基于非线性力反馈模型的软组织变形仿真

Simulation of Soft Tissue Deformation Based on Non-linear Force Feedback Model

虚拟手术仿真研究中反馈力一般采用线性模型,但软组织的反馈力往往呈现出非线性的特点。通过对软组织生物力学特性的分析,将非线性性质应用到软组织力反馈模型的研究。在保持原线性反馈力方向不变的前提下,加入非线性扰动,建立了反馈力的非线性模型,从而使反馈力更加真实。首先构建了人体肝脏物理模型,然后给出了非线性力反馈模型方程,并对人体肝脏物理模型变形和反馈力进行了仿真。为了减小计算量采用了整体刚度矩阵缩减算法。仿真结果表明该模型有较好的非线性和可调节性。

The existing methods in force feedback are usually based on linear model, but the non -linear characteristic of the feedback force is shown. Through analysis of biomechanics property of soft tissue, this paper applies the non - linear characteristic to study soft tissue force feedback model. Adding non - linear factor to the force feedback model in which the direction of original linear feedback force keeps invariable, a non - linear force feedback model is created, so the feed -back force can be more realistic. In this paper, we first construct physical model of liver, and then give the model equations, at last simulate deformation of hepatic model and feedback force of this model. In order to reduce the calculating work condensation of the entire stiffness matrix is used. The result indicates that the model shows good non -linearity and adjustability.