柔性針穿刺的幾何控制理論研究.pdf

1、1柔性針穿刺的幾何控制理論研究摘要隨著微創(chuàng)技術(shù)介入臨床醫(yī)學(xué)治療，穿刺在經(jīng)皮手術(shù)治療、組織取樣等手術(shù)中被廣泛應(yīng)用，柔性針因相對組織有足夠的柔性能夠靈活準(zhǔn)確的到達(dá)傳統(tǒng)鋼針達(dá)不到的靶點(diǎn)位置，因此對柔性針穿刺的路徑規(guī)劃研究對于準(zhǔn)確穿刺有重要意義。本文討論了斜尖柔性針穿刺的路徑規(guī)劃問題以及基于不確定參數(shù)的柔性針模型，設(shè)計自適應(yīng)輸出反饋控制器去處理柔性針路徑導(dǎo)向問題。首先，在剛性組織假設(shè)前提下，分別討論了柔性針在二維和三維有障礙環(huán)境中的路徑規(guī)劃問題

2、。在二維有障礙環(huán)境中，過入針點(diǎn)和目標(biāo)點(diǎn)向障礙圓做切線，求出切線交點(diǎn)坐標(biāo)，過入針點(diǎn)、切線交點(diǎn)、目標(biāo)點(diǎn)的圓弧即為可行路徑，通過弧長最短確定最優(yōu)路徑。在三維有障礙環(huán)境中，首先通過快速搜索隨機(jī)樹法找到可行路徑，考慮路徑長度最短及與障礙的間隙盡可能大，建立優(yōu)化目標(biāo)函數(shù)，從而找到最優(yōu)路徑，并通過增大障礙球的半徑進(jìn)行障礙規(guī)避。仿真結(jié)果表明這兩種路徑規(guī)劃均能找到最優(yōu)路徑，驗證了此規(guī)劃方法的有效性。其次，對約化后的柔性針系統(tǒng)進(jìn)行反饋線性化，在反饋線性化系

3、統(tǒng)中增加不確定參數(shù)，通過濾波變換將系統(tǒng)變換為自適應(yīng)跟蹤型，設(shè)計自適應(yīng)輸出反饋跟蹤控制律，可以隨時跟蹤時變參考輸出信號，實現(xiàn)柔性針與靶點(diǎn)的距離跟蹤。3GEOMETRICCONTROLTHEYFTHEPUNCTUREOFSTEERINGFLEXIBLENEEDLEABSTRACTABSTRACTABSTRACTABSTRACTAsminimallyinvasivetechniquesinvolvedinclinicalmedicaltrea

4、tmentneedlepunctureiswidespreadinmanyproceduresincludingpercutaneousproceduresrequiringtherapydeliverytosampleremovalfromaspecificlocation.Whenflexibleneedlewithabeveltippushesthroughsofttissuetheasymmetryofthetipcausest

5、heneedletobendcouldreachthetargetwhichthetraditionalneedlecannotreach.Sotheresearchofpathplanningofflexibleneedleissignificantfaccuratepuncture.Inthisthesisthepathplanningtheadaptiveoutputfeedbacktrackingcontrolarediscus

6、sedftheflexibleneedle.Firstlyundertheassumptionofrigidtissuethepathplanningofflexibleneedlein2D3Denvironmentwithobstaclesarediscussed.In2Dtochoosethetangentfrominitialpointtotargetpointcalculatethecodinatesofthetangentst

7、henthecirculararcspassingthroughinitialpoint、thetangentpointtargetpointisthefeasiblepaththeshtestarcistheoptimalpath.In3DbasedontheRapidlyexplingRomTrees(RRTs)method，asetoffeasiblepathsarefoundthenanoptimalpathwhichcould

8、avoidobstaclesbyminimizingtheoptimizationcriterionisgiven.Simulationresultsshowthatbothofthetwopathplanningmethodscouldfindtheoptimalpathswhichillustratetheeffectivenessofthepathplanningmethods.Secondlytheflexibleneedlec

9、anbefeedbacklinearizedviaatransfmationofstateinputcodinates.Whilesubjectedtoparametricuncertaintythesystemistransfmedtoadaptivetrackingfmbyafilteredtransfmation.Theadaptiveoutputfeedbacktrackingcontrollerisdesignedtotrac

10、ktimevaryingreferenceoutputsignalswhichrealizethetrackingbetweenflexibleneedlethetargetpoint.ZhouLi(Appliedmathematics)SupervisedbyKangJianlingKEYWDS:nonholonomicsystems；flexibleneedles；pathplanning；rapidlyexplingromtree