Enhancing manual flight precision and reducing pilot workload using a new manual control augmentation system for energy angle

With rising demands on flight precision and more complex flight trajectories, pilots' workload during manual flight is increasing. This is especially the case for thrust and spoiler control during approach and landing. The presented nxControl system enables pilots to manually control the longitudinal load factor nx instead of engine parameters and spoiler deflections. This load factor is equivalent to total energy angle and is directly influenced by engine thrust and aerodynamic drag. The nxController complements existing control augmentation systems such as the fly-by-wire control laws of today's commercial airliners. It aims at higher precision with lower workload during manual flight. The controller input can be set and monitored by an adapted human-machine interface consisting of a thrust-lever-like inceptor and additional display elements to enhance energy awareness. This paper presents the nxControl system with focus on the command control system and an evaluation study with 24 airline pilots in a research flight simulator. The task was a demanding and steep approach with required navigation performance RNP 0.1 in a mountainous area. The results show higher precision and lower workload with the nxControl system despite minimal amount of training

A linear systems analysis of the yaw dynamics of a dynamically scaled insect model

Recent studies suggest that fruit flies use subtle changes to their wing motion to actively generate forces during aerial maneuvers. In addition, it has been estimated that the passive rotational damping caused by the flapping wings of an insect is around two orders of magnitude greater than that for the body alone. At present, however, the relationships between the active regulation of wing kinematics, passive damping produced by the flapping wings and the overall trajectory of the animal are still poorly understood. In this study, we use a dynamically scaled robotic model equipped with a torque feedback mechanism to study the dynamics of yaw turns in the fruit fly Drosophila melanogaster. Four plausible mechanisms for the active generation of yaw torque are examined. The mechanisms deform the wing kinematics of hovering in order to introduce asymmetry that results in the active production of yaw torque by the flapping wings. The results demonstrate that the stroke-averaged yaw torque is well approximated by a model that is linear with respect to both the yaw velocity and the magnitude of the kinematic deformations. Dynamic measurements, in which the yaw torque produced by the flapping wings was used in real-time to determine the rotation of the robot, suggest that a first-order linear model with stroke-average coefficients accurately captures the yaw dynamics of the system. Finally, an analysis of the stroke-average dynamics suggests that both damping and inertia will be important factors during rapid body saccades of a fruit fly

Implementing energy status in head-down cockpit displays: impact of augmented energy information on pilot’s performance

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.It is safety critical for pilots to be aware of the aircraft’s energy state in terms of proper altitude and airspeed. A loss of energy awareness is an important human factors issue in modern civil aircraft. In order to maintain the energy awareness and support the manual flying skills, several cockpit display concepts suggest to augment the current energy status of the aircraft on primary flight displays in terms of the total energy angle. An experiment was carried out to determine which effect this additional energy information has on pilots’ flight path control, instrument scanning, and situation awareness. Outcomes of the study show a significant shift of the scanning pattern from airspeed, altitude scale, and engine parameter towards the center of the primary flight display with unchanged situation awareness. In addition, pilots are better able to maintain given speed targets

nxControl instead of pitch-and-power : concept and first results of a control system for manual flight

A command system for manual control of the longitudinal load factor (nx) of an aircraft is designed that completes existing flight control command systems (e.g. sidesticks normal load factor nz). nxControl's aim is to assist pilots during manual flight by reducing the workload for monitoring flight parameters and the controlling of thrust and airbrakes. Important for nxControl concept is the direct relation between load factor and changes of the total aircraft energy. In the current paper a system concept and a prototype realisation are presented. The nxControl system consists of the control law that combines the actuation commands for engines and airbrakes in flight, a new input device for the longitudinal load factor command and new display elements that informs pilots about energy states to assure situation awareness. In order to investigate the feasibility of the concept as well as human performance consequences and cognitive demands, a flight simulator study with airline pilots was conducted.The results provide first evidence for the feasibility of the concept. As expected a change of scanning behaviour became apparent. For test scenarios with standard flight tasks, no impact in situation awareness and performance was observable. However, for more demanding tasks benefits are expected. Additionally, the assumed effect of a lower input device activity with the use of nxControl can be confirmed

Preliminary Sub-Systems Design Integrated in a Multidisciplinary Design Optimization Framework

The aircraft design is a complex subject since several and completely different design disciplines are involved in the project. Many efforts are made to harmonize and optimize the design trying to combine all disciplines together at the same level of detail. Within the ongoing AGILE (Horizon 2020) research, an aircraft MDO (Multidisciplinary Design Optimization) process is setting up connecting several design tools and competences together. Each tool covers a different design discipline such as aerodynamics, structure, propulsion and systems. This paper focuses on the integration of the sub-system design discipline with the others in order to obtain a complete and optimized aircraft preliminary design. All design parameters used to integrate the sub-system branch with the others are discussed as for their redefinition within the different detail level of the design

Manual flying and energy awareness : Beneficial effects of energy displays combined with a new approach of augmented thrust control

In order to enable pilots to better maintain energy awareness and energy management in manual flight, a new concept has been proposed, which transfers the demand control principle of fly-by-wire control laws also to the control of thrust. It includes a total-energy-related augmented thrust controller combined with a modified cockpit instrumentation enriched by specific energy displays. In order to empirically evaluate the human performance consequences of this new approach, an experimental study was conducted in a flight simulator investigating its effects on pilots’ performance, workload, and situation awareness. A total of 24 commercial aircraft pilots performed a landing and approach on a complex flight trajectory with and without the new system elements. The results confirm the expected beneficial effects of the new system on flight precision and lowered effort involved in thrust control as compared with conventional raw data flying. No negative side effects, for example, impaired situation awareness, were found

Modelling and Simulation at The University of Liverpool in Support of UK Naval Aviation

Along with the restricted landing area and the rolling, pitching and heaving of the ship's deck, the pilot also needs to contend with the turbulent wake produced by the air flow over the ship's superstructure. There has been significant research in the past decade or more to better understand the flying environment around the ship and how it impacts the helicopter’s handling qualities and pilot workload. Central to this research has been the use of modelling and simulation, with a particular emphasis on understanding the unsteady airflow over the ship and how this is affected by the superstructure geometry. In the UK, this flight simulation research has been led by the Flight Science and Technology Research Group at the University of Liverpool. This paper reviews the research that has been carried out at Liverpool, and how this has led to simulated flight trials to establish a simulated Ship-Helicopter Operating Limits envelope and how modelling and simulation is being used to assess the aerodynamic characteristics of the ship while it is still in the design phase, and to inform at-sea first of class flight trials

Dynamic Response and Pitch Damper Design for a Moderately Flexible, High-Aspect Ratio Aircraft

TCC (graduação) - Universidade Federal de Santa Catarina. Campus Joinville. Engenharia Aeroespacial.This work presents the dynamic response of a slightly flexible hight-aspect-ratio aircraft in time domain and the design of a pitch damper controller to augment pitch moments. The methodology adopted in this work extends the rigid body equations of motion and consider the effects of structural flexibility on the aircraft flight dynamics. The aircraft equations of motion are linearized and a flight control system to augment the pitch rate is designed. Firstly, the methodology to model a slightly flexible hight-aspect-ratio aircraft in time domain is revised. The mean axes reference frame is presented to situate the aircraft in time and space. Next, in order to consider the flexibility effects in the flight dynamics, the linearized structural dynamics in modal coordinates as well as the traditional modal superposition technique are briefly explained. The aerodynamic theory adopted in the methodology is also revised, where the incremental aerodynamic theory with the unsteady strip theory formulation in the time domain based on the Wagner function is described. The equations of motion are written by adding the flexible with rigid body terms. The methodology has been implemented at TU Berlin resulting in the software FlexSim, which was used in this work. Moreover, the linearized equations of motion in state space formulation and the decoupling to model the longitudinal aircraft dynamics are given to design the pitch damper. The controller gains are calculated following the frequency and damping values presented in the flying qualities for piloted aircrafts given by the American Military Specifications MIL-F-8785C. Two aircraft are investigated in this work. The first one is the motor glider Stemme S15, which is referred in this work as the reference aircraft. Since the Stemme S15 has its wing structural properties redesigned without changes in geometry. The Stemme S15 had its name changed to Ecarys ES15. Due this fact, the flight dynamic model is updated, comprehending the second aircraft model. The utility aircraft Ecarys ES15 is investigated using two configurations: with and without attached pods at wing. The structural properties of the aircraft are obtained by means of a linear interpolation of ground vibrations test data (GVT). The results compare the flight dynamic responses of aircraft’s rigid body model and the flexible model. The comparison gives the flight dynamic angle rates in pitch, roll and yaw after an input step in aircraft’s elevator and rudder controls. Furthermore, the modal amplitudes are also presented and the effects of longitudinal and lateral controls on the excitation of the vibrational modes is shown. The pitch damper is implemented and the variation of system roots is depicted. Besides that, the controller gains for the two aircraft models. The results compare the responses of the rigid aircraft model and the flexible aircraft models to step inputs in elevator and rudder.O presente trabalho tem como objetivo investigar a resposta dinâmica de uma aeronave moderadamente flexível com alta razão de aspecto no domínio do tempo e projetar um controlador de resposta de arfagem. Primeiramente, a metodologia aplicada nesse trabalho para modelar os efeitos elásticos da aeronave é revisada. O sistema de coordenadas dos eixos médios é apresentado para situar a aeronave no tempo e espaço. Em seguida, as equações de dinâmica estrutural em coordenadas modais bem como a técnica de superposição modal são brevemente revisadas. Na sequência a teoria aerodinâmica incremental com formulação não estacionária baseada na teoria das faixas é apresentada no domínio do tempo com a função de Wagner. O equacionamento apresentado na revisão da metodologia foi implementado pela TU Berlim no software FlexSim, o qual é utilizado no presente trabalho com o intuito de automatizar a análise aeroelástica. Ademais, com a linearização das equações do movimento o sistema de equações é reescrito na forma de espaço de estados e o sistema de controle é apresentado. As equações linearizadas de primeira ordem são então desacopladas e reescritas para o movimento longitudinal. A aproximação com dois graus de liberdade para o período curto é dada e um sistema de controle em malha fechada é definido. A frequência e o amortecimento das qualidades de voo requeridas para projetar o controlador são definidas com base na especificação militar americana MIL-F-8785C. Duas aeronaves são investigadas no trabalho. A primeira aeronave é o motoplanador Stemme S15, que é considerado como aeronave de referência, devido ao mesmo ser investigado na literatura para validação da metodologia utilizada no presente trabalho. A segunda aeronave é a Ecarys ES15, fruto de modificações nas propriedades estruturais da longarina e da superfície da asa da aeronave Stemme S15. Duas configurações da aeronave Ecarys ES15 são investigadas: com e sem pods fixados na parte inferior da asa. As propriedades estruturais da Ecarys ES15 são obtidas com ensaios de vibração em solo. Os resultados do ensaio são interpolados linearmente sobre toda a geometria da aeronave para consideração dos efeitos elásticos. Os resultados apresentados comparam as respostas dinâmicas das duas aeronaves com modelos de corpo rígido e flexível da estrutura. As variações das velocidades de rolamento, arfagem e guinada são plotadas com comandos no profundor e leme para representar a resposta dinâmica . Além disso, as amplitudes modais são representadas e a relação entre as superfícies de comando e a excitação de modos de vibração simétricos e não simétricos é comentada. Finalmente, o controlador de resposta de arfagem é implementado e os ganhos são calculados. A influência dos efeitos de flexibilidade nas raízes do sistema de equações, bem como na resposta dinâmica são apresentados e a relevância da consideração dos efeitos elásticos da estrutura é justificada

nxControl instead of pitch-and-power: a concept for enhanced manual flight control

A command system for manual control of the longitudinal load factor in flight path direction of an aircraft is designed that completes existing flight control command systems (e.g. with sidesticks that command normal load factor). The system is called nxControl. It aims to assist pilots during manual flight by reducing the workload for monitoring flight parameters as well as for controlling thrust and airbrakes. Important for the nxControl concept is the direct flight mechanical relation between longitudinal load factor and changes of the total aircraft energy. This paper presents the system concept and a prototype realization. The nxControl system consists of the control law that combines the actuation commands for engines and airbrakes, a new input device for the longitudinal load factor command and augmented display elements informing pilots about aircraft energy states to assure situation awareness. In order to investigate the feasibility of the concept as well as to evaluate consequences on human performance, a flight simulator study with airline pilots was conducted. The nxControl prototype was used by the pilots as expected. Changes in instrument scanning behaviour and thrust lever usage confirmed this. After just a short familiarization and practice, the pilots were able to perform standard flight tasks with nxControl without exceeding given tolerance limits. So, the results provide first evidence for the feasibility of the concept