Piloted Simulation Study Findings On Stall Recovery Guidance

AIAA Scitech 2020 Forum

et al. 2020

Modern aircraft use a variety of fly-by-wire control devices and combine these with a flight envelope protection system to limit pilot control inputs when approaching the aircraft limits. The current research project aims to increase pilot awareness of such a protection system through the use of force feedback on the control device, i.e., haptics. This paper describes a new iteration of a design with the specific aim to warn the pilot when approaching a limit and provide a clear direction of suggested control input. This is achieved by using vibrations asymmetric in both amplitude, i.e. the mean of the signal is non-zero, and time, i.e. a cue which has a rise time different from the fall time. An evaluation is performed where 24 active PPL/LAPL pilots flew a challenging vertical profile and encountered a windshear. The pilots are divided in two groups: one group performing four flights with haptic feedback, followed by four without, the other groups has a reversed order. Although acceptance ratings slightly improved when providing haptic feedback, the other metrics are unchanged when switching between haptic feedback conditions, due to a large training effect during the first four runs. The results do show that enabling the haptic feedback does seem to improve the learning rate over the first runs, and no after effects are present when feedback is removed. As such, next to the fact that most pilots indicated that they expect an improved safety, this experiment shows a potential training benefit of haptic feedback. Nomenclature Symbols b Damping, Nms/rad I Amplitude of the discrete tick, Nm k Spring, N/rad m Mass, kg n Load factor, g q Pitch rate (θ), rad/s V Velocity, m/s α Angle of attack, rad δ Control device deflection, rad θ Pitch angle, rad φ Bank angle, rad

Section: Introductionmentioning

confidence: 99%

Using Asymmetric Vibrations for Feedback on Flight Envelope Protection

AIAA Scitech 2020 Forum

et al. 2020

“…Research showed that this can improve safety by reducing the risk of violations of those limits (Ackerman et al, 2017). Once the limits are exceeded, for example, in a stall, the information on the pfd can be augmented with recovery guidance which delivers recovery performance improvements, as shown in three simulator evaluations (Schuet et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Flying by Feeling: Communicating Flight Envelope Protection through Haptic Feedback

International Journal of Human–Computer Interaction

et al. 2021

Modern aircraft can be equipped with a flight envelope protection system: automation which modifies pilot control inputs to ensure that the aircraft remains within the allowable limits. Overruling the pilot inputs may lead to mode confusion, even when visual or auditory feedback is provided to alert pilots. We advocate using active control devices to make the flight envelope protection system tangible to the pilot. This paper presents the main findings of an evaluation of three haptic feedback designs for flight envelope protection. The first concept used both force feedback and vibro-tactile alerts, producing promising, yet inconclusive, results. The second concept used asymmetric vibrations to give directional alerting cues, which did not result in improved performance on initial use, but which did yield improved learning rate for the task. The third system employed force feedback to physically guide the pilot away from flight envelope limits, which yielded safety improvements from the first use, but created dependence: pilot performance degraded immediately after the force feedback was removed. From this, we advise to use asymmetric vibrations during training for flight envelope excursions, to leverage active control interfaces for providing force feedback during operation, and reevaluate a combination of both to combine their advantages for single-pilot operations.

“…[3] Once the limits are exceeded, for example in a stall, the information on the Primary Flight Display (PFD) can be augmented with recovery guidance which delivers recovery performance improvements as shown in three simulator evaluations. [4] Apart from the visual channel, pilots can also perceive information through the sense of touch. An example is the haptic interface, which provides force feedback through the control device.…”

Section: Introductionmentioning

confidence: 99%

Evaluating Stick Stiffness and Position Guidance for Feedback on Flight Envelope Protection

AIAA Scitech 2021 Forum

et al. 2021

Contrary to this, however, it was found that haptic feedback mainly contributed to pilot learning, and performance persisted after haptic support was removed. In addition, haptic support did not improve performance during the first run, which indicates that when implemented on an aircraft, it might not provide pilots with support the very first time they encounter a new situation. As the haptic feedback system aimed to support pilots also in new, unforeseen circumstances, a new iteration of the haptic feedback is required.Actively supporting the pilot has been found to help at the first encounter, yet is subject to reversion to base performance when the support is removed. In a skill acquisition task where a slider had to be moved left and right, four groups of participants received feedback on their performance in a training phase at different times: after each run, or an average score after every five, ten or fifteen runs. [9] Their results showed that increasing the amount of feedback increases performance. Immediately after the training phase, another set of measurements was performed where no feedback was provided. There, the group with the most amount of feedback in the training performed worst, although not significantly different from the other groups. Another measurement was performed two days after the initial training, which showed again a tendency for decreasing performance with increasing feedback during training. This phenomenon is called the "guidance hypothesis": a dependency on the feedback develops while learning the task; disabling this feedback then results in worse performance, due to required re-adaption. This phenomenon was also reported in a similar, vertical task. [10] Within the field of haptic feedback, different applications have been recently designed to support the human operator in a task, and to provide support from the first encounter. Examples of this are a support for an abstract control task ([11]), a lane keeping assist in the automotive domain ([12, 13]), and an obstacle-avoidance system for UAV tele-operation. [14] These examples used active haptic feedback, for example an increased stiffness or actively moving control device, to guide the operator to complete the task. Transferring these active haptic feedback principles to the aircraft flight envelope protection system might provide a feedback system which supports pilots from the first run and solve the issue with our previous 'cueing' system. [8] Nevertheless, such implementations of haptic support have been found to be also hindered by to the guidance hypothesis described before, and it should be investigated whether this is also true in our particular application.The aim of this paper is to present a new haptic feedback for FEP design which is more actively 'guiding' the pilot, and to compare the results of this guidance haptic feedback system, as well as the existing 'cueing' haptic feedback system, to the results of a group of pilots who did not receive any haptic feedback at all. It is hypothesised that the group wi...