MINISTRY OF EDUCATION, SCIENCE, YOUTH AND SPORT OF UKRAIN
National Aviation University
Term Paper
On subject: ‘Control flight theory’
Done by Yasvinskyi Eugene
Group IACS 405
Kyiv 2012
Automatic control of the center of mass motion
Automatic control of the center of mass motion of the aircraft (CM) can be attributed to a higher hierarchical level of control than controlling the angular position and overloading. Management CM also called trajectory control. The need to automate the movement of military aircraft trajectory determined by the following factors: - complexity O strike aircraft to a position relative to the target, which ensures efficient use of weapons; - Heavy Traffic Management pilot onboard complex; - strong dependence of the efficiency of combat missions on the characteristics of the trajectory control. Management aircraft of CM is reduced to the solution of two problems: - Spatio-temporal trajectory; - Stability of aircraft on this trajectory. The trajectory is usually set in two directions: vertical (flight profile) and horizontal (flight path). When controlling the vertical main controllable parameters are speed and altitude, the horizontal - lateral deviation from the specified route and track angle. The main object of the ACS for each flight stage, is monitoring the specified control parameters:
,
or
Automatic control of the center of mass in the horizontal plane
Systems of co-ordinates, applied in navigation complexes
In aircraft navigation systems are used mainly spherical (geographic and orthodromic) and rectangular coordinates. In the geographic coordinate system (Figure 1) is determined by the position of the aircraft altitude and angular coordinates: longitude and latitude. For the main plane of the system adopted in the geographic equator plane and the plane of the prime meridian. The poles of the system coincide with the geographic poles of the earth elepsoida. The geographic coordinate system as the meridians and parallels is applied to all charts and is the basis for determining the coordinates of points on the map.
Movement
of
the
aircraft
relative
to
the
earth's
land
surface
is
characterized by
a
rate of
which
,
,
related
to
geographic
coordinates
by
the following relations.
;
;
.
(1)
Under
certain
current
speed
,
,
and
initial
values of
the
coordinates
,
,
current
geographical
coordinates
are
determined
by
integration
of
(1).
Orthodromic
coordinate system
(Figure
2)
is also a spherical
system,
but
with
arbitrary
poles.
This
system
for
the main
axes
adopted
two
great
circle
(hence
the
name).
Orthodrome,
combined with
a line of
a
given path
(LGP),
or with
the axis of
the
route,
called
the principal
and
is taken
as
the axis of
.
Axis
is
a kind of
conditional
equator.
Another
orthodrome
perpendicular
to
the
main,
carried
out
through
the point of
origin
of
coordinates
is
taken as the
axis
.
This
axis
is
a
conventional
meridian.
The
position of any
point
on the
Earth's
surface
is
indicated
by
two coordinates
and
,
usually
expressed
in kilometers.
By selecting the position of the main Great Circle can ensure that the flight took place with the smallest possible deviation from it, ie, for small values of the coordinates . This allows you to within acceptable distance from the main Great Circle (350 ... 400 km) do not take into account the sphericity of the earth and ease of navigation. Therefore, the system is basic in navigation devices. In addition, orthodromic coordinate system is most useful for keeping a given direction of flight using gyroscopic devices coursework.
Current
angular
coordinates
orthodromic
and
,
the
relevant provisions of
the
aircraft
along
the
equator
and
orthodromic
deviation
from
it
along
the
meridian
orthodromic
respectively,
are
defined by
geographical
coordinates
and
by
formulas
;
,
where
and
=-geographical
coordinates
of
the
origin
of
coordinates
orthodromic.
In
flight
from
the known
and
calculated
and
.
Then
traveled
from
origin
point
distance
along
the
equator
orthodromic
and
linear
deviation
from
it
defined
as follows
;
.
(2)
Dependence
(2)
is used
to control the
movement
of
the
aircraft.
In
the
event that
the
flight path
is
a
polyline
with
straight
lines
between
successive
points
of
the
route
can
be used by
private
orthodromic
coordinate
system for
each
segment.
The
equator
passes
through
such
a system,
the
start and
end
points of the
leg.
In
any
position
relative
to
the
Earth's surface
the
aircraft
to
withstand
a
given route
and
travel
programs
need
to combine
signals
and
know
and
great
circle course
.
Great
circle course
determined
by the
directional
gyro,
put up in
a given direction
of
flight.
However,
the high
level
of
measurement error,
especially for long
flights,
making
it necessary
to
use other
methods
of determining the
great
circle course.
For
this purpose,
the
known values of
the
coordinates
of
the
start
orthodromic
,
and
current
values of
variables
and
calculated
azimuth
correction
,
also
known as the
angle
of
convergence
of
the meridians
and
orthodromic
geographic
coordinate
systems.
Knowledge
of
the
amendment and
the
azimuthal
magnetic
course
,
allows
you to calculate
the
required
great
circle course
.
As
sensors
magnetic
course
in
exchange
systems
are
the
inductive
sensors
used
in
conjunction with
corrective
mechanisms.
Cartesian
coordinate system
(Figure
1)
is flat system.
Start
the
system
is
placed,
usually at
the
current position of
the
aircraft,
the axis
head
north
in
the direction
of
the current
meridian
axis
-
along
the
radius
of the sphere
up.
Axis
complements.
Small
spherical
parts
of
the Earth
is
almost equal to
the
plane tangential
to
the point
of
this site.
Therefore,
the
rectangular coordinates
can
quite
accurately
determine
the position
of
points on the
Earth's
surface
within
certain limits.
Cartesian coordinate system is used to solve a number of combat missions, as well as for the automated approach. Studies show that over 1,000 km along the main strip in the Great Circle 600 km away orthodromic coordinate system is virtually identical to a rectangular (error in determining the location of the aircraft is less than 1%). To program a flight path defined by control points, landmarks, correction and navigation stations. These coordinates are in the coordinate system in which the software device receives information specific navigation system. In the navigation system with digital computer introduced geographical coordinates, which are chosen from special catalogs or determined from maps.