Drift indication for helicopter approach and landing

Transcription

1 Chart 1 Drift indication for helicopter approach and landing Sven Schmerwitz, Patrizia Knabl, Hans-Ullrich Döhler, and Thomas Lüken

2 Chart 2 Overview Overview Brownout mitigation Motivation and concepts Experimental study GECO and JEDEYE TM HMD-design and drift indication Experimental design Results Approach path deviation Deviations at touchdown Subjective rating Conclusion and outlook

3 Chart 3 Motivation Brownout mitigation 75% of coalition helicopter mishaps are attributed to brownout. (HFM Task Group 162, 2012) Three common misperceptions: 1. sub-threshold lateral drifts (unrecognized) 2. Illusion of self-motion (vection) 3. Loss of visual reference (somatogravic) qype(com) All lead to spatial disorientation. openwalls(net)

4 Chart 4 Concepts Brownout mitigation Four strategies to counteract with technology: 1. Increase situation awareness by adding information (audio, tactile cues, and display incl. HMDs) 2. Database- (SVS) and sensor-based (EVS) landing zone information 3. Increase helicopter stability (e.g. auto-hover/auto-land) 4. Preventing the dust cloud (aerodynamics, procedures) (de Reus, Nijland, and ter Veer, 2012)

5 Chart 5 Generic Cockpit Simulator GECO Experimental study collimated outside vision 180 x 40 degree electromechanical force-feedback center-stick and collective helicopter simulation based on X-Plane 10 EC135 model recording of A/C flight data events line-of-sight heart rate skin resistance

6 Chart 6 Helmet Mounted Display JEDEYE TM Experimental study Item Value Resolution 2 x 1920 x 1200 pixel Field of view binocular, 80 x 40 degree each Frame rate fixed 60 Hz Head tracker hybrid 400 Hz, accuracy 0.25 degree Weight approx. 2.3 kg including helmet Interfaces DVI-D, HDMI, SDI, RS-170 Color monochrome green (stereo capable) Built-in symbol set JEDEYE-DLR format

7 Chart 7 HMD symbol set landing zone Experimental study speed, altitude and torque tape remain fixed All other elements are virtual-conformal or have a real world equivalent

8 Chart 8 HMD symbol set drift indication Experimental study drift indicator: animated dashed line

9 Chart 9 HMD symbol set drift indication AUDIENCE TRYOUT Experimental study

10 Chart 10 HMD symbol set drift indication VIDEO Experimental study

11 Chart 11 Experimental Design Experimental study 18 pilots total: 9 federal police/air rescue flight hours 4400 (SD = 3867) 9 military age 45 (SD = 7) 1/17 VFR/IFR HMD exp. 10 (6 simulator only) 12 flights per pilot: timescale: 3 trials HMD w/o drift indicator 1h briefing, 1.5h training, lunch, 3 trials HMD with drift indicator 6 trials (1.5h), break, 6 trials PFD/ND 6 trials (1.5h) and debriefing straight in landing: minutes path following visibility POOR 0.43nmi FAF 300ft at DME 0.64nmi AVG 0.65nmi no winds

12 Chart 12 Approach path deviation All scenarios Scenarios 5 Results

13 Chart 13 Deviation at touchdown heading offset Results The standard deviation (1σ) for flight without HMD three times larger No difference between the two HMD displays No influence between all flights and those finished on the landing pad

14 Chart 14 Deviation at touchdown lateral offset Results Reducing from all flights to those finishing on the landing pad impacts the display types differently Outlier values No matter what the HMD with drift indication is 40% closer to the center With the reduced subset the HMD without drift indication is only marginally better than baseline

15 Chart 15 Deviation at touchdown longitudinal offset Results Reducing from all flights to those finishing on the landing pad impacts the display types differently Outlier values With the reduced subset the HMD seems to be worse than baseline 3σ (99.3%) is larger 5m Not normally distributed

16 Chart 16 Deviation at touchdown distribution LAT/LON Results

17 Chart 17 Subjective ratings Results All components except altitude scale were rated slightly above average Overall rather disagreed with moving pattern to perceive drift They prefer STATIC over MOVING representation: Intuitively understandable Complexity Increase situational awareness Captures to much attention Contains unnecessary information

18 Chart 18 Conclusion Conformal HMD display assist well during approach and landing Drift indication led to a more precise lateral position after landing No other objective indicator for or against drift indication found Pilots prefer the symbol set without drift indication Much less training effort Conclusion and outlook The HMD provides a world-referenced synthetic vision for brownout

19 Chart 19 Outlook Mechanism of subconscious drift indication need to be studied closely It is believed to enhance reaction times Different gains need to be tested Different visualizations need to be tried out Comparison to BOSS under simulated brownout Comparison to SVS headdown concepts under moderate wind and gusts Technical flight trials Conclusion and outlook

20 Chart 20 2D format on the example of BOSS Brownout mitigation

21 Chart 21 2D format Brownout mitigation symbol set has a fixed position independent from head tracker movement is different from outside scene symbol set has shared information location center of display scale is shared orientation of shared information is different o high training effort o possible mental fixation o reduction of eyes-out advantage o comparably low cost o easy to integrate

22 Chart 22 3D perspective format Brownout mitigation If displayed on look through HMDs and using a head tracker symbols can be presented world-referenced ferranti (virtual) conformal, identical optical flow, intuitive