【作者】 李显凌；

【导师】 王树国； 付宜利；

【作者基本信息】 哈尔滨工业大学 ， 机械电子工程， 2009， 博士

【摘要】 近年来,微创介入手术由于具有减少病人痛苦、降低并发症等优点而在血管疾病治疗中得到越来越广泛的关注。导管是血管疾病治疗过程中常用的微创介入手术工具之一。导管是一种细长的管状物,依赖于医生的技巧和经验,可以从腹股沟经由血管进入心脏或从手臂经由血管进入脑部。由于血管系统的复杂和狭小,在血管内操作类似于导管之类的血管手术工具十分困难。特别是医生要在患者体外用手扭转、推拉导管的一端,这种手工操作不仅粗鲁,而且效率低下,始自于体外的扭转操作只能在几英尺外的导丝远端产生很小的运动。而且,这些困难带来的后果不仅是手术时间的延长,还容易造成医生和患者的疲劳。针对血管介入手术中存在的上述问题,本文提出了在血管介入手术过程中利用微型导向机器人引导导管的方案,并进行了相关技术的研究。本文围绕导管导向机器人的结构和控制系统设计、SMA螺旋弹簧驱动器的力学特性分析、导管导向机器人设计计算方法、导管导向机器人运动学分析、样机研制和模拟介入手术实验等关键技术进行了深入的研究,成功地研制了微创介入手术用导管导向机器人。本文首先进行了导管导向机器人的结构和控制系统设计。根据血管微创介入手术的特点,详细分析了导管导向机器人的设计目标,进行了导管导向机器人结构方案的设计,然后设计了基于PIC16F877单片机的导管导向机器人电阻反馈控制系统,并采用模块化的程序设计思想,完成了电阻反馈控制系统的程序设计。其次,进行了SMA弹簧驱动器的力学特性分析。将Brinson静态拉伸相变本构模型进行修正,得到了适用于剪切变形的SMA相变本构关系,然后结合普通弹簧的理论公式,推导出了SMA弹簧的热力学特性公式,并通过实验进行了和仿真进行了分析,进而得到了SMA弹簧驱动器的设计计算公式。再次,进行了导管导向机器人的参数设计计算方法研究。针对目前没有系统的导管导向机器人设计计算方法的现状,详细推导了圆柱螺旋弹簧骨架的尺寸参数确定方法、SMA驱动器在已知导管导向机器人弯曲角度下的输出力和输出位移以及单节导管导向机器人的轴线弯曲曲线形状微分方程,最终建立了一套完整的导管导向机器人参数设计计算方法。本文还针对导管导向机器人没有明确关节和连杆的特点,进行了详细的运动学分析。在对导管导向机器人的SMA驱动器进行了运动学分析基础上,运用D-H法对单节导管导向机器人进行了平面运动学分析,进而运用D-H法进行了带有连接件的单节导管导向机器人的空间运动学分析。针对导管导向机器人是一种多节结构的特点,对导管导向机器人整体进行了运动学分析,得到了4节型导管导向机器人正运动学齐次变换矩阵。利用该运动学模型能够很容易地对含有任何节数的导管导向机器人进行运动学分析。最后进行了导管导向机器人样机研制和模拟介入手术实验。应用本文的设计计算方法研制了导管导向机器人样机,并对导管导向机器人进行转向性能实验和弯曲角度与PWM占空比的关系实验。在人体胸部血管模型中,在导向机器人的引导下,经由主动脉弓分别完成了进入左椎动脉和右颈总动脉的模拟介入手术过程。更多还原

【Abstract】 In recent years, minimal invasive surgery (MIS) is getting greater attention in vascular surgeries. The technique allows reducing patient pain and lower potential sequelae. Catheter is one of the MIS tools used in intravascular surgeries. Catheter is a long, narrow tube that is inserted from the groin to the heart or from the arm to the head via blood vessels depending on the surgeon’s skill and experience. To operate intravascular surgical devices such as a catheter inside the blood vessels is very difficult because of the complexity and narrowness of blood vessels. In particular, physicians manually rotate, push and pull one end of the catheter outside the body. This kind of manual operations are not only somewhat crude, but also inefficient. Twists initiated outside the body yield much smaller movements at the wire’s tip several feet away. Moreover, this difficulty causes not only an extension of operating time, but also the fatigue of operators and patients.In order to solve the disadvantages existed in vascular invasive surgery, we put forward to use a micro steering robot to lead the catheters in the vascular invasive surgery, and the related technology were developed. In this paper, around the structure and control system design of the steering robot, mechanics characteristic of the shape memory alloy (SMA) coil spring actuators, design calculation theory of the steering robot, kinematics of the steering robot for catheter, prototype development and simulated vascular invasive surgery, and other key techniques, a series of research were developed in depth, and a steering robot used for minimally invasive surgery was developed successfully.Firstly, structure and control system of the steering robot were designed. According to the characteristics of the minimally invasive vascular operation, the design goals of the steering robot were analyzed in detail. The structure project of the steering robot was designed. Then the resistance feedback control system of catheter steering robot based on PIC16F877 chip was developed, and the resistance feedback control program was developed with modular idea.Secondly, mechanical properties of the SMA spring actuator were discussed. The SMA phase transition constitutive relation applied to shear deformation was obtained through the amended Brinson static stretching phase transition constitutive model. Combined with the formula of the general spring theory, the formula of the SMA spring thermodynamic property was derived, further it was analyzed through the experiment and simulation. Finally, the dimension calculation formulas of the SMA helical spring were deduced.Thirdly, the design calculation theory of the steering robot for catheters was investigated. According to the current situation that there is not systemic design calculation method for the catheter steering robot, the calculation methods of dimension parameters of cylinder helical spring skeleton, the output force and the output displacement of the SMA actuator under the known bending angle of the catheter steering robot, and the axis curve shape of the one segment catheter steering robot were deduced. Ultimately, a set of systemic design calculation method for the catheter steering robot was established.Fourthly, kinematics of the steering robot was analyzed in consideration of the characteristics of the steering robot that has no clear joints and links. In this paper, the axis bending shape of one segment steering robot was investigated, and kinematics of the SMA actuators was analyzed. The D-H method was used to analyze the planar kinematics of one segment steering robot, and the spatial kinematics of one segment steering robot with a connective part was analyzed. According to the multi-segments characteristics, the whole steering robot’s kinematics was analyzed. Utilize this kinematics model, we can obtain the kinematics of the catheter steering robot included any segments very easily.Finally, a prototype was developed and a series of invasive surgeries were simulated. By the design calculation method, a prototype of catheter steering robot was developed. A series of test change direction capability and the relationship between bending angle and PWM duty cycle were carried out. In the human chest vessels model, the simulant invasive surgeries through the aortic arch into the left vertebral artery and right common carotid artery were accomplished respectively in the direction of the steering robot.更多还原