Optimized trajectory of a robot deploying wireless sensor nodes

Abstract

Mobile robots can be used to deploy static wireless sensor nodes to achieve the coverage and connectivity requirements of the applications considered. Many solutions have been provided in the literature to compute the set of locations where the sensor nodes should be placed. In this paper, we show how this set of locations can be used by a mobile robot to optimize its tour to deploy the sensor nodes to their right locations. In order to reduce both the energy consumed by the robot, its exposure time to a hostile environment, as well as the time at which the wireless network becomes operational, the optimal tour of the robot is this minimizing the delay. This delay must take into account not only the time needed by the robot to travel the tour distance but also the time spent in the rotations performed by the robot each time it changes its direction. This problem is called the Robot Deploying Sensor nodes problem, in short RDS. We first show how this problem differs from the well-known traveling salesman problem. We then propose an integer linear program formulation of the RDS problem. We propose various algorithms relevant to iterative improvement by exchanging tour edges, genetic approach and hybridization. The solutions provided by these algorithms are compared and their closeness to the optimal is evaluated in various configurations.

Optimized trajectories of multi-robot deploying wireless sensor nodes

“…When one robot is involved, this problem becomes similar to the Traveling Salesman Problem, TSP [3], whose goal is to find the shortest tour visiting all sensor nodes positions (representing the cities) only once and going back to its initial position. In [4], we propose the RDS problem, Robot Deploying Sensor, where one robot is in charge of placing sensor nodes at their precomputed positions. The RDS problem is based on the principle of TSP.…”

“…The output is two child vectors, which have certain features from both parents. For the sensor-part, we will apply the same crossover operator as used in the RDS problem [4], that is PMX (Partially Matched Crossover) due to its good performances [9].…”

A game theory-based approach for robots deploying wireless sensor nodes

“…This tour should, on the one hand, allow the robot to communicate with every sensor node during the tour with a minimum number of pause points, and on the other hand, it should have the minimum length in terms of distance traveled. In a previous study [1], we proposed a Robot Deploying Sensor nodes problem (RDS) which aims to minimize the robot tour duration (i.e. the time spent by the robot to place its sensor nodes and return to its starting position).…”

“…We first notice that if C max,i < n/2 for any i ∈ [1,2], it is impossible to cover all the PoIs with two robots.…”

“…This is a variant of the Traveling Salesman Problem (TSP), where the changes of direction of the robot have to be taken into account in the tour duration as computed in Eq. 1 (see [1] for examples). • Several robots are available.…”