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触觉可视化技术的出现开辟了虚拟现实技术新的应用前景,柔性物体变形技术成为其中的研究热点。论文对触觉可视化技术中柔性物体变形技术进行深入研究,系统地讨论了基于几何的力变形模型与基于物理意义力变形模型,分析了相关模型的基本思想和优缺点,对这些建模方法的性能进行了细致的比较。结果表明随着硬件技术的不断发展,基于物理意义的有限元模型将会得到越来越多的应用。最后对柔性物体物理形变建模的未来发展趋势做了探讨。 相似文献
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触觉可视化技术的出现开辟了虚拟现实技术新的应用前景,柔性物体变形技术成为其中的研究热点。论文对触觉可视化技术中柔性物体变形技术进行深入研究,系统地讨论了基于几何的力变形模型与基于物理意义力变形模型,分析了相关模型的基本思想和优缺点,对这些建模方法的性能进行了细致的比较。结果表明随着硬件技术的不断发展,基于物理意义的有限元模型将会得到越来越多的应用。最后对柔性物体物理形变建模的未来发展趋势做了探讨。 相似文献
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力/触觉再现技术的出现,为虚拟现实开辟了全新的应用领域,促使基于物理意义的柔性物体形变建模成为一个研究热点.系统地讨论了近年来基于物理意义的柔性物体形变建模方法,分析了基于直接构建的模型、基于连续介质力学的模型和其他相关模型的基本思想和优缺点.对这些建模方法的性能进行了细致的比较,并探讨了柔性物体物理形变建模的未来发展趋势. 相似文献
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A Survey of Haptic Rendering Techniques 总被引:3,自引:0,他引:3
Computer Graphics technologies have developed considerably over the past decades. Realistic virtual environments can be produced incorporating complex geometry for graphical objects and utilising hardware acceleration for per pixel effects. To enhance these environments, in terms of the immersive experience perceived by users, the human's sense of touch, or haptic system, can be exploited. To this end haptic feedback devices capable of exerting forces on the user are incorporated. The process of determining a reaction force for a given position of the haptic device is known as haptic rendering. For over a decade users have been able to interact with a virtual environment with a haptic device. This paper focuses on the haptic rendering algorithms which have been developed to compute forces as users manipulate the haptic device in the virtual environment. 相似文献
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在力/触觉建模技术中,高效的实时性与基于物理意义的准确性是与生俱来的一对矛盾.为了提高实时性与准确性的和谐程度,提出一种分析虚拟柔性体力/变形关系的框架结构模型.在柔性体内部建立一定数量并相互独立的钢架结构,运用虚功原理计算每根钢架上节点的位移;根据接触点和节点的分布,采用分水岭法将柔性体表面分割成若干区域,通过本区域内节点和接触点的位移插值计算区域内顶点的变形,进而得到柔性体的整体变形.仿真实验结果表明,该模型简便、实时性好,在具体的虚拟建模力反馈工作中可操作性强. 相似文献
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针对图像纹理力/触觉再现技术中用灰度变化表征纹理所导致的彩色图像在灰度变换后丢失纹理信息的缺点,用颜色变化表征纹理,提出彩色图像的纹理力/触觉渲染方法.该方法中,切向力的计算基于像素力场算法,法向力的计算基于惩罚算法,根据颜色和空间感的心理学效应提出由亮度和色调决定约束空间,合力通过手控器反馈给操作者.实验结果表明,文中方法能够有效地对彩色图像纹理进行力/触觉渲染. 相似文献
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高度复杂拟凸体的实时触觉绘制 总被引:4,自引:3,他引:1
触觉绘制目前已成为虚拟现实的研究热点之一,其核心是触觉代理与目标物体的实时碰撞检测与距离计算,对高度复杂模型的触觉绘制仍然是虚拟现实领域的难题,原因是对模型复杂度敏感的算法均不能满足触觉绘制苛刻的时间要求.提出触觉包围盒概念,并针对拟凸体提出一种基于触觉包围盒的实时触觉绘制算法.触觉包围盒记录了离散的采样光线与目标物体的相交信息,进行触觉计算时,只需要执行1次线段与包围盒求交运算和5次双线性插值运算即可高速求出碰撞信息,且所得到的碰撞信息可直接用于反馈力计算.实验结果表明,该算法不仅快速有效,而且具有与触觉绘制模型复杂度不相关的优点. 相似文献
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针对虚拟环境力/触觉再现系统中作用力计算的实时性要求,研究了Windows操作系统下循环控制的实现方法:时间查询法、多媒体定时器法和基于实时扩展RTX(real-time extension)的方法.利用Delta 6-DOF力/触觉手控器建立了一个基于PC的力/触觉再现原型系统,分别在系统空载、并存网络通信、并存音频播放和并存视频播放4种系统负载状态下对3种实现方法进行了实验.实验结果表明,基于RTX的方法能够获得较理想的实时循环控制性能,适用于力/触觉再现等需要较高实时性计算循环的应用系统. 相似文献
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Kyungno Lee Doo Yong Lee 《Robotics, IEEE Transactions on》2007,23(3):481-493
This paper presents an output-estimation method with reduced multirate sampling for real-time multi-input-multi-output (MIMO) haptic rendering. Haptic systems employ physics-based deformation models such as finite-element models and mass-spring models. These physics-based deformation models for high fidelity have to deal with complex geometries, material properties, and realistic behavior of virtual objects. This incurs heavy computational burden and time delays so that the reflective force often cannot be computed at 1 kHz which is a safe frequency for stability of the haptic systems. Lower update rates of the haptic loop and the computational time delay also deteriorate the realism of the haptic system. This problem is resolved by the proposed MIMO output-estimation method. The haptic system is designed to have two sampling times, T and JT, for the haptic loop and the graphic loop, respectively. Dynamics of the physics-based deformation is captured in a discrete and deterministic input-output model. The MIMO output estimation method is developed drawing on a least-squares algorithm and an output-error estimation model. The P-matrix resetting algorithm is also designed to deal with the changing input-output relationship of the deformation model. The parameters of the discrete input-output model are adjusted online. Intersample outputs are computed from the estimated input-output model at a high rate, and traces the correct output computed from the deformation model. This method enables graphics rendering at a lower update rate, and haptic rendering at a higher update rate. Convergence of the proposed method is proved, and performance is demonstrated through simulation with both a linear tensor-mass and a linear mass-spring models. 相似文献
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触/力觉交互技术应用环境的复杂化,对复杂触/力觉场景的研究提出了新的挑战.文中以虚拟现实牙科手术训练系统为背景,研究基于速度驱动的复杂场景多层级力觉交互算法.文中采用CATIA对下牙列大量数据进行网格简化,建立了下牙列场景的层次细节(Levels Of Detail,LOD)模型;基于人类触觉感知的精度随交互速度的变化规律,设计了速度驱动的LOD模型触发机制;提出了虚拟工具化身SCP(Surface Contact Point)层级映射算法,保证了力觉交互设备的稳定性,并发现了映射约束线段的长度是保证力觉逼真性及实时性协调的关键变量;最后,设计了针对一般儿何体和复杂曲面的实验,量化评价文中算法的逼真性及实时性,证明了将人手运动速度作为场景模型复杂度切换驱动条件的有效性. 相似文献
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This paper combines image processing with 3D magnetic tracking method to develop a scalpel for haptic simulation in surgical cutting. First, a cutting parameter acquisition setup is presented and the performance is validated from soft tissue cutting. Then, based on the acquired input-output data pairs, a method for fuzzy system modeling is presented, that is, after partitioning each input space equally and giving the premises and the total number of fuzzy rules, the consequent parameters and the fuzzy membership functions (MF) of the input variables are learned and optimized via a neurofuzzy modeling technique. Finally, a haptic scalpel implemented with the established cutting model is described. Preliminary results show the feasibility of the haptic display system for real-time interaction. 相似文献
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文字输入是人机交互的基本方式,而中文输入法在其中占有重要地位。本文基于资源有限的STM32嵌入式开发环境和T9输入法基本原理设计了一种中英文输入法的实现方案。通过对程序和码表的设计,结合键盘和TFT显示屏的数字串输入,可以对目标文字进行查找和锁定,从而实现了中、英文的输入功能。 相似文献
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传统的力触觉渲染多采用阻抗控制,不能很好地满足虚拟装配的应用要求,相比之下导纳控制模式更适用这一领域.为此提出一种基于导纳控制的双线程力觉渲染构架,并给出相应的力觉渲染算法.首先建立用于导纳控制的动力学模型,并讨论了碰撞和约束这2个状态下的力觉渲染;为了使用力觉交互接口进行虚拟装配中的小间隙装配,提出物理约束与几何约束结合的力觉渲染方法;最后针对物理计算和力反馈循环2个线程刷新频率不匹配的问题,利用二次拉格朗日多项式进行数值插值,实现了力觉交互接口的平稳输出.通过力反馈设备与自主开发的虚拟装配原型系统VAPP的连接与应用,验证了所提出的算法满足虚拟装配系统中力觉交互的应用要求. 相似文献
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In this paper, we show that for haptic rendering using position feedback, the structure of the feedback loop imposes a fundamental tradeoff between accurate rendering of virtual environments and sensitivity of closed-loop responses to hardware variations and uncertainty. Due to this tradeoff, any feedback design that achieves high-fidelity rendering incurs a quantifiable cost in terms of sensitivity. Analysis of the tradeoff reveals certain combinations of virtual environment and haptic device dynamics for which performance is achieved only by accepting very poor sensitivity. This analysis may be used to show that certain design specifications are infeasible and may guide the choice of hardware to mitigate the tradeoff severity. We illustrate the predicted consequences of the tradeoff with an experimental study. 相似文献
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