碩士 / 國立中央大學 / 資訊工程研究所 / 96 / In this thesis, we propose a mobile robot navigation and coordination algorithm using directional antennas in positionless wireless sensor networks. When a specific node, called waiting-for-rescue node (WFR node), detects the occurrence of an event, it broadcasts an event announcement message to the entire network for asking a mobile robot to come to help. In many existent schemes, the broadcast is achieved by the flooding scheme and thus incurs many redundant forwarding messages. We propose an energy efficient broadcast scheme called farthest node forwarding (FNF), which utilizes received signal strength for a node to determine the backoff time to forward the broadcast message. Farther nodes have shorter backoff times. And a node does not forward the message if it hears another node forwarding the message before the backoff time elapses. This can reduce a lot of redundant forwarding messages to save energy for prolonging the network lifetime. The simulation results show that FNF can not only reduce a great deal of forwarding messages but also achieve high reachability. We also utilize FNF scheme to establish a spanning tree rooted at WFR node and containing only forwarding nodes for planning paths from mobile nodes to WFR nodes. With the consideration of multiple WFR nodes and multiple mobile robots, we also develop an energy- and time-efficient mobile robot coordination scheme. The scheme is distributed and greedy-based; each WFR node selects the nearest mobile robot to ask it to come to help. In mobile robot design, we equip a directional antenna on a mobile robot for guiding it to move to the WFR node in positionless wireless sensor networks. In our simulation experiments, the sensor nodes can successfully guide the mobile robot to move towards the WFR node efficiently.
| Identifer | oai:union.ndltd.org:TW/096NCU05392035 |
| Date | January 2008 |
| Creators | Fu-jheng Deng, 鄧福錚 |
| Contributors | Jehn-Ruey Jiang, 江振瑞 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 34 |
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