实时多组织虚拟手术的反馈力模拟

Real-Time Force Simulation in Multi-tissue Virtual Surgery

为了在虚拟下颌整形手术系统中提供实时和真实的触觉交互,分别构建了基于虚拟中介平面的推操作触觉模型、基于粘附力的拉操作触觉模型和基于非线性粘弹性的针刺触觉模型,以模拟皮肤拉钩、整形镊和针的典型手术操作;同时通过相邻组织间的动态触觉约束建立了多组织联合形变模型,以避免表面弹簧-质点模型形变过程中可能出现的表面间相互穿透的异常现象;并进一步将触觉交互模型和多组织形变模型集成于虚拟下颌手术系统,从而为医生提供一个手术训练的虚拟平台.触觉感知和交互效率的实验结果表明,通过触觉交互识别皮肤、肌肉和骨骼能够获得较高的识别正确率,并能提供实时的触觉和视觉交互体验.

To realistically integrate haptic feedback in real time during virtual surgery simulation, three haptic models have been proposed and realized, including pushing operation model based on intermediate virtual plane, pulling operation model based on adhering force and needle puncturing operation model based on non-linear viscoelasticity force. Using these models, the operations of retractor, tweezers and needle are simulated. Under the force constraints in adjacent tissue layers, multi-tissue deformation model is also developed. This deformation model avoided the layers puncturing phenomenon in surface mass-spring model. Furthermore, the haptic interaction models with multi-tissue deformation have been integrated into a virtual craniofacial surgery framework to assist medicine training. A set of experiments about multi-tissue identification and computational efficiency are conducted. The experimental results show that the high accuracy rates of multi-tissue identification are achieved via haptic feedback in pushing and needle puncturing operations. The high computational rate of force and deformation can be guaranteed.