Design of a haptic obstacle avoidance for low-speed helicopter operations using active sidesticks

Helicopter collisions with obstacles are one of the most frequent and most devastating causes of accidents. To avoid these collisions in low-speed operations a haptic ticker cue in form of repetitive impulses as a force feedback was designed for an active sidestick. Various design questions were examined in pilot campaigns using a full flight simulator and four test scenarios. As a result, the pilots always knew which distance-based hazard area (green, yellow, red) they were in. Furthermore, the ticker is disruptive and roughly reduces the handling qualities from Level 1 to Level 2. It is therefore primarily activated as a hazard warning and not as a main input to control the distance. As a warning cue the ticker was evaluated as non-disturbing. The force threshold to detect the direction of a tick was determined. With tick strengths above this threshold, the direction is still not recognised at all in around 2% of the ticks. For the remaining ticks, the accuracy with which the direction is recognised is about 15 & DEG;. In the fourth scenario, obstacles were moved towards the hovering helicopter, potentially forcing a collision. However, with the ticker a collision occurred in less than 4% of the cases, instead of 84% without the ticker. The ticker was rated as very intuitive and worth recommending. When asked how many accidents of this kind could be prevented with this ticker, all five pilots independently estimated 75%.

Automated summary

Helicopter collisions with obstacles are a common and severe cause of accidents. In this study, a haptic ticker cue was designed for an active sidestick to prevent these collisions during low-speed operations. Pilot campaigns and simulations were conducted to evaluate the performance of the ticker in different scenarios. The results showed that the ticker effectively warned the pilots about the hazard area they were in and significantly reduced the collision rate.