Techniczne nauki

Nickolay Zosimovych1, Vira Mazur2

1Sharda University (India, UP)

2National Aviation University (Kiev, Ukraine)

DESIGNING COMPUTER ANALOG OF HEAD-UP DISPLAYS IN CONTROL OF UAV

 

Summary. In this paper studies the task based on structural and parametric designing method considers the technique of design an analogue computer display on a windshield as a main indicator in the system of unmanned aerial vehicle ground control complex. Shown evaluation of current and prospective items when selecting a constructive solution.

Key words: an analogue computer display on a windshield (ACDW), display on a windshield (DW), unmanned aerial vehicle (UAV), flying vehicle (FV), structural and parametric design, cathode-ray tube (CRТ), indicator of the situation in vertical plane (ISVP).

Introduction. The computer analog display on a windshield (ACDW) may be a key indicator of UAV various applications [1]. By the principle of it belongs to the class of projection optical indicators with a projection of piloting, the survey, navigation and supporting information on the computer analogue of FV windscreen - semitransparent screen, through which at the same time observed the space of behind a cabin. Combining images on one screen - integration of information allows to reduce the workloads an operator and UAV establish normal operating conditions of the visual analyzer since is not required next [2]:

1.     Moving glance at devices and search for the appropriate device.

2.     Refocusing (changing accommodation) of the various objects.

3.     Changing (change adaptation) on the field of view different illumination.

Problem statement. Computer analogues of DW can be divided into such [3]:

1.     Electromechanical and electro-optical (by methods of imaging).

2.     Analog and digital (by control methods).

3.     Refractive and reflective type (by structures of the optical system).

4.     Conventional and diffractive (holographic) by type of optical elements.

Currently most widespread the electro-optical DW due to simple construction and ease of operation [4].

The structure consists of the following blocks of ACDW:

1.     Of image formation.

2.     The indicating with power supply.

3.     Control.

The basic element of the structural and parametric design the imager is a symbol generator in which is recorded the program painting symbols as letters, numbers, scales, geometric shapes, vectors, etc. The program of painting tends to implement the so called bar (italic) method, when forming a beam paints the symbols on screen like a pencil on a paper.

For imaging of onboard survey systems (television, infrared, radar) may be on a television screen. For obtaining a combined image and symbolism of survey system can be use a mixer image.

Display console includes a projection cathode-ray tube (CRT) with very high brightness of the screen [4]. Basic element of optical imaging system is a collimating system, which provides reproduction images from a projection CRT in the imaginary infinity that excludes parallax between the external (behind a cabin), real situation and symbolism generated on the screen of the tube, and requires no changes focusing (change of accommodation) view, which is necessary when observed objects deleted at various distances from the eye.

As a collimating lenses system are used, well as diffractive (holographic) optical elements (ACDW diffractive) [5].

At the diffraction ACDW as windscreen used an analog diffractive optical element. The control unit enables automatic controller ACDW screen brightness and the mode switch [2].

Fig. 1. The scheme of indicating on the windshield [2]: 1 – assigned course; 2- sliding; 3 – course; 4 – indexes the angle of attack; 5 – UAV (FV) index; 6 – the indicator’s speed; 7 – speed error; 8 – the pitching line +300; 9 – altitude; 10 – skyline; 11 – vertical speed; 12 – the pitching line -300

 

The final recommendations for type and volume of appears on ACDW symbolism still are not developed and therefore each developer offers its own interpretation [3]. However, in different stages of flight required on the display the character representation in the form of an aircraft rolling silhouette to move you’re according to the evolutions of the angles of attack and glide, roll, and pitch [6].

Increase field of vision along the vertical can be reached due to installation of two or more head-shields placed on the ACDW one after another and which give two or more images. If properly imaging is obtained integrating this increase in the total vertical image [2].

Fig. 2. The display view on the windshield ACDW for UAV

 

For structural and parametric representation information about course is used horizontal scale with a movable label, and the vertical scale is used to represent the information about vertical speed and altitude [7]. There may also be displayed on the screen such UAV parameters, as indicated air speed and director semi-automatic control (Fig. 1).

The analysis of results. Increase field of view may be partially accomplished by using the effect of binocular vision, which always exists in a horizontal plane. Using in ACDW diffractive (holographic) element (Fig. 2) with the given optical properties allows excluding a bulky and expensive collimating lens [6].

The main characteristics of DW given in Table 1.

The indicator of the situation in vertical plane (ISVP) is used for displaying synthesized image the real picture of surrounding area with distinct horizon line, focusing on which an operator can pilot the UAV as the usual a visual flight.

Table 1

The main characteristics of DW [3]

Characteristic

DW a refractive optical circuit

ACDW a diffractive circuit

Fields of view both horizontally and vertically, degrees

 

170 х 11,5

 

350 х 20

Luminous transmittance

70 %

90 %

The light reflection coefficient

25 %

80 %

Brightness of symbols, cd/m2

5400

17000

Brightness of the bitmap, cd/m2

1300

4000

Accuracy of symbols (mrad)

2,0 – 2,5

0,6 – 1,0

The mass, kg

15 – 18

10

 

Furthermore the quality information on quantitative values of the ​​derived ISVP basic flight parameters (roll, pitch, airspeed, etc.) for all phases of flight: takeoff, climb, en-route, and landing. On the basis of that information operator receives an idea of ​​the spatial position of UAV and its trajectory. ISVP is also used for structural and parametric representation of information-board survey radars, infrared systems, and television, including with imposing piloting synthesized symbolism.

As a flight director display overlap with the responsibilities ISVP ACDW, but also enables greater opportunities for output to information display on-board survey systems and to have TV ahead an image laying space with which to implement the takeoff and landing.

In order to color code can be recommended the following distributions of colors: green - motionless scale; yellow - alarm warning; blue - fixed signs, sky; red - alarm, prohibitions; bright red - sample numerical values ​​and symbols; white - the current value of parameters and symbols; black - the background, the negative image.

In structural and parametric representation of information on ISVP an increasingly observed switching to graphic picture of uniform presentation, best perceived the operator of UAV, which contributes to the development of digital technologies. The foundation was laid in the pseudo indication of a perspective view of the so-called "Road to the Sky" [3], the movable far end of which allows predicting the position of UAV. On the «Road» are applied transverse lines which characterize the range intervals. The further development of picture indicating a representation moving images in real time by using high complexity symbols the forms and color coding [5].

On the indicator submitted three dimensional perspective of the cockpit form on which such a line of black, specified projected onto flight path («Road to the Sky»), and information about the spatial position shown changing of position UAV respect to earth surface (Fig. 3). Information about the restricted areas appears as dome-shaped zones, dyed red.

Fig. 3. Three-dimensional perspective indication on the windscreen DARPA of UAV

 

The formation of moving image of indication with high complexity forms from the large number of elements in real time requires the development of generating images, processes and related hardware, allowing obtain images from 40000-400000 elements with frequency over 40 Hz [8, 9], significantly higher than of existing display systems, in which moving objects can be represented basically just by conventional symbols.

Conclusion. Based on the structural and parametric design method considers the technique of designing an analogue of computer indicator on the windshield in the system of ground control complex the unmanned FV. Demonstrated the assessment of the existing and future items the choice a constructive solution.

 

References

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