虚拟现实技术在远程制图软件中的应用

在开发的“机械制图多媒体辅助教学系统”课件的基础上,对虚拟现实技术在远程制图课件中的应用作进一步研究。该文简要介绍了实现虚拟现实场景的方法,详细阐明用VRML97和3DSMAX虚拟现实技术开发远程制图软件虚拟现实场景的方法、关键技术及异同点。     

曲线最佳点测设法

介绍了曲线最佳点测设法简化计算的原理、施测方法及困难地区圆曲线测设中障碍测设技巧．     

Fair webs

Fair webs are energy-minimizing curve networks. Obtained via an extension of cubic splines or splines in tension to networks of curves, they are efficiently computable and possess a variety of interesting applications. We present properties of fair webs and their discrete counterparts, i.e., fair polygon networks. Applications of fair curve and polygon networks include fair surface design and approximation under constraints such as obstacle avoidance or guaranteed error bounds, aesthetic remeshing, parameterization and texture mapping, and surface restoration in geometric models.     

嵌入式Linux下多路超声波测距系统设计

本文描述了机器人避障过程中超声波测距的工作原理和设计方法。介绍了多路超声波测距系统的硬件设计及软件工作流程。分析了嵌入式Linux系统下超声波测距模块驱动程序的结构,并结合S3C44B0X uClinux系统的轮式移动机器人平台,实现了机器人在未知环境下的导航避障过程。     

一种混联码垛机器人智能避障轨迹规划与仿真

由于码垛机器人应用环境复杂、不确定条件多等诸多问题,针对现有的避障轨迹规划算法存在的划分空间上的繁琐情况,提出了一种智能避障轨迹规划算法,包括障碍物信息提取和避障轨迹设计,最大程度降低障碍物信息与轨迹设计部分的耦合度,达到减少动态空间下频繁划分空间的目的.最后在OPENGL软件上研发的三维仿真平台上进行运动学仿真与验证.仿真结果表明,改进算法规划出的轨迹能有效避开障碍物且轨迹符合预期的要求,充分验证了轨迹规划算法的可行性和有效性.     

Tangential Gap Flow (TGF) navigation: A new reactive obstacle avoidance approach for highly cluttered environments

This paper presents a novel reactive collision avoidance method for mobile robots moving in dense and cluttered environments. The proposed method, entitled Tangential Gap flow (TGF), simplifies the navigation problem using a divide and conquer strategy inspired by the well-known Nearness-Diagram Navigation (ND) techniques. At each control cycle, the TGF extracts free openings surrounding the robot and identifies the suitable heading which makes the best progress towards the goal. This heading is then adjusted to avoid the risk of collision with nearby obstacles based on two concepts namely, tangential and gap flow navigation. The tangential navigation steers the robot parallel to the boundary of the closest obstacle while still emphasizing the progress towards the goal. The gap flow navigation safely and smoothly drives the robot towards the free area in between obstacles that lead to the target. The resultant trajectory is faster, shorter and less-oscillatory when compared to the ND methods. Furthermore, identifying the avoidance maneuver is extended to consider all nearby obstacle points and generate an avoidance rule applicable for all obstacle configurations. Consequently, a smoother yet much more stable behavior is achieved. The stability of the motion controller, that guides the robot towards the desired goal, is proved in the Lyapunov sense. Experimental results including a performance evaluation in very dense and complex environments demonstrate the power of the proposed approach. Additionally, a discussion and comparison with existing Nearness-Diagram Navigation variants is presented.     

绿色设计及其在城市建设实践中的难点

简要论述了可持续发展战略与绿色设计的关系，在阐明绿色设计的要领原则及其操作的基础上，分析了在城市建设实践中贯彻绿色设计思想的六个难点。     

市民参与城市规划的主要障碍及对策——基于苏州、扬州的调查数据分析

受公共参与理论大环境的影响，学术界已将触角伸入到城市规划中的市民参与之中；政府在一定程度上也开始倡导公众参与并付诸实施。但由于存在着信息不对称、对市民利益的忽视、自治组织的缺失等诸多影响市民参与的因素．我国城市规划中的市民参与虽有量的变迁．却缺少质的变化。要使城市规划中市民实际参与率提高并向更深层次发展，需着力培养充分知情的市民、注意市民利益的关联度和发展市民的自治组织。     

Numerical investigation of the mechanism behind the deflagration to detonation transition in homogeneous and inhomogeneous mixtures of H2-air in an obstructed channel

The accidental release of hydrogen into enclosures can result in a flammable mixture with concentration gradients and possible deflagration-to-detonation transition (DDT). This numerical study aims to investigate the effect of obstacle spacing and mixture concentration on the DDT in a homogeneous and inhomogeneous hydrogen-air mixture. The paper focuses on the mechanisms behind the DDT in two mixtures with an average hydrogen concentration of 15% and 30%. Unlike the near-stoichiometric mixture, in the lean mixture, DDT only occurs in the inhomogeneous mixture. Depending on obstacle spacing, three different regimes of DDT were observed in the near-stoichiometric inhomogeneous mixture: i) Detonation was ignited when a strong Mach stem formed and propagated between the obstacles; ii) two explosion centers appeared when incident shock and Mach stem reflected from upper and lower obstacles, respectively; iii) Mach stem did not form but DDT occurred behind the flame front at the top of the obstacle.     

Matching free stereovision for detecting obstacles on a ground plane

This paper presents a method for detecting obstacles on a ground plane from a stereo pair of images. Although we use stereovision, the obstacle detection algorithm relies neither on stereo matching nor 3D reconstruction. The principle here is to apply the projective transformation constraining the left and right images to obtain a frame of superimposed features (e.g. edges). By analysing feature superimposition after the projective transformation, a free moving space or space occupied by obstacles/occluded features can be determined.