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斜角柔性針穿刺的摩擦與切割模型的研究

發(fā)布時間:2018-04-20 10:59

  本文選題:微創(chuàng)手術(shù)機(jī)器人 + 柔性針穿刺 ; 參考:《哈爾濱工業(yè)大學(xué)》2012年碩士論文


【摘要】:近年來,微創(chuàng)手術(shù)輔助機(jī)器人系統(tǒng)的研究成為了醫(yī)療機(jī)器人技術(shù)的熱點(diǎn)與難點(diǎn)。由于經(jīng)皮穿刺微創(chuàng)手術(shù)輔助機(jī)器人系統(tǒng)在活體切片、靶向注射、短程放射性治療以及神經(jīng)外科手術(shù)等方面有著極為重要的應(yīng)用,,特別是在癌癥早期診斷和治療領(lǐng)域的優(yōu)異表現(xiàn),使之成為了微創(chuàng)手術(shù)輔助機(jī)器人系統(tǒng)目前研究的焦點(diǎn)與前沿。作為經(jīng)皮微創(chuàng)手術(shù)最有力的核心技術(shù),經(jīng)皮穿刺斜角柔性針的控制技術(shù)能夠在諸多方面代替?zhèn)鹘y(tǒng)的剛性針穿刺技術(shù)。 在斜角柔性針穿刺的過程中,由于針尖斜面的存在,使得組織對針尖斜面產(chǎn)生側(cè)向作用力,加之柔性針自身的剛度很低,致使針體產(chǎn)生彎曲。柔性針在組織中的軌跡完全受控于兩個運(yùn)動輸入:軸向進(jìn)給和周向轉(zhuǎn)動。為了使得針體跟隨預(yù)定軌跡,需要轉(zhuǎn)動針軸來改變針尖斜面的方向,這會使得針體和組織之間有摩擦力的作用。鑒于此,本文首先分析了柔性針穿刺過程中影響針體彎曲曲率以及針體和組織之間摩擦力大小的因素。假設(shè)針軸在組織中是直線軌跡,運(yùn)用力學(xué)基本原理對針軸直線進(jìn)給和旋轉(zhuǎn)運(yùn)動時針體和針尖處的受力情況分別作了詳細(xì)的理論分析,同時也考慮了針軸整體的受力情況。 在柔性針穿刺的過程中,為了使得針尖更精確的到達(dá)病灶靶點(diǎn),對斜角針切割組織的過程進(jìn)行研究相當(dāng)重要。斜角針與組織之間的切割機(jī)理借助材料的斷裂機(jī)理同時結(jié)合能量守恒定律進(jìn)行研究。為了使得針體跟隨預(yù)定軌跡,基座處的轉(zhuǎn)向裝置需要轉(zhuǎn)動一定的角度。由于針尖處的尺寸小于針體的尺寸,針尖被組織夾緊,組織對針尖斜面有正壓力的作用。軸向轉(zhuǎn)動使得柔性針刃部勢必對劈開組織產(chǎn)生絞動,導(dǎo)致組織產(chǎn)生嚴(yán)重的變形甚至破壞。同時,刃部作用力的復(fù)雜性致使軸向轉(zhuǎn)動的精度很難控制。為了減小轉(zhuǎn)動誤差,將針體退回一段距離,再進(jìn)行柔性針的軸向轉(zhuǎn)動,將相對容易控制。結(jié)合材料的時滯特性得到了柔性針退回距離的有效值。 最后搭建了實(shí)驗(yàn)平臺,并結(jié)合實(shí)驗(yàn)對針體彎曲和直線軌跡兩種情形柔性針的受力情況作了相應(yīng)的對比。針對柔性針穿刺過程中針軸直線進(jìn)給和旋轉(zhuǎn)運(yùn)動兩種情況下針尖和針體所受的力以及減小軸向轉(zhuǎn)動誤差的措施進(jìn)行了實(shí)驗(yàn)驗(yàn)證。
[Abstract]:In recent years, the research of the minimally invasive surgery assisted robot system has become a hot and difficult point in the medical robot technology. The minimally invasive surgery assisted by percutaneous puncture has a very important application in living section, target injection, short-range radiation therapy and Department of Neurosurgery surgery, especially in the early diagnosis and treatment of cancer. The excellent performance in the field of treatment has made it the focus and front of the current research on the minimally invasive surgery assistant robot system. As the most powerful core technique of percutaneous minimally invasive surgery, the control technique of the percutaneous puncture inclined angle flexible needle can replace the traditional rigid needle puncture technique in many aspects.
In the process of inclined angle flexible needle puncture, due to the existence of the tip of the tip, the tissue produces the lateral force on the tip of the needle and the stiffness of the flexible needle is very low, resulting in the bending of the needle. The trajectory of the flexible needle in the tissue is completely controlled by two movement inputs: axial feed and circumferential rotation. It is necessary to turn the needle axis to change the direction of the tip of the tip of the needle. This will cause friction between the needle body and the tissue. In view of this, this paper first analyzes the factors that affect the curvature of the needle body and the friction between the needle body and the tissue during the needle puncture. The basic principle of the needle axis linear feed and rotating movement of the needle body and the tip of the tip of the force of the detailed analysis of the theoretical analysis, but also considered the overall force of the needle axis.
In the process of flexible needle puncture, it is very important to study the process of cutting the tissue in a bevel needle in order to make the tip more accurate to reach the target of the focus. The cutting mechanism between the needles and the tissue is studied with the help of the fracture mechanism of the material and the law of conservation of energy. It is necessary to turn a certain angle to the device. Because the size of the needle is smaller than the size of the needle body, the needle tip is organized to be clamped by the needle, and the organization is responsible for the positive pressure on the tip of the needle. The axial rotation makes the flexible needle blade bound to the cleavage tissue, causing serious deformation and even destruction. At the same time, the complexity of the force of the blade is caused by the complexity. It is difficult to control the accuracy of the axial rotation. In order to reduce the rotation error, the needle body is returned to a certain distance, and the axial rotation of the flexible needle will be relatively easy to control. The effective value of the return distance of the flexible needle is obtained with the time delay characteristics of the material.
At last, the experimental platform was set up, and the force conditions of the flexible needle were compared with the two cases of the needle body bending and the straight line track. In the two cases of the needle and axis straight feed and the rotation movement, the force of the needle and the needle body and the measures to reduce the axis rotation error were experimentally verified.

【學(xué)位授予單位】:哈爾濱工業(yè)大學(xué)
【學(xué)位級別】:碩士
【學(xué)位授予年份】:2012
【分類號】:R608;TP242

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 趙燕江;張永德;邵俊鵬;;柔性針的運(yùn)動學(xué)建模及實(shí)驗(yàn)研究[J];機(jī)器人;2010年05期



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