Power Management Strategies for Small Electric Fixed Wing UAVs Employed in Natural Resources Mapping

摘要

Small Electric fixed-wing unmanned Aerial Vehicles (SE-FW UAVs) constitute a very powerful tool for mapping natural resources because of their numerous capabilities for remote sensing and their low environmental footprint, e.g. emissions and noise. However, mapping extensive areas with this type of UAVs remains as a challenge because of their low performance at high altitudes and harsh environmental conditions, e.g. strong winds, low air density, and low temperature). This work investigates practical strategies to enhance the performance of existing SE-FW UAVs, based on a more efficient management of their battery power, considering that current performance models for battery-powered UAVs do not account for the energy management of the different UAV subsystems such as the avionics or the payload used. Through an analytic and experimental approach the power characteristics of avionics and payloads widely employed in SE-FW UAVs are determined. The parametric and experimental bench tests are based on a commercial UAV, which is currently employed to monitor natural resources. The UAV is equipped with an autopilot system, telemetry, payload for imagery gathering, and a series of sensors for in-flight data acquisition. Furthermore three different payload weights which represents commonly surveillance applications have been evaluated. In this analysis, the influence of the battery electrical parameters such as its capacity, number of cells, and its rate of discharge are assessed to define their impact on UAV performance. The range of operation for these electrical component is defined based on a benchmarking analysis. In addition, volume, mass and stability constraints have been incorporated into the analysis to determine the power architecture that provides maximum endurance and fulfills the operating requirements. Results indicate the effectiveness of increasing the battery capacity for achieving longer endurance. In addition, it is observed the importance of accounting for the power consumtion of each system to have reliable performance calculations. In this regard, it is observed that approximately 50% of the UAV endurance is reduced when avionics and the entire mission energy consumption is considered. Nevertheless, these results are related to the assumptions of constant MTOW and fixed UAV propulsion system scheme. The incorporation of the aforesaid aspects will be examined in future works.