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1、摘要超聲波傳感器因其價格低廉、硬件容易實現(xiàn)而被廣泛應用于移動機器人測距領域。為了獲得更多的環(huán)境信息,通常采用多個超聲換能器組成傳感器環(huán)。傳感器環(huán)上相鄰換能器之間會產生超聲串擾現(xiàn)象,導致錯誤的距離測量。常用的消除超聲串擾的方法分為兩種:基于啟發(fā)式的軟件處理法和基于硬件的編碼法。為了消除超聲串擾,本文在對現(xiàn)有文獻進行研究和實驗分析的基礎上做了以下工作:1.總結了該領域的研究現(xiàn)狀,在對超聲串擾問題進行分析的基礎上,找到了解決問題的切入點。2.利用DC.DC激勵超聲換能器。與原變壓器激勵模式相比,有效地減小了系統(tǒng)振蕩。3.采用ARMA模型建立了超聲測距系
2、統(tǒng)的數(shù)學模型,在此模型基礎上對該系統(tǒng)電路特性進行了研究,并對不同的激勵方式做了比較研究。4.基于ARMA系統(tǒng)模型對脈沖寬度調制、頻率調制和相位調制等方法進行仿真,分析了三種調制方式的傳輸特性,并比較了各自的相關結果。5.通過對不同長度序列的仿真分析,給出了序列長度與序列相關性之間的關系;對于短序列相關性不易確定的問題,引入了短序列相關柵格圖的概念。關鍵詞:移動機器人、超聲換能器、串擾、相關、編碼、調制ABSTRACTUltrasonicsensorshavebeenwidelyusedinthefeildofmobileroboticsfordi
3、stancemeasurementwithresonablecostandmodestsystem’scomplexity.Inordertoprovidemobilerobotswith.moreenvironmentalinformation,normallyasensorringwithmultipleultrasonictransducersisrequired.Crosstalkphenomenon,whichcanresultinerroneousdistancemeasurement,oftenoccursamongadjacent
4、transducersonthesensorring.Twodifferentkindofmethodshavebeenusedbyresearcherstoeliminateultrasoniccrosstalk,whicharecalledheuristicsbasedsoft—processingmethodandhardwarebasedcodemethod,respectively.Thefollowingworkhasbeendoneinthisthesis.1.Thestateofartsofeliminatingofultraso
5、niccrosstalkissummarized.Thecut—inpointisfoundtosolvetheultrasoniccrosstalkproblem.2.TheultrasonictransducerisexcitedbythecircuitbasedonDC—DCmodule.Thesystemoscillatingtimeiseffectivelyreduced,comparedwiththetransformerbaseddrivemode.3.TheMathematicsmodeloftheultrasonicranges
6、ystemisbuilt.Thecircuitcharacteristicisstudiedbasedonthismodelanddifferenttriggeringmethodsarecompared.4.Pulsewidthmodulation,frequencymodulationaswelasphasemodulationaresimulatedbythesystemmodel.Thesemodulatingmethodsaleanalyzedandtheircorrelationresultsarecompared.一5.Byanal
7、yzingthecorrelationresults.ofsequenceswithdifferentlength,therelationshipbetweenlengthandcorrelationvalueofsequencesispresented.Toovercometheunpredictabilityofshortsequencecorrelations,theconceptofcorrelationgridmapofshortsequenceisputforward.KEYWORDS:Mobilerobot,Ultrasonictr
8、ansducebCrosstalk,Correlation,Code,Modulation獨創(chuàng)性聲明本人聲明所呈交的學位論文是本人在導師