Hybrid design combining position and rate control allows intuitive workspace extension for ...

67 Pages·2015·10.99 MB·English

Hybrid design combining
position and rate control
allows intuitive workspace
extension for teleoperation
Maria J. Voskuil
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H
YBRID DESIGN COMBINING POSITION AND
RATE CONTROL ALLOWS INTUITIVE
WORKSPACE EXTENSION FOR
TELEOPERATION
by
MariaJ.Voskuil
inpartialfulfillmentoftherequirementsforthedegreeof
MasterofScience
inAppliedPhysics
attheDelftUniversityofTechnology,
tobedefendedpubliclyonWednesdayJune3,2015at10:00AM.
Supervisor: Dr.ir.D.A.Abbink
Thesiscommittee: Ir.R.J.Kuiper, TUDelft
Ir.J.G.W. Wildenbeest, TUDelft
Dr.Ir.R.vanPaassen TUDelft
Anelectronicversionofthisthesisisavailableathttp://repository.tudelft.nl/.

P
REFACE
ThismasterthesisisthefinalresearchformymasterinMechanicalEngineeringandisdevelopedincooper-
ationwithandundersupervissionofthetheHapticsLabfromtheTUDelft. Inmybachelor,Ilearntalotof
theorythatshouldeducatemetoaengineer.Therefore,mymasterthesiswasverychallengingforme:using
mytheoreticalknowlegdetobuilda“real”measurementset-upandalsomakethisrobustforthedifferent
tacticshumansuse. Stepbystep, Igotmorefamiliarwiththematerialandtheexperimentalset-upandI
alongtheprocesIgotmoreandmoreenthousiasticformyresearch. Therefore,Iamproudtopresentmy
results.
Thegoalofmyresearchwastodetermineifahybriddesign,combiningbothpositionandratecontrol
withinonedesign,improvesperformanceforataskcombininglargeaccuratefree-spacemotionandaforce
taskwithrespecttoindexingorratecontrol. Thefocusofthisresearchwasimplementingthehybriddesign
anddevelopingawithinsubjecthuman-in-the-loophapticteleoperationexperiment. Thepaperprovidesa
conciseinformationaboutthegoal,thehybriddesign,theexperimentalset-upandtheresultsandispre-
sentedaccordingtotheIEEEWorldHapticsConference2015lay-outbecausethispaperwillbesubmitted
aftermygraduation. Theappendicesincludemoredetaileddescriptionofthesectionsinthepaper. Thisis
meantforresearcherswhowanttoobtainmoreinsightinmyresearchandresults,orwanttoreproduceor
continuewithmyresearch.
WorkpresentedinthismasterthesiswasmadepossiblebytheHapticsLabfromtheTUDelft. Iwould
like to thank my supervisors: David Abbink, Roel Kuiper en Jeroen Wildenbeest for their help throughout
the process. Besides interesting conversations about the goal and content of this research and providing
constructivefeedback, theyalsoprovidedsupportduringthementalupanddownsthatarepartofdoing
yourmasterproject. IalsowouldliketothankSuzanneWeller,MarleenvanCharlottePaiman,Nienkevan
DrielandIngeKalsbeekfortheirhelpandsupport. Forayear,weconductedresearchformasterthesisat
3Me.andthisreallygavememotivationtokeepupthehardwork.
MariaJ.Voskuil
Delft,June2015
iii

C
ONTENTS
1 Paper:Hybriddesigncombiningpositionandratecontrolallowsintuitiveworkspaceextension
forteleoperation 1
A AppendixA:Threeworkspaceextensiondesigns:free-spacemotionandforcefeedback 11
A.1 Indexing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
A.2 Ratecontrol. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
A.3 Hybriddesign. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
A.3.1 Additionsmadetoselectedhybriddesignsfromliterature. . . . . . . . . . . . . . . . . 14
B AppendixB:Modelinginteractionbetweenvirtualslaveandenvironment 19
B.1 Schematicmodel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
B.2 Assumptionsformodelsimplification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
C AppendixC:Definitiontaskexperimentandparameters 23
C.1 Definetaskexperiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
C.2 DefinealltaskandWESdesignparameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
C.2.1 Taskspecificparameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
C.2.2 ConstantparametersWESdesigns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
C.2.3 Constantparametersdynamicsproperties . . . . . . . . . . . . . . . . . . . . . . . . 26
D AppendixD:ImplementationallthreeWESdesignsinSimulink 27
D.1 Subsystem1:CalculatepositionslaveforallthreeWESdesigns. . . . . . . . . . . . . . . . . . 28
D.1.1 Positionslaveforindexing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
D.1.2 Positionslaveforratecontrol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
D.1.3 Positionslaveforhybriddesign . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
D.2 Subsystem2:ImplementationinteractionforceslaveandvirtualenvironmentF . . . . . . . . 35
e
D.3 Subsystem3:Implementationtaskcriteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
D.4 Subsystem4:ImplementationForcefeedback . . . . . . . . . . . . . . . . . . . . . . . . . . 36
D.5 Subsystem5:Implementationsafety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
E AppendixE:Experimentalset-up 39
E.1 Experimentalset-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
E.2 Visualfeedback. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
F AppendixG:PilotExperiment 43
F.1 Experimentalprotocolpilotexperiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
F.2 Resultspilotexperiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
F.3 Discussionandconclusionpilotexperiment . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
F.4 Consequences/discussionforfinalexperiment. . . . . . . . . . . . . . . . . . . . . . . . . . 49
G AppendixH:ResultsExperiment 51
G.1 Rawdatafromexperiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
G.2 Definitionandcalculationmetrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
G.3 Resultsmetricsforeachtrial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
G.4 Resultsone-wayrepeatedAnova . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
G.5 Posthoc:Taskperformanceandeffort. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
G.5.1 Posthoc:Subtaskfree-spacemotionmetrics. . . . . . . . . . . . . . . . . . . . . . . . 56
G.5.2 Posthoc:Subtaskexertingaforcemetrics . . . . . . . . . . . . . . . . . . . . . . . . . 57
G.5.3 Posthoc:Totaltaskmetrics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Bibliography 59
v

1
Hybrid design combining position and rate
control allows intuitive workspace extension for
teleoperation
Maria J. Voskuil, Roel J. Kuiper, Jeroen G.W. Wildenbeest, David A. Abbink
Abstract—
Acommonmethodtoobtainworkspaceextensionoftheslave’sworkspaceisthroughratecontrolbecauseithasanunlimited
workspaceoftheslave.However,whencontactinteractionwiththeremoteenvironmentisneeded,positioncontrolisoftenproposed
duetotheforcefeedback.Tobenefitfromthestrengthsofbothofthesecontroltypes,hybriddesignshavebeenproposedwhich
combinebothpositionandratecontrolwithinonedesign.Humanfactorsevaluationislackingtocomparebenefitsandlimitationsof
hybriddesignsagainstthetwocommonappliedworkspaceextensiondesigns:indexingandratecontrol.Noneofthehybriddesigns
wereevaluatedforvarioustaskssuchasaforcetask.Therefore,theobjectiveofthisstudyistoevaluateifahybriddesigncan
combinethestrengthsoflargefree-spacemotionforratecontrol,andaccuratepositioningandexecutingaforcetaskforindexing.In
thisresearch,ahybriddesignwasdeveloped(basedonexistingdesigns)inwhichforcefeedbackforratecontrolwasadded.Awithin
subjecthuman-in-the-loophapticteleoperationexperiment(N=12)wasperformedtocompareperformanceforthishybriddesign
againstindexingandratecontrolforataskincludingtraversingasubstantialdistance(free-spacesubtask)andexertingaconstant
forceagainstaremoteenvironment(forcesubtask).Theresultsshowthatthehybriddesignallowedsubjectstorealizesimilar
performanceforthesubtaskfree-spacemotionasforratecontrol,incombinationwithsimilarperformanceforthesubtaskexertinga
forceasforpositioncontrolwithclutching.Thisindicatesthatthishybridworkspaceextensiondesignenablestheoperatortousethe
benefitsofpositionandratecontrol.
IndexTerms—Teleoperation,Indexing,positioncontrolClutching,Ratecontrol,Hybriddesign,Hapticexperimentaldesign
F
1 INTRODUCTION master, controller and the slave and is shown in Figure 1.
In this example of a teleoperation system the Workspace
Teleoperationenablehumanstoperformataskinaremote Extension Subsystem (WES) is included in the controller.
or hazardous environment at different scales and finds its The WES determines how the dimensions of the masters’
applicationindifferenttypeoffieldssuchasinhealthcare, workspacecommandtheslaves’workspace.
nuclearpowerplantsorindeepsea[11][16].Inmanycases The two common used control methods to extend the
forfree-spacemotion,theslaveneedstobeabletotraverse workspace of the slave with respect to the master are
largermotionsthanthemasterdeviceallows.Teleoperation position control and rate control. For position control, the
can be used for different type of tasks such as free-space position of the master commands the position of the slave.
motion, contact transition tasks, constrained position tasks For rate control, the position of the master commands the
andforcetasks[22].Anexampleofataskincludingmultiple velocityoftheslave[15].
types of tasks is a robot that performs maintenance in a
nuclear power plant. The robot needs to traverse large dis-
tancetowardsthecomponentrequiringmaintenance.Once
therobothasarrivedatthatcomponent,accuratemotionis
required in which the interaction force between the robot
andtheenvironmentshouldbecontrolledsotherobotdoes
not damage its environment [5]. Another similar example
combiningmotionandaforcetask,butonverysmallscale,
is surgery. Even though the scale is different, accurate free-
spacemotionshavetobecombinedwithaccuratelyexerting
Fig. 1: System model with five subsystems of a human operator
forcesagainstthetissue[1].
controllingateleoperatorthatinteractswiththeenvironment,in
To understand how teleoperation works, one should
whichtheworkspaceextension(WES)includesacontroller,based
understandthethreemainsubsystemsofateleoperator[22]. on[8][23]
Thetotalsystemconsistofthehuman,theteleoperatorand
the environment. The human controls the master, which Ingeneral,positioncontrolisusedforshortandprecise
configuration is transformed to the configuration of the movement, accurate placing task or for performing a task
slavebythecontroller,theslaveinteractswiththeenviron- that requires contact of the slave with an object in the
ment[8].Theteleoperatorconsistsofthreesubsystems:the environment. The advantage of position control is that it
2
provides natural force feedback about the interaction force ofthemasterdeviceis,thehigherthescalingfactor.Conse-
of the slave with the environment [21] due to the cou- quentlyfinemovementscanbeaccomplishedbymovingthe
pling between the master and the slave. This natural force master with a low rate. On the other hand, coarse motions
feedback has been proven to improve task performance, can be accomplished by high rates of the master [9] [15].
sinceoperatorscanmakeamoreaccurateestimationofthe Conti implemented a drift to shift the physical workspace
exerted force by the slave in its environment [20] [21]. The ofthemasterdevicewithrespecttothevirtualenvironment
disadvantageofpositioncontrolisthattheworkspaceofthe of the slave without the human operator consciously per-
slave is limited due to limitations of the workspace of the ceiving this drift [9]. The higher the rate of the master, the
master [15]. Position control can also include an additional largerthedriftcanbewithouttheoperatornoticingthedrift.
mode, called clutching, in which the master and the slave Both designs have the disadvantage that large workspaces
are decoupled. This decoupling enables the operator to of the slave can only be achieved at high speeds of the
move the master back to its origin without moving the master. To make results applicable for both fast and slow
slave, restore the coupling between the master and slave, dynamic systems, therefore this category was not used in
and repeat the motion of the master to further extend thisresearch.
the workspace of the slave [15]. This type of workspace Inthesecondcategory,thepositionofthemasterdeter-
extensiondesignisreferredtoasindexing.. mineswhichtypeofcontrol,positionorrate,thatisusedto
Rate control is commonly applied for achieving large commandtheslave.Differentapplicationsofthishavebeen
workspace extension of the slave [9] [17]. Since the master developed and all validation experiments only included
commandsthevelocityoftheslave,aconstantvelocitycan free-space motion and positioning of the slave. Dominjon
be achieved for large motions of the slave. However, con- [10] compared performance of such a hybrid design with
trollingthevelocityoftheslavemakesaccuratepositioning scaling and indexing (both position control WES designs)
more difficult because there is no direct coupling between inanexperimentincludingmotionandpaintingaface.The
the motion of the master and slave. Most applications of totaltasktime(paintingandnotpainingtimetogether)was
rate control do not include natural force feedback but co- higher for indexing than for scaling and the hybrid design
ordinated force feedback [20]. Co-ordinated force feedback andscalinghadlessaccuratemotions.Therefore,Dominjon
enables the operator to perceive the position of the master didnotprovethathishybriddesignoutperformedscaling.
in which the commanded velocity of the slave is zero and Barrios [3] performed a similar experiment to Dominjon
is implemented as a static spring around the origin of the andperformedtheexperimentforthehybriddesignversus
workspace of the master. This co-ordinated force feedback scaling.BarriodrewsimilarconclusionsasDominjons.
doesnotincludeinformationabouttheinteractionforceFe Casiez[?Casiez2007a]alsodevelopedasimilardesign
so the operator cannot perceive trough the force feedback asDominjon,butwithaverystiffspringforthepartofthe
howmuchforcehe/sheisexertingwiththeslaveagainstthe workspace of the master in which rate control is used. The
environment. The proposed force feedback about Fe from experiment and the results did not show significant results
literatureforratecontrolisthederivativeoftheinteraction comparing the hybrid design with scaling. Forlines [12]
force F˙e [20]. Another option for the force feedback is developed a hybrid design on a touch screen. What object
natural force feedback, the interaction force Fe, also used onthescreenwaspointedat,determinedthetypeofcontrol
for position control. Since rate control is a basic reference usedtocommandthevirtualslave.Thishybriddesignwas
in this experiment, to use as a comparison for the hybrid proventooutperformindexingbutnotratecontrolforfree-
design, the proposed force feedback from literature F˙ is space motion. None of these four hybrid designs included
e
used. forcefeedbackabouttheinteractionforceforratecontrol.
For both control methods, increasing the scaling factor Summarizing, this research focused on the category
between the position of the master and slave decreases of hybrid designs in which the position of the master
completion time and decreases achieved accuracy of the determines the type of control used to command the slave
free-spacemotionsubtask[15].Adecreaseintheachieved because that also works for slow dynamic system. The
accuracy of the free-space motion results in a higher hybrid designs of Barrio [3], Dominjons [10] and Forlines
variationintheexertedforce,solowertaskperformancefor [12]wereproventohavealowercompletiontimecompared
theforcesubtask.Thusthereisatrade-offbetweenthetotal to indexing for free-space motion. Scaling was proven to
timeofthefree-spacemotion,andtheachievedaccuracyof have a lower completion time, but also lower accuracy of
the free-space motion [5] as well as the performance of a themotionbyDominjon[10].
forcetask.
None of these designs were validated for a contact
Preliminary research tried to combine the strengths of transition or a force task and no design included force
thetwocontrolmethods,thestrengthsofperformingaforce feedbackforratecontrol.Furthermore,noresearchhasbeen
task and achieving accurate positioning of position control done to validate the hybrid design for a task combining
with the strength of large free-space movements of rate free-space motion with a force task. Due to the different
control, within one design. These designs combining both modes of the hybrid design, performance of large motion
position and rate control were called hybrid designs and and a task requiring a contact force with the environment
weredividedintotwocategories. might influence each other. Performing such a task would
The first category, combines both position and rate con- enable research to evaluate performance for both free-
trolatthesametime.Forballisticcontrol,thescalingfactor space motion, a force task and a combination altogether
dependsontherateofthemasterdevice.Thehighertherate for a hybrid design. Furthermore, no research measured