Thermal Updraft Profiling with an Array of Show Drones

Abstract

Localized thermal convective updrafts in the atmosphere, commonly referred to as thermals, serve as a significant source of energy-efficient flight for birds, human pilots, and autonomous aircraft. Measuring the vertical airspeed distribution within these updrafts to estimate their strength and characteristics is a significant empirical challenge. In this study, we introduce a proof-of-concept distributed thermal measurement system that uses small, cost-effective multirotor drones equipped with standard sensors, eliminating the need for specialized airspeed instruments. These drones estimate updraft strength by analyzing performance parameters such as power consumption or rotor rotation speed. First, we conducted extensive investigations in a simulated environment that incorporated varying windy conditions to establish the relationship between the updraft speed (the vertical speed of the air) and the performance parameters of the drones. Following this, we conducted outdoor experiments involving up to 49 multirotor drones to demonstrate the effectiveness of the distributed measurement system in action. By advancing our understanding of thermal updrafts, this research contributes valuable information to analyze avian flight behavior and also facilitates the development of realistic simulation environments. These advancements can enhance the design of thermal-utilizing self-driving algorithms for unmanned aerial vehicles (UAVs), paving the way for more efficient and adaptive robotic systems.