Visual Homing: Surfing on the Epipoles

We introduce a novel method for visual homing. Using this method a robot can be sent to desired positions and orientations in 3D space specified by single images taken from these positions. Our method is based on recovering the epipolar geometry relating the current image taken by the robot and the target image. Using the epipolar geometry, most of the parameters which specify the differences in position and orientation of the camera between the two images are recovered. However, since not all of the parameters can be recovered from two images, we have developed specific methods to bypass these missing parameters and resolve the ambiguities that exist. We present two homing algorithms for two standard projection models, weak and full perspective.Our method determines the path of the robot on-line, the starting position of the robot is relatively not constrained, and a 3D model of the environment is not required. The method is almost entirely memoryless, in the sense that at every step the path to the target position is determined independently of the previous path taken by the robot. Because of this property the robot may be able, while moving toward the target, to perform auxiliary tasks or to avoid obstacles, without this impairing its ability to eventually reach the target position. We have performed simulations and real experiments which demonstrate the robustness of the method and that the algorithms always converge to the target pose.     

Improved Rover State Estimation in Challenging Terrain

Given ambitious mission objectives and long delay times between command-uplink/data-downlink sessions, increased autonomy is required for planetary rovers. Specifically, NASA's planned 2003 and 2005 Mars rover missions must incorporate increased autonomy if their desired mission goals are to be realized. Increased autonomy, including autonomous path planning and navigation to user designated goals, relies on good quality estimates of the rover's state, e.g., its position and orientation relative to some initial reference frame. The challenging terrain over which the rover will necessarily traverse tends to seriously degrade a dead-reckoned state estimate, given severe wheel slip and/or interaction with obstacles. In this paper, we present the implementation of a complete rover navigation system. First, the system is able to adaptively construct semi-sparse terrain maps based on the current ground texture and distances to possible nearby obstacles. Second, the rover is able to match successively constructed terrain maps to obtain a vision-based state estimate which can then be fused with wheel odometry to obtain a much improved state estimate. Finally the rover makes use of this state estimate to perform autonomous real-time path planning and navigation to user designated goals. Reactive obstacle avoidance is also implemented for roaming in an environment in the absence of a user designated goal. The system is demonstrated in soft soil and relatively dense rock fields, achieving state estimates that are significantly improved with respect to dead reckoning alone (e.g., 0.38 m mean absolute error vs. 1.34 m), and successfully navigating in multiple trials to user designated goals.     

Automatic Mapping of Dynamic Office Environments

We present a robot, InductoBeast, that greets a new office building by learning the floorplan automatically, with minimal human intervention and a priori knowledge. Our robot architecture is unique because it combines aspects of both abductive and inductive mapping methods to solve this problem. We present experimental results spanning three ofiice environments, mapped and navigated during normal business hours. We hope these results help to establish a performance benchmark against which robust and adaptive mapping robots of the future may be measured.     

网址导航界面链接按钮形式对视觉搜索的影响

为了探索网址导航界面中网站链接按钮的形式对用户认知以及绩效的影响。文中在对现有网址导航界面进行分析和设计的基础上,通过眼动追踪技术获取网站导航网页界面中视觉搜索的眼动数据,并按注视程度将其划分水平,结合网站链接按钮的另外两个设计要素(颜色和有无图标)作为实验材料的编码元素,设计实验并测试用户在上述网址导航原型上操作任务的绩效。结果表明,链接所处位置的注视水平和有无图标对链接按钮的搜索绩效有显著影响,更高的注视水平位置和有图标的编码形式能够促进网址导航的搜索绩效。鉴于链接按钮不同编码形式对网址导航界面搜索绩效的影响,网址导航界面设计可以采用更有区分度的链接按钮排列,以提高界面的可用性。     

攻击机动目标的最优导引规律研究

针对纵轴方向没有轨控发动机的ＫＫＶ,建立空间拦载的线性运动学模型,通过采用新的剩余时间计算方法,提出了拦截任意机动目标的最优导引规律,最后,分别采用最优制导律和比例导引,对平面拦截过程进行计算机仿真。仿真结果表明,最优制导律和比例导引相比更能有效地拦截机动目标。     

一种新型航姿系统

介绍了一种新型多功能惯性器件,它将双轴陀螺丐加速度计巧妙于民一体用它可构成新型垂直陀螺,再与磁通门传感器合成新型航姿系统,该系统能消除载体的变速运动对输出航姿角的影响,结构简单、紧凑,成本较低,可用于定向性移动卫星通信天线跟踪卫星的开环控制系统中。     

运载火箭初始对准仿真系统的研究

本文讨论并建立了运载火箭初始对准系统的物理数学模型,并用多媒体手段对系统实际工作过程进行了仿真模拟。结果表明,仿真系统完全满足训练要求。     

GPS／GLONASS组合导航中的星历计算与数据融合

针对ＧＰＳ／ＧＬＯＮＡＳＳ组合导航中的需要,分析了ＧＬＯＮＡＳＳ卫星的广播星历格式,简化受力模型和星历计算方法,并给出了ＧＰＳ／ＧＬＯＮＡＳＳ的数据融合模型。     

一种特殊的螺旋输送机中间支承结构的设计

在一种特殊的快速螺旋输送机中采用了中间支承结构。在工作过程中,螺旋旋转产生的惯性离心力引起中间支承的动反力。与慢速螺旋相比,这种动反力要大得多,它不仅减小支承的承载能力,还将造成支承的弯曲,因此,在设计支承结构时,必须充分考虑。计算时,首先综合考虑预紧力、螺旋重力、惯性离心力引起的动反力及螺纹力矩的影响,建立强度条件方程,确定支承结构尺寸。随后,检验变形。另外,支承的预紧与防松也是相当重要的。     

一个多媒体教学系统的设计

本文介绍了工程制图多媒体CAI软件的开发思想,并就其实现作了详细论述.