U.S. patent application number 09/729354 was filed with the patent office on 2001-06-07 for indicator of a variable for aircraft.
Invention is credited to Baudry, Jean-Pierre, Berlioz, Raymond.
Application Number | 20010002817 09/729354 |
Document ID | / |
Family ID | 26212697 |
Filed Date | 2001-06-07 |
United States Patent
Application |
20010002817 |
Kind Code |
A1 |
Berlioz, Raymond ; et
al. |
June 7, 2001 |
Indicator of a variable for aircraft
Abstract
Indicator of a variable for an aircraft. The indicator (1A)
according to the invention comprises means (13) for determining
first and second target values respectively of a variable and of
its derivative with respect to time, and display means (5, 6, 7)
which depict on a display screen (7) a means of indication (14) of
the first target value, which is arranged in such a way as to
indicate this first target value on a graduated scale (8), and a
means of indication (16B) of the second target value which is
associated at least with an indicator element (11) indicating said
derivative so that, when the latter points toward said means of
indication (16B), said variable of the aircraft becomes equal to
and remains equal to said first target value and said derivative is
equal to said second target value.
Inventors: |
Berlioz, Raymond; (Boulevard
Charpenel, FR) ; Baudry, Jean-Pierre; (Le Castigneau
B Rue Henri Barbusse, FR) |
Correspondence
Address: |
STEVENS, DAVIS, MILLER & MOSHER, L.L.P.
1615 L. Street, N.W., Suite 850
Washington
DC
20036
US
|
Family ID: |
26212697 |
Appl. No.: |
09/729354 |
Filed: |
December 5, 2000 |
Current U.S.
Class: |
340/978 ;
340/971; 340/973; 340/977; 701/4; 701/7 |
Current CPC
Class: |
G01D 21/02 20130101;
G01C 23/00 20130101; G01D 7/04 20130101 |
Class at
Publication: |
340/978 ;
340/971; 340/977; 340/973; 701/4; 701/7 |
International
Class: |
G01C 021/00; G01C
023/00; G05D 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 7, 1999 |
FR |
99 15394 |
Oct 25, 2000 |
FR |
00 13677 |
Claims
1. An indicator of a variable and its derivative for an aircraft,
comprising: first means (2, 3, 4) for determining the variable and
its derivative with respect to time; and display means (5, 6, 7)
which depict on a display screen (7): to indicate said variable, a
graduated scale (8) which bears values relating to said variable
and which is rectilinearly mobile past a fixed mark (9), marking
the value of said variable of said aircraft (He); and to indicate
said derivative, an indicator element (11, 12), wherein it
furthermore comprises second means (13) for determining a first
target value relating to said variable and a second target value
relating to said derivative, and wherein said display means (5, 6,
7) furthermore depict on said display screen (7): a first means of
indication (14, 19) of the first target value, which is arranged in
such a way as to indicate said first target value on said graduated
scale (8); and a second means of indication (16A, 16B) of the
second target value, which is associated at least with said
indicator element (11) so that, when the latter points toward said
second means of indication (16A, 16B), said variable of the
aircraft (He) approaches said first target value until it is
substantially equal to the latter and as appropriate remains
substantially equal to said first target value, while said
derivative is substantially equal to said second target value.
2. The indicator as claimed in claim 1, for indicating the altitude
and the vertical speed of an aircraft, wherein it includes: said
first means (2, 3, 4) for determining the altitude and the vertical
speed of the aircraft (He); said display means (5, 6, 7), which
depict on the display screen (7): to indicate the altitude, the
graduated scale (8) which bears altitude values and which is
rectilinearly mobile past the fixed mark (9), marking the value of
the altitude of said aircraft (He); and to indicate the vertical
speed, said indicator element (11, 12) comprising a needle (11)
which is mobile in rotation about the point (O) of intersection of
the extension of said fixed mark (9) and of the extension of said
needle (11) and which points toward said graduated scale (8), the
angle (.alpha.) defined by said fixed mark (9) and said mobile
needle (11) being representative of the vertical speed of said
aircraft (He); and said second means (13) for determining a target
altitude and a target vertical speed which correspond,
respectively, to the altitude of a target trajectory (TC) and to
the vertical speed making it possible to capture and as appropriate
to follow said target trajectory (TC), and wherein said display
means (5, 6, 7) furthermore depict on said display screen (7): said
first means of indication (14, 19) of the target altitude, which is
arranged in such a way as to indicate said target altitude on said
graduated scale (8) bearing altitude values; and said second means
of indication (16A, 16B) of the target vertical speed, which is
associated at least with said mobile needle (11) so that, when the
latter points toward said second means of indication (16A, 16B),
said aircraft (He) meets up with and as appropriate follows said
target trajectory (TC) at said target vertical speed.
3. The indicator as claimed in claim 2, wherein said first means of
indication comprises a mobile mark (14) which is provided on said
graduated scale (8).
4. The indicator as claimed in claim 3, wherein said display means
(5, 6, 7) moreover depict on said display screen (7) a reading
window (10), revealing a part of said graduated scale (8), and
wherein said first means of indication (19) is formed in such a way
as to display the numerical value of said target altitude, when
said mobile mark (14) arrives at one of the ends of said reading
window (10).
5. The indicator as claimed in claim 2, wherein said second means
of indication is symbolized on said display screen (7) by a first
straight line segment (15A, 15B) which is inclinable, the
inclination of said first straight line segment (15A, 15B) being
representative of the vertical speed making it possible to follow
the target trajectory (TC), and which is arranged in such a way
that its direction coincides with the direction of said needle (11)
when the aircraft (He) is situated on the target trajectory (TC)
and is following it.
6. The indicator as claimed in claim 5, wherein said first straight
line segment (15A) is arranged on said graduated scale (8).
7. The indicator as claimed in claim 5, wherein said first straight
line segment (15B) is arranged on a vertical speed scale (12)
defined at the level of said needle (11).
8. The indicator as claimed in claim 3, wherein said display means
(5, 6, 7) furthermore depict on said display screen (7) a second
straight line segment (17A, 17B) joining said mobile mark (14) to
said first straight line segment (15A, 15B).
9. The indicator as claimed in claim 2, wherein said second means
(13) determine a target trajectory (TC) exhibiting at least two
successive rectilinear portions, of different slopes, and wherein
said display means (5, 6, 7) moreover depict on said display screen
(7) a visual symbol (20) alerting a pilot of the aircraft (He) to a
future change of the current portion, to which said aircraft (He)
is guided.
10. The indicator as claimed in claim 9, wherein said visual symbol
(20) comprises a flashing disk.
11. The indicator as claimed in claim 9, wherein said visual symbol
(20) is arranged in such a way as to indicate the vertical speed
making it possible to follow the portion of the target trajectory,
which follows said change of current portion.
12. The indicator as claimed in claim 2, applied to an aircraft
comprising an automatic pilot, wherein said automatic pilot is
formed in such a way as to receive and to use the information
relating to the target vertical speed so as to meet up with and
follow said target trajectory (TC) automatically.
13. The indicator as claimed in claim 1, wherein said variable
corresponds to the speed of the aircraft, said derivative to its
acceleration, said first target value to a target speed and said
second target value to a target acceleration, in a horizontal plane
exhibiting a substantially constant altitude.
14. The indicator as claimed in claim 13, wherein said indicator
element comprises a needle which is mobile in rotation about the
point of intersection of the extension of said fixed mark and of
the extension of said needle and which points toward said graduated
scale, the angle defined by said fixed mark and said mobile needle
being representative of the acceleration of said aircraft in said
horizontal plane.
15. The indicator as claimed in claim 13, wherein said indicator
element comprises an arrow indicating the acceleration of said
aircraft in said horizontal plane.
16. The indicator as claimed in claim 13, wherein said first means
of indication comprises a mobile mark which is provided on said
graduated scale.
17. The indicator as claimed in claim 16, wherein said display
means moreover depict on said display screen a reading window,
revealing a part of said graduated scale, and wherein said first
means of indication is formed in such a way as to display the
numerical value of said target speed, when said mobile mark arrives
at one of the ends of said reading window.
Description
[0001] The present invention relates to an indicator of a variable
for an aircraft.
[0002] More particularly, although not exclusively, it relates to
an indicator of altitude and of vertical speed (which is the
derivative with respect to time of the variable representing the
altitude) for an aircraft.
BACKGROUND OF THE INVENTION
[0003] It is known that for an aircraft, for example a helicopter
or an airplane, when climbing (or descending), the acquisition of a
given altitude, for example a flight level imposed by air control,
is generally performed at a stable vertical speed.
[0004] On the approach to the intended altitude, the pilot of the
aircraft progressively reduces its vertical speed so as to
intercept said altitude with a vertical speed low enough to avoid
any significant overshoot of the intended altitude.
[0005] This reduction in the vertical speed on approaching the
intended altitude can be performed by intuition or with the help of
empirical rules by monitoring the alterations (in position and in
speed) of the altitude indication [needle for conventional
instrumentation or index on symbology known in aeronautics by the
acronym EFIS (Electronic Flight Instruments System)].
[0006] For example, a common empirical rule consists in commencing
the reduction in the vertical speed on overstepping a fraction of
the deviation between the intended altitude and the current
altitude ({fraction (1/10)} for example), then in repeating this
approach so as to progressively reduce the vertical speed.
[0007] Nevertheless, whatever strategy is used (intuition or with
the help of an empirical rule), these methods require, on the one
hand, good knowledge and good conduct of the performance of the
aircraft and give rise, on the other hand, to a considerable work
load in a phase of change of flight circumstance, that is to say
when the pilot must devote himself to other tasks relating, for
example, to air traffic or to navigation. Consequently, none of
these known methods is satisfactory, the difficulties of
organization and of gaging being due essentially to the fact that
the standard instruments are not organized so as to depict an
obvious summary of the situation.
DESCRIPTION OF THE PRIOR ART
[0008] To try to afford a solution to this problem, the documents
EP-0 324 195 and FR-2 742 226 each disclose an altitude and
vertical speed indicator making it possible to remedy, at least
partially, the aforesaid drawbacks. To this end, the indicator
disclosed by the document FR-2 742 226 comprises:
[0009] first and second sensors of altitude and vertical speed of
the aircraft, respectively;
[0010] means for processing the signals delivered by said first and
second sensors; and
[0011] means for displaying the processed signals depicting on a
display screen:
[0012] altitude indication means, and
[0013] vertical speed indication means arranged opposite said
altitude indication means,
[0014] said altitude indication means and said vertical speed
indication means being coupled so that the altitude indication
situated opposite the vertical speed indication represents, at any
instant, a forthcoming altitude for the current vertical speed.
[0015] Thus, once the vertical speed indication arrives opposite
the intended altitude indication, it is sufficient to keep the
vertical speed indication locked onto the intended altitude
indication until the latter is attained, this resulting in a
progressive reduction in the vertical speed until an at least
substantially zero vertical speed is reached. This known indicator
consequently makes it possible to provide the pilot of the aircraft
with an analog and coupled altitude and vertical speed indication,
on a display screen, making it possible to guide any barometric (or
radar) altitude capture without displaying the current value of the
altitude of the aircraft, except when the intended altitude has
actually been reached.
[0016] Moreover, in this known document FR-2 742 226, said altitude
indication means consist of a graduated scale, rectilinearly
(vertically) mobile past a fixed mark, and said vertical speed
indication means consist of a needle mobile in rotation about the
point of intersection of the extension of said fixed mark and of
the extension of said needle and pointing toward said mobile scale,
the angle defined by said fixed mark and said needle being
representative of the value of the vertical speed.
[0017] Consequently, this known indicator enables the pilot of the
aircraft to easily modulate the vertical speed so as to accurately
capture and follow a desired altitude. At the moment of capture,
the aircraft therefore exhibits a zero or substantially zero
vertical speed.
[0018] Such a mode of interception, which is particularly
advantageous for meeting up with a specified altitude or for
capturing a trajectory with zero slope, cannot be applied to the
interception of a trajectory exhibiting a nonzero slope since, with
this known mode of interception, the aircraft captures the
trajectory with a zero vertical speed, while this vertical speed
ought to be such that it makes it possible to follow the trajectory
(with nonzero slope) as soon as it is intercepted.
[0019] Also, to intercept a slopewise target trajectory, for
example an approach trajectory, the pilot of the aircraft generally
performs the following operations:
[0020] he determines beforehand by calculation the vertical speed
factor making it possible to follow the slope while taking account
of the ground speed of the aircraft;
[0021] he displays a vertical interception speed making it possible
to converge toward the slopewise trajectory; and
[0022] on the approach to the slopewise trajectory, he
progressively modulates the vertical speed, on the one hand so as
to intercept said trajectory without significant overshoot and, on
the other hand, so as to alter his vertical speed from the
interception value to the value for following (also determined
beforehand by calculation).
[0023] Once the interception has been achieved, the same strategy
is applied each time the aircraft exhibits a significant deviation
with respect to the target trajectory.
[0024] This known method of intercepting a slopewise target
trajectory thus exhibits the same drawbacks as those stated above
relating to the known methods of approach, by intuition or with the
help of empirical rules, to a specified altitude. In particular, it
requires, on the one hand, good knowledge and good conduct of the
performance of the aircraft and gives rise, on the other hand, to a
considerable work load in a particular phase of flight, in which
the pilot generally has to devote himself to other tasks relating,
for example to air traffic or to navigation. This known method of
intercepting a target trajectory exhibiting a nonzero slope is
therefore scarcely satisfactory.
SUMMARY OF THE INVENTION
[0025] The object of the present invention is to remedy these
drawbacks. It relates to an indicator of a variable for an
aircraft, providing a pilot of the aircraft with a visual guide
which is integrated into an environment which is familiar to him
and which enables him to anticipate and to gage in an optimal
manner the piloting of the aircraft so as to capture and follow a
target trajectory.
[0026] To this end, the indicator of a variable and its derivative
for an aircraft, comprising:
[0027] first means for determining the variable and its derivative
with respect to time; and
[0028] display means which depict on a display screen:
[0029] to indicate said variable, a graduated scale which bears
values relating to said variable and which is rectilinearly mobile
past a fixed mark, marking the value of said variable of said
aircraft; and
[0030] to indicate said derivative, an indicator element,
[0031] is noteworthy in that it furthermore comprises second means
for determining a first target value relating to said variable and
a second target value relating to said derivative, and wherein said
display means furthermore depict on said display screen:
[0032] a first means of indication of the first target value, which
is arranged in such a way as to indicate said first target value on
said graduated scale; and
[0033] a second means of indication of the second target value,
which is associated at least with said indicator element so that,
when the latter points toward said second means of indication, said
variable of the aircraft approaches said first target value until
it is substantially equal to the latter and as appropriate remains
substantially equal to said first target value, while said
derivative is substantially equal to said second target value.
[0034] Thus, by virtue of the invention, to implement the desired
piloting, that is to say to contrive matters so that said variable
becomes substantially equal to and remains equal to its target
value (first target value), it suffices for the pilot simply to
control the aircraft in such a way as to keep said indicator
element (derivative of the variable) pointed at said second means
of indication (target value of said derivative).
[0035] Consequently, a variable is controlled by way of its
derivative with respect to time.
[0036] It will be noted that the present invention is applicable
for example to a horizontal plane or a vertical plane, or even to
any plane.
[0037] In a first embodiment (relating to piloting in a vertical
plane), said indicator is an indicator of altitude (variable) and
of vertical speed (derivative).
[0038] In this case, said altitude and vertical speed indicator is
noteworthy, according to the invention, in that it includes:
[0039] said first means for determining the altitude and the
vertical speed of the aircraft;
[0040] said display means, which depict on the display screen:
[0041] to indicate the altitude, the graduated scale which bears
altitude values and which is rectilinearly mobile past the fixed
mark, marking the value of the altitude of said aircraft; and
[0042] to indicate the vertical speed, said indicator element
comprising a needle which is mobile in rotation about the point of
intersection of the extension of said fixed mark and of the
extension of said needle and which points toward said graduated
scale, the angle defined by said fixed mark and said mobile needle
being representative of the vertical speed of said aircraft;
and
[0043] said second means for determining a target altitude and a
target vertical speed which correspond, respectively, to the
altitude of a target trajectory and to the vertical speed making it
possible to capture and as appropriate to follow said target
trajectory, and wherein said display means furthermore depict on
said display screen:
[0044] said first means of indication of the target altitude, which
is arranged in such a way as to indicate said target altitude on
said graduated scale bearing altitude values; and
[0045] said second means of indication of the target vertical
speed, which is associated at least with said mobile needle so
that, when the latter points toward said second means of
indication, said aircraft meets up with and as appropriate follows
said target trajectory at said target vertical speed.
[0046] Thus, by virtue of the invention:
[0047] in order to achieve the capture of the target trajectory, it
is sufficient for the pilot simply to command the aircraft in such
a way as to keep said needle pointed at said second means of
indication;
[0048] the altitude deviation between the actual altitude of the
aircraft and the corresponding altitude of the target trajectory is
displayed clearly and accurately by the relative positioning or the
deviation between said fixed mark (indicating the actual altitude
of the aircraft) and said first means of indication (indicating the
target altitude);
[0049] the capture of the target trajectory is therefore displayed
by the facing positioning (zero altitude deviation) of said fixed
mark and of said first means of indication; and
[0050] after capture, in order to achieve the following of the
target trajectory, it is sufficient for the pilot to simply command
the aircraft in such a way as to keep said needle pointed at said
second means of indication.
[0051] Consequently, the indicator in accordance with the invention
provides a pilot with a visual guide enabling him to pilot the
aircraft optimally so as to capture and follow any target
trajectory (with zero or nonzero slope).
[0052] Moreover, the elements envisaged in accordance with the
invention are arranged on a known indicator, that is to say are
integrated into an environment which is familiar to the pilot,
thereby facilitating the understanding and the reading of the
various information displayed.
[0053] Furthermore, advantageously:
[0054] said first means of indication comprises a mark which is
mobile and which is provided on said graduated scale; and
[0055] said display means moreover depict on said display screen a
reading window, revealing a part of said graduated scale, and said
first means of indication is formed in such a way as to display the
numerical value of said target altitude, when said mobile mark
arrives at one of the ends of said reading window.
[0056] Additionally, according to the invention, said second means
of indication is symbolized on said display screen by a first
straight line segment which is inclinable, the inclination of said
first straight line segment being representative of the vertical
speed making it possible to follow the target trajectory, and which
is arranged in such a way that its direction coincides with the
direction of said needle when the aircraft is situated on the
target trajectory and is following it.
[0057] Moreover:
[0058] in a first embodiment, said first straight line segment is
arranged on said graduated scale, so that said straight line
segment and said needle are aligned at the time of capture and
during the following of the target trajectory; and
[0059] in a second embodiment, said first straight line segment is
arranged on a vertical speed scale defined at the level of said
needle, so that said straight line segment and said needle are in
this case superimposed at the time of capture and during the
following of the target trajectory.
[0060] Additionally, in particular to facilitate the reading of
said indicator, advantageously, said display means furthermore
depict on said display screen a second straight line segment
joining said mobile mark (indicating the target altitude) to said
first straight line segment (indicating the vertical speed making
it possible to follow the target trajectory).
[0061] Furthermore, advantageously, said second means determine a
target trajectory exhibiting at least two successive rectilinear
portions, of different slopes, and said display means moreover
depict on said display screen a visual symbol alerting a pilot of
the aircraft to a future change of the current portion, to which
said aircraft is guided, thereby making it possible to alert the
pilot to a change of flight configuration.
[0062] Moreover, advantageously, said visual symbol, preferably a
flashing disk, is arranged in such a way as to indicate the
vertical speed making it possible to follow the portion of the
target trajectory, which follows said change of current
portion.
[0063] Furthermore, according to the invention, when said aircraft
is furnished with an automatic pilot, advantageously, said
automatic pilot is formed in such a way as to receive and to use
the information relating to the target vertical speed so as to meet
up with and follow said target trajectory automatically.
[0064] Additionally, in a second embodiment (relating to piloting
in a horizontal plane, that is to say a plane exhibiting a
substantially constant altitude), said variable corresponds to the
speed of the aircraft, said derivative to its acceleration, said
first target value to a target speed and said second target value
to a target acceleration, all these parameters being defined in
said horizontal plane exhibiting a substantially constant
altitude.
[0065] In this case, said indicator element can comprise:
[0066] a needle which is mobile in rotation about the point of
intersection of the extension of said fixed mark and of the
extension of said needle and which points toward said graduated
scale, the angle defined by said fixed mark and said mobile needle
being representative of the acceleration of said aircraft in said
horizontal plane; or
[0067] simply an arrow indicating the acceleration.
[0068] The elements of said first embodiment, described above, can
moreover be integrated by analogy, into this second embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0069] The figures of the appended drawing will elucidate the
manner in which the invention may be embodied. In these figures,
identical references denote similar elements.
[0070] FIGS. 1 and 2 diagrammatically illustrate an exemplary
indicator in accordance with the invention intended to indicate
simultaneously the altitude and the vertical speed of an aircraft,
respectively in first and second embodiments.
[0071] FIGS. 3 and 4 show a limit position in a reading window of a
means for indicating the target altitude, respectively a top limit
and a bottom limit.
[0072] FIGS. 5 and 6 show an alerting visual symbol for warning of
a change of flight configuration, on an indicator in accordance
with said first and second embodiments respectively.
[0073] FIGS. 7 and 8 illustrate, on an indicator in accordance with
said first and second embodiments respectively, a particular mode
of interception or of capture.
[0074] FIGS. 9A, 9B and 9C and FIGS. 10A, 10B and 10C illustrate,
for an indicator in accordance with said first and second
embodiments respectively, various phases leading to the capture and
to the following of a slopewise target trajectory.
[0075] FIG. 11 is a graph showing the variation in altitude as a
function of time, during the capture of a target trajectory.
[0076] FIGS. 12 and 13 show, on an indicator in accordance with
said first and second embodiments respectively, various speed and
altitude values represented in FIG. 11.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0077] The indicator in accordance with the invention and
represented diagrammatically according to two different embodiments
1A and 1B respectively in FIGS. 1 and 2, is intended in particular
to indicate vertical speeds and altitudes on an aircraft, in
particular a rotary-wing aircraft, such as a helicopter He.
[0078] In a known manner, said indicator 1A, 1B comprises various
sensors, in particular a sensor 2 relating to altitude measurements
(for example barometric, radar, GPS, DGPS, GLONASS, EGNOSS, etc.)
and a sensor 3 relating to measurements of vertical speed. These
sensors 2, 3 deliver their measurements by way of a system of
primary references 4 and a computer 5 to a generator of symbols 6
which displays, side by side on a display screen 7, the altitude
and vertical speed processed information. Of course, the sensors 2
and 3 may be of some other kind entirely.
[0079] More precisely, the system of primary references 4 delivers,
by measurement of the atmospheric pressure, the altitude and
vertical speed information in numerical form. It will be noted that
the atmospheric pressure is associated with the barometric devices,
this measurement being able, however, to relate to other types of
physical quantities, if the device is no longer barometric, but of
some other type (GPS for example). Additionally, the computer 5 is
a digital computer ensuring the transformation of these physical
data into data suitable for display on the screen. Furthermore, the
symbol generator 6, or plotting machine, makes it possible to
portray on the display screen 7, from the information delivered by
the transformation computer 5, the graphical characteristics of the
depiction of the altitude and vertical speed information.
[0080] Moreover, on the display screen 7, the altitude and vertical
speed information are depicted as follows:
[0081] the altitude indication consists of a scrolling graduated
scale 8 bearing altitude values and moving rectilinearly
("vertically") past an index or fixed mark 9, the whole being
displayed inside a reading window 10;
[0082] the vertical speed indication is presented by an indicator
element 11, 12 so as to be represented, on a vertical speed scale
12, by the angular rotation of a symbol in the form of a needle 11
(shown diagrammatically in particular by a straight line segment)
about an axis perpendicular to the plane of the screen 7 (angle
.alpha. about the point O which is the intersection of the
extension of the fixed mark 9 and of the needle 11). The greater
the speed of climb (descent), the greater is the upward (downward)
angle of rotation .alpha. of this needle 11 with respect to said
fixed mark 9 (the relation not necessarily being linear over the
entire measurement span).
[0083] It will be noted that the end of the vertical speed symbol
(needle 11) points toward the scrolling altitude scale 8, and the
two scales 8, 12 are such that the altitude graduation situated in
the extension of the vertical speed symbol represents a predicted
altitude if the pilot continues to climb (or to descend). The
measurement swing and the resolution of the vertical speed
indication are matched to those of the altitude, so that the
altitude and vertical speed symbols are coupled, thereby
facilitating the acquisition of an altitude.
[0084] According to the invention, said indicator 1A, 1B for an
aircraft, comprising:
[0085] first means 2, 3, 4 for determining the altitude and the
vertical speed of the aircraft; and
[0086] display means 5, 6, 7,
[0087] moreover comprises second means 13 for determining a target
altitude and a target vertical speed which correspond respectively
to the altitude of a target trajectory and to the vertical speed
making it possible to capture and as appropriate to follow said
target trajectory.
[0088] Moreover, according to the invention, said display means 5,
6, 7 also depict on said display screen 7:
[0089] a first means 14 of indicating the target altitude, which is
embodied in the form of a mobile mark arranged on the scale 8 in
such a way as to indicate said target altitude on said scale 8
(bearing altitude values); and
[0090] a second means 15A, 15B of indicating said target vertical
speed, which is associated at least with said mobile needle 11 in
such a way that, when the latter is pointing toward a specified end
16A, 16B of said second means of indication 15A, 15B, said aircraft
meets up with and as appropriate follows said target trajectory at
said target vertical speed.
[0091] Thus, by virtue of the invention, one obtains an altitude
and vertical speed indicator 1A, 13 which is capable of providing a
pilot of the aircraft with a visual guide which is integrated into
an environment which is familiar to him and which enables him to
anticipate and to gage in an optimal manner the piloting of the
aircraft so as to capture and follow a target trajectory exhibiting
a predefined slope (zero or nonzero).
[0092] According to the invention, with said indicator 1A, 1B:
[0093] to achieve the capture of the target trajectory, it is
sufficient for the pilot to simply command the aircraft in such a
way as to keep said needle 11 pointed at said end 16A, 16B of said
second means of indication 15A, 15B;
[0094] the altitude deviation between the actual altitude of the
aircraft and the corresponding altitude of the target trajectory is
displayed clearly and accurately by the relative positioning or the
deviation .beta. between said fixed mark 9 (indicating the altitude
of the aircraft) and said mobile mark 14 (indicating the target
altitude);
[0095] the capture of the target trajectory is therefore displayed
by the opposite positioning (zero altitude deviation .beta.) of
said fixed mark 9 and of said mobile mark 14; and
[0096] after capture, to achieve the following of the target
trajectory, it is sufficient for the pilot to simply command the
aircraft in such a way as to keep said needle 11 pointed at said
end 16A, 16B of said second means of indication 15A, 15B, as will
be seen in greater detail hereinbelow.
[0097] It will be noted that said second aforesaid means comprise a
navigation computer 13 which maintains the current position of the
aircraft, with the help of navigation sensors (not represented),
and determines at any moment the altitude of the target trajectory
or target altitude, that is to say the altitude which the aircraft
would have if it were located on said target trajectory, as well as
the slope of the latter.
[0098] Moreover, knowing the slope of the target trajectory, as
well as the speed Vs of the aircraft relative to the ground (which
speed emanates from a Doppler sensor or is determined from the
alteration in the position of the aircraft), said navigation
computer 13 also determines the vertical speed which makes it
possible to follow said target trajectory with said speed Vs of the
aircraft relative to the ground.
[0099] Additionally, according to the invention, said second means
of indication is symbolized on the display screen 7 by a straight
line segment 15A, 15B which is inclinable, the inclination of said
straight line segment 15A, 15B being representative of the vertical
speed making it possible to follow the target trajectory, and which
is arranged in such a way that its direction coincides with the
direction of said needle 11 when the aircraft is situated on the
target trajectory and is following it.
[0100] In a first embodiment represented in FIG. 1, said straight
line segment 15A is arranged on the scale 8 in such a way that the
needle 11 and the straight line segment 15A are aligned when the
aircraft follows the target trajectory (FIG. 9C).
[0101] Furthermore, in a second embodiment represented in FIG. 2,
said straight line segment 15B is arranged on the vertical speed
scale 12 in such a way that the needle 11 is at least partially
superimposed on the straight line segment 15B (or conversely as a
variant) when the aircraft is following the target trajectory (FIG.
10C).
[0102] As may be seen in FIGS. 1 and 2, said display means 5, 6, 7
moreover depict on said display screen 7 a second "vertical"
straight line segment 17A, 17B, joining said mobile mark 14 to said
first straight line segment 15A, 15B and forming with these latter
a symbol 18A, 18B, thereby facilitating the understanding and the
reading of the various information items which are thus depicted by
a unitary symbol 18A, 18B.
[0103] It will be noted that the information items depicted
respectively by the mobile mark 14 and the straight line segment
15A, 15B are closely associated. This is because the first items
make it possible to verify the deviation .beta. with respect to the
target altitude and the second items make it possible, firstly, to
reduce this deviation .beta. to zero (capture of the target
trajectory) and, secondly, to keep it zero (following of the target
trajectory).
[0104] Moreover, a display element 19 is envisaged which displays
the target altitude, when the mobile mark 14 abuts against an end
of the reading window 10 associated with the scrolling altitude
scale 8, as represented:
[0105] for a top limit in FIG. 3, the element 19 displaying an
altitude of 6032 feet; and
[0106] for a bottom limit in FIG. 4, the element 19 displaying an
altitude of 4060 feet.
[0107] Additionally, in the case where the target trajectory
comprises a plurality of successive rectilinear portions, of
different slopes, the indicator 1A, 1B moreover comprises a visual
symbol 20 alerting the pilot to a change of current portion, that
is to say of portion with respect to which the aircraft is
guided.
[0108] This visual symbol 20 which is preferably embodied in the
form of a flashing disk and which is envisaged in FIGS. 5 and 6
respectively on the indicators 1A and 1B, in particular enables the
pilot to anticipate a change of flight configuration.
[0109] According to the invention, this symbol 20 relating to the
portion which follows the current portion can be displayed for the
first time at various moments, in particular:
[0110] from the moment when the aircraft is piloted toward the
current portion; or
[0111] from the moment when the aircraft is located a predetermined
distance ahead of the point of change of current portion; or
[0112] with a predetermined duration, before said change of current
portion.
[0113] Moreover, said symbol 20 is envisaged on the vertical speed
scale 12 at a variable location which corresponds to the vertical
speed making it possible to follow said portion which follows the
change of current portion of the target trajectory.
[0114] As indicated earlier and set forth hereinbelow with
reference to FIGS. 9B and 10B, the preferred mode of capture
according to the invention consists in piloting the aircraft in
such a way as to point the needle 11 toward the end 16A, 16B of the
second means of indication 15A, 15B. However, within the framework
of the present invention, in particular depending on the
operational requirements, the pilot can also achieve capture more
rapidly or more slowly, by pointing the vertical speed needle 11,
as the case may be, above or below the vertical speed target (end
16A, 16B of the means of indication 15A, 15B), both for a climbing
and descending target trajectory.
[0115] By way of example, represented in FIGS. 7 and 8 are more
rapid captures or interceptions of a climbing target trajectory,
for the indicators 1A and 1B respectively.
[0116] Moreover, represented in these FIGS. 7 and 8 are standard
reference signals 21 making it possible to reveal a possible
arrangement of the display screen 7 on a standard instrument panel
screen of an aircraft.
[0117] According to the invention, the capture or the interception
of a target trajectory TC, according to a theoretical capture
trajectory T1 continuously reupdated by taking account of the
actual position of the aircraft He, is done in three steps E1, E2,
E3 specified hereinbelow, as represented:
[0118] for the indicator 1A in FIGS. 9A, 9B and 9C respectively;
and
[0119] for the indicator 1B in FIGS. 10A, 10B and 10C
respectively.
[0120] In these figures, the right-hand part illustrates on each
occasion the position of the aircraft He, in this instance a
helicopter, with respect to the target trajectory TC, and the
left-hand part shows the screen 7 corresponding to such a
position.
[0121] During step E1, the pilot commands the aircraft He with a
vertical speed illustrated in FIGS. 9A and 10A and making it
possible to climb toward the target trajectory TC with positive
slope. The mobile mark 14 is at the top limit in the reading window
10 so that the display element 19 displays the altitude of the
target trajectory TC, in this instance 5514 feet.
[0122] During the next step E2, illustrated in FIGS. 9B and 10B,
the straight line segment 15A, 15B now being visible in the window
10 subsequent to the approach to the target trajectory TC, the
pilot commands the aircraft with a vertical speed such that the
needle 11 is pointed toward the end 16A, 16B of the straight line
segment 15A, 15B. Then, he adjusts the vertical speed in such a way
as to keep this pointing. Simultaneously, the altitude deviation
.beta. is reduced, the mobile mark 14 thus approaching the fixed
mark 9.
[0123] This mode of interception leads to the vertical speed of the
aircraft He being brought progressively and in a damped manner to
the target vertical speed, so that at the moment of interception or
of capture, the needle 11 is:
[0124] aligned with the straight line segment 15A; and
[0125] superimposed on the straight line segment 15B, and
simultaneously the mobile mark 14 arrives opposite the fixed mark 9
(zero altitude deviation).
[0126] The aircraft He:
[0127] is then on the target trajectory TC; and
[0128] exhibits a vertical speed enabling it to keep itself
there.
[0129] Finally, in step E3 of tracking the captured target
trajectory TC, it is sufficient to pilot the aircraft so as to keep
the needle 11 aligned (or superimposed) with the straight line
segment 15A (or 15B), so as to keep the aircraft He on the target
trajectory TC with an appropriate vertical speed.
[0130] Of course, any upward or downward deviations in trajectory
(with respect to the target trajectory TC) are corrected in an
identical manner, by pointing the vertical speed needle 11 at the
end 16A, 16B of the straight line segment 15A, 15B. This ensures a
new capture and the tracking of the target trajectory TC.
[0131] It will be noted that, according to the invention, the pilot
can alter the vertical speed in various ways: either continuously,
or in the form of successive corrections (for example when the
trajectory deviation overshoots a predefined value), the number and
frequency of which may be modified.
[0132] Thus, since he has the possibility of continuously
monitoring, directly and visually (hence in an analog manner), the
trajectory T1 of the aircraft He with respect to the "ideal" target
trajectory TC, the pilot can without difficulty cope with a
speeding up or slowing down of the capture procedure.
[0133] It will be noted moreover that, in the case where the
aircraft He comprises an automatic pilot, the modulation of the
speed of interception or of capture can also be applied to said
automatic pilot (concept of modulation of automata). To do this,
the initial value of vertical speed displayed by the pilot must be
stored as a relative value with respect to the current deviation in
vertical speed and be applied up to interception of the target
trajectory TC.
[0134] To further specify the piloting implemented with the help of
the present invention, there is represented, by way of example, in
FIG. 11 which shows a graph illustrating the variation in altitude
as a function of time, both of the target trajectory TC and of the
trajectory T1 of the aircraft He, various successive phases of
piloting, namely:
[0135] a first phase P1 of approaching the target trajectory TC,
without implementing the present invention;
[0136] a second phase P2 of capture in accordance with the
invention of said target trajectory TC, which begins at a time t0
where the altitude and the speed of the aircraft He are
respectively Z(t0) and V(t0) and the target altitude is Zref(t0).
It will be noted that at any time t, these various values are
written Z(t), V(t) and Zref(t) respectively;
[0137] a third phase P3 of stabilization of the trajectory T1 of
the aircraft He on the target trajectory TC; and
[0138] a fourth and last phase P4 of following the target
trajectory TC.
[0139] It will be noted that, during capture (phase P2), if the
needle 11 (vertical speed indicator) is pointed (FIGS. 12 and 13)
at the end 16A, 16B of the straight line segment 15A, 15B (target
vertical speed indicator), we have, at time t, the following
relation (I):
Vz(t)=k(Zref(t)-Z(t))+Vzref(t) (I)
[0140] in which:
[0141] Vz is the vertical speed of the aircraft He (vertical
component of the speed V);
[0142] Vzref is the vertical speed associated with the following of
the target trajectory TC (the speed Vzref is revealed by the
inclination of the straight line segment 15A, 15B);
[0143] Zref is the target altitude; and
[0144] k is a constant, which is dependent on the display ratio
between the vertical speed scale 12 and the altitude scale 8.
[0145] Moreover, by definition: 1 z ( t ) t = Vz ( t ) and Zref ( t
) t = Vzref ( t )
[0146] Relation (I) can therefore be written: 2 ( Z ( t ) - Zref (
t ) ) t = - k ( Z ( t ) - Zref ( t ) ) or alternatively : ( Z ( t )
- Zref ( t ) ) ( Z ( t ) - Zref ( t ) ) = - k t
[0147] By integrating the above relation, we obtain:
ln(Z(t)-Zref(t))=-k t+constant
[0148] By taking into account the initial conditions at time t0, we
obtain the relation:
Z(t)=Zref(t)+(Z(t0)-Zref(t0))e.sup.-k(t-t0)
[0149] This relation conveys the convergence of the aircraft He
toward the target trajectory TC (during the aforesaid phase P2), as
a function of the initial deviation with respect to this trajectory
(Z(t0)-Zref(t0)) and of the constant k.
[0150] The altitude and vertical speed indicator 1A, 1B described
hereinabove represents merely one particular embodiment of the
indicator in accordance with the invention of a variable and of its
derivative with respect to time.
[0151] More precisely, the indicator in accordance with the
invention includes, in a general manner:
[0152] first means 2, 3, 4 for determining the variable and its
derivative with respect to time; and
[0153] display means 5, 6, 7 which depict on a display screen
7:
[0154] to indicate said variable, a graduated scale 8 which bears
values relating to said variable and which is rectilinearly mobile
past a fixed mark 9, marking the value of said variable of said
aircraft He; and
[0155] to indicate said derivative, an indicator element 11, 12;
and
[0156] second means 13 for determining a first target value
relating to said variable and a second target value relating to
said derivative.
[0157] Moreover, according to the invention, said display means 5,
6, 7 furthermore depict on said display screen 7:
[0158] a first means of indication 14, 19 of the first target
value, which is arranged in such a way as to indicate said first
target value on said graduated scale 8; and
[0159] a second means of indication 16A, 16B of the second target
value, which is associated at least with said indicator element 11
so that, when the latter points toward said second means of
indication 16A, 16B, said variable of the aircraft He approaches
said first target value until it is substantially equal to the
latter and as appropriate remains substantially equal to said first
target value, while said derivative is and remains substantially
equal to said second target value.
[0160] Thus, by virtue of the invention, to implement the desired
piloting, that is to say to contrive matters so that said variable
becomes substantially equal to and remains equal to its target
value (first target value), it suffices for the pilot simply to
control the aircraft in such a way as to keep said indicator
element (derivative of the variable) pointed at said second means
of indication (target value of said derivative).
[0161] In another embodiment (not represented), the indicator in
accordance with the invention can be intended to indicate the
horizontal speed and the horizontal acceleration of the
aircraft.
[0162] In this case, said variable corresponds to the horizontal
speed of the aircraft, said derivative to its horizontal
acceleration, said first target value to a target horizontal speed
and said second target value to a target horizontal acceleration,
all these elements being defined in a horizontal plane exhibiting a
substantially constant altitude.
[0163] This last embodiment can include the aforesaid particular
elements of said indicator 1A, 1B by adapting these latter by
analogy.
[0164] Thus, by virtue of this last embodiment, the horizontal
speed of the aircraft (increasing or decreasing) is controlled by
way of the horizontal acceleration. Of course, acceleration is
understood to mean the derivative of the speed, that is to say both
an acceleration proper (increasing) and a deceleration
(decreasing), according to the situation encountered.
* * * * *