Effects of Haptic and 3D Audio Feedback on Pilot Performance and Workload for Quadrotor UAVs in Indoor Environments

• Main Author: Philbrick, Robert Mark
• Format: Others
• Published: BYU ScholarsArchive 2012
• Subjects: unmanned aerial vehicles; haptics; force feedback; 3D audio; multimodal interaction; behavioral entropy; Mechanical Engineering
• Online Access: https://scholarsarchive.byu.edu/etd/3369; https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=4368&context=etd

Indoor flight of unmanned aerial vehicles (UAVs) has many applications in environments in which it is undesirable or dangerous for humans to be, such as military reconnaissance or searching for trapped victims in a collapsed building. However, limited visual feedback makes it difficult to pilot UAVs in cluttered and enclosed spaces. Haptic feedback combined with visual feedback has shown to reduce the number of collisions of UAVs in indoor environments; however, it has increased the mental workload of the operator. This thesis investigates the potential of combining novel haptic and 3D audio feedback to provide additional information to operators of UAVs in order to improve performance and reduce workload. Many haptic feedback algorithms, such as Time to Impact (TTI)~cite{Brandt2009}, have been developed to help pilot UAVs. This thesis compares TTI with two new haptic feedback algorithms: Omni-Directional Dynamics Springs (ODDS) and Velocity Scaled Omni-Directional Dynamic Springs (VSODDS). These novel algorithms are based on the idea that dynamic springs are attached to the haptic controller in all directions. This thesis is unique by augmenting visual and haptic feedback with real-time 3D audio feedback. Continuous Directional Graded Threshold (CDGT) and Discrete Directional Graded Threshold (DDGT) are two novel algorithms that were developed to provide 3D audio warning cues to operators. To reduce sensory overload, these algorithms play a graded audio alert cue in the direction of velocity and when within a threshold distance of an obstacle. In order to measure operator workload, many researchers have used subjective measures, which suffer from subject bias, preconceptions, and ordering. Instead of using a subjective measure, experimental data is used to objectively measure operator workload using behavioral entropy, which works on the idea that humans work to reduce entropy by skilled behavior. QuadSim, a robust and versatile indoor quadrotor simulator, was developed as a test bed for visual, haptic, and 3D audio feedback. Using QuadSim, a human subject experiment was performed to determine the effectiveness of haptic and 3D audio feedback on operator performance and workload. The results of the study indicate that haptic feedback significantly reduced the number of collisions and collision length. Operator workload was decreased in the side-to-side direction by VSODDS but was adversely increased by TTI. Overall, VSODDS outperformed the other haptic algorithms. Unlike haptic feedback, audio feedback proved to be neither helpful nor harmful in improving performance or reducing workload.