Haptic Feedback for UAV Tele-operation - Force offset and spring load modification

Haptic feedback is often suggested to complement visual information through the sense of touch to improve efficiency and safety in the tele-operation of unmanned aerial vehicles. It is, however, of great importance that the improvements are not at the cost of higher operator workload and control activity, which strongly depends on how haptic feedback is presented to the operator. This paper describes the study on two different techniques of haptic feedback for collision avoidance in the tele-operation of a UAV helicopter. The first technique considers the addition of an external force offset generated by an artificial force field, whereas the second technique considers the addition of an external spring constant. The study involves a theoretical analysis and an experimental evaluation of the two haptic feedback implementations. Experiment results indicate that the use of the external spring constant outperforms the force offset. Operator performance improves and workload decreases with equivalent control activity and level of safety with respect to the use of force offset.