Research On Path Planning For Robot In Water Environment Monitoring System Based On WSN

Using wireless sensor networks to monitor water environment, real time waterenvironment information can be obtained. Generally, sampling nodes need to bedistributed to appointed positions in advance in the water monitoring environment, sothat the water information at appointed positons could be sampled. This kind ofmonitoring networks is regarded as static networks. The mobile robots based onwireless sensor networks can implement dynamic monitoring to water environment.Water environment information can be sampled by mobile robots with sampling nodeson them.Water environment monitoring system based on wireless sensor networksdesigned in this paper is composed of turbidity sampling nodes, mobile nodes, basestation and management nodes. The design of sampling nodes includes both hardwareand software, which aims to sample information periodically and send it to the basestation through multi-hop Mesh networks. The communication module of mobilenodes designed based on CC2420is responsible for receive down-stream messagesfrom base station. The manage nodes parse raw data sending from sampling nodes, sothat sensor information could be viewed directly.The strengths of received signals which are sent from preinstalled positions arerecorded in both indoor and outdoor environments. The relationships are establishedbetween RSSI and transmission distance after fitting the experiment data usingMATLAB in both environments. On this basis, the coordinates of the measured nodecan be got based on maximum likelihood estimation. The location error is0.71meterswithin2.4-meter radius.The path planning for robot is implemented based on ant colony algorithm.Firstly, the modeling of robot’s working environment is established based onMAKLINK graph theory; Secondly, an initial path which is the staring value of antcolony algorithm is found by Dijksta algorithm; Finally, an optimal path is generated using ant colony algorithm.There are two innovators in this paper. One is the proposition of introducingmobile robot to water environment monitoring system, which realizes the dynamicmonitoring of the environment; The other one is the optimizing of importantparameters in ant colony system according to the average iteration numbers cost tofind the optimal path.