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1、第十五篇WingedRobotLearnstoFlyLearninghowtoflytooknaturemillionsofyearsoftrialanderror1—butawingedrobothascracked2itinonlyafewhours,usingthesameevolutionaryprinciples.KristerWolffandPeterNordinofChalmersUniversityofTechnology(CUT)inGothenburg,Sweden,builtawingedrobotandsetabout3testingwhetheritcouldle
2、arntoflybyitself,withoutanypre-programmeddataonwhatflappingisorhowtodoit.Tobeginwith4,therobotjusttwitchedandjerkederratically.But,gradually,itmademovementsthatgainedheight.Atfirst,itcheated—simplystandingonitswingtipswasoneearlyshortcut5.Afterthreehours,however,therobotabandonedsuchmethodsinfavor
3、of6amoreeffectiveflappingtechniquewhereitrotateditswingsthrough90degreesandraisedthembeforetwistingthembacktothehorizontalandpushingdown.“Thistellsusthatthiskindofevolutioniscapableof7comingup8withflyingmotion,”saysPeterBentley,whoworksonevolutionarycomputingatUniversityCollegeLondon.Butwhile9ther
4、obothadworkedouthowbesttoproducelift10,itwasnotabouttotakeoff.“There’sonlysomuchthatevolutioncando,”Bentleysays.“Thisthingisnevergoingtoflybecausethemotorswillneverhavethestrengthtodoit,”hesays.Therobothadmetre-longwingsmadefrombalsawoodandcoveredwithalightplasticfilm.Smallmotorsontherobotletitmov
5、eitswingsforwardsorbackwards.upordownortwistthemineitherdirection.Theteamattachedtherobottotwoverticalrods,soitcouldslideupanddown.Atthestartofatest,therobotwassuspendedbyanelasticband.Amovementdetectormeasuredhowmuchlift,ifany11,therobotproducedforanygivenmovement.Acomputerprogramfedtherobotrando
6、minstructions12,attherateof1320persecond,totestitsflappingabilities.Eachinstructiontoldtheroboteithertodonothingortomovethewingsslightlyinthevariousdirections.Feedbackfromthemovementdetectorlettheprogramworkoutwhichsetsofinstructionswerebestatproducinglift.Themostsuccessfuloneswerepairedup14and“of
7、fspring”setsofinstructions15weregeneratedbyswappinginstructionsrandomlybetweensuccessfulpairs.Thesenext-generationinstructionswerethensenttotherobotandevaluatedbeforebreedinganewgeneration,andtheprocesswasrepeate
