Flight Simulator Experiments Research Articles

Effect of Haptic Feedback on Pilot/Operator Performance During Flight Simulation

Flying an unmanned aerial vehicle (UAV) is a challenging task, due to the absence of direct sensory information such as a view of surroundings, sound, vibrations, and motion. It is important to provide these sensory stimulations to an operator for better situational awareness and efficient control. In this research, we study the effects of incorporating haptic feedback in UAV flight control. We present an experimental evaluation of three flight control scenarios, that is, in the absence of haptic feedback, in the presence of realistic haptic feedback, and an exaggerated haptic feedback. These three conditions are tested for an altitude hold, gain, and descent task in the flight simulation environment. A linear mathematical model is used to simulate the flight dynamics of a UAV controlled by a 6 DOF Touch 3D Stylus haptic device. Fifteen untrained users are recruited to participate in the flight simulation experiment. The analysis of the results of the experiment indicates an improvement in the longitudinal flight control performance. Specifically, the altitude hold task is better performed with no feedback, the altitude gain with exaggerated haptic feedback, and the altitude descent with realistic haptic feedback. A subjective evaluation in the end corroborates these findings.

On Flight Risk Quantitative Evaluation under Icing Conditions

The quantitative assessment of flight risk under icing conditions was taken as the research object. Based on multifactor coupling modeling idea, the pilot-aircraft-environment coupling system was built. Considering the physical characteristics and randomness of aircraft icing, the extreme values of critical flight risk parameters were extracted by the Monte Carlo flight simulation experiment. The flight characteristics were studied comprehensively and heavy-tail characteristics and the distributions of different flight parameters were verified. Flight risk criterion was developed and one-dimensional extreme flight risk probability was calculated. Further, in order to solve the limitation of one-dimensional extreme value, with the Copula theory, the joint distribution model of flight parameters with three distinct distribution types was built. The optimal Copula model was selected by identification of unknown parameters and goodness of fit tests, and the three-dimensional extreme flight risk probability was defined. Based on the quantitative flight risk, the accident induction mechanism under icing conditions was discussed. Airspeed and roll angle under asymmetry icing conditions were more sensitive and had a more significant impact on flight safety. This method can provide reference for safety manipulation, boundary protection, and risk warning during icing flight.

Pilot Control Modeling With Stochastic Periodical Discrete Movement

This paper proposes a novel pilot control model which reflects the following three characteristics of the pilot control behavior: stochastic, periodical, and discrete movement. The focus is on the final descent phase when the pilot controls the aircraft manually based on the flight director commands. The proposed model is developed based on an existing model as well as highly experienced pilot's comments. A flight simulator experiment is conducted and three pilots’ landing data are obtained. The parameters of the pilot model are tuned via a genetic algorithm. The simulation result reveals that the proposed model captures well the characteristics of the data obtained in the simulator experiment and shows a good accordance with actual command tracking capability. The obtained parameters also identify the difference of control strategies between the pilots.

A real-time airborne terrain aided inertial navigation system and its performance analysis

The current terrain aided navigation system has a shortcoming that it depends on terrain feature, so we need to select the terrain matching area and plan the flight path according to the flight mission in advance. In this paper, we present a real-time airborne terrain aided inertial navigation system. The system can plan and select the matching area online according to the heading angle and estimated position errors during aircraft flight, and adopt the appropriate terrain-aided navigation algorithm for different terrain areas and flight conditions. So it can ensure the positioning accuracy and improve the ability of carrier to maneuver at the same time. In order to verify the performance of the system, a flight simulation experiment and a real flight test are carried out, and we conduct a research on the performance of matching area planning and real-time positioning. The tests results show that the system can improve the ability of carrier to maneuver and the performance of real-time positioning. In addition, the system has a higher positioning accuracy and reliability than traditional TERCOM and SITAN methods. The position error is less than 50 m in acquisition mode and less than 18 m in tracking mode with the terrain elevation map of 25 m-resolution.

Development of a Generic Time-to-Contact Pilot Guidance Model

The time-to-contact theory posits that purposeful actions can be conducted by coupling the actor’s motion onto the so-called guides generated internally by their central nervous system. Although significant advances have been made in the application of for flight control purposes, little research has been conducted to investigate how pilots are able to adapt their -guidance strategy to different aircraft dynamics, or how a -guide-based pilot–aircraft model might be used to represent control behavior. This paper reports on the development of such a model to characterize the adaptation of pilot guidance to variations in aircraft dynamics using data obtained from a clinical pilot-in-the-loop flight simulation experiment. The results indicate that pilots tend to maintain a constant coupling between the dynamic system’s motion and the guide across a range of different configuration parameters. Simultaneously, the pilot modulates the guidance maneuver period to adapt to these different aircraft dynamics that result in changes in workload. Modeling the complete pilot stabilization and guidance function as a regulator plus inverter yields good comparative results between the pilot–aircraft model and simulator trajectory data, and it supports the hypothesis that the following -based guidance strategies suppress an aircraft’s natural dynamics.

Risk analysis of the EASA minimum fuel requirements considering the ACARE-defined safety target

We present the results of flight simulator experiments (60 runs) with randomly selected airline pilots under realistic operational conditions and discuss them in light of current fuel regulations and potential fuel starvation. The experiments were conducted to assess flight crew performance in handling complex technical malfunctions including decision-making in fourth-generation jet aircraft. Our analysis shows that the current fuel requirements of the European Aviation Safety Agency (EASA) are not sufficient to guarantee the safety target of the Advisory Council for Aviation Research and Innovation in Europe (ACARE), which is less than one accident in 10 million flights. To comply with this safety target, we recommend increasing the Final Reserve Fuel from 30 min to 45 min for jet aircraft. The minimum dispatched fuel upon landing should be at least 1 h.

Mechanical and physiological effect of partial pressure suit: Experiment and numerical study.

During high-altitude flight, the protection of the pilot is vital. A partial pressure suit may affect human physiology, especially circulatory physiology. The purpose of this study was to investigate how a partial pressure suit works. Ten subjects took part in the flight simulation experiments. Counter pressure at the chest, abdomen, thigh and shank were detected, together with physiological parameters such as heart rate (HR), mean arterial pressure (MAP), stroke volume (SV), cardiac output (CO) and total peripheral resistance (TPR). A numerical model was also established to simulate hemo-physiological effects of the partial pressure suit. The experiment's results show the non-uniform counter pressure distribution in different parts of the body. There is a linear, proportional relation between TPR and the pressurizing level. HR and MAP increase along with that of the pressure level. SV and CO decrease with the increase of the pressure level. The numerical model simulated the physiological effect of a partial pressure suit. The results were verified by experiment data. The simulation estimated the change of blood flow with the pressure level. The numerical model provides a potential way to improve the protection of pilots.

Graph theoretical analysis of EEG functional network during multi-workload flight simulation experiment in virtual reality environment.

The research field of mental workload has attracted abundant researchers as mental workload plays a crucial role in real-life performance and safety. While previous studies have examined the neural correlates of mental workload in 2D scenarios (i.e., presenting stimuli on a computer screen (CS) environment using univariate methods (e.g., EEG channel power), it is still unclear of the findings of one that uses multivariate approach using graphical theory and the effects of a 3D environment (i.e., presenting stimuli on a Virtual Reality (VR)). In this study, twenty subjects undergo flight simulation in both CS and VR environment with three stages each. After preprocessing, the Electroencephalogram (EEG) signals were a connectivity matrix based on Phase Lag Index (PLI) will be constructed. Graph theory analysis then will be applied based on their global efficiency, local efficiency and nodal efficiency on both alpha and theta band. For global efficiency and local efficiency, VR values are generally lower than CS in both bands. For nodal efficiency, the regions that show at least marginally significant decreases are very different for CS and VR. These findings suggest that 3D simulation effects a higher mental workload than 2D simulation and that they each involved a different brain region.

Identification of fixations in noisy eye movement data via recursive subdivision

When solving problems, multi-person airline crews can choose whether to work together, or to address different aspects of a situation with a divide and conquer strategy. Knowing which of these strategies is most effective may help airlines develop better procedures and training. This paper concentrates on joint attention as a measure of crew coordination. We report results obtained by applying cross recurrence analysis to eye movement data from two-person crews, collected in a flight simulator experiment. The analysis shows that crews exhibit coordinated gaze roughly one sixth of the time, with a tendency for the captain to lead the first officers visual attention. The degree to which crews coordinate their gaze is not significantly correlated with performance ratings assigned by instructors; further research questions and approaches are discussed.

Prediction and Simulator Verification of Roll/Lateral Adverse Aeroservoelastic Rotorcraft–Pilot Couplings

The involuntary interaction of a pilot with an aircraft can be described as pilot-assisted oscillations. Such phenomena are usually only addressed late in the design process when they manifest themselves during ground/flight testing. Methods to be able to predict such phenomena as early as possible are therefore useful. This work describes a technique to predict the adverse aeroservoelastic rotorcraft–pilot couplings, specifically between a rotorcraft’s roll motion and the resultant involuntary pilot lateral cyclic motion. By coupling linear vehicle aeroservoelastic models and experimentally identified pilot biodynamic models, pilot-assisted oscillations and no-pilot-assisted oscillation conditions have been numerically predicted for a soft-in-plane hingeless helicopter with a lightly damped regressive lead–lag mode that strongly interacts with the roll mode at a frequency within the biodynamic band of the pilots. These predictions have then been verified using real-time flight-simulation experiments. The absence of any similar adverse couplings experienced while using only rigid-body models in the flight simulator verified that the observed phenomena were indeed aeroelastic in nature. The excellent agreement between the numerical predictions and the observed experimental results indicates that the techniques developed in this paper can be used to highlight the proneness of new or existing designs to pilot-assisted oscillations.

Hear me Flying! Does Visual Impairment Improve Auditory Display Usability during a Simulated Flight?

Sonification refers to systems that convey information into the non-speech audio modality [1]. This technique has been largely invested in developing guidance systems for visually impaired individuals. In 2008, more than 140 systems of this type used in various application areas were referenced [2]. In aeronautics, such a system –namely the Sound Flyer– is currently used by visually impaired pilots in real flight context to control the aircraft attitude. However, it is unclear if this system would be acceptable for sighted individuals. Indeed, early visual deprivation leads to compensatory mechanisms which often result in better auditory attentional skills [7,8]. In the present study we assessed this issue. Two groups of pilots (blind vs. sighted) took part in a flight simulator experiment. They were all blindfolded to avoid potential visual information acquisition (i.e. some blind individuals had residual visual capacities). Participants had to perform successive aircraft maneuvers on the sole basis of auditory information provided by the sound flyer. Maneuvers difficulty varied with the number of parameters to apply: easy (none), medium (one: pitch or bank) or hard (two: pitch and bank). The Sound Flyer generated a pure tone (53dB SPL) modulated as a function of pitch (tonal variation) and bank (inter-aural and rhythmic variations). We assessed flight performance along with subjective (NASA-TLX) and neurological (irrelevant auditory-probe technique; [9]) measures of cognitive workload. We hypothesized that the automatic cerebral reaction to deviant auditory stimuli (10% “ti” among 90% “ta”; 56db SPL) would be affected by the difficulty [10,11] and participants’ auditory attention. Preliminary data analyses revealed that blind and sighted participants reached target-attitudes with good accuracy (mean error of 2.04°). Globally, subjective cognitive workload and brain responses to the auditory probe were influenced by the difficulty of the maneuver but not by the visual impairment. These initial results provide evidence that auditory displays are effective, not only for maintaining straight and level flight [6], but also for attaining precise aircraft attitudes. Results also suggest that flight maneuvers should remain quite simple to avoid too high cognitive workload. In other words, attitude sonification can provide robust information and, along with Brungart and Simpson [3] specifications, could contribute to the fight against spatial disorientation in the cockpit.

The Effects of Using an Angle of Attack System on Pilot Performance and Workload during Selected Phases of Flight

In-flight loss of control (LoC-I) is the number one fatal accident category for light airplanes. The most common type of LoC-I accident involves a stall/spin and inadequate airspeed management and is frequently cited as a causal factor. An aircraft stalls when the critical angle of attack is exceeded and this may occur at any indicated airspeed, hence the use of airspeed as an indication to the proximity to stall is unreliable. This is of particular importance during the take-off, approach and landing where stall margins are reduced. Military aircraft commonly use angle of attack (AoA) devices to indicate proximity to the stall and these have been in continuous use for almost 60 years. More recently, with the simplification of light airplane design approval requirements, an increasing number of AoA designs are appearing on the market, installed in light airplanes to complement airspeed indication and stall warning systems, to notify pilots of proximity to the stall. This paper reviews a selection of current types of AoA devices and presents the preliminary results of practical flight testing and flight simulation experiments to investigate the effects of using an AoA on pilot performance and workload during selected phases of flight. The results have implications for the operational use of current AoA devices and future AoA design.

Are monarch butterflies true navigators? The jury is still out

Mouritsen et al. (1) used a flight-simulator experiment and recapture data to examine two hypotheses: whether monarchs use true navigation or a vector-navigation strategy. In the flight-simulator experiment, flight directions of wild-captured, migratory butterflies were assessed near their capture location, and then ∼2,500 km west. The authors’ finding that monarchs flew southwest in both locations does not rule out true navigation because: (i) the experiment did not include reciprocal translocations and therefore lacked controls; (ii) experimental monarchs were moved to a location that an Ontario monarch would never traverse and where monarchs are only rarely found, and thus tell us little about monarchs following a normal migratory trajectory; …

A40 低速域における航空機の短周期モードとフゴイドモードの関係(M-OS9-2 ビークルの運動と制御II,M-OS9 ビークルの運動と制御,「海を越え,国を越え,世代を超えて!」)

The longitudinal flying qualities of airplanes is going to worse in lower airspeed region, as shown in the criteria for short-period mode in MIL-F-8785C. However, Background Information and User Guide for MIL-F-8785B does not give the detailed explanation on this degradation. Our study pays attention to the deviation in lower airspeed region from short-period mode approximation, which is valid in higher airspeed region. The main parameter of this deviation is Phugoid-mode natural angular frequency ω_<n ph>, which cannot be neglected in lower airspeed region because its oscillation period is going to be shorter in that region. Also, we investigated the relations between short-period mode natural angular frequency ω_<n ph>, and ω_<n ph>. The results of flight simulator experiment show that the flying qualities evaluation based on Short-period mode approximation is improper in lower airspeed region and then upper limit of ω_<n ph> should be added into the criteria for longitudinal flying qualities.

Pilot’s Information Use During TCAS Events, and Relationship to Compliance to TCAS Resolution Advisories

The Traffic alert and Collision Avoidance System (TCAS) is intended to serve as a backup, redundant system that alerts and advises the pilot when all other methods of aircraft separation assurance fail. A flight simulator experiment examined pilot responses to TCAS advisories in a full air traffic environment. This paper discusses two analyses of the pilots’ use of information within their environment. The first analysis examined air traffic communications manipulated according to four conditions: traffic call-outs, instructions conflicting with the TCAS advised avoidance maneuver, the ability to over-hear relevant party-line information, and no relevant communications. The second analysis used data from an eye tracker to identify when the pilot examined the traffic situation display provided by TCAS. These patterns of information use are then compared with pilot compliance to the Resolution Advisories provided by TCAS.

Electrohydraulic force control design of a hardware-in-the-loop load emulator using a nonlinear QFT technique

This paper presents the design of a robust force control system for an electrohydraulic load emulator utilized as part of a hardware-in-the-loop flight simulation experiment. In this application, the force controlled hydraulic actuator is used to artificially recreate in-service loads upon a second hydraulic flight actuator operated in closed-loop position control. Electrohydraulic force control is more difficult than electrohydraulic position tracking because the load dynamics influence the force transfer function in a way that makes it challenging to develop an accurate force tracking system using simple feedback control. Nonlinear quantitative feedback theory (QFT) is applied in this paper to address this issue. First, an effective and robust feedback controller is designed by nonlinear QFT to desensitize the force control loop to nonlinear servovalve flow/pressure effects and typical system uncertainties. A secondary compensator is also designed within the QFT framework to extend the force tracking bandwidth with respect to the load motion. Experiments demonstrate acceptable force tracking performance within the scope of a representative flight-simulation experiment.

Pilot Procedure-Following Behavior During Closely Spaced Parallel Approaches

A flight simulator experiment was run to examine pilot procedure-following behavior during closely spaced parallel approaches. Such approaches are being considered under the Next Generation Air Transportation System (NextGen) to increase the capacity of runway systems, possibly without the need to increase the footprint of airports. Pilots flying these approaches utilized a simple heuristic to fly the procedure consistently, despite the heuristic being suboptimal for any of the three conditions. Moreover, procedure compliance was relatively low, but noncompliance itself was not unsafe unless accompanied by situation awareness problems. In some cases, noncompliance could be shown to be a better choice than compliance. These results have implications for assumptions regarding procedure-following by pilots utilizing novel procedures in NextGen.

Eye Movements as an Indicator of Situation Awareness in a Flight Simulator Experiment

This article discusses the potential for eye movements as a means to assess situation awareness (SA) in a flight simulator setting. In a scenario, SA was hampered by introducing a system malfunction in the form of a fuel leak that resulted in a fuel imbalance. Twelve airline pilots participated in the experiment. An eye tracker was used to track the pilot's visual scanning behavior across the areas of interest (AoIs) in the cockpit. Differences in attentional focus and scanning entropy were observed when the crews searched for the malfunction. The results provided insight into the use of fixation rates and dwell times as information acquisition indicators (Level 1 SA), and the use of entropy as an indicator of new information acquisition activities (Level 3 SA). These findings contribute to the further development and exploration of eye movement analyses as an objective indicator of SA in a civil aviation cockpit setting.

A Coherent Impression of the Pilots' Situation Awareness: Studying Relevant Human Factors Tools

A flight simulator experiment was set up to study relevant human factors tools for situation awareness assessment of pilots. A specific scenario was designed in which a malfunction of the aircraft was introduced during flight: an indicated air speed discrepancy. Pilot behavior was studied while pilots tried to figure out the correct speed. Eye movement metrics alone provided an insufficient picture of pilot situation awareness, but when purposefully combined with subjective, self-rating metrics, they offered a more comprehensive look at situation awareness, covering all 3 levels of Endsley's situation awareness definition.

Fault tolerant flight control: from theory to piloted flight simulator experiments

Loss of control accounts for over 25% of aircraft accidents worldwide. This study presents a fault tolerant flight control strategy for increasing aircraft safety. The work has been undertaken within the Action Group on fault tolerant control (FTC) of the European GARTEUR programme, which develops collaborative efforts in Europe to create new FTC technologies that could significantly advance the goals of the aviation safety. After the fault detection and confirmation by the in-flight dedicated systems, a compensation loop is activated to ensure safe recovery. The design of the FTC loop is achieved without any changes in the nominal (and certificated) flight control system (FCS). The FTC scheme design is formulated as an H∞ strong stabilisation problem. Fault compensability is subsequently discussed and formulated as a trim-deficiency analysis problem. The proposed technique is implemented on the SIMONA flight simulator and evaluated through a pilot experiment. The tested scenario corresponds to the landing approach of a large transport aircraft (B747-100/200). The faulty situation is related to trimmable horizontal stabiliser (THS) failures. Piloted flight simulator experiments show that fault tolerance can be achieved under the condition that there exists sufficient remaining control authority.