Using the distributed controller, each
robot in the group computes its virtual potential force based on its own neighbors
and sensing of the obstacles.
(a) Initial deployment (b) Lost 1 node
(c) Lost 2 nodes (d) lost 4 nodes
Fig. 14. Redeployment of mobile sensors after a failure of one or more sensors.
4.3 Fault tolerance
One of the most import features for a mobile sensor network is its redundancy and
fault tolerance. If one or more robots fail, the other robots can redeploy their positions
according to the requirement of the task. Figure 14 shows the validity of the
deployment algorithm for this situation. Starting with a system configuration shown
in Figure 14(a), Figures 14(b), (c) and (d) show the adjustment of the system after 1,
2, and 4 nodes are lost respectively. Under the deployment algorithm, the system can
reorganize itself if some nodes fail. Figure 14 shows the Delaunay triangulation and
Voronoi diagram after the redeployment.
??’60 ??’40 ??’20 0 20 40 60
??’60
??’40
??’20
0
20
40
60
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
??’60 ??’40 ??’20 0 20 40 60
??’60
??’40
??’20
0
20
40
60
1
2
3
4
5
6
7
8
9
10
11
12 13
14
??’60 ??’40 ??’20 0 20 40 60
??’60
??’40
??’20
0
20
40
60
1
2
3
4
5 6
7
8
9
10
11
12
13
??’60 ??’40 ??’20 0 20 40 60
??’60
??’40
??’20
0
20
40
60
1
2
3
4
5
6
7
8
9
10
11
Chapter 3 A Scalable Graph Model and Coordination Algorithms 81
5 Conclusion
This chapter presents a distributed model for mobile sensor network based on graph
theory, which uniquely defines the relationship of one robot with its neighbors.
Pages:
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154