JPS59171794A - Automatic flight control and variable trim engagement system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic flight control system, and more particularly, the present invention relates to an automatic flight control system.
Relates to establishing trim standards.

The attitude of the aircraft is controlled by the control frame positions of the flight controls, which affect the positioning of positionable aerodynamic surfaces. In the case of a helicopter, these positionable aerodynamic surfaces are Although a variable trim engagement system applicable to helicopters is described herein, the disclosure has application to many fixed wing aircraft applications.

The periodic control column is movable in two axes7, and the forward and backward (i.e. longitudinal) movements of the periodic control column are determined by the helicopter's pitch profile 9Il (nose down/4Fi eT L).
control). The periodic rightward and muh (ie, lateral) motion of the control stick controls the roll attitude of the helicopter as measured from the wing horizontal. The 1 o'clock control stick controls the lift of the helicopter. The pitch, roll and lift of the pig are controlled by influencing the periodic and simultaneous pitch of the main rotor blades. Yaw pedal movement controls the pig's heading (yaw) by affecting the simultaneous pitch of the tail rotor blades.

The main and tail rotor blade bids can also be influenced by the automatic flight control system (AFC8). The outer loop AFC8 is configured to control the heading, attitude and =J-
There is a trim actuator that positions the flight controls to maintain control. Typically, the desired flight characteristics are achieved by manual control and then the outer loop I-rim is engaged.

For simplicity, pitch attitude control will be specifically discussed below, but it will be appreciated that the invention is also applicable to roll, yaw, and lift.

The electro-hydraulic trim actuator acts through an A-perlite spring to position the periodic control stick. When trim is engaged, the trim actuator position (trim position) is maintained through the rim feedback loop. The trim position corresponds to the control frame position. Therefore, when trim is engaged, the control column position is maintained. A given control frame position corresponds to a given attitude in the standard state. However, attitude and control frame position are not always consistent because they are related to prevailing and transient environmental factors. Therefore, the attitude is determined by A which detects the change in attitude from the desired attitude and gives an error signal <J' -t-pilot[-command] based on the difference between
It is also maintained by FC8. 1~ When the rim is engaged, the rim actuator is not capable of quickly obtaining a trim position in response to an error signal to maintain the desired attitude (trim reference). ), it is possible to move the control stick against trim (with trim engaged) or without trim (with trim released).

Trim is engaged and released by the trim switch. For example, a pilot desiring to acquire a new attitude may release the limbs, perform a flight maneuver to the desired attitude, and then re-engage trim to establish a trim reference. Or, the pilot makes a flight motion against the trim and quickly sets a new trim group 1 before making any other flight motion?
= Take 1! may wish to do so. This is done by releasing and re-engaging the trim.

When trim is released, the trim actuator follows the control stick rather than positioning it. Therefore, a series damper is installed between the trim actuator 1 and the end ().
It is known that Now, consider the following case
``The 11th movement is performed against the trim.The override spring (well, the trim aim is maintained, so...
Expanded or compressed. The trim is then released. However, because of the series damper, the trim actuator accelerates quickly while trying to obtain alignment with the control frame position, resulting in overshoot. The force felt through the A-perlite spring changes accordingly and can move the control stick. This is called "ringing."

A series damper should correct this problem (limiting the rate of change in trim position).

However, due to the delay in the trim position in obtaining alignment with the steering position guard, an erroneous 1 to rim zero may be obtained when the trim overrides the engagement. It is known to delay trim engagement based on the worst-case scenario that could occur. This is the time by which the trim position is delayed in order to obtain coincidence with the control stick position when the position is at the aft end, for example.Depending on the characteristics of the goomba, this delay time can amount to a considerable amount of time. This requires the pilot to maintain the control column position from when the pilot commands the first engagement until the trim is actually engaged, which reduces the workload of the pilot. It also delays the establishment of trim standards and subsequent flight movements.Furthermore,
When the delay cannot be determined on a worst-case basis, the pilot should hold the control column position for at least 2i better than the time required to obtain trim position agreement. (
]Reponara/, T. This is especially true when small flight movements are typically performed.

Accordingly, it is an object of the present invention to minimize redundancy between trim engagement commands and trim engagement commands. It is an object of the present invention to quickly establish a 1-rim reference immediately after a flight motion with or without trim and just before initiating a subsequent flight motion against a 1-rim. It's about getting it. This reduces the operator's workload.

Therefore, the variable trim engagement system 1~ system of the present invention includes a delay circuit that responds to a pilot command (switch closure) to engage the trim, and at the moment the trim engagement command is given, the trim position and the control stick position are adjusted. Delay trim engagement based on the difference between Although the present invention is described as applying to a bitch channel, this disclosure is applicable to other A.I.
It is also applicable to CS channels.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of preferred embodiments of the invention with reference to the drawings.

Figure @1 shows AFC3's Bitch Goose and Nell in a simplified manner. A pitch signal (F) is sent to the pitch signal (F) on the conductor 11'. When the tracking-storage circuit 13 (Y) is turned off, the pitch signal 5 (P) is tracked.
R) is theory 11J! HQ 11, switch 1
2 is open. The tracking-storage circuit 13 is connected to the switch 1
An accumulated pitch signal (1) S) indicating the value of the pitch buoy No. 5 (E)) at the moment when PIB 2 is opened is provided on the conductor 14. When the trim command signal (R) is logic n1'' (
When trim 1 is commanded), switch 12 is open. The adder 15 gives a pitch error (No. 3 (Per)) as the difference between the pitch signal (P) and the accumulated pitch No. 11 (1) S). The signal (P) is accumulated and coincides with the signal (iN (+) S), and the pitch error signal (Per) is O. During flight without disturbance (L, pitch error signal ( Per) is O in the standard state.
Dekumoru. When the aircraft pitch is disturbed, the pitch signal (P) will no longer match the stored pitch signal (PS) and the pitch error signal (Per) will no longer be O.

The pitch error signal (POr) is
1, 8F CS which are appropriately shaped (proportional, differential and integral paths) in the shaping circuit 1G to generate the command (pac)
controls the aircraft in response to the motorcycle command (pac), thereby controlling the aircraft in response to the selected pitch attitude ((~
Rim base t (maintains 0.

A known trim position feedback loop 101 is shown in FIG. The trim loop 101 is enabled by the 1 to rim engage word (C) ([・sl\ is engaged),, (,:i 3<C',> is logic "1" When the trim is engaged.

When the signal (C) is logic "On", the 1-rim is released. The manner in which the signal (C) is formed will be explained later (FIG. 3).

Vertical direction Lz'? Kuchi Unitaro 0 is piston 61
and cylinder 62. The screw 1 hem 61 defines within the cylinder 62 a 2':) titan bar 63.6/I containing fluid. Fluid is supplied under pressure to the electro-hydraulic servo valve 68 by a fluid source 71. This servo valve is connected to chamber 63.64 via inlet 69.70 in response to control 49 (P) of conductor 28.
can be operated to modulate the pressure applied to the By modulating the fluid pressure on each side of the piston 61, the revo valve 68 can position the screw 1-61 in response to a control signal (P).

Bypass circuit 67 is disabled when valve 65 is closed in response to signal (C-' 1 ''). Valve 65 opens and piston The fluid pressure on each side of 61 is equalized.Thus, the piston is
from the other chamber through a bypass 67, e.g. 64.
) is moved freely by the movement of fluid to 1q. However, if a series damper such as the Olinois 66 is used, the bypass 6
7 to brake the movement of the piston 61, such as the linear variable displacement transformer 30.
VL! The sensor detects the position of the piston 61 and indicates the trim position (i.e., the position to the trim engagement member 1).
T RM P OS N ) is applied to conductor 25''-.

When the trim is released (C="O"), the switch 20 is closed and the tracking-storage circuit 22 tracks the value of the trim position signal (TRMl)OSN>. Trim is engaged (C=”
1"), the switch 20 is open, and the track-storage circuit 22 provides the accumulated trim position signal (MrRMS) to the adder 24.
8N) coincides with the accumulated trim position signal ("rRtvls) at the time when the F-rim is engaged.
) and the accumulated trim error signals (TRMs) in amplifier 2.
Give to 7. The trim error signal (DingRMer) is -gain I
< 1, and the control signal (P) is amplified by S line 2.
A valve 68 is provided which positions the piston 61 via 8. A feedback loop is thereby established. 1 to rim base 11 are maintained by trim loop 101 as the trim position when the rim is engaged.

Bidge autopilot command (paC) is added to adder 24
C1 - Added to the rim error signal ('r RM er) (:1, +1', +i Set VJJ Ni response S L/
T 1□! Jmu error X-faith"r4 ('r'
r) to bias. This biases the trim position and therefore also the control frame position to maintain attitude.

Trim screws 1 to 61 [Yo control frame linkage 33 and A
- Through the pearlite spring 31 (acts on the control culm 34. When the rim is engaged (state C1 control charge is)
■The vertical frame 34 can be moved.゛4'th JJ, A-Pearlite spring 31 is expanded (J, j1 is compressed,
1. The rim position does not change. Control frame 3i4 is 1'i￥
Machine pitch figure 9! ). Control frame 3 /l i,
I, movable; the position at - defines the grade pitch of the main rotor 44; In the standard state, the blade pitch corresponds to the pitch attitude. The blade pitch of the main rotor 44 is also influenced by the control frame 34 in the 1]-le mode 39 and by the simultaneous control frame 40. The pitch of the periodic control frame 34 and the position of the simultaneous control frame 40 in its pitch and roll modes are mixed by a mixer 41 and are influenced by the blade pitch of the main rotor 44 through the servo 42 and the steering wheel 43. . The yaw begle has a shadow 1 on the blade pitch of the tail rotor (not shown).
jru.

The periodic control frame 34 has a handle 35 in which a trim switch 36 is disposed 5,[-rim switch 36 provides a [-rim command signal 〈[] on conductor 37. When the signal (R)C is driven (that is, pressed), the trim switch 3G is at logic "0" (
The trim is released. trim switch 36
When the command signal (R) is 1 pulsed, the command signal (R) is logic I
T 1 II and avoids trim engagement. However, for trim, the command signal (R) is logic "1 I
J, who is not directly engaged when becoming I, is explained below.

It will be delayed.

In FIG. 3, a known trim engager (~delay circuit is shown. Trim command signal (1)) is set to FJ! n
1 'I, timer 47 starts timing and provides time signals (Z) to the four comparators. When the value of the time signal (Z) reaches 1 second as indicated by the reference numeral 74, the comparator 4 passes a logic "1" to the AND circuit 17 via conductor 19. AND circuit 117
also responds to the command signal <[g>>. Trim command signal (R
) and the output signal of comparator 49 are both at logic ``1n'', a trim-engage signal (C) of logic Iri'1n is generated to engage the 1-rim.
The Bonn gauge signal (C - logic "1") causes the command signal to engage the trim (R = logic "1").
Delay by seconds. As mentioned above, it is known to establish criteria 1- for the 'worst case'.

When the trim switch (36 in Figure 2) is activated, 1
~Rim command (8@(R) becomes 1'0", indicating that the trim has been released tJ' o (8jl;i (R
A signal complementary to the inverter 455 (J - "0") is formed at the inverter 455, and this logic "1n signal resets the timer 717. The time signal (Z) immediately becomes nO" and the comparator 49 The output of becomes O'', and the trim/engage @(C) becomes II O'', and the rim is released. In this way, when the signal (R) becomes 11011, no occurrence occurs until the trim is actually released.

Referring again to FIG. 2, the variable rim engagement member 1-portion 102 of the present invention is shown. Control frame position signal on conductor 50 (STECK P OSN)
is given by a position sensor such as a linear variable displacement transformer 32, and an adder 51 is provided by a position sensor such as a linear variable displacement transformer 32.
K PO3H> and [・Rim position signal ('rRM P
A position difference signal, (Pd) is given as the difference between O3H). When the trim is engaged, the position difference (fi
@(Pd) is zero in the standard state. Position difference @(+)
(1) is converted into time units by an amplifier 53 with a gain of 2.

The gain (K2) is J5 based on the ``worst case'' position of ε, and the time to be converted is the trim position of n
The time C required to obtain a match in the worst case
-Yes. The absolute value of the amplified position difference signal is determined by the absolute value circuit 5.
5 and is applied to an adder 57 via a conductor 56. In the booster 57, a small bias (t) 58 is added to the signal on the conductor 560 to provide a reference signal (RS>) on the conductor 59. The bias ([) is the minimum value for closing a valve, etc. Thus, the reference signal (Rs) always changes in proportion to the degree of discrepancy between the trim position and the control column position IN (flight against trim).
4) Move (, L, position difference signal Y" ((d) (1) (J,
Deal out non-zero numbers, like this: [Three thresholds can be taken. [-ri l
1 without X - Flying when the rim is released
-7 Movement-〇・The position difference signal (Pd) is required for the Turin price to match the control frame position.11. ``1 period (1 non-zero.

When the signal (R) is equal to zero, indicating that the rim is released, the switch 72 switches the tracking-storage cycle ff1.
73 single signal (f's) can be transmitted. When the trim is engaged (R-"1"), the switch 72 is turned on 611 and the reference 74 is set between the rim position and the control frame position at the moment when trim engagement is commanded. It is established in 1 second according to the degree of discrepancy.The output of the tracking-storage circuit 73 is the
Helim]] Ngujimen [-(C-“1”) is the king of standard 74 in order to control the delay. Variable trim”
- The criteria 74 established within the engagement portion 102 is established in the rolling circuit of FIG. given to.

In flight motion against the i-rim, the rim position remains constant and the control frame position changes. Therefore, the X signal (Pd
> can become large. If the operator momentarily presses the trim switch 36 (R=nO), the trim position will gradually match the control frame position. is big. ``Blip''
If the trim switch 36 is operated for a longer time than J
, redorim command (R-"1") and trim engage <C
-nl").

Similarly, in a non-trim flight motion, the trim position may be squeezed but substantially correspond to the control column rotation in relation to movement of the control frame relative to the trim position. This match is
It is enhanced if the pilot holds the control frame in a certain position for more than a moment. Typically, the degree of discrepancy between control frame position and 1-rim position is very small for such flight movements. Therefore, the final delay when trim engagement is commanded is proportionally small, and in most cases the variable trim engagement system of the present invention provides the operator with a It enables trim 1 engagement that seems to be possible.

The above description is in simplified block form. It is clear that many of the required functions can be achieved in a simpler manner 19 by using more true and complementary outputs and fewer inverters. In many cases, the positive logic illustrated here can be easily replaced with inverted logic that is more suitable for the available hardware. Therefore, the above explanation has been made in principle in the form of blocks that achieve the functions, and it is true or not that the same or equivalent functions and combinations thereof can be realized in various modified IC forms. As will be understood, FIG.
]-dya← is shown on the top of the digital rubon. This routine is accessed at entry boat 76. A first test step 77 determines whether trim 1 engagement is commanded. If the answer is negative, the operator drives the trim switch (36 in FIG. 2) and the signal (R) is zero. When signal (R) is zero, the delay counter is rehit with a pull-up 78. The difference between the trim position and the control frame position is then calculated at step 79. The trim 1 engagement delay (T) is then determined by the position difference and a constant (amplifier 53 in FIG.
It is calculated based on the absolute value of the product of the gain of and 2>. The routine is then exited on port 83. delay(
T) is continuously calculated during trim release (R=no"), and trim engagement is commanded (R-
It is important that the value is fixed immediately ("1").
! 0 For example, if a trim engagement is commanded at the end of a flight maneuver, then signal (R) 4-1n should occur and the routine proceeds to test step 81. At this point, it is determined whether the delay counter has finished running for T seconds based on 1% of the duty cycle of the computer.If negative, step 82 'r uffi delay counter is Clemented and Routine exits. If the delay counter is 1
If the inflation condition has been set to 1, the trim is engaged in step 84 by setting the signal (C) to 11j n1''. Rune L takes the value of 1
Within the same 1-knee-tay cycle as the 11-sue-up 82, there is always a small difference between the trim command and the trim-engage based on the duty cycle, except that 1-reno\engagement (step 84) is not allowed. 6. .

The desirability of the minimum delay of 0.01 to 0.05 is the same as the IC explained earlier in the hardware embodiment.

It will be appreciated that the digital routines described herein can be easily integrated into existing routines that include other tests and functions based on relative frame position and trim position, such as fault indicators.

The routine of FIG. 4 digitally performs some of the functions of the hardware of FIG. It will be appreciated that much more of the hardware of FIGS. 1 and 2, such as summing points, amplifiers, etc., can be implemented digitally in a manner known to those skilled in the art.

The digital functions illustrated by the simplified flowchart 1r-) in FIG. It can also be implemented by
It is understood that ζ can always be implemented by dedicated digital equipment.

Although the present invention has been illustrated and described in terms of exemplary embodiments thereof, those skilled in the art will appreciate that various modifications, omissions, and additions may be made within the scope of the invention.

[Brief explanation of the drawing]

FIG. 1 is an exploded view of the AF CS pitch channel. FIG. 2 is a simplified diagram of the rim return loop and associated helicopter components in combination with the variable trim engagement portion of the present invention. FIG. 3 is a simplified diagram of a delay circuit. . FIG. 4 shows a flowchart t-1 of a routine for digitally implementing the present invention. 10... Pitch Jitoiro, 12... Suin J-1
13... Tracking-storage circuit, 15... Adder, 16.
...Molding circuit, 20...Switch, 22...Follow-
storage circuit. 24...Adder, 31...A-Pearlite spring, 3
3... Control stick Nkuji, 34... Control frame, 36.
...Trim switch, 40...Simultaneous control frame, /12.
··The servo. 43... Suossico plate, 44... Main rotor,
/i5...Inverter, 47...Timer, 4...
・Comparator. 53...Amplifier, 55...Absolute value circuit, 57...
Adder. 72...Switch, 73...Following-storage circuit, 10
2...Variable Trim Engagement Men [・Partial Patent Applicant United Decnoluses・] - Boreishi 21
Representative Patent Attorney Akira
Ishimasa Takeshi Fl, 4

Claims (2)

[Claims] (1) It has a trim position sensor for providing a signal indicating trim position "1" and a trim loop responsive to a trim engage signal to maintain the rim reference to M<1 for the trim position signal. , also includes a 1-rim switch that generates a command signal to command the trim engage men 1 and releases the rotor rim, and further releases the trim after the 61-rim command signal is given. In an automatic flight control system that has a delay circuit for I and C, which gives a trim signal to the trim loop based on the i1 reference signal, the signal is sent based on the control column position. The control stick position to be given is determined by the relay, and the control stick position signal and the trim position signal are as indicated by J, giving a signal to the delay circuit based on the difference between the control stick position and the trim position. An automatic flight control system comprising: signal processing means for; (2) for aircraft including an outer-loop automatic flight control system having trim actuators actuatable to position the flight controls; variable trim engagement member I for assuring the °C trim thickness Sγ in response to a C1 trim engagement signal; ~ In the system, 71 (a first position sensor for giving a signal indicating the row control position; 1 ~ a second position sensor for giving a signal indicating the position of the rim actuator) and a Cth switch means (for providing a signal to release the rim and a command signal to engage the Torino), and are responsively connected to the first position sensor, the second position sensor, and the switch means. , - trim] - After the command to engage (i9) is detected, the control column position signal and the trim position (-trim) are detected at a point in time based on the difference between the trim position and the control column position as indicated by the g-bow. A variable trim engagement system characterized by comprising: signal processing means for providing a trim engagement signal to establish a normal position.