Pilot Control Research Articles

Aircraft Take-off and Landing Performance Calculation Method Based on Flight Simulation

In order to comply with the existing standard requirements or specifications, a new computational method for aircraft take-off and landing performance, which deals with the characteristics of the high precision of parameters in the process of take-off and landing based on flight simulation technique. The simulation model for a twin-engine normal layout aircraft is constructed in detail, including nonlinear motion equation, aerodynamic, engine, landing gear and dynamical mass model. According to performance calculation standard and pilot control specification for different take-off modes and landing stages, the simulation process for one engine inoperative(OEI) take-off, angle of attack(AoA) hold take-off, standard take-off, reject take-off and landing are designed, and corresponding performance computer software is developed to achieve the goal of accuracy as well as full parameters calculation. Compared with the existing methods, the computational complexity of this method is increased, the process is detailed, the parameters are increased, and more influencing factors can be analyzed quantitatively. Results show that OEI take-off distance is the longest, standard take-off is suitable for light aircraft, angle of attack hold take-off is appropriate in plateau or limited thrust. Landing distance is related to glide angle. Therefore, light aircraft landing can reduce the approach speed and increase the glide angle.

Design and Flight Evaluation of Primary Control System for Learjet-25B Aircraft

In this paper, a multi-input/multi-output servomechanism primary flight controller is presented. Also discussed are flight data related to the system performance and pilot assessments of handling qualities. The data were collected during flight-test experiments (March 2018) on the Calspan Variable Stability In-Flight Simulator Learjet-25B aircraft. Aircraft body angular rates and linear accelerations are used to enable decoupled command tracking in pitch, roll, and yaw axes. Angle of attack and angle of sideslip measurements are not required for the system to operate. The developed primary flight controller translates pilot controls into the corresponding pitch, roll, and yaw commands for the aircraft to track. The system consists of a gain-scheduled robust linear baseline augmented with a direct adaptive model reference output feedback. The baseline is designed via the Observer-Based Loop Transfer Recovery method. The adaptive component incorporates the closed-loop reference model, whereby a state observer from the baseline Observer-Based Loop Transfer Recovery system also acts as the reference model for the adaptive augmentation. In March 2018, the Observer-Based Loop Transfer Recovery controller was successfully flight verified on the Calspan Learjet-25B aircraft, at the U.S. Air Force Test Pilot School, Edwards Air Force Base, California. Flight-test results are discussed, and a brief summary is given at the end.

Modeling of alternative testing strategies to demonstrate freedom from Mycobacterium avium ssp. paratuberculosis infection in test-negative dairy herds in the Republic of Ireland

In light of the various adverse effects of Johne's disease on animal productivity and the debate on the role of its causative organism, Mycobacterium avium ssp. paratuberculosis, in the etiology of Crohn's disease, major dairy-producing countries around the world have implemented national control programs aimed at reducing the prevalence of this infection in cattle. A pilot control program was initiated in Ireland in 2013, with a key objective to provide farmers with test-negative dairy herds with tools and knowledge to increase their confidence of freedom over time. The aim of this study was to estimate the confidence of freedom obtained in test-negative Irish dairy herds over time with various sampling scenarios and to evaluate the cost-effectiveness of alternative scenarios for achieving an acceptable level of confidence of freedom in herds with no evidence of infection. A stochastic model was developed to simulate repeated annual testing of individual animals using ELISA and confirmatory assays over a period of 20 yr. Two scenarios modeled the current herd-screening options, whereas 14 alternative scenarios explored the effect of varying parameters from the current testing strategies, such as the frequency of testing, the eligibility criteria for selecting animals, the type of assay, the probability of introduction, and the assay sensitivity. Results showed that the current testing strategy with milk twice a year or serum once a year in all animals over 2 yr old provided the highest annual herd sensitivity, with a median value of 55%. Although the median confidence of freedom increased over time for all scenarios, the time required to reach 90 and 95% confidence of freedom was highly variable between scenarios. Under the testing scenario where serum tests were used once a year, the confidence of freedom reached 90% after 4 yr and 95% after 7 yr of testing. Some of the alternative scenarios achieved an acceptable level of confidence of freedom in a reasonable timeframe and at lesser cost than the current testing strategies. The results of this work are used to provide recommendations for the next phases of the program.

A Game Theoretic Approach to Uplink Pilot and Data Power Control in Multi-Cell Multi-User MIMO Systems

In multi-user multiple-input–multiple-output (MU-MIMO) systems that employ pilot-symbol aided channel estimation, the pilot-to-data power ratio (PDPR) has a large impact on the system performance. In this paper, we consider the problem of setting the PDPR in multi-cell MU-MIMO systems in the presence of channel estimation errors, intercell interference and pilot contamination. To analyze and address this problem, we first develop a model of the multi-cell MU-MIMO system and derive a closed-form expression for the mean squared error of the uplink received data symbols. Building on this result, we then propose two decentralized PDPR-setting algorithms based on game theoretic approaches that are applicable in multi-cell systems. We find that both algorithms converge to a Nash equilibrium and provide performance improvements over systems that do not properly set the PDPR, while they maintain different levels of fairness.

Online Identification of Pilot Adaptation to Sudden Degradations in Vehicle Stability

Abstract Time-varying pilot control identification is essential for better understanding of how pilots respond when faced with sudden changes in the dynamics of the vehicle they control, such as when automatic control and stabilization systems disengage or undergo a mode transition. This paper presents the results of a human-in-the-loop experiment performed at TU Delft to test a promising online pilot identification method, based on recursive low-order ARX identification, developed in earlier work. In the experiment, eight skilled participants performed tracking tasks with time-varying vehicle dynamics, where at an unpredictable moment during each tracking run a sudden degradation in vehicle stability was induced. In addition to controlling the time-varying vehicle, participants were asked to indicate when they detected the change in the vehicle dynamics with a button push. This paper compares the effectiveness of two different approaches to detect the moment when pilot adaptation occurs from online identified pilot parameter traces. Overall, the results indicate that the lag in this detection of identified pilot adaptation is equivalent to the subjective detection times, or less. This implies that these online techniques have clear potential for ensuring timely and effective changes in adaptive pilot support systems.

A Protocol-Driven, Digital Conversational Agent at the Hospital Bedside to Support Nurse Teams and to Mitigate Delirium and Falls Risk

Background: Up to 1 million falls per year occur during hospital stays in the US, costing hospitals up to $7 billion per year to treat. Delirium, a major cause of falls, is highly prevalent (29%-64%) among hospitalized elders. Our team is developing a care technology that provides 24x7 proactive patient support to mitigate falls and delirium in a scalable, cost-effective, yet person-centered manner. We were awarded an NIH SBIR Fast-Track grant to further our work. Objective: Prior research showed that digital avatars can build psychosocially supportive relationships with older adults living in the community. We conducted a pilot study of these digital avatars in a community hospital setting, and found that bedside avatars helped reduce the rate of falls among elderly inpatients while mitigating delirium and loneliness. Thus, in our present NIH-funded work, we seek to enhance the clinical robustness of our avatar intervention by implementing a more complete set of protocols derived from the evidence-based Hospital Elder Life Program (HELP), and to validate the benefits of this next-generation intervention in a larger scale, multi-site clinical study. Methods: Avatars are displayed on tablets as virtual dogs or cats, responding to touch. They are able to talk intelligently due to live support from a 24x7 team of trained humans combined with protocol guidance and process automation software. At the bedside, avatars talk with patients and implement protocols including reorientation and bed exercises, based on HELP. English-speaking patients aged 65+ on three medical surgical units were selected in our pilot study based on subjective nursing risk assessment and patient consent. Participants on two intervention units received an avatar for their entire hospital stay. Participants on a control unit received a daily visit from a nursing student. Measures were administered upon study enrollment and discharge. Quarterly fall rates by unit were reported by the hospital. In our present work, we will conduct a larger, multi-site clinical study starting with two hospitals in late 2018 and incorporating electronic medical record integration to increase the objectivity of patient enrollment, ease the patient enrollment process, and apply interventions intelligently tailored to each patient. Additional hospitals may join the two-year study through 2020. Results: In our pilot study, intervention (n=41) and control (n=54) patients were equivalent except for an intervention group bias toward females (P=.02). Mean age was 76.5 years, with 55% female, 46% African-American, and 44% speaking English as a second language. Typical length of stay was 3-6 days. On average, avatars performed 71.3 observational check-ins, 61 minutes of engagement using 11.5 images or audio files, and 6.5 protocol-driven tasks per patient per day. Compared to control patients, intervention patients showed a significantly greater reduction in delirium score (CAM, P=.003) and loneliness (UCLA-LS, P=.008). The primary intervention unit had 0.9 falls per 1000-patient days during the 3-month study period, compared to 6.5 on the control unit (86% reduction). Conclusions: Previous findings support the use and development of avatar technology for hospitalized patients at risk for delirium or falls. Hospitals interested in joining our two-year clinical study may contact the principal investigator.

The Age of Neuroergonomics: Towards Ubiquitous and Continuous Measurement of Brain Function with fNIRS

AbstractNeuroergonomics is an emerging field that investigates the human brain in relation to behavioral performance in natural environments and everyday settings. Functional near‐infrared spectroscopy (fNIRS), a noninvasive brain‐monitoring technology that relies on optical techniques to detect changes of cortical hemodynamic responses to human perceptual, cognitive, and motor functioning, is an ideal candidate tool. Ultraportable wearable and wireless fNIRS sensors are already breaking the limitations of traditional neuroimaging approaches that have imposed limitations on experimental protocols, data‐collection settings, and task conditions at the expense of ecological validity. This review summarizes emerging trends for fNIRS applications, from aerospace to medicine, with diverse populations and towards clinical solutions. We will review recent studies, such as mental workload assessment of specialized operators performing standardized and complex cognitive tasks and development of expertise during practice of complex cognitive and visuomotor tasks (ranging from aircraft piloting and robot control). Various recent synergistic fNIRS applications for human–human and human–machine interaction, including synthetic speech perception, interpersonal neural synchronization, and brain computer interfaces, highlight the potential use and are ushering the dawn of a new age in applied neuroscience and neuroengineering.

Motor imagery ability in stroke patients with and without neglect: A pilot control case series study

Individuals with stroke may experience sensory-motor deficit and/or neglect, with possible reduction in motor imagery ability (MI). To date, no study completely investigated MI ability in the same individual using measures adapted to clinical setting. This study aims to investigate MI ability in stroke patients with or without neglect as compared to aged-matched healthy individuals. We assessed explicit MI (EMI) using 3 questionnaires (Movement Imagery Questionnaire-RS–MIQ-RS, Kinesthetic and Visual Imagery Questionnaire-20–KVIQ-20, Vividness of Movement Imagery Questionnaire-2) and 2 tests (Time Up and Go, Box and Block test), measuring (i) vividness, (ii) electrodermal activity and (iii) temporal equivalence between MI and physical practice (PP). We also assessed implicit MI (IMI) using a hand laterality judgment task, measuring response time and percentage of correct responses. We recruited a total of 12 stroke patients including one patient with neglect (experimental group, EG) and 12 healthy subjects (control group, CG). For EMI, comparison between EG and CG showed no significant decrease in vividness and electrodermal activity but an increase in MI duration regarding PP for both KVIQ and MIQ-RS. For IMI, comparison revealed similar response time but a significant decrease in percentage of correct responses for EG. Interestingly, the patient with neglect exhibited similar IMI performance to the one of other patients but the lowest vividness and the longest MI duration regarding PP for EMI. Stroke patients without neglect have reduced MI ability but seem still able to imagine movements. Conversely, neglect may sharply decrease EMI while sparing IMI. Although further interpretation should be formulated with caution given the small number of patients, one could likely include stroke patients without neglect in MI rehabilitation programs as suggested by other studies, but definitive exclusion from MI programs in case of neglect requires further investigations.

Augmented flight dynamics model for pilot workload evaluation in tilt-rotor aircraft optimal landing procedure after one engine failure

An augmented flight dynamics model is developed to extend the existing flight dynamics model of tilt-rotor aircraft for optimal landing procedure analysis in the event of one engine failure. Compared with the existing flight dynamics model, the augmented model involves with more pilot control information in cockpit and is validated against the flight test data. Based on the augmented flight dynamics model, the optimal landing procedure of XV-15 tilt-rotor aircraft after one engine failure is formulated into a Nonlinear Optimal Control Problem (NOCP), solved by collocation and numerical optimization method. The time histories of pilot controls in cockpit during the optimal landing procedure are obtained for the evaluation of pilot workload. An evaluation method which can synthetically quantify the pilot workload in time and frequency domains is proposed with metrics of aggressiveness and cutoff frequencies of pilot controls. The scale of the pilot workload is compared with those of the shipboard landing procedures, bob-up/bob-down and dash/quick-stop maneuvers of UH-60 helicopter. The results show that the aggressiveness of pilot collective and longitudinal controls for the tilt-rotor aircraft optimal landing procedure after one engine failure are higher than those for UH-60 helicopter shipboard landing procedures up to the condition of sea state 4, while the pilot cutoff frequency of collective control is lower than that of the bob-up/bob-down maneuver but the pilot cutoff frequency of longitudinal control is higher than that of the dash/quick-stop maneuver. The evaluated pilot workload level is between Cooper–Harper HQR Level 2 and Level 3.

Parametric Study on Fluid Dynamics of Pilot-Control Angle Globe Valve

Globe valve is widely used in numerous industries, and its driving energy consumption accounts for high percentages of the whole piping system. In order to figure out novel globe valves with low energy consumption, the pilot control globe valve (PCGV) is proposed, which is made up of a main valve and a pilot valve. By the pressure difference of fluid itself, the opened/closed status of the main valve can be controlled by the pilot valve, which can save driving energy and shorten the response time. In order to fit PCGV in an angle displaced piping system, the pilot control angle globe valve (PCAGV) is developed. In this paper, with validated numerical methods, both steady and transient simulations focusing on the valve core diameter, the single/multi orifices, orifice diameters and their arrangements located on the valve core bottom are presented. The results show that the pressure difference increases with the increase of the valve core diameter and the decrease of the orifice diameter, and large orifice diameters (d > 12 mm) should be avoided in case the valve cannot be opened. As for the multi orifices, it can be treated as a single orifice which having similar cross-sectional area. Meanwhile, the opening time of the main valve also increases with the increase of the valve core diameter correspondingly. Besides, a fitting formula of pressure difference calculation depending on the inlet velocity and the valve core diameter is obtained, which is a power–law relationship.

Sky Lanterns And Aviation Safety : A Study At The Mae Fah Luang Chiangrai Airport

The purpose of this research is to study explore the challenges emerging due to use of sky lantern at the Mae Fah Luang Chiangrai Airport, which has threat to aviation safety. The current pertaining is qualitative research done by in-depth interview of aviation personnel at Chiangrai Airport. The finding of the study can be summarized as follows: 1) Lantern obstructs visibility of flight path posing challenge to both pilot and air traffic controller. 2) Lantern can accidentally slip into aircraft engine and it could jam the engine or could cause engine explosion. 3) Lantern slips into aircraft controlling equipment, this could cause aircraft unable to control its direction. 4) Lantern that floats and sticks with aircraft body, could cause fire to aircraft body. 5) Lantern that falls onto runway or airport drive way, may endanger aircraft while takeoff and landing or it could damage aircraft during taxiing on the runway. However, it is opined by respondent to jointly organize community awareness campaign to educate people and mitigate the associated threat.

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.

Joint Pilot and Payload Power Control for Uplink MIMO-NOMA With MRC-SIC Receivers

This letter proposes a joint pilot and payload power allocation (JPA) scheme to mitigate the error propagation problem for uplink multiple-input multiple-output non-orthogonal multiple access (MIMO-NOMA) systems. A base station equipped with a maximum ratio combining and successive interference cancellation (MRC-SIC) receiver is adopted for multiuser detection. The average signal-to-interference-plus-noise ratio (ASINR) of each user during the MRC-SIC decoding is analyzed by taking into account the error propagation due to the channel estimation error. Furthermore, the JPA design is formulated as a nonconvex optimization problem to maximize the minimum weighted ASINR and is solved optimally with geometric programming. Simulation results confirm the developed performance analysis and show that our proposed scheme can effectively alleviate the error propagation of MRC-SIC and enhance the detection performance, especially for users with moderate energy budgets.

Emulation of pilot control behavior across a Stewart platform simulator

SUMMARYThis paper presents a model-based controller consisting of a feedback linearization scheme and a state-dependent proportional derivative (PD) controller adapted to a parallel flight simulator Stewart mechanism. This parallel robot is considered to emulate motions of highly maneuverable aircrafts, which require well-trained pilots. The simulations are based upon a reduced-model prototype built in order to verify kinematic design aspects and control laws. Indeterminacies in the mass distribution of the system will generally affect model-based controllers, necessitating compensation or the employment of robust control methods. Through introducing the pilot's sensorial feedback of acceleration, the pilot's behavior in giving commands is emulated via an optimization process, which tunes the controller coefficients accordingly. Stability of the designed control system is guaranteed via the Lyapunov approach. To further explore the system through perilous flight scenarios, three pre-designed maneuvers are selected as test cases. It is expected that closed-loop control tasks in which a pilot tracks a target, while at the same time the controller rejects disturbances and adapts itself to the pilot's progressive skills, are ameliorated through this arrangement. Numerical results show that the proposed method is found robust in the training process in conditions of parameters indeterminacy.

Improving Early Childhood Development among Vulnerable Populations: A Pilot Initiative at a Women, Infants, and Children Clinic

Objective. Early childhood development (ECD) programs have demonstrated drastic improvements in survival, growth, health, and social productivity. An ECD pilot intervention was delivered to vulnerable populations of a Women, Infants, and Children (WIC) clinic in Des Moines, Iowa, to assess ECD outcomes and parental receivability in this setting. Study Design. In a randomized, single blinded control initiative, WIC group sessions of mothers (children aged 2 years and younger) were selected for pilot ECD intervention (37 participants) or control (36). Care for Child Development ECD course material was supplemented to intervention groups. Survey results were assessed with paired samples T-testing and by an ANOVA. Results. Pilot session receivability demonstrated significance in all areas relative to control: enjoyment, p=0.008; learning capacity, p=0.011; and participant sharing, p=0.023. Furthermore, the previously validated ECD intervention demonstrated significantly improved cumulative 1 month behavior outcomes following the intervention: p=0.006. Conclusions. The WIC setting provides an ideal environment for delivering ECD education beyond traditional counseling in nutrition. High receivability indices among parents demonstrate remarkable capacity for improvement and growth. The significance in receivability, as well as 1 month behavior outcomes, represents parents’ overall readiness to enhance the home environment for their child if merely educated how.

Mathematical modeling and linearized analysis of the jet-pipe hydraulic amplifier applied to a servovalve

The accurate mathematical model of the jet-pipe hydraulic amplifier, which is the pilot control stage of a jet-pipe servovalve, is very necessary to analyze and control the performance of a jet-pipe servovalve. In this paper, based on the hydraulic bridge’s flow balance equations, an improved nonlinear explicit model with the absorption effect is developed. The linearized model and valve coefficients are derived from the nonlinear improve model. To test and verify the improved models, the pressure and flow characteristic model of jet-pipe hydraulic amplifier are verified by the experiment. The results show that the model is approximate to the experimental data. In addition, the influence of structural parameters on performance of jet-pipe hydraulic amplifier is analyzed by simulation.

A Decadal Revisiting of the Assessment of Pilot Control Interfaces for Unmanned Aircraft Systems

Unmanned Aircraft System (UAS) control design is critical for mitigating the negative human factors effects associated with operating the aircraft remotely, such as latency in the transfer of information and loss of sensory information. With this in mind, we conducted a systematic review of the human factors UAS literature to identify control automation and input devices with the objective of modernizing the seminal Williams (2007) assessment of UAS control interfaces. We also identified compatible automation-input device pairs, and characterized the literature based on the control strategies. The characterization of the literature reflected our identified compatibilities between the levels of control and input devices. Generally, the levels of UAS control identified by Williams (2007) are still prevalent in the literature, but we identified two levels that he did not account for in his taxonomy, including guided manual control (similar to LNAV/VNAV guidance in manned aircraft) and objective control (in which the remote pilot in command uploads an objective to the UAS and automation creates a route and controls the aircraft to meet the objective).

A general method for closed-loop inverse simulation of helicopter maneuver flight

Maneuverability is a key factor to determine whether a helicopter could finish certain flight missions successfully or not. Inverse simulation is commonly used to calculate the pilot controls of a helicopter to complete a certain kind of maneuver flight and to assess its maneuverability. A general method for inverse simulation of maneuver flight for helicopters with the flight control system online is developed in this paper. A general mathematical describing function is established to provide mathematical descriptions of different kinds of maneuvers. A comprehensive control solver based on the optimal linear quadratic regulator theory is developed to calculate the pilot controls of different maneuvers. The coupling problem between pilot controls and flight control system outputs is well solved by taking the flight control system model into the control solver. Inverse simulation of three different kinds of maneuvers with different agility requirements defined in the ADS-33E-PRF is implemented based on the developed method for a UH-60 helicopter. The results show that the method developed in this paper can solve the closed-loop inverse simulation problem of helicopter maneuver flight with high reliability as well as efficiency.

A Cybernetic Analysis of Maximum Unnoticeable Added Dynamics for Different Baseline Controlled Systems

Maximum unnoticeable added dynamics (MUAD) envelopes have been largely used to assess the adequacy of low-order equivalent systems (LOES) in handling qualities assessment and simulator validation. However, research has shown that more thorough verification of the adequacy of this method is required. This paper studies the influence of the baseline aircraft dynamics on the MUAD envelopes. The assessment is based on quantitative measures of pilot control behaviour obtained with the cybernetic approach. The measures were taken from a human-in-the-loop pitch tracking task experiment with compensatory display. The results are consistent with the MUAD envelopes and reveal no interaction effects of the baseline and added dynamics on the pilot control behaviour. This suggests that, under the considered conditions, the MUAD envelopes shall remain constant independently of the bandwidth of the baseline controlled dynamics.

Experimental and numerical analysis of spring stiffness on flow and valve core movement in pilot control globe valve

Valves are widely used for fluid flow control, not only for conventional fluid like water, gas and oil, but also for hydrogen under high pressure and so forth. Under these new conditions, the response time and energy consumption of valves are closely related to the whole performance of the piping system. Pilot-control globe valve (PCGV) is a novel quick response valve, which can utilize the pressure difference before and after the valve core to control the open/close states of the main valve. In this paper, the effects of spring stiffness inside PCGV on the flow and the valve core movement are carried out, respectively. To begin with, the experimental setup is introduces and the 3D numerical model is established. The simulation is carried out in software FLUENT with RNG k-ε turbulence model, User Defined Function method and dynamic mesh regeneration methods under transmit state. Then, a comparison of steady valve core displacements between experiment and simulation is carried out. After that, the effects of spring stiffness on flow characteristics, valve core movement and response times during opening and closing periods are presented. Finally, a spring chosen correction equation is proposed. This work can benefit the further design work of PCGVs or similar valves with springs, and it can be also referred by someone dealing with novel control valves design or flow control issues.