斜角柔性针穿刺的摩擦与切割模型的研究

发布时间：2018-04-20 10:59

本文选题：微创手术机器人 + 柔性针穿刺　；参考：《哈尔滨工业大学》2012年硕士论文

【摘要】：近年来，微创手术辅助机器人系统的研究成为了医疗机器人技术的热点与难点。由于经皮穿刺微创手术辅助机器人系统在活体切片、靶向注射、短程放射性治疗以及神经外科手术等方面有着极为重要的应用，，特别是在癌症早期诊断和治疗领域的优异表现，使之成为了微创手术辅助机器人系统目前研究的焦点与前沿。作为经皮微创手术最有力的核心技术，经皮穿刺斜角柔性针的控制技术能够在诸多方面代替传统的刚性针穿刺技术。在斜角柔性针穿刺的过程中，由于针尖斜面的存在，使得组织对针尖斜面产生侧向作用力，加之柔性针自身的刚度很低，致使针体产生弯曲。柔性针在组织中的轨迹完全受控于两个运动输入：轴向进给和周向转动。为了使得针体跟随预定轨迹，需要转动针轴来改变针尖斜面的方向，这会使得针体和组织之间有摩擦力的作用。鉴于此，本文首先分析了柔性针穿刺过程中影响针体弯曲曲率以及针体和组织之间摩擦力大小的因素。假设针轴在组织中是直线轨迹，运用力学基本原理对针轴直线进给和旋转运动时针体和针尖处的受力情况分别作了详细的理论分析，同时也考虑了针轴整体的受力情况。在柔性针穿刺的过程中，为了使得针尖更精确的到达病灶靶点，对斜角针切割组织的过程进行研究相当重要。斜角针与组织之间的切割机理借助材料的断裂机理同时结合能量守恒定律进行研究。为了使得针体跟随预定轨迹，基座处的转向装置需要转动一定的角度。由于针尖处的尺寸小于针体的尺寸，针尖被组织夹紧，组织对针尖斜面有正压力的作用。轴向转动使得柔性针刃部势必对劈开组织产生绞动，导致组织产生严重的变形甚至破坏。同时，刃部作用力的复杂性致使轴向转动的精度很难控制。为了减小转动误差，将针体退回一段距离，再进行柔性针的轴向转动，将相对容易控制。结合材料的时滞特性得到了柔性针退回距离的有效值。最后搭建了实验平台，并结合实验对针体弯曲和直线轨迹两种情形柔性针的受力情况作了相应的对比。针对柔性针穿刺过程中针轴直线进给和旋转运动两种情况下针尖和针体所受的力以及减小轴向转动误差的措施进行了实验验证。
[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.

【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R608;TP242

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