共查询到20条相似文献,搜索用时 109 毫秒
1.
非接触式磁悬浮视触觉交互克服了机械式交互的固有摩擦,具有广阔应用前景,但存在交互过程中虚拟工具穿透物体、图形渲染与触觉渲染速率不一致等问题。针对上述问题,提出面向磁悬浮视触觉交互的多速率系统框架,通过扩展三自由度(3-DOF)单射线触觉渲染方法,利用多射线对虚拟工具进行建模,避免工具穿透,实现六自由度(6-DOF)触觉渲染;通过多速率并行,实现速率不一致模块间相互协同;通过构建映射滤波算法,实现视觉定位数据到虚拟工具位姿的稳定映射。实验结果表明,该系统能有效避免交互过程中的穿透现象,并提供稳定、真实的视触觉反馈。 相似文献
2.
为了在虚拟手术仿真中获得快速、准确的力触觉形变效果,提出一种基于导纳控制的力触觉形变模型.基于该模型,采用PHANTOM OMNI力触觉交互设备,以3DS MAX 2013,Microsoft Visual C++2012,Open GL函数库为基础搭建了实时柔性体力触觉再现系统,实现了虚拟双手对心脏双点的拉拽交互操作.感知实验和交互效率的结果表明,所提出的模型简单有效,形变效果逼真、视觉反馈流畅、力触觉反馈平稳,操作者对虚拟环境的感知和交互准确可靠,能够满足虚拟手术仿真系统的要求. 相似文献
3.
用于软组织变形仿真的层状菱形链连接模型 总被引:3,自引:1,他引:2
为提高软组织变形仿真的精度与实时性,提出一种新颖的、基于物理意义的层状菱形链连接模型.该模型中每层各个链结构单元相对位移的叠加对外等效为物体表面的变形,与之相连的弹簧弹性力的合力等效为物体表面接触力.利用6-DOFDelta手控器构建了力触觉交互实验系统,使用虚拟软组织模型进行按压、拉拽等交互操作,并通过反馈力产生触觉感.实验结果表明,该模型不仅计算简单,而且能够保证触觉接触力和变形计算具有较高精度;同时在交互过程中,力触觉感觉平稳、模拟效果逼真、满足虚拟现实系统对精细作业和实时性的要求. 相似文献
4.
为了提高柔性体变形仿真运行速度并且解决切割对变形计算稳定性的负面影响,提出了能与GPU加速的变形算法协同运作的基于虚拟节点法的柔性体实时切割仿真方法.柔性体模型由真实四面体网格嵌入虚拟四面体网格中构成,前者用于碰撞处理和图形渲染,而后者则用于变形计算.切割算法首先分裂真实四面体网格;然后复制包含超过一块真实四面体连通碎片的虚拟四面体,每个复制品包含一块真实四面体碎片;再根据真实四面体之间的连接关系更新虚拟四面体之间的连接关系;最后更新真实四面体网格与虚拟四面体网格之间的镶嵌关系.为了确保仿真系统不被限制在NVIDIA公司的GPU上,GPU加速使用OpenCL实现.仿真测试结果表明,该方法可以在任意多次切割情况下保持变形计算稳定不发散,并且在NVIDIA公司和AMD公司的GPU上都可以正确运行. 相似文献
5.
实时多组织虚拟手术的反馈力模拟 总被引:1,自引:1,他引:0
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. 相似文献
6.
7.
虚拟体空间中的触觉雕刻 总被引:5,自引:0,他引:5
目前,在虚拟环境中大多数的信息获取是通过视觉、听觉等非接触感觉获得的。然而缺乏触觉反馈的信息减少了很大一部分的信息源。在看和听之外,能够触摸、感觉和操纵物体,在很大程度上提高了虚拟环境的真实性。该文研究了触觉绘制的基本模型,提出了采用虚平面作为中介实现体数据的实时触觉绘制。并在此基础上探讨了体的局部变形及结合触觉反馈模型,实现了具有触觉反馈的虚拟雕刻交互系统。该系统可应用于融化、燃烧、印记、构造和着色实时交互操作。 相似文献
8.
研究虚拟牙齿矫正系统,牙龈变形是开发虚拟牙齿矫正系统一个重要部分.传统的质点-弹簧模型无法实现抗弯曲变形效果,因此建立一种既能仿真拉伸变形又能实现抗弯曲变形效果的物理模型成为牙龈变形过程中亟待解决的难题.在分析质点-弹簧模型的基础上,提出并建立了一种针对软组织面模型变形的力学模型,用来解决牙龈变形问题.实验将变形的动态过程离散化,用迭代的方法求出所有牙龈质点变形的位移量.随着牙齿一步一步移动,用STL( Stereo Lithographic)文件构成的模型是由不规则三角面片组成的特点,绘制出一系列牙龈变形图像.实验结果表明方法有效,仿真效果逼真,适用于小范围移动的牙齿矫正手术方案参考. 相似文献
9.
针对烟雾在自然无规则状态下对其变形控制困难的问题,提出一种可控的烟雾变形模拟方法.为实现烟雾的变形,在N-S (Navier-Stokes)方程中引入控制形变的吸引力和驱动力;利用MacCormack方法,有效减少了N-S方程求解过程中的数值耗散,使烟雾更好的保持细节;为加快烟雾的变形速度,在预处理阶段采用体素化的方法把目标三维模型数据离散到局部网格上,并计算出模型外网格点处的吸引力系数;为避免变形烟雾与自由运动烟雾交互时吸引力系数的重新计算,在全局网格中动态跟踪包围目标模型的局部网格.实验证明,采用文中方法,能够有效控制烟雾的变形,并实现变形烟雾与自由运动烟雾的快速交互. 相似文献
10.
为了在虚拟现实柔性体力触觉交互研究中得到稳定、连续、真实的力触感,提出一种基于球面调和函数表达的虚拟柔性体实时形变仿真模型,利用球面调和函数的正交归一、旋转不变、多尺度等特性实现物体的快速准确表达.在变形体的密度、杨氏模量、泊松比等参数已知的情况下,基于径向基函数神经网络模型预测柔性体受力形变后的SH模型.仿真结果表明,该方法不仅可以准确表达柔性体的实时形变,而且使得基于SH表达的柔性体形变的视觉刷新描述与柔性体反馈力的触觉刷新描述同步,从而满足虚拟手术仿真训练等虚拟柔性体力触觉交互研究要求. 相似文献
11.
The modeling and simulation of deformable objects is a challenging topic in the field of haptic rendering between human and virtual environment. In this paper, a novel and efficient layered rhombus-chain-connected haptic deformation model based on physics is proposed for an excellent haptic rendering. During the modeling, the accumulation of relative displacements in each chain structure unit in each layer is equal to the deformation on the virtual object surface, and the resultant force of corresponding springs is equivalent to the external force. The layered rhombus-chain-connected model is convenient and fast to calculate, and can satisfy real-time requirement due to its simplicity. Experimental study in both homogenous and non-homogenous virtual human liver and lungs based on the proposed model are conducted, and the results demonstrate that our model provides stable and realistic haptic feeling in real time. Meanwhile, the display result is vivid. 相似文献
12.
Desktop haptic virtual assembly using physically based modelling 总被引:1,自引:0,他引:1
This research investigates the feasibility of using a desktop haptic virtual environment as a design tool for evaluating assembly
operations. Bringing virtual reality characteristics to the desktop, such as stereo vision, further promotes the use of this
technology into the every day engineering design process. In creating such a system, the affordability and availability of
hardware/software tools is taken into consideration. The resulting application combines several software packages including
VR Juggler, open dynamics engine (ODE)/open physics abstraction layer (OPAL), OpenHaptics, and OpenGL/GLM/GLUT libraries to
explore the benefits and limitations of combining haptics with physically based modelling. The equipment used to display stereo
graphics includes a Stereographics emitter, Crystal Eyes shutter glasses, and a high refresh rate CRT Monitor. One or two-handed
force feedback is obtained from various PHANTOM haptic devices from SensAble Technologies Inc. The application’s ability to
handle complex part interactions is tested using two different computer systems, which approximate the higher and lower end
of a typical engineer’s workstation. Different test scenarios are analyzed and results presented. 相似文献
13.
Currently, interactive data exploration in virtual environments is mainly focused on vision-based and non-contact sensory
channels such as visual/auditory displays. The lack of tactile sensation in virtual environments removes an important source
of information to be delivered to the users. In this paper, we propose the touch-enabled haptic modeling of deformable multi-resolution
surfaces in real time. The 6-DOF haptic manipulation is based on a dynamic model of Loop surfaces, where the dynamic parameters
are computed easily without subdividing the control mesh recursively. A local deforming scheme is developed to approximate
the solution of the dynamics equations, thus the order of the linear equations is reduced greatly. During each of the haptic
interaction loop, the contact point is traced and reflected to the rendering of updated graphics and haptics. The sense of
touch against the deforming surface is calculated according to the surface properties and the damping-spring force profile.
Our haptic system supports the dynamic modeling of deformable Loop surfaces intuitively through the touch-enabled interactive
manipulation. 相似文献
14.
This article is concerned with the haptic deformation display of discrete viscoelastic surfaces by means of a human fingertip. The virtual surface of a deformable quadrilateral mesh is interactively deformed by a Kelvin–Voigt soft fingertip model attached to the end-effector of a haptic interface device. In achieving this task, a nonlinear constitutive model approximating experimental data from literature is developed for determining the contact point deformations. By employing a new kernel weighting function, the deformations are distributed dependently on the discrete surface topology based on a nonlinear spring–damper net around the contact location. For illustration and evaluation of the proposed approach, a parallel robotic device with a constraint-based controller is adopted. The grip of the device is moved by the user to feel a sense of touch as the soft fingertip deforms the mesh surface of an ex vivo porcine liver tissue. Experimental data indicates stable realistic interactions thorough mechanical coupling between the soft fingertip and the deforming liver tissue. Dynamic response data of liver show rate-dependent hysteretic deformations and match closely with experimental indentation data from literature. A thorough analysis of mesh node count on the sample rate and the rendering quality is also presented. 相似文献
15.
精度高且实时性好的柔性触觉变形模型是实现触觉再现系统的关键。提出了一种新的基于物理意义的平行菱形链连接触觉变形模型,系统中各个链结构单元相对位移的叠加对外等效为物体表面的变形,与之相连的弹簧弹性力的合力等效为物体表面的接触力。使用Delta 6-DOF手控器,建立了触觉再现实验系统,对柔性体的接触变形和实时虚拟触觉反馈进行仿真, 实验结果表明所提出的模型不仅计算简单,而且能够保证触觉接触力和形变计算具有较高精度,满足虚拟现实系统对精细作业和实时性的要求。 相似文献
16.
Recently, physically-based simulations with haptics interaction attracted many researchers. In this paper, we propose an adaptive Six Degrees-of-Freedom (6-DOF) haptic rendering algorithm based on virtual coupling, which can automatically adjust virtual coupling parameters according to mass values of the simulated virtual tools. The algorithm can overcome the virtual tool displacement problem caused by the large mass values of the virtual tool and can provide stable force/torque display. The force/torque magnitude is saturated to the maximum force/torque values of the haptic device automatically. The implemented algorithm is tested on the simple and complex standard benchmarks. The experimental results confirm that the proposed adaptive 6-DOF haptic rendering algorithm displays good stability and accuracy for haptic rendering of dynamic virtual objects with mass values. 相似文献
17.
一种基于物理的实时细节保持变形算法 总被引:1,自引:0,他引:1
实时变形是计算机图形学研究的热点问题之一,复杂物体的实时变形至今仍未得到很好的解决.从物理变形方法和多分辨率网格编辑技术的优点出发,提出了一种适合于复杂弹性物体的实时变形算法.在预处理阶段,将原始精细网格模型进行简化以建立其基网格表示,基于基网格对模型的局部细节特征进行编码;在实时绘制阶段,在基网格上进行物理变形操作,并通过变形后的基网格和细节编码重构出变形后的精细网格.以上过程充分利用图形硬件的并行处理能力,利用像素处理器进行大部分计算操作.实验结果表明,该算法在变形过程中较好地保持了物体的局部特征,适合于表面细节复杂物体的实时变形应用. 相似文献
18.
虚拟环境中多视觉通道图形显示的实现 总被引:3,自引:0,他引:3
该文在分析虚拟环境中单视觉通道图形显示不足之处的基础上,研究了多视觉通道图形显示的一套实现方法,并给出了一个多视觉通道图形显示实例--虚拟坦克的多视觉通道图形显示。结果表明多视觉通道图形显示可以更好地增进虚拟环境的"沉浸"效果。 相似文献
19.
《Advanced Robotics》2013,27(3):349-365
Colonoscopy is a safe and effective procedure to diagnose and treat the large bowel with the help of the flexible endoscope. This paper presents a new colonoscopy training simulator to help trainees practice and acquire the necessary skills and experiences with no risk to the patients and possibly less cost. The simulator includes a specialized haptic interface to transfer force feedback through a long and flexible tube, and graphics algorithms to display the virtual colon realistically while managing the large number of polygons. A new 2-d.o.f. haptic device with folding guides is developed to transmit large decoupled forces of the colonoscopy simulation to the user. The physicians apply a jiggling motion to the colonoscopy tube to advance the scope. This jiggling is an important skill of colonoscopy and is incorporated for the first time by using the new sensor mechanism. A colonoscope handle that shares the look, feel and functions with an actual colonoscope is developed with the necessary electronics inside. The simulator contains controllers to compensate for the inertia and friction effects, and is evaluated by physicians. New graphics algorithms including polygon reduction, navigation and collision detection are developed to compute the deformation and the corresponding reflective force in real-time. 相似文献
20.
Roni Yagel Don Stredney Gregory J. Wiet Petra Schmalbrock Louis Rosenberg Dennis J. Sessanna Yair Kurzion 《Computers & Graphics》1996,20(6):143-823
Advanced display technologies have made the virtual exploration of relatively complex models feasible in many applications. Unfortunately, only a few human interfaces allow natural interaction with the environment. Moreover, in surgical applications, such realistic interaction requires real-time rendering of volumetric data—placing an overwhelming performance burden on the system. We report on our advances towards developing a virtual reality system that provides intuitive interaction with complex volume data by employing real-time realistic volume rendering and convincing forece feedback (haptic) sensations. We describe our methods for real-time volume rendering, model deformation, interaction, and the haptic devices, and demonstrate the utilization of this system in the real-world application of Endoscopic Sinus Surgery (ESS) simulation. 相似文献