Design and Analysis of a Small Unmanned Aerial System (UAS) Power Distribution System

All electrically powered autonomous vehicles possess a system that distributes power to all the vital components of the vehicle. The U.S. Army Combat Capabilities Development Command (DEVCOM) Army Research Laboratory (ARL) uses group 1 unmanned aerial systems (UASs) (weighing 20 lb) as the vehicle platform in several projects.

Army Research Laboratory, Aberdeen Proving Ground, MD

All electrically powered autonomous vehicles possess a system that distributes power to all the vital components of the vehicle. At the U.S. Army Combat Capabilities Development Command (DEVCOM) Army Research Laboratory (ARL), several projects are using unmanned aerial systems (UASs) as a vehicle platform. Some UAS being used are classified as group 1, meaning they weigh under 20 lb. The group 1 UASs that ARL conducts research with are very fast and agile quadrotors. Such quadrotors typically have four rotors and light payloads and can very quickly accelerate and effortlessly reach speeds over 100 kph. To do this, these quadrotors can draw upward of 400 A at 30 VDC in bursts. To meet those requirements, the motor/propeller combination requires large amounts of power relative to the size of the UAS. Up until this point, ARL's UASs have been using commercial off-the-shelf power distribution boards (PDBs) to meet the power distribution demands. A custom PDB would satisfy the DOD's desire to source more UAS components domestically, as it would be designed and made in the U.S., which is unique for this type of UAS component.

This report considers all aspects of design of a PDB to include shape, size, components, cost, voltage regulators, peripherals, and so on. This report explores these issues in the context of a custom designed PDB needed for a specific ARL project, but can be used as a starting point for ARL engineers who are working on semiautonomous and fully autonomous vehicle projects. For the custom PDB to succeed, the board needs to perform just as well, if not better, than the current PDBs used on the UAS. The two PDBs this project currently uses are the following: Advanced Power Drives' (APD's) 500X (Fig. 1) and Matek Systems' FCHUB-12S PDB (Fig. 2).