Human Factors and Trainability of Piloting a Simulated Micro Unmanned Aerial Vehicle

Abstract

In 2004, the U.S. Army Research Institute's (ARI) Simulator Systems Research Unit began studies involving the training requirements for operators of a micro-unmanned aerial vehicle (MAV). Our research involved the use of a touch-screen operator control interface developed for the DARPA MAV Advanced Technology Demonstration. This control system allowed operators to plan and run autonomous flight missions or to tele-operate a simulated MAV around a static synthetic environment. An initial study focused primarily on the usability of the system. Extensive heuristic evaluations were conducted by seven volunteers with backgrounds in human factors and military training systems. Each evaluator completed a self-paced training session including exercises that tested their ability to perform various control functions. Lack of immediate feedback from touch-screen inputs and missing or obscure status information formed the basis of several of the usability issues. Manually piloting the MAV presented the most difficulty to operators. As such, a second study was conducted that focused specifically on manual control tasks. In this study, participants were trained on manual control of the MAV, and then completed four increasingly difficult missions, requiring them to pilot the vehicle through the synthetic environment. This experiment was designed to compare the effect of supplemental sensor imagery on mission performance. During Study 1, operators could choose to view a sensor image taken from a fixed camera pointed 15 degrees below horizontal or straight down (90 degrees), but only one view was available at a time. During Study 2, operators were provided with three sensor views simultaneously. The 15-degree view was presented in a primary sensor window, and two additional views were displayed in smaller windows below it. The camera angle of one of these supplemental views was the manipulated independent variable — 30, 60, or 90 degrees from horizontal. The remaining window always contained an overhead satellite view (downward view from 5000 feet above the MAV). Data were collected on time to complete each mission, the number of physical interactions each user made with the interface, SME ratings, workload, and usability. Results indicated that mission requirements had a greater effect on performance and workload ratings than the camera angle of the supplemental view, though the camera angle of the supplemental view did affect mission time required to capture images of designated target buildings. Session averages of workload, usability, mission completion time, and SME rating were significantly inter-correlated. Higher SME ratings were associated with lower participant ratings of workload, shorter mission completion times, and higher usability ratings.