基于Vega的虚拟漫游场景中的路径规划研究

针对当前虚拟漫游系统存在的问题,对虚拟漫游场景中两种运动方式进行分析,将避障路经规划中的可视图法进行适当改进,提出了"左右判断法",简化了原有算法的时间复杂度,并将运用扩展到三维空间中.在手动漫游方式下实现了漫游物体的智能"滑行"避障.给出了Vega中这两种运动方式的实现步骤.算法在虚拟空间会议系统中得到了验证.     

基于模糊算法的机器人漫游避障的实现

由于机器人漫游运动的随机性和环境的不可预测性,导致机器人漫游运动的避障非常困难.本文应用模糊算法来实现机器人的漫游避障,在Pioneer 3-Dx型移动机器人的仿真平台MobileSim上进行了仿真实验,仿真结果表明了算法的有效性和可行性.     

用VRML和Java实现虚拟小区的交互漫游

为了实现虚拟小区的交互漫游,在系统实现过程中采用了几种方式的交互技术,文中对这些交互技术进行了讨论和实现。阐述了在虚拟小区中交互漫游的两种方式,即由用户交互控制视点和由计算机自动控制视点的方式,并对这两种交互漫游方式给出了VRML编码的具体实现;最后采用外部编程接口（EAI）实现了用户界面中的二维平面图和三维场景图的交互。     

用VRML和Java实现虚拟小区的交互漫游

为了实现虚拟小区的交互漫游,在系统实现过程中采用了几种方式的交互技术,文中对这些交互技术进行了讨论和实现.阐述了在虚拟小区中交互漫游的两种方式,即由用户交互控制视点和由计算机自动控制视点的方式,并对这两种交互漫游方式给出了VRML编码的具体实现;最后采用外部编程接口(EAI)实现了用户界面中的二维平面图和三维场景图的交互.     

移动机器人漫游避障的研究

移动机器人在做漫游运动时,它的运动是随机的,因而避障是漫游过程中必须要解决的问题.本文应用多超声波传感器设计了移动机器人漫游避障的控制算法,在Pioneer 3-Dx型移动机器人自带的仿真平台SRIsim上进行了仿真实验,仿真结果表明了所设计算法的有效性和可行性.     

一种冗余机械臂的多运动障碍物避障算法

冗余机械臂的避障问题一直是工业机器人应用领域的研究热点之一;为了改进传统避障算法的不足,提出了一种多运动障碍物的避障算法;该算法利用各障碍物的运动状态得到与机械臂之间的最小预测距离,并将其利用雅可比转置矩阵转化为机械臂对应杆件上的躲避速度,再将躲避速度引入梯度投影法中求得机械臂的关节角速度,并通过积分得到避障运动中机械臂的关节角度值,在完成末端轨迹跟踪的同时实现冗余机械臂的实时避障;利用一款七自由度冗余机械臂对该算法进行了仿真验证,结果表明该算法能有效实现冗余机械臂对多运动障碍物的避障。     

基于球面全景图的虚拟场景实时漫游系统

设计并实现一种基于球面全景图的虚拟场景实时漫游系统。虚拟场景的实时漫游可以通过对球面全景图进行重投影完成。通过重投影球面全景图的可视部分到视平面上,可以生成虚拟场景在不同视线方向上的透视视图。使用球面全景图的重投影算法可以模拟相机的旋转运动,通过改变相机的视域,可以模拟相机的变焦运动。针对直接使用重投影不能满足球面全景图实时绘制的问题,在对球面全景图的重投影算法进行仔细分析的基础上,提出使用查找表和增量计算进行加速的策略。实验结果表明,优化后的系统能够对基于球面全景图的虚拟场景进行实时漫游     

多移动机器人的领航-跟随编队避障控制

针对多移动机器人的编队控制问题,提出了一种结合Polar Histogram避障法的领航-跟随协调编队控制算法。该算法在领航-跟随l-φ编队控制结构的基础上引入虚拟跟随机器人,将编队控制转化为跟随机器人对虚拟跟随机器人的轨迹跟踪控制。结合移动机器人自身传感器技术,在简单甚至复杂的环境下为机器人提供相应的路径运动策略,实现实时导航的目的。以两轮差动Qbot移动机器人为研究对象,搭建半实物仿真平台,进行仿真实验。仿真结果表明:该方法可以有效地实现多移动机器人协调编队和避障控制。     

三维网上虚拟商场的绘制与漫游

介绍了一个三维虚拟商场的系统框架，用OpenGL解决了过程中的两个关键问题——三维场景绘制和碰撞检测。根据虚拟商场自身的特点，将纹理应用于多层次细节显示优化中，并采用多层次纹理的方式来提高三维场景绘制速度。设计并实现了一个适用于虚拟商场漫游的碰撞检测算法，采用平面图以及区域划分的方法，极大地降低了碰撞检测时间，实现了流畅的漫游效果。     

基于VRML模型和ASP技术虚拟漫游展厅构建的研究

针对民族体育数字化保护和展示宣教的需要,根据虚拟现实中两种不同虚拟漫游方式:实景漫游和虚拟漫游,探讨了实现这两种方式的关键技术.结合新疆民族体育虚拟展厅的具体实践,设计完成了实景和虚景的构造过程.     

集成几何约束与物性仿真技术的虚拟装配

针对传统装配定位导航中零部件位姿的突变问题,利用线性插值与四元数球形插值 的方法,求解零部件约束定位变换过程的渐变运动;同时利用导纳式力觉交互控制模式,解决了 约束定位变换后的控制信号分离问题;在装配运动导航阶段,将约束几何元素具象化为力觉约束 模型,以满足虚拟装配对力觉反馈的需求。针对虚拟装配对物性仿真的需求,将开源物理引擎 Bullet 集成到仿真系统中,提出几何约束与物性仿真技术相结合的装配流程,最后在自主研发的 虚拟装配原型系统中进行了应用实例验证。     

基于虚拟导航线的农业机器人精确视觉导航方法

针对农田、野外环境中无人工标记情况下的导航问题，提出了一种基于虚拟导航线的农业机器人精确视觉导航方法。该方法不需要铺设导航线或者路标即可引导机器人行走直线。首先，根据需求确定需要跟踪的目标区域，之后控制机器人调整方向直到目标移至视野中央；其次，根据机器人和目标的位置确定参照目标，并依据两个目标的位置确定虚拟导航线；然后，动态更新导航线，并结合虚拟定标线和虚拟导航线确定偏移角度和偏移距离；最后，利用偏移参数构建模糊控制表，并以此实现对机器人旋转角度和行走速度的调整。实验结果表明，该算法能较为精确地实现对导航路线的识别，进而利用模糊控制策略使机器人沿直线向目标行走，且导航精度在10 cm以内。     

Intelligent Cruise-Control Navigation: A new navigation/travel method for use in virtual environments

An important feature of virtual reality is the facility for the user to move around a virtual environment in a natural and easily controlled manner. Navigation, also called locomotion, travel or motion, involves changing the perspective of the user in the virtual environment (VE). It allows the user to move in the VE as well as reorient themselves to look at the world differently. Natural locomotion methods are able to contribute to a sense of presence and reality. The illusion of presence can be lost through unnatural experiences during travel in the VE. This can be caused by poor interactive metaphors or by experiences which do not agree with the user's everyday understanding of the real world. This paper focuses on the navigation method in the VE, one of the major interfaces for the interactivity between human and VE in virtual reality circumstances and worlds. It proposes a new navigation method. Intelligent Cruise-Control Navigation (ICCN), which provides a natural and user-centred approach to navigation in the VE and can improve the user's sense of reality and presence. ICCN is composed of three major phases: Constant Velocity Navigation, Collision Detection and Avoidance, and Path Adjustment. The ICCN can reduce the user's fatigue and improve the user's presence in the VE. The small experimental study reported in this paper suggests that the ICCN will be a natural, straightforward, and useful navigation interface in VE.     

交互式虚拟导航技术研究

研究基于体单元的交互式导航技术,是一具有虚拟现实特征的交互式方法可用于带空腔的人体器官的疾病疹断。其内容涉及虚拟相机的概念设计,受控运动的特性研究,潜在可见表面集的缩减技术和交互式演示技术。     

Indoor space art design based on immersive VR and embedded system

Indoor space systems are mainly used in outdoor environments, but indoor navigation systems are still under development. This article introduces indoor spatial analysis based on virtual reality to people who help in indoor environments. Work is done with the mechanisms and methods used for storage, dynamic reconstruction, and navigation in 3D virtual space using databases. The characteristics of the room are shown in the database table. The proposed Virtual Reality Environment Modeling (VREM) method is used to create a 3D image to analyze the room space. The client browser requests the virtual world through the server that provides the URL. The selected virtual world and server virtual format is returned to the client. The new 3D simulation embedded system is used to act as an agent for the behavior of simulation embedded system and other objects on the Internet and their associated syntactic structures. This method is first applied to the forward transform 3D to enhance the virtual and reconstructed images of the discrete cosine transform. Effectively view large virtual worlds and easily modify them. The size, shape, or other aspects of the virtual world's elements can be changed by changing the data in the database. Finally, virtual block matching algorithms are applied to analyze virtual indoor components or objects to provide better results than existing methods.     

用势场法改进的极限环导航方法在移动机器人中的应用

结合人工势场法,提出一种新的极限环方法.它可以在诸如机器人足球赛等动态变化的环境中为自主移动机器人进行很好的实时路径规划.将障碍物的运动速度和一些不易直接表达的策略① 等转化成势场,然后把势场抽象成虚拟的障碍物,通过改变非线性方程的极限环半径,获得动态运动路径规划.这种方法能让机器人对高速运动的障碍物有很平滑的避障能力,并且能综合复杂的路径规划要求达到目标.仿真和试验都表明了这种方法在机 器人足球赛中的应用价值.􀁱 􀁽     

An immersive multi-agent system for interactive applications

This paper presents an interactive multi-agent system based on a fully immersive virtual environment. A user can interact with the virtual characters in real time via an avatar by changing their moving behavior. Moreover, the user is allowed to select any character as the avatar to be controlled. A path planning algorithm is proposed to address the problem of dynamic navigation of individual and groups of characters in the multi-agent system. A natural interface is designed for the interaction between the user and the virtual characters, as well as the virtual environment, based on gesture recognition. To evaluate the efficiency of the dynamic navigation method, performance results are provided. The presented system has the potential to be used in the training and evaluation of emergency evacuation and other real-time applications of crowd simulation with interaction.     

基于虚拟子目标的移动机器人主动寻径导航

纯粹的反应式导航算法有时会出现“没有远见现象”,为此设计了一种基于行为和虚拟路径子目标的 移动机器人主动寻径导航策略．该策略首先在机器人的局部探测域内运用改进的可视点寻径法寻找最优虚拟子目 标,接着使用行为决策树实现快速的行为决策．机器人将如人类寻路一样,主动地灵巧绕过障碍物,基于圆弧轨迹 的运动方式使之能以平滑的路径到达目标．仿真结果验证了本策略的可行性和有效性．     

Navigation in hypertext through virtual environments

Users of hypertext systems require some form of navigation aid or 'browser'. Typically these have been produced as schematic representations of the hypertext network. The advent of 'virtual reality' technology, and particularly less costly forms of this, offers new possibilities for hypertext navigation whereby information can be presented in the form of a virtual environment. Users can then move around the virtual world in much the same conceptual fashion as they move around the real world. Based upon an extensive review of hypertext navigation problems and the aiding systems proposed to deal with these, four different types of navigation aid have been built; these are schematic and spatial representations in two and three dimensions. Of particular interest is the 3D spatial representation, built as a virtual environment in Virtus Walkthrough; the proposition is that such a virtual world navigation aid will offer substantial usability advantages for hypertext databases.     

一种新的基于图象的虚拟场景重建与漫游框架

本文介绍了利用图象产生虚拟场景的方法，分析了基于图象的虚拟的实的结构，提出了一种新的基于图象的虚拟场景的重建与游框架，并对其中的深度恢复这一关键２技术进行了讨论。