Causes and Fixes of Unexpected Drone Shutoffs

Abstract

Drones suffer unpredictable battery performance that may cause crashes or fatal accidents during aerial missions. Users have reported that their drones unexpectedly shutoff even when they show more than 10% remaining battery capacity. After examining both the drones and battery sides, we discovered that the causes of these unexpected shutoffs to be unbalanced cell thermal degradation caused by thermal coupling between the drones and their battery cells. Drone heat dissipation differently affects battery cells, causes a different cell voltage drop, and results in unpredictable supply voltage and unexpected shutoffs. This paper describes the design and implementation of a thermal and battery-aware power management framework designed specifically for drones. Our framework transparently profiles each battery cell's resistance to capture the cell-level thermal degradation using novel discharging pulses, and estimates an accurate cell capacity, state-of-charge, and state-of-power in real-time to prevent unexpected shutoffs. We have implemented and deployed our framework on commercial drones without additional hardware or system modifications. We have evaluated its effectiveness across different drones and three different batteries demonstrating our framework generates accurate cell state-of-charge and prevents unexpected shutoffs. © 2024 Copyright is held by the owner/author(s). Publication rights licensed to ACM.