Flight Simulation Assessment of Autorotation Algorithms and Cues

Abstract

Autorotation is a challenging flight maneuver that involves highly coordinated control actions and competing constraints. It is generally recognized that pilot performance in autorotation may benefit from additional cues that improve decision-making as well as timing and coordination of control inputs. This paper describes the development and simulator testing of various pilot cues designed for autorotation. A set of discrete and continuous cues are defined to assist in the initiation and execution of various phases of the maneuver. Furthermore, a reachability cue is created to assist a pilot in rapidly evaluating the vehicle glide distance, thereby facilitating selection of a landing site. Piloted simulated flight trials are performed using various combinations of cues in both good and degraded visual environments. Results are evaluated through assessment of pilot workload as well as quantitative measures of landing performance with and without the cues. Overall, results and pilot evaluations show the potential utility of several of the cueing methods but point to specific improvements to them that may facilitate more precise pilot tracking as well as reductions in task workload.

Tau Theory-Based Flare Control in Autonomous Helicopter Autorotation

“…To demonstrate the methodology, simulation results are compared to piloted flight simulations for the case of a flare maneuver initiated at 80 kts total speed, at a downrange target landing distance of 1000 ft from the autorotation initiation point, for a flare entry altitude of 140 ft. While Figure 5c shows that the speed for minimum descent rate is 60 kt, it was found in piloted simulations [33,40,41] that this speed left very little energy for the flare at the end of the maneuver. Thus, 80 kts was chosen as initial speed.…”

“…It has been previously shown to be capable of modeling other flight maneuvers like helicopter pilots stopping, turning, and pulling up [27,31], and for fixed wing pilots in the landing flare [32]. In the context of helicopter flare maneuvers, it can be shown that longitudinal speed trajectories can be generated using the following equation [15,33]:…”

“…Fourteen autorotation maneuvers were performed by the Test Pilot who is an ex-Royal Navy rotary wing pilot and a graduate of the UK's Empire Test Pilot School (ETPS). These piloted simulations are shown in Figure 8, taken from [33,40,41]. Note that the piloted flight simulations were performed using FLIGHTLAB TM , a mid-fidelity flight dynamics model [43].…”