MILS and HILS Analysis of Power Management System for UAVs

Abstract

This study developed four different power management system (PMS) prototypes based on the most popular mission computers used for offboard mission operation by the PX4 (open-source UAV flight controller software platform) user community for a photovoltaic (PV)-powered unmanned aerial vehicle (UAV). The four PMS prototypes were compared in terms of operational performance through an analysis of data obtained from a model-in-the-loop simulation and hardware-in-the-loop simulation using charging and discharging current patterns, saved from an outdoor PV panel power generation and multirotor UAV flight tests, respectively, under varying environmental temperature. Two types of simulations were performed, depending upon the additional placement of a supercapacitor in parallel with a Li-ion battery pack, to verify the effectiveness of the Li-ion battery pack life extension through high current shock mitigation. Simulation results demonstrated that the application of a supercapacitor in parallel with a Li-ion battery pack resulted in poor performance indicated by in-flow current fluctuation deviation measurements during the end of the constant current and constant voltage charging process. Moreover, this behavior was confirmed to be mainly because of the inherent high C-rate performance capability of the Li-ion battery pack compared to the supercapacitor. Among the four PMS candidates, under 25 degrees C without supercapacitor, Jetson TX2 was found to exhibit the best functionality in terms of power management (0.41 W of power fluctuation deviation), whereas AMega yielded the best functionality in terms of energy management (1165.4 s of flight time).