Haptic Feedback as a Supplemental Method of Alerting UAV Operators to the Onset of Turbulence

Unmanned Aerial Vehicle (UAV) operators have identified sudden turbulence as being potentially detrimental to safe and effective UAV control. This is especially true for those UAVs that require direct manual control in order to land. Turbulence is currently indicated solely by an unexpected perturbation of video images being transmitted from a UAV-mounted camera to the operator control station. This study investigated the usefulness of haptic feedback technology to provide the UAV operator with an enhanced indication of the sudden onset of turbulence. Visual feedback was supplemented by haptic feedback applied directly to the operator's control stick, providing a redundant kinesthetic alert. Five rated pilots performed 16 simulated UAV landing trials in a within-subject design with four independent variables: haptic feedback (off, on), turbulence strength (mild, severe), turbulence direction (primarily horizontal or vertical), and proximity to the runway when the turbulence occurred (near, far). Dependent measures included subjective assessments of situation awareness at turbulence onset, assessments of landing difficulty and landing performance, and post-test workload ratings and preferences. Results indicated that awareness of turbulence was significantly improved in the haptic feedback condition. Participant comments indicated that haptic feedback was a useful tool for the task, however, the magnitude of the control stick force deflections was judged to be too severe for actual use. The application of haptic feedback technologies to UAV interfaces is discussed and current research directions are described.