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https://dspace-erf.nlr.nl/handle/20.500.11881/1
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Browsing ERF by Subject "Aircraft Systems, Avionics & Sensors"
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    Amplified ego motion drift indication for helicopter landing
    ( 2015) Schmerwitz, S. ; Knabl, P.M. ; Lueken, T. ; Doehler, H.-U.
    Helicopter flight in degraded visual environment (DVE) can pose a serious safety hazard especially during lowlevel operations. One cause for rapidly losing the visual cues is introduced by surface properties such as sand or snow. They are prone to stir up particles due to the helicopters downwash and encase the helicopter in a nontransparent cloud. This effect is referred to as brownout or whiteout. Under such conditions lateral speeds introduce a high risk that when touching the ground may cause the helicopter to rollover. Therefore helicopter operators could benefit from some type of "drift indication" that mitigates the influence of degraded visual environment. To enhance the perception of ego motion in a conformal HMD symbol set the measured own ship movement was used to generate a "pattern motion" in the forward field of view close or on the landing pad [4]. As a next step the part task study presented here takes a closer look at the mechanism of subconscious drift indication. It is believed that providing this type of constant subliminal information can enhance the reaction time to unforeseen movements like from gusts. The study focused on none-professional participants. 31 candidates took part in this study. The main task was to steer the lateral position to the center of the presented landing pad. A second task forced the participant to react as fast as possible to a frequent presentation of two different characters on the display. The experiment was displayed on an Oculus Rift DK2™ virtual reality glass. The added "pattern motion" significantly supported participants in assessing drift, which reflected in lower lateral speeds during touchdown compared to the static presentation. Two of the three visualization concepts did not show a change in reaction time of the secondary task. Only marginally fewer correct responses to the secondary task were found. 24 candidates favoured the moving presentation rather than the static one. Few but some participants experienced pilot induced oscillation revealing that the chosen gain might have been too large. A follow-up experiment will try to optimize the gain.
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    Dynamic landing site ranking for helicopter emergency situations
    ( 2015) Zimmermann, M. ; Peinecke, N.
    Landing on unprepared sites is a typical mission task in day-to-day helicopter operations. Right after the event of an emergency which requires an immediate landing, the choice of a proper landing site is one of various time-critical and vital tasks which a helicopter pilot has to handle under intensive stress. This paper proposes a preventive procedure of landing site ranking to guide the pilot's attention to places with an increased chance of survivability. For that purpose, LIDAR data acquired during the flight by DLR's research rotorcraft ACT/FHS (Active Control Technology/Flying Helicopter Simulator, a highly modified EC135) is used for algorithm development and demonstration. Three types of results are shown. Starting with a landing site test-geometry, the algorithm's capabilities are demonstrated based on LIDAR data generated in DLR's AVES flight simulator. Secondly, a test-case using recorded LIDAR data acquired during previous flight tests is shown as an example close to real life with additional emergency ranking. Since wind is a major influence factor when choosing an appropriate landing site, varying ranking results of the real-life testcase with head-, cross- and rearwind conditions complete this paper.
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    Helicopter rotorstrike alerting system
    ( 2015) Waanders, T. ; Scheiblhofer, R. ; Qian, Q. ; Noort, B. van ; Ziegler, V. ; Schubert, F. ; Koerber, R.
    This paper reports on the development of a miniaturized and low-cost, near-field obstacle warning system for helicopters based on mass-market automotive radar technology. This so-called Rotorstrike Alerting System (RSAS) supports the flight crew in detecting obstacles in the direct vicinity of the helicopter (H/C) to avoid main and tail rotor strike accidents. The system is designed as a flight aid to enhance situational awareness and flight safety when manoeuvring in ground or obstacle vicinity possibly under reduced visibility conditions. The activities described herein were performed in the frame of a research project partially funded by the German Federal Ministry for Economic Affairs and Energy (BMWi). Between December 2012 and June 2014 the system concept was elaborated and a prototype system was developed and successfully tested both in ground and flight tests. This paper describes the system concept, its design considerations and it presents first test results.
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    Virtual cockpit instrumentation using helmet mounted display technology
    ( 2015) Lueken, T. ; Ernst, J.M. ; Doehler, H.-U.
    DLR's Institute of Flight Guidance has developed a new concept for virtual cockpit instrumentation based on a monochrome green "looking-through" helmet mounted display system (JedEye™). The resolution of the helmet is more than HD-TV, good enough to show detailed information as on presently installed head-down instruments. In addition to our latest 3D helicopter landing symbology, basic virtual instruments like Primary Flight Display, Navigation Display, and knee-board have been implemented in the near field of the cockpit environment in "no-window" areas. Pilots perceive these display elements as if they were located within the cockpit structure at a fixed and stable location in space. Besides, we have realized a "drag and drop" mechanism, which enables pilots to interactively arrange instrumentation on their personal preference by moving the display to another location, and additionally to adapt the display size. To prevent the pilot from dealing with too many different buttons, the interface comprises only three push buttons, which can easily be configured to be driven by already existing buttons on collective or center stick. The employment of only three push buttons and the pilot's head movements tries to make the mechanism intuitive and straightforward. First pilots' feedback show, our concept offers a great potential to be introduced into the future flight deck. This paper describes the implementation of both the helmet based virtual cockpit instrumentation in combination with a visual-conformal landing display format and the HMI concept with the usage of a high sophisticated helmet mounted display system.
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