  Unmanned aerial vehicles (UAVs) have received plenty of attention due to
their high flexibility and enhanced communication ability, nonetheless, the
limited onboard energy restricts UAVs' application on persistent data
collection missions in large areas. In this paper, we propose a rechargeable
UAV-assisted periodic data collection scheme, where a UAV is dispatched to
periodically collect data from sensor nodes (SNs) in the mission area and
charged by a wireless charging platform. Specifically, the periodic data
collection completion time is minimized by optimizing the UAV trajectory to
reach the optimal balance among the collection time, flight time, and
recharging time. The formulated problem is non-convex and difficult to solve
directly. To tackle this problem, we divide the main problem into two
sub-problems and address them by leveraging successive convex approximation
(SCA), bisection search, and heuristic methods. Then, we propose a periodic
trajectory optimization algorithm to iteratively solve the two sub-problems to
minimize the completion time. Furthermore, to deal with the dynamics of SNs, we
propose a low-complexity trajectory adjustment strategy, where the trajectory
can be maintained or adjusted locally at the SNs change, which significantly
mitigates the computation cost of re-optimization. The simulation results show
the superiority and robustness of the proposed scheme and the completion time
is on average 39% and 33% lower than the two benchmarks, respectively.
