Miller Nitro 7310 - Four Wheel Steer (4 WS) if Equipped; Operation Characteristics

4-OPERATINGINSTRUCTIONS
FourWheelSteer(4WS)ifequipped
Yourvehiclemaybeequippedwithfourwheelsteer
(4WS)steering.Thefollowingaredescriptionsand
operatingstepsfortheuseof4WS.
FourWheelSteer(4WS)modes
TheFourWheelSteer(4WS)optionprovidestheoperatorwithanchoiceoftwosteeringcontrolmodes;TwoWheel
Steer(2WS)andFourWheelSteer(4WS).Thereisasignicantdifferenceintheoperationofthemachinebetween
thesetwomodes.The2WSmodeprovidesforbettercontrolofincreasedguidancebutpreventstheoperatorfrom
makingtightturns.The2WSmodeisdesirablewhenoperatingathigherspeeds,orwhenmoreprecisevehiclepo-
sitioningisrequired.The4WSmodehelpsthevehiclereducesoildisturbanceandcropdamage.4WSalsoprovides
forquickervehicledirectionchanges(tightturning),toassistminorpathcorrections(guidance).
NOTE:Careshouldalwaysbetakenonhills,4WSoperationdoesnotreducetheprobabilityofroll-over.
Operationcharacteristics
In4WSmode,therearwheelsteeringangle100%matches,orcoordinates,withthefrontwheelsatspeedsfrom0
to8mph.Twomeasuresof4WSperformancearetrackingandactualcropdamage.Trackingperformancevaries
withtherelationshipbetweensteeringwheelspeedandvehiclespeed.Thebesttrackingoccurs,drivingstraight
orinturns,whenthesteeringwheelpositionissetandheldconstant,andthevehiclehastraveledforwardbeyond
onewheelbaselength.Thebestreductionofcropdamageoccurswithpracticedcoordinationofvehiclespeedand
steeringwheelspeed.Below8mph,trackingperformancealsodependsuponotherfactors,includingtheamountof
tractionavailable,topographyoftheoperatingarena,soiltypeandmoisture,vehicleweightanditsdistribution,and
theamount,typeandmoisturecontentofanyvegetativelayer.Thesefactorscontributetolateralslipofthefrontand
reartires,resultinginlesswheeltrackingandpossibledamagetocrops.
Above8mph,lateralwheelslipandvehiclestabilitybecomemorepronounced.Therearwheelsteeringcommand
isreduced,proportionaltoincreasingspeed,from100%matchingofthefrontwheelsat8mphto35%matchingat
12mphandabove.Also,thesystemwilldisengage4WSmodeentirelyinthehigherspeedranges.Thehigher
speedrangesare3rdand4thspeed.Uponswitchingtotheseranges,themachinewillrevertto2WSmode,whether
ornot4WSistheselected.Ineithercase,whenin2WSmode,themachinewillturntherearwheelsstraightand
thenhydraulicallyengagemechanicallocksbuiltintotherearkingpins.Thelocksaresupplementalsecurity,andare
intendedtokeeptherearwheelsstraightincaseofhydraulicorelectricfailure.Innormaloperation,thesteering
cylindersdeterminetherearwheelsposition,andthelocksareneverresponsibleforholdingthetoe.
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