Learned parametrized dynamic movement primitives with shared synergies for controlling robotic and musculoskeletal systems

Elmar Rückert, Andrea d'Avella

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Asalientfeatureofhumanmotorskilllearningistheabilitytoexploitsimilaritiesacrossrelatedtasks.Inbiologicalmotorcontrol,ithasbeenhypothesizedthatmusclesynergies,coherentactivationsofgroupsofmuscles,allowforexploitingsharedknowledge.Recentstudieshaveshownthatarichsetofcomplexmotorskillscanbegeneratedbyacombinationofasmallnumberofmusclesynergies.Inrobotics,dynamicmovementprimitivesarecommonlyusedformotorskilllearning.Thismachinelearningapproachimplementsastableattractorsystemthatfacilitateslearninganditcanbeusedinhigh-dimensionalcontinuousspaces.However,itdoesnotallowforreusingsharedknowledge,i.e.,foreachtaskanindividualsetofparametershastobelearned.Weproposeanovelmovementprimitiverepresentationthatemploysparametrizedbasisfunctions,whichcombinesthebenefitsofmusclesynergiesanddynamicmovementprimitives.Foreachtaskasuperpositionofsynergiesmodulatesastableattractorsystem.Thisapproachleadstoacompactrepresentationofmultiplemotorskillsandatthesametimeenablesefficientlearninginhigh-dimensionalcontinuoussystems.Themovementrepresentationsupportsdiscreteandrhythmicmovementsandinparticularincludesthedynamicmovementprimitiveapproachasaspecialcase.Wedemonstratethefeasibilityofthemovementrepresentationinthreemulti-tasklearningsimulatedscenarios.First,thecharacteristicsoftheproposedrepresentationareillustratedinapoint-masstask.Second,incomplexhumanoidwalkingexperiments,multiplewalkingpatternswithdifferentstepheightsarelearnedrobustlyandefficiently.Finally,inamulti-directionalreachingtasksimulatedwithamusculoskeletalmodelofthehumanarm,weshowhowtheproposedmovementprimitivescanbeusedtolearnappropriatemuscleexcitationpatternsandtogeneralizeeffectivelytonewreachingskills.
Original languageUndefined/Unknown
Number of pages18
JournalFrontiers in computational neuroscience
Volume7.2013
Issue numberOctober
DOIs
Publication statusPublished - 17 Oct 2013
Externally publishedYes

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