Force-Stiffness Feedback in Uninhabited Aerial Vehicle Teleoperation with Time Delay

Abstract

This study investigates the use of haptic feedback to support the teleoperation of an uninhabited aerial vehicle with time delay. Two means of supplying the haptic feedback are investigated: first, an additional force on the control inceptor, and second, an additional force combined with an increased stiffness of the control inceptor. The advantage of combining the force feedback with stiffness feedback, over force feedback alone, is that the additional stiffness of the control inceptor increases the authority of the haptic feedback system in critical situations. The goal of this study is to increase the safety of teleoperation while reducing operator workload. A theoretical analysis shows that force― stiffness feedback improves the stability in the human control loop while allowing for lower force-feedback gain settings as compared with force feedback alone, which indicates that this could contribute to reducing operator workload. In an experiment, the two haptic feedback conditions were compared with a baseline condition without haptic feedback. The fidelity of the experiment was improved over an earlier experiment by introducing a time penalty for collisions. The number of collisions was different for all three conditions, with the lowest number for the force―stiffness condition and the highest number for the baseline condition. Both haptic feedback conditions were rated equally on subjective workload metrics and scored better than the baseline. This finding is in contrast with results from earlier experiments, which indicated a higher workload with haptic feedback, and shows the importance of creating realistic test conditions when using subjective workload ratings.