机器人辅助柔性针穿刺路径的悬臂梁预测模型

Projecting beam model for robot-assisted flexible needle insertion

路径操控技术是机器人辅助柔性针穿刺的重要技术之一。软组织变形、多层软组织相对滑移和针挠曲是引起靶点位置移动,降低穿刺精度的3个主要原因。该文在研究针受力的基础上,利用柔性针挠曲规律提出了一种预测穿刺路径的悬臂梁模型,通过准静态过程将柔性针分为有限段并将每段都视为一个悬臂梁,从而建立起三维空间中针体路径预测算法。仿真实验表明,该模型能够实现柔性针路径预测功能,为机器人辅助柔性针穿刺路径规划和避障运动提供了理论基础。

Needle path steering is one of the most important techniques during robotic-assisted needle insertion. Soft tissue deformation, multi-layer tissue relative sliding and needle deflection ean easily make the needle miss the target, which decreases the needle insertion precision. Based on the analysis of needle forces, a projecting beam model was proposed to predict the needle path through laws of needle deflection, with a flexible needle divided into finite segments with quasi-static process during needle insertion and each segment regarded as a projecting beam. An algorithm was then developed to predict the needle path in thre^dimensional space. Simulation results show that the proposed model can effectively predict the flexible needle path, which provides a theoretical fundamental for path planning and obstacle avoidance during robot-assisted needle insertion.