Implementation of position–force and position–position teleoperator controllers with cable-driven mechanisms

Bilateral teleoperation involves the motion control of a slave mechanism with a master mechanism that is capable of reflecting the sensory information such as force and torque signals captured from the master mechanism. Normally, the master and slave mechanisms in a teleoperator system are physically separated and are connected via some communication interface. As technology in robotic mechanism design continuously develops, advanced teleoperator systems are emerging. From the handling of hazardous and delicate materials in nuclear decommissioning to medical applications such as orthopedic and laparoscopic surgery, the demand for high bandwidth and fine-force reflecting bilateral teleoperator systems has become more and more important. This paper focuses on the implementation of an advanced master–slave teleoperator system using cable-driven WAM and PHANToM devices. Special emphasis is placed on the pragmatic issues on the implementation based two different designs of the teleoperator control schemes and the performance of the system under these two teleoperator control schemes.     

Mapping land cover change in a reindeer herding area of the Russian Arctic using Landsat TM and ETM+ imagery and indigenous knowledge

Much of Russia north of the treeline is grazed by reindeer, and this grazing has materially altered the vegetation cover in many places. Monitoring vegetation change in these remote but ecologically sensitive regions is an important task for which satellite remote sensing is well suited. Further difficulties are imposed by the highly dynamic nature of arctic phenology, and by the difficulty of obtaining accurate official data on land cover in arctic Russia even where such data exist. We have approached the problem in a novel fashion by combining a conventional multispectral analysis of satellite imagery with data on current and historical land use gathered by the techniques of social anthropology, using a study site in the Nenets Autonomous Okrug (NAO). A Landsat-7 ETM+ image from the year 2000 was used to generate a current land cover classification. A Landsat-5 TM image was used to generate a land-cover classification for 1988, taking due account of phenological differences and between the two dates. A cautious comparison of these two classifications, again taking account of possible effects of phenological differences, shows that much of the study area has already undergone a notable transformation to grass-dominated tundra, almost certainly as a result of heavy grazing by reindeer. The grazing pattern is quite heterogeneous, and may have reached unsustainable levels in some areas. Finally, we suggest that this situation is unlikely to be unique to our study area and may well be widespread throughout the Eurasian tundra zone, particularly in the west.     

多机器人系统中的动态避碰规划

研究冲突区域中多机器人间的协调和避碰问题。采用集中-分布相结合的规划方法，根据系统的拓扑结构为每个机器人规划路径，在冲突区域内使用优先级策略对机器人的运动特征进行分布式规划。通过上下层智能的融合，提高整个系统的智能。     

An Efficient Representation of Edge Shapes in Topological Maps

There are nodes and edges in a topological map. Node data has been used as a main source of information for the localization of mobile robots. In contrast, edge data is regarded as a minor source of information, and it has been used in an intuitive and heuristic way. However, edge data also can be used as a good source of information and provide a way to use edge data efficiently. For that purpose, we define a data format which describes the shape of an edge. This format is called local generalized Voronoi graph's angle (LGA). However, the LGA is constituted of too many samples; therefore, real time localization cannot be performed. To reduce the number of samples, we propose a compression method which utilizes wavelet transformation. This method abstracts the LGA by key factors using far fewer samples than the LGA. Experiments show that the LGA accurately describes the shape of the edges and that the key factors preserve most information of the LGA while reducing the number of samples.     

Symbolic Place Recognition in Voronoi-Based Maps by Using Hidden Markov Models

This article presents a new algorithm to recognize natural distinctive places such as corridors, halls, narrowings, corridors with doors opening on the left side, etc., from indoor environments using Hidden Markov Models (HMM). HMM give a stochastic solution which can be used to make decisions on localization, navigation and path-planning. The environment is modeled as a topo-geometric map which combines topological and geometric information. This map is obtained from a Voronoi diagram using measurements of a laser telemeter. The characteristics of topo-geometric map (nodes, number of edges adjacent to nodes, slope of edges, etc.) are used to learn and to recognize the different places typical of indoor environments. This map can be used in order to resolve several problems in robotics such as localization, navigation and path-planning. Our method of place recognition is a fast and effective way for a robot to recognize typical places of indoor environments from a topo-geometric map.     

An Architecture for Distributed Environment Sensing with Application to Robotic Cliff Exploration

Future planetary exploration missions will use cooperative robots to explore and sample rough terrain. To succeed robots will need to cooperatively acquire and share data. Here a cooperative multi-agent sensing architecture is presented and applied to the mapping of a cliff surface. This algorithm efficiently repositions the systems' sensing agents using an information theoretic approach and fuses sensory information using physical models to yield a geometrically consistent environment map. This map is then distributed among the agents using an information based relevant data reduction scheme. Experimental results for cliff face mapping using the JPL Sample Return Rover (SRR) are presented. The method is shown to significantly improve mapping efficiency over conventional methods.     

串联磁路结构直接驱动电动机及相关技术概述

在介绍了直接驱动电动机主要分类的基础上，回顾了国内外直接驱动电动机的研究现状，提出了串联磁路结构直接驱动电动机的新方案及其具体结构。     

从系统的观点看湘西土家族苗族自治州的战略发展

湘西土家族苗族自治州的主要优势是资源优势 ,而资源优势中最大的优势是得天独厚的旅游资源优势和生态环境资源优势。未来的湘西州应发展成为旅游和生态农业产业化为主导的民族特色和绿色经济地区。湘西州开发的重点领域和主攻方向主要为生态环保、生态农业与农业产业化、旅游、交通、能源、通讯和信息化以及科技教育八个方面     

空间三臂机器人在操作中的平衡问题

就三臂空间机器人的一臂与航天器固抓、一臂操作、第三臂作平衡协调操作的问题进行了理论研究,取得了在线动量和角动量守衡意义上的平衡操作结论.对一个在气浮平台上运动的简单的三臂空间机器人的实例进行了仿真计算,证明该方法是可行的.为三臂多关节空间机器人的平衡协调操作提供了一种实用的方法.     

全自主型足球机器人目标识别与定位方法研究

以全自主型足球机器人的视觉系统为研究对象，介绍了一种基于彩色图象的目标识别与定位方法，重点研究了颜色空间的选取，目标识别中确定阀值的策略及特征点的选取方法，对如何提高颜色识别算法的鲁棒性，稳定性等问题进行了较为深入的探讨。实验结果验证了算法的有效性。所提出的算法已经在国内国际比赛中应用，收到了很好的比赛效果。