Time Optimal Control for Data Harvesting in Mobile Wireless Sensor Networks

In this article, we consider the problem of finding an optimal trajectory of a single agent tasked with harvesting data from multiple mobile sensor nodes in a wireless sensor network. We describe data transmission using a free-space broadcast communication model and formulate an optimal control problem to extract the data from all the nodes in minimal time. In a 1-D mission space, we demonstrate that the optimal motion strategy can be expressed in parametric form. Within this strategy, the agent's motion is determined by a sequence of two modes, alternating between full-speed travel and a motion derived from a parametric convex combination function of sensor velocities. We present two approaches for solving the parametric optimal control problem, a gradient-descent-based scheme and a heuristic search method. The effectiveness of these methods is demonstrated through simulations.