nxControl: Konzept zur Vorgaberegelung für die Längsbeschleunigung des Flugzeugs

Der zukünftige Luftverkehr erfordert präzisere Einhaltung von komplexeren Trajektorien. Automatische Flugführung mittels Autopilot und Autothrottle erlauben bereits heute die Einhaltung komplexer Flugtrajektorien. Jedoch muss stets gewährleistet sein, dass die Piloten die erhöhten Anforderungen an die Bahnführung auch im manuellen Flug erfüllen können. Moderne Verkehrsflugzeuge sind mit elektronischen Flugregelungscomputern ausgestattet, die die manuelle Flugsteuerung unterstützen. Die sogenannten Vorgaberegler nutzen ausschließlich die aerodynamischen Stellelemente und verwenden diese bisher nur für die Lageregelung. Die für die Bahnführung zusätzlich notwendigen und in Längsrichtung wirkenden Stellelemente für Schub und Widerstand müssen hingegen konventionell angesteuert werden, was im Bezug zu den zukünftigen Anforderungen zu erhöhter Arbeitsbelastung führen kann. Im Projekt nxControl wird ergänzend zu den bereits bestehenden Flugsteuerungssystemen ein Regler zur Vorgabe der Längsbeschleunigung entwickelt, der alle in Längsrichtung wirkenden Stellelemente verwendet. Daran angepasst wird eine Mensch-Maschine-Schnittstelle entwickelt, die das Situationsbewusstsein und die Führungsgenauigkeit verbessert, ohne die Arbeitsbelastung zu erhöhen. In diesem Beitrag wird das Konzept des Vorgabereglers und der Mensch-Maschine-Schnittstelle erläutert

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

Verbesserung von Flugpräzision und Arbeitsbeanspruchung bei manuellen RNP-Anflügen durch Vorgaberegler und Anzeigen für den Energiewinkel (nxControl)

Mit steigenden Präzisionsanforderungen bei immer komplexeren Flugtrajektorien erhöht sich die Arbeitsbeanspruchung der Piloten im manuellen Flug besonders bei der Ansteuerung von Triebwerken und Bremsklappen. Die konventionelle Steuerung über Hilfsparameter wie Triebwerksdrehzahl bzw. Hebelstellung erlaubt keine exakte Vorhersage der Zustandsänderung. Stattdessen muss abgewartet und die Eingaben gegebenenfalls angepasst werden. Ergänzend zu bestehenden Vorgaberegelungen im Cockpit (z. B. am Sidestick bzw. Steuerhorn) wurde deshalb im DFG-Vorhaben nxControl für die Steuerung von Triebwerken und Bremsklappen ein Vorgaberegler entwickelt, der das Lastvielfache in Flugbahnrichtung nx als Kommandowert verwendet (nxController). Das x-Lastvielfache ist synonym zum Gesamtenergiewinkel und wird direkt durch Schub- und Widerstandskraft aber auch durch Wind beeinflusst. Dieser Parameter gibt Auskunft über die Stärke der Zustands- bzw. der Gesamtenergieänderung, weshalb ein direkter Zusammenhang zwischen erwarteter Reaktion und Eingabe hergestellt wird. Der nxController soll somit ermöglichen, im manuellen Flug hohe Präzisionsanforderungen mit geringer Arbeitsbeanspruchung zu erfüllen. Eine Mensch-Maschine-Schnittstelle, bestehend aus Eingabehebel und Anzeigeelementen in den primären und sekundären Anzeigen des Cockpits, zur Ansteuerung und Überwachung soll zudem das Energiebewusstsein erhöhen. Das Gesamtsystem wurde in einen Forschungssimulator integriert und in verschiedenen Studien evaluiert. Dieser Beitrag stellt das nxControl-System mit Fokus auf dem Vorgaberegler und die Evaluationsergebnisse bei Standard-ILS-Landeanflügen ohne Störungen sowie anspruchsvoller und steiler RNP-Landeanflüge vor. Die Ergebnisse der Studien zeigen, dass die Versuchspersonen nach kurzem Training mit dem System die gestellten Aufgaben mit der geforderten Präzision erfüllen können. Beim RNP-Landeanflug sind zudem Verbesserungen in der Flugpräzision bei verringerter Arbeitsbeanspruchung durch das nxControl-System zu beobachten. Das System verspricht somit, manuelles Fliegen unter hohen Präzisionsansprüchen bei akzeptabler Beanspruchung zu ermöglichen

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

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

Development of Simplified Models of Water Quality in Lignite Mining Areas

The development of complex decision support model systems for the analysis of regional water policies for regions with intense socio-economic development effecting and being affected by the water resources system is of increasing importance. One of the most illustrative examples are regions with open-pit lignite mining. Such model systems have to be based on appropriate submodels e.g. for water quality processes. The paper describes submodel for groundwater and surface water quality with special regard to open-pit lignite mining regions. We consider the discharge of acid ferruginous water into rivers as having the most important impact on water quality in open-pit lignite mining areas. One goal of the model system is the choice of the necessary degree of purification for mine water treatment plants, taking into account self-purification in rivers and remaining pits as well as the water quality demand of down-stream water users. Based on comprehensive water quality models, the development of which is described in the paper, the possibilities for the derivation of reduced models are described. Those model have been elaborated for groundwater, as the source of pollution, mine water treatment plants as control units, river sections with an intake of acid ferruginous water, and remaining pits, which can also serve as effective control units. Related with each other, these models form the complex system model, a system of differential equations. They were numerically solved. The computer program is included in the paper

Water Policies: Regions with Open-Pit Lignite Mining (Introduction to the IIASA Study)

There is an apparent need for the analysis of long-term regional water policies to reconcile conflicting interests in regions with open-pit lignite mining. The most important. interest groups in such regions are mining, municipal and industrial water supply, agriculture as well as the "environment". A scientifically sound and practically simple policy-oriented system of methods and computerized procedures has to be developed. To develop such a system is part of the research work in the Regional Water Policies project carried out at the International Institute for Applied Systems Analysis (IIASA) in collaboration with research institutes in the German Democratic Republic, Poland, and in other countries as well. A test area that includes typical water-related elements of mining regions and significant conflicts and interest groups has been chosen. The first stage in the analysis is oriented towards developing a scenario generating system as a tool to choose "good" policies from the regional point of view. Therefore a policy-oriented interactive decision support model system is under development, considering the dynamic, nonlinear and uncertain systems behaviour. It combines a model for multi-criteria analysis in planning periods with a simulation model for monthly systems behaviour. The paper outlines the methodological approach. describes the test region in the GDR, and the submodels for the test region

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