柔性针的运动学建模及实验研究

针对在微创手术中传统采用的钢针的不足，如与组织作用，双方均产生较大变形，造成很大误差，严重影响治疗效果。另外在手术中常常遇到一些重要的组织和器官要避开，传统的钢针无法满足需要。本文采用带斜尖的柔性针，完全利用进针时斜尖与组织的侧向作用力使针轴产生弯转。这样不但可以更精确控制针的轨迹，而且还能绕过障碍物准确达到靶点。本文首先简化了WebsterIII等人提出的柔性针非完整约束系统的自行车模型，提出了自行车前、后轮模型。在此基础上，又提出了更符合实际的带返程度的自行车模型，并进行了运动学建模研究。以实验数据拟合了模型中各参数，同时验证了此模型的合理性和准确性。

Kinematic Modeling and Experimental Study of Flexible Needle

Aiming at the disadvantages of traditional steel needle adopted in minimally invasive surgery, such as large distortions of both needle and tissue as the effects between them, etc. These give rise to large errors and influence the treatment effect badly. Besides, it is incapable in the operation in presence of important tissues and organs to be avoid. This paper adopts a bevel-tip flexible needle instead, which is flexible enough to tissues. The needle is bent entirely depending on the force between bevel tip and tissue when insertion, so the needle track can be controlled more precisely. What’s more, it can steer clear of obstacles and reach the target accurately. In this paper, the bicycle model for the nonholonomic system, proposed by Webster III et al, is simplified to front and back wheel model of bicycle. Based on this, a new bicycle model with retrace ratio is proposed, which more accords with the facts. and kinematics modeling is studied. The parameters of the model are fitted by experiment data. Meanwhile, the rationality and veracity are validated.