Research On Actuator Mobile Path Planning For Nodes Localization In Wireless Sensor And Actuator Networks

WSAN (Wireless Sensor and Actor Networks) is a special type of WSN (Wireless Sensor Networks), in which there is a kind of mobile node named as Actor node. The actor node can move and carry out some schedule jobs, therefore, this network come into a new self-organization wireless network. This network is capable of monitoring environment, detecting events, responding and operating some events. In these years, WSAN has been applied to several areas such as disaster detecting, intelligent building, home automation, smart space, cyber-physical system (short for CPS) and chemical attack detecting. As a bridge between physical world and digital world, WSAN has become a focus of research. In this area, in order to get node position information, the location techniques are also a core topic interested. Considering the mobility of the actor node, it’s a very effective and energy-saving method to locate the unknown sensor nods with the actor node which is used for a mobile anchor node. Mean while, to improve the precision of location technique and lessen the energy consumption, it is a necessity to plan a best moving path of actor nodes. So, the research of path planning with actor node in localization for WSAN has important theoretical and practical significance. In this thesis, the path planning of actor nodes is studied considering several aspects, such as the ratio of network coverage, the ratio of the locatable node, the precision of location and the length of the actor moving path.First of all, this thesis summarizes the research status of present mobile anchor node assisted location techniques, path plan techniques, and mobile models. Then, the physical architecture, information propagation model, and information procession link structure of WSAN are introduced. There are also some representative and detail descriptions of recent location algorithm related with WSAN.Secondly, this thesis analyzes available algorithms of path planning, and proposes a new dynamic path planning algorithm based on improved BFS algorithm. After description of the path planning algorithm, the first step of path planning is introduced, that is the selection of beacon position utilizing the improved algorithm. There is introduced the basic BFS, the enhanced work, and the comparison of simulation results of BFS, improved BFS and SCAN. We can see that if the precision of location is set, this algorithm need less virtual beacons, so that this algorithm is the energy-saving one. In other simulation, almost all the sensors can be covered.Thirdly, this thesis describes the basic Ant Colony algorithm and Ant System with Elitist Strategy, and makes some improvement based on these. The second step of path planning is the application of improved ant colony algorithm to the path planning method. Like TSP problem, all the virtual beacons are traversed to bring out the planned path. Comparing with SCAN, it can be seen that the result path length is shorter, so this algorithm can save more energy.At last, the path optimization in the real environments is studied. This thesis analyzes some mobile models, focusing on Gauss-Markov mobility model and smooth Gauss-semi-Markov mobility model, and applies these models to the planned path. The simulation results show that, the style of actor moving is smoother and more realistic. The situation with some obstacles in the moving path is also considered, and the path is optimized by Artificial Potential Field algorithm. The mobile anchor can avoid obstacles smoothly. That has practical significance.