IEEE - Aerospace and Electronic Systems - April 2021 - 24

Virtual Cockpit Instruments-How Head-Worn Displays Can Enhance the Obstacle Awareness of Helicopter Pilots

Figure 6.
Experimental setup of the two simulator studies. (a) Study I-fully virtual setup with a pilot wearing the Oculus Rift VR goggles. (b) Study
II-pilot wearing the JEDEYE see-through HWD in the GECO simulator.

PARTICIPANTS
Study I. In total, 11 subjects (1 female, 10 male) with a
mean age of 38 (between 26 and 61) took part in the first
simulator study. All participants had experience with helicopter-flying, either in the simulator or in real flight. Three
held a helicopter license [2 airline transport pilot license
(ATPL), 1 commercial pilot license (CPL)], five held a
fixed-wing license. The actual flight hours (without simulator hours) ranged from 0 to 6400 (mean: 1248 h). Seven
subjects had a mean experience of 56 h with HWDs.
Study II. In total, 7 male helicopter pilots with an average age of 46 (range from 38 to 62) participated in the second experiment. They had a mean flight experience of
1985 h. One held a private pilot license (PPL), four a
CPL, and two an ATPL. Five pilots reported prior HWD
experience (mean: 108 h). Three of them already participated in the first VCI study.

APPARATUS
Study I. The first experiment used a fully virtual setup. As
pictured in Figure 6(a), the participants wore the Oculus
Rift CV 1 VR goggles and steered the helicopter with professional, active force-feedback flight controls [27]. The
VR HWD simulated the pilot's view through a seethrough HWD as it is used on a flight deck. The virtual
world comprised the surroundings, the cockpit, and the
overlaid symbology [cf. Figure 2(a)]. The HWD had a resolution of 1080 Â 1200 pixels per eye and a diagonal
FOV of around 110 .
The flight mechanics were simulated by DLR's
custom-made EC135 flight model. It includes an automatic flight control system (AFCS) offering several upper
24

modes [28]. For these trials, the cyclic axes were in
" attitude command, attitude hold, " which enables direct
control of pitch and roll attitude via the center stick. If the
pilot let go of the cyclic, the helicopter returned to
trimmed attitude. The yaw rate was commanded via the
pedals being in " rate command, direction hold. " Finally,
height changes were issued via the collective. Each deflection of the collective led to a certain climb or sink rate.
While in neutral position, the AFCS held the current altitude (vertical velocity command, height hold).
Study II. The follow-up experiment was conducted in
DLR's Generic Experimental Cockpit (GECO). This fixedbase simulator provides a collimated outside vision with
180 Â 40 FOV. It has a highly modifiable flight deck,
which can be equipped with helicopter flight controls [27] as
well as with our flight-certified see-through HMD.
For the evaluation of the VCI concept, we used the
Elbit JEDEYE. It is a binocular, optical see-through HMD
with a wide FOV of 80 Â 40 (60 overlap). The resolution of the monochrome green image sources is
1920 px Â 1200 px per eye (2200 px Â 1200 px in total).
Correct spatial integration of the virtual symbology with
the outside vision and the real-world environment is
ensured by an electromagnetic head-tracking system.
Figure 6(b) illustrates the whole setup with the HWD, the
PMD, and the offshore windpark presented on the projection system. As visible in the picture, the cockpit shell of
the GECO replicates an Airbus A350, which leads to a
restricted out-the-window view compared to most helicopters. Despite this limitation, the collimated outside vision
and the integrated flight-certified HMD make this simulator a good choice for this experiment and the study a valuable step before the flight test with DLR's research
helicopter.

IEEE A&E SYSTEMS MAGAZINE

APRIL 2021

IEEE - Aerospace and Electronic Systems - April 2021

Table of Contents for the Digital Edition of IEEE - Aerospace and Electronic Systems - April 2021