheneedtoincreasecapacitywithinalimitedphysicalfootprintdrivestheneedformobileroboticsystemsthatcanbeflexiblydeployed.Withexistingwirelesstechnologystillpresentingsometechnicalhurdles,maximizingproductivityofthesesystemscanbechallenging.5Gcommunicationsaddressesmanyofthesechallengesandlookstohavesignificantlong-termimpactoncommunicationsinmanufacturing.

Therearealotofconsiderationswhenitcomestoaddressingconnectivityonmobileequipmentbutfortunatelysolutionsexisttoensurethatcriticaldatawillbeavailablewhenneeded.

AutomatedGuidedVehicles(AGVs)areincreasinglybeingusedinmanufacturingandwarehouseoperationsfordeploymentofrawandfinishedgoods.Theyemploycomplexsystemsformotion,safety,powermanagementandtrafficmanagementoftenusingmultiplecommunicationstechnologies.Oneofthebiggestchallengesisensuringthatthesesystemsareinterconnectedsodatacanmoveseamlesslybetweendifferentcontroltasks.JoinHMSNetworksforthis30-minutewebinartolearnhowwecanhelpyouovercomethesechallenges.

AsSolutionManagerforHMSNetworks,JasonBlockhelpsHMScustomersanddistributorsenableIIoTbysolvingchallengingapplicationsfornetworkinterconnectivityandremotemanagementusingourAnybus,IXXAT,andeWONproductlines.Withover20yearsofexperience,hebringsvaluetocustomersasananalytical,consultativesalesprofessional.

Jason BlockSolution ManagerHMS Networks

PartNo:USSP001Version404/2019-©HMSIndustrialNetworks-Allrightsreserved-HMSreservestherighttomakemodificationswithoutpriornotice.

www.hms-networks.com

HMS Industrial Networks – a global company with local presence

HMS - Sweden (HQ) Tel:+4635172900(HalmstadHQ) E-mail:[email protected]

HMS - China Tel:+8601085323183 E-mail:[email protected]

HMS - France Tel:+33(0)367880250(Mulhouseoffice) E-mail:[email protected]

HMS - Finland Tel:+358404557381 E-mail:[email protected]

HMS - Germany Tel:+49721989777-000 E-mail:[email protected]

HMS - India Tel:+918380066578 E-mail:[email protected]

HMS - Italy Tel:+390395966227 E-mail:[email protected]

HMS - Japan Tel:+81454785340 E-mail:[email protected]

HMS - Singapore Tel:+6590886335 E-mail:[email protected]

HMS - Switzerland Tel:+4161511342-0 E-mail:[email protected]

HMS - UK Tel:+441926405599 E-mail:[email protected]

HMS - United States Tel:+13128290601 E-mail:[email protected]

Work with HMS Networks. The number one choice for industrial communication

and IIoT.

Documents

Whitepaper 5G and Mobile Robotics - HMS Networks