Design and evaluation of a taxi display with integrated data link

Aerospace Engineerin

Reconstruction of Pilot Behaviour from Cockpit Image Recorder

A method to automatically identify pilot actions from cockpit camera footage is reported in this paper. Although they have long been considered for the enhancement of flight safety, cockpit image recorders have not yet been standard equipment in aircraft cockpits. The rules on Flight Data Recorders have been changed, however, to include a cockpit image recorder as one of the safety devices, and it is recommended to be installed in small aircraft as a substitute for a Flight Data Recorder. With cockpit images becoming available, it would surely be useful for accident analysis as well as for daily flight analysis. Especially for the latter purpose, pilot behavior should be automatically analyzed and classified into specific actions, or procedures. The authors conducted a study to assess the feasibility of automatic detection of pilot actions in the cockpit by a machine learning process. Results show that even with a small amount of training data, the resulting algorithm could identify some typical actions, such as manipulation of the switches on the glare shield, with 80% accuracy. Even in cases with a button and a switch positioned very close to each other, the actions ‘pushing the switch’ and ‘pushing the button’ could be distinguished by the algorithm. The action estimation accuracy improves up to 90% when using the training data focused on the pilot’s body parts, rather than the data focused on the whole body.Invited paperControl & Simulatio

Incremental Nonlinear Dynamic Inversion Control for Hydraulic Hexapod Flight Simulator Motion Systems

Hydraulic driven manipulators face serious control problems due to the nonlinear system dynamics and model and parametric uncertainties of hydraulic actuators. In this paper, a novel sensor-based Incremental Nonlinear Dynamic Inversion controller is applied to force tracking control of hydraulic actuators of a hexapod flight simulator motion system, which together with an outer-loop motion tracking controller forms a motion control system. Due to the use of feedback of pressure difference derivatives, the proposed technique is not dependent on accurate model and parameters, which makes the controller inherently robust to model uncertainties. Furthermore, The sensor-based control approach is particularly suitable for hydraulic force tracking in existence of an outer-loop controller decoupling hydraulic-mechanic interaction term from the inner-loop dynamics. Simulation results indicate that the novel approach yields better tracking performance and confirm the greater robustness to model and parametric uncertainties compared with a traditional nonlinear dynamic invention approach.Control & Simulatio

Simulator Assessment of the Lateral-Directional Handling Qualities of the Flying-V

Flying wings are known for their limited lateral-directional stability and handling qualities. This study aims at assessing the lateral-directional handling qualities of a conceptual flying wing aircraft currently in development at TU Delft, the Flying-V, in a moving-base flight simulator. It focuses on two aspects: First assess the lateral-directional handling qualities of the bare-airframe Flying-V, and the compliance to quantitative requirements. Second, improve these handling qualities through a prototype flight control system, and assess its effect on the handling qualities and the requirement compliance. These assessments were performed both analytically and with a pilot-in-the-loop simulator experiment, in order to experimentally validate analytical findings and obtain new pilot-subjective insights. The analytical and experimental assessment for lowspeed flight conditions both show the lateral-directional handling qualities of the Flying-V to be insufficient for requirement compliance, due to a lack of pitch, roll and yaw control authority and an insufficiently stable Dutch roll eigenmode. The prototype flight control system, consisting of an adapted control allocation and a stability augmentation system, showed both analytically and experimentally to improve the control authority, stability, and handling qualities of the Flying-V. While the effect on the lateral-directional stability was sufficient for stability requirement compliance, the control authority was not sufficiently increased for maneuverability requirement compliance at low speed. Thus, if the landing speed is not increased from the current baseline, a challenge remains to improve the handling qualities of the Flying-V. An approximation of the control authority required for full requirement compliance in the low-speed flight conditions tested showed a control authority increase of over a factor four to be required in that case.Control & SimulationFlight Performance and Propulsio

DUECA - Data-driven activation in distributed real-time computation

Experiments and flight simulation programs for a research flight simulator can be considered as a combination of real-time distributed calculation processes. Current tools and architectures for implementing these processes are complicated to use and require considerable real-time programming skills. The created programs are not sufficiently flexible. A new middleware layer, DUECA, was developed to facilitate implementation of programs on a research flight simulator. It combines a publish and subscribe mechanism and message passing facilities with some novel elements, namely explicit allocation of process activation and the conditions under which that allocation should take place, synchronisation of data from different sources, and a mechanism to transparently combine processes running at different update rates.Control & Simulatio

Simulator Evaluation of Flightpath-oriented Control Allocation for the Flying-V

A novel aircraft configuration, the tailless Flying-V, is examined for its longitudinal handling qualities in cruise by means of piloted simulations. The Flying-V is controlled by two aileron/elevator (elevon) surfaces on each side, and rudders on each wingtip. Two control allocation schemes were created: a conventional one where both inboard and outboard elevons deflect in the same direction, and one where the change in lift the elevons generate is countered by deploying the inboard and outboard elevons in opposite directions, allowing more direct control of the resulting flight path. The longitudinal handling qualities in cruise conditions were investigated by pilot opinion in a moving base simulator. Three experiments were conducted: a traditional pitch tracking experiment with the conventional control allocation, and a new flight-path-angle tracking experiment, using both the conventional and the flight-path-oriented control allocation. The pilots indicated the conventional pitch attitude control to have Level 1 handling qualities for the pitch control task, and Level 2 for the flight path control task. The flight-path-oriented control allocation improved the performance of the pilots during the flight-part tracking experiment, but the perceived control authority was considered too small for most pilots to consistently rate it at Level 1.Control & SimulationFlight Performance and Propulsio

Perceptual Eigenmode Distortion Analysis for Motion Cueing Evaluation in Fixed-Wing Aircraft Simulators

The Perceptual Eigenmode Distortion (PEMD), an extension to the Eigenmode Distortion (EMD), is a method for objectively evaluating simulator motion fidelity, developed over the last few years. EMD assesses how the Motion Cueing Algorithm (MCA) distorts the vehicle's perceived eigenmodes. In this paper, EMD is extended by a human perception model, which helps to balance the various motion cue contributions in a more human-centered context. Additionally, a new automatic MCA tuning approach is introduced to create an MCA parameter set that is optimal in terms of eigenmode distortion. The method is applied to a combined linear model of the Cessna Citation 500 for asymmetrical flight and the Classical Washout Algorithm (CWA). A pilot-in-the-loop experiment was performed, with six pilots in the SIMONA Research Simulator, to compare the PEMD method's parameter set with sets designed with the current state-of-the-art method of the Objective Motion Cueing Test (OMCT), and with a baseline motion configuration, as well as a condition without any simulator motion. Throughout each run of the double-blind pairwise comparisons, the Dutch roll eigenmode was externally excited with a gust of semi-random amplitude and direction. Two hypotheses were tested using subjective preferences and through measuring the Dutch roll suppression performance. Subjective preferences varied between and within pilots, and similar results for PEMD and OMCT were found. A significant improvement in performance was found, however, between the no-motion condition and the PEMD. Although the perceived differences between a PEMD-tuned and alternative MCA settings seem very subtle, the improved mode suppression performance suggests the method having merit in flight scenarios where the aircraft's dynamic modes play an important role.Virtual/online event due to COVID-19Control & Simulatio

Piloted Simulator Evaluation of Low-Speed Handling Qualities of the Flying-V

An improved understanding of pilot’s control behavior adaptations in response to sudden changes in the vehicle dynamics is essential for realizing adaptive support systems that remain effective when task characteristics suddenly change. In this paper, we replicate, extend, and validate the ‘adaptive pilot model’ proposed by Hess to verify its effectiveness for predicting human adaptive behavior in pursuit tracking tasks. The model relies on a Triggering function, that compares the current tracking performance to a stored nominal (pre-transition) state, and an Adaptation mechanism which determines new adapted human operator gain settings proportional to the magnitude of the off-nominal error occurrences. For model validation data from a previous experiment were used, where ten participants performed a pursuit tracking task with transitions in controlled element dynamics from a single to a double integrator, and vice versa. Overall, with an added human operator delay and participant-specific inner- and outer-loop gain adjustments, the model was found to accurately describe the measured steady-state tracking behavior for the participants in our data set. The results for the time-varying single integrator to double integrator transitions showed that the model can capture the transient control behavior of participants. However, the adaptive logic could only be tuned to activate for participants that had a pre-transition crossover frequency above 0.9 rad/s. Furthermore, the model was not able to capture the change in control behavior for transitions from a double to a single integrator. Here, as no distinct degradation in tracking performance occurs for such a transition to a more easily controlled system, the model's proposed Triggering logic will not activate. Further investigation and more experiment data are required for improving the applicability of the model's adaptive logic and to enable more accurate prediction of adaptive human control behavior.Control & SimulationFlight Performance and Propulsio

Extending the Objective Motion Cueing Test to Measure Rotorcraft Simulator Motion Characteristics

Control & Simulatio

Incremento de la localidad de datos en Sistemas de Ficheros

Los principales objetivos del trabajo presentado en esta memoria son los siguientes: La implementación de una cache en el sistema de ficheros paralelo PVFS2 que permita incrementar las prestaciones de aplicaciones de uso intensivo de datos (procesamiento de imágenes, simulaciones de ingeniería, bioinformática en computadores multi-núcleo (multi-core). Obsérvese que, al usar la aplicación un único computador, el mantenimiento de coherencia entre caches de distintos computadores (clientes) no es un requisito crítico para esta implementación de cache. Pueden aprovechar la implementación de cache tanto aplicaciones distribuidas en varios programas que usen ficheros para trasferir entre ellos los datos como aplicaciones con código paralelo que trabajan con un flujo continuo de datos (streaming), es decir, que leen y escriban datos en ficheros sin usarlos para comunicación. Se puede obtener un buen partido de los núcleos presentes actualmente en cualquier computador de propósito general sin tener que modificar el código aprovechando el sistema de ficheros en red o NAS, más concretamente, aprovechando su cache. La cache en PVFS permitirá: - Para aplicaciones del primer tipo, mejorar la comunicación entre los programas de la aplicación al poder encontrar los datos de entrada en la cache local del sistema de ficheros. Estos programas de la aplicación se podrían ejecutar uno detrás de otro o en paralelo, cada uno en un núcleo distinto del computador. - Adicionalmente, la presencia de cache en el sistema de ficheros puede incrementar las prestaciones de aplicaciones con código paralelos, el segundo tipo de aplicaciones comentado más arriba, sin que el programador tenga que modificar el código ni añadir comunicación/sincronización extra entre los núcleos. Las prestaciones en la escritura de resultados en ficheros mejora porque la cache del sistema de ficheros se puede utilizar como buffer o almacenamiento para combinar escrituras de distintos núcleos o del mismo núcleo antes de enviarlos a los servidores de datos. Las lecturas de datos de ficheros mejora porque los datos de entrada para diferentes núcleos se pueden pre-captar por anticipado a la cache del sistema de ficheros. El acceso a datos de fichero de un núcleo del computador podría también traer del servidor hasta la cache del cliente datos que otros núcleos van a leer a continuación, por lo que estos núcleos los encontrarían en cache ahorrando el tiempo de trasferencia desde el servidor y disminuyendo la cogestión del servidor. - Si los sistemas de ficheros tienen en cuenta en su implementación el hardware disponible actualmente, las aplicaciones mejorarán sus prestaciones. Otro objetivo en esta implementación es que se pueda utilizar en aplicaciones con ejecución distribuida o paralela en varios computadores, para ello, como no incluye mantenimiento de coherencia, la implementación debe ofrecer al programador funciones para que explícitamente mantenga el mismo la coherencia cuando resulte necesario. La implementación de cache de metadatos y datos en servidores y en clientes, manteniendo coherencia cuando se escribe en las caches de distintos nodos clientes evitando tener que añadir capas extras en el sistema de ficheros para la implementación de cache. Con ello se pretende conseguir unas buenas prestaciones eliminando los retardos extra de las capas de software para compensar en parte los retardos extra requeridos por las transferencias para garantizar coherencia en las escrituras. El mantenimiento de coherencia en las escrituras supone trasferir paquetes adicionales a través de la red antes de dar por terminada un acceso de entrada/salida, esto hace que se incremente el tiempo que requiere un acceso. Mientras que evitar incluir capas extras de software ahorra tiempo de procesamiento del software del sistema de ficheros. Para poder realizar esta implementación se ha utilizado un sistema de ficheros, AbFS, en el que se tiene total control ya que se está desarrollando en nuestro grupo de investigación,. Las implementaciones de cache coherente ocasionan una sobrecarga de los servidores debido a que se los clientes tienen que informarles siempre que realizan una escritura haya o no acierto en la cache. Un objetivo adicional en la implementación es disminuir las sobrecargas de los servidores de datos debido al mantenimiento de coherencia.Tesis Univ. Granada. Departamento de Arquitectura y Tecnología de Computadore