简介：Inthispaper,weestablishasurfaceelectromyography(sEMG)signalmodelandstudythesignaldecompositionmethodfromnoisybackground.Firstly,singlefiberactionpotential(SFAP),motorunitactionpotential(MUAP)andmotorunitactionpotentialtrain(MUAPT)aresimulatedbasedonthetripolarsignalsourcemodel,andthenthesEMGisobtained;secondly,thesimulatedsEMGsignalisextractedfromthemixedsignalsthatconsistsofwhitenoises,powerfrequencyinterferencesignalandelectrocardiosignalbyindependentcomponentanalysis(ICA)algorithms;lastly,thespikescorrespondingtoeachmotorunitactionpotentialfromthesimulatedsEMGsignalsweredetectedbyapplyingthewavelettransform(WT)method.SimulationresultsshowedthatsEMGmodelcoulddescribethephysiologicalprocessofsEMG,ICAandWTmethodscouldextractthesEMGsignalanditsfeatures,whichwilllayafoundationforfurtherclassifyingtheMUAP.

简介：Itiscurrentlydifficultfortheamputeetoperceiveenvironmentalinformationsuchastactilepressureonthefingertipofthepresentupperlimbprostheses.Sensoryfeedbackinducedbycutaneouselectricalstimulationcanbeusedtotransmittactileinformationfromhandprosthesestosensorynerveofintactupperarm,thusproducingthecorrespondingperceptionsinhumanbrain.Inordertohaveadeeperunderstandingonthedistributionofstimulationcurrentwithinthelimb,andfindabetterplacementofthestimulatingandreferenceelectrodes,weconstructedathree-dimensionalupper-limbmodeltosystematicallystudytheeffectofelectrodeplacementoncurrentdistributionbasedonfiniteelementanalysis.Inthesesimulations,thereferenceelectrodeispositionedatfourdifferentlocationsaroundandontheaxialdirectionofthearm.Theresultsshowthatwiththeincreaseofdistancebetweenreferenceelectrodeandstimulatingelectrode,thecurrentdensityincreasesintheskinlayeroftheupperlimb.Whenthereferenceelectrodeisontheoppositesideofstimulatingelectrodearoundthearm,thecurrentismoreconcentratedintheskinlayer,whichisinlinewithrecentfindingsinpsychophysiologicalexperiments.Butbetterspatialselectivitycouldbeachievedwhenthereferenceelectrodeisclosertothestimulatingelectrodearoundthearm,anditismoreobviousincomparisonwiththatontheaxialdirection.Thesefindingswillprovideinsightsforthedesignofelectrodearrayusedforevokingcutaneoussensoryafferents.