Drones and delivery robots have a range problem. Their batteries limit how far they can travel from a depot, which limits how many deliveries they can make per trip. The standard solution is larger batteries, but larger batteries mean heavier vehicles, which means more energy per delivery — a diminishing-returns spiral.
The FINDER algorithm (arXiv:2505.23584) proposes a different solution: use trucks as mobile charging platforms. Drones and robots ride on the truck between delivery zones, recharging from the truck's electrical system while in transit. The truck's idle time — driving between stops with no delivery happening — becomes the charging window.
The counterintuitive result: deliberately routing the truck through longer paths can reduce total delivery time. A truck detour that adds five minutes of driving gives the drone ten minutes of charging, enabling three additional deliveries that would otherwise require a return trip to depot. The system optimizes the joint truck-drone-robot schedule rather than minimizing any single vehicle's path.
This inverts standard logistics thinking. Vehicle routing problems traditionally minimize distance or time for each vehicle independently. Multi-platform delivery requires maximizing the overlap between one vehicle's idle time and another vehicle's charging need. The objective function isn't distance; it's temporal synchronization across platforms with different energy constraints.
The practical implication: en-route charging makes vehicle range a function of the schedule, not the battery. A drone that can fly 15 minutes becomes a drone that can deliver all day, provided the truck's route creates sufficient charging windows. The constraint migrates from hardware (battery capacity) to software (route optimization) — which is exactly the kind of constraint that gets cheaper over time.