RU2455201C1 - Method of aircraft flight control with allowance for stabilisation of preset flight speed - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to aircraft instrumentation. Proposed method comprises defining preset flight speed, measuring engine rpm, lengthwise overload, path inclination, and flight speed. Difference between preset and actual speeds and that between lengthwise overload and path inclination sine are used to define design rpm for preset speed. Variation in engine rpm is defined. For this, engine control levers deflection from their medium position defined by ''moving average'' for time corresponding to rpm change time with lag corresponding to time lag in rpm variation on shifting engine control lever. Generated is signal of error between designed and actual rpm of every engine to be displayed as rpm excess symbol shifting relative to reference symbol. Preset flight speed is stabilised by shifting or retaining engine control lever so that rpm exceed symbol stays nearby reference symbol.

EFFECT: improved quality of transients, simplified control.

2 cl, 3 dwg

Description

Technical field

The invention relates to the field of aviation, more specifically to instrumentation, and can be used to stabilize a given flight speed to improve the quality of transients and simplify aircraft control.

State of the art

There are two ways to stabilize a given flight speed: through the elevator with constant engine thrust and a method of stabilizing a given flight speed by changing the engine thrust at a constant angle of inclination of the trajectory and a constant angle of heel. In this case, we consider a method of stabilizing a given flight speed by changing the engine thrust.

It is known that to stabilize a given flight speed, special indices of set values are used, which are located on the scales of speed indicators. The stabilization of speed in this case is carried out by combining the pointer (arrow) speed with the index of the set value.

The disadvantage of the above method of stabilizing a given flight speed is that the pilot is forced, manually, by trial and error, to select the necessary mode of operation of the engines. The number of control movements of the throttle (engine control levers) increases significantly in the case of flight in the second mode, which complicates the piloting technique, increases the pilot's load, which reduces flight safety, especially in instrument flight conditions.

A known method of piloting an aircraft along a predetermined path with a predetermined speed (Patent RU 2129699, B64D 43/00, publ. 04/27/1999), which consists in setting the trajectory, determining the position and parameters of the aircraft in space to form an electronic screen indicator of a moving index, combined by the pilot by deflecting the control levers with a preset point on the screen, while representing a moving index in the form of a triangle depicting an aircraft when viewed from go along the velocity vector and the variable-length vector starting from it, at the end of which a circle of variable diameter is located, and the restriction on the length of the vector is represented by a segment, depict the set flight path in the form of a line in space connected by vertical segments with its projection onto a horizontal plane, while the set point of the screen is depicted in the form of a cross moving along the set path, combine the moving index with the set point of the screen by bordering the cross ok uzhnostyu vector, wherein when removing the force from the control handles provide movement of the aircraft in the direction indicated by the vector end. The features of this method compared to those described above are the replacement of the arrow and index, which indicate the actual and target values, respectively, with a cross and a circle, the size of which symbolizes the actual and target values, as well as the variable value of the “set flight speed”. With a constant approach speed, this method has the disadvantages indicated above.

At a constant speed, this method has the disadvantages indicated above.

Thrust automatic machines (AT) used on airplanes solve the problem of stabilization of a given flight speed [S. Belogorodsky "Automation of aircraft landing control." Moscow. "Transport", 1972, 352 p. Pages 202-216].

The drawbacks of automatic traction control (AT) are the complexity of the design, the large weight and the complexity of providing the necessary reliability. In particular, it is necessary to ensure the movement of the throttle during AT operation for ergonomic reasons: the pilot must be able to control the operation of the AT according to the movements of the throttle. Moreover, the frequent use of automation leads to a partial loss of manual control skills by the pilot, which reduces the reliability of the system as a whole.

SUMMARY OF THE INVENTION

The objective of the invention is the creation of such a method of manual stabilization of a given flight speed, which would provide an increase in the quality of transients and simplification of manual control of the aircraft.

The problem is solved due to the fact that to stabilize a given flight speed, a predetermined flight speed is determined, engine rpm, longitudinal overload, path inclination angle and actual flight speed are measured, then by the difference between the set and actual flight speeds, the difference between longitudinal overload and coefficient, taking into account the compensation for the acceleration of gravity, numerically equal to the sine of the angle of inclination of the trajectory, determine the estimated engine speed for a given speed, calculate the required a change in the revolutions of each engine, for which an additional measure is made of the deviation of the engine control levers from their average position, determined by the “moving average” method for a time approximately corresponding to the sum of the time of the change in speed and the delay time of the change (“response” time) of the speed when the throttle is moved they form a mismatch signal between the calculated revolutions and the actual revolutions of each engine, which is indicated as a mark of excess revolutions moving relative but reference marks stabilization predetermined airspeed is performed by holding the label in excess of turns of reference marks by moving the throttle.

In addition, the deviation of the mark of excess revolutions (which shows the pilot's recommendation on moving the throttle to control engine thrust) is indicated relative to the mark of the velocity vector.

The technical result, to which the claimed invention is directed, consists in improving the quality of transients and simplifying the manual control of the aircraft.

The achievement of the technical result is due to the control of the aircraft, taking into account the stabilization of the flight speed due to the use of the calculated predicted value of the throttle movement to the required position, which ensures "inertialess" speed changes to the specified, i.e. its stabilization at a given value.

Thanks to these features, an improvement in the quality of transients is ensured, which eliminates the need to "manually" select the necessary mode of operation of the engines.

The claimed method of manual stabilization of a given flight speed is illustrated by the drawings shown in figures 1-3.

Figure 1 shows an example of a change in engine speed when moving the throttle.

Figure 2 shows an example of an indication of the difference between the predicted and calculated revolutions relative to the label of the velocity vector.

Figure 3 shows an example of an indication with the coincidence of the predicted and calculated revolutions. In the figures indicated:

1. The position of the ore.

2. Actual engine speed.

3. Predicted engine speeds.

4. The moment (time) of the beginning of the movement of the ore.

5. The moment (time) of the beginning of the change in the actual engine speed.

6. The moment (time) of the end of the transition process.

7. The label of the velocity vector.

8. The mark of the overspeed of the first engine.

9. The mark of the overspeed of the second engine.

Information confirming the possibility of carrying out the invention

The method of stabilization of a given flight speed with manual control is as follows.

At the first stage, the calculated (for a given speed) engine speed is determined.

The calculated revolutions N _{calc are the} same for all engines.

Where

n is the number of engines.

n _x - longitudinal overload in a high-speed coordinate system.

θ is the current angle of inclination of the trajectory [deg.].

V _CR - instrumental flight speed, m / s.

V _calculation - the set (calculated) approach speed, m / s.

Estimated speed can be determined through weight or angle of attack.

зависит от тяговооруженности самолета.

depends on the thrust-weight ratio of the aircraft.

Shows how much you need to change the engine speed to change the longitudinal overload (in the high-speed coordinate system) by one.

также зависит от тяговооруженности самолета и показывает, на какую величину нужно изменить обороты двигателя для изменения скорости на 1 м/с. При этом правильнее говорить о влиянии тяги (оборотов) на продольное ускорение. В этом случае в формулу [2] нужно ввести еще один сомножитель: Δt. В данном расчете этот сомножитель входит в неявном виде в коэффициент k_V.

also depends on the thrust-weight ratio of the aircraft and shows by what value it is necessary to change the engine speed to change the speed by 1 m / s. In this case, it is more correct to talk about the influence of traction (revolutions) on longitudinal acceleration. In this case, one more factor must be introduced into formula [2]: Δt. In this calculation, this factor is implicitly included in the coefficient k _V.

Formula [2] shows what engine speed needs to be set in order to eliminate the mismatch between the actual and estimated flight speeds. In this formula, longitudinal acceleration is taken into account by the expression:

From the expression below [5] it is clear that positive longitudinal overload can be used either to increase speed, or, if n _{x is} equal to the sine of the angle of inclination of the trajectory, to gain altitude at a constant true speed. In the particular case, the deviation of the actual flight speed from the calculated one can be compensated by longitudinal overload. In this case, N _calc = N _cf , i.e. change of revolutions is not required.

Next, determine the predicted, depending on the position of the lever, engine speed.

The meaning of this forecast is as follows.

Due to the “inertia” of the system, the engine does not immediately respond to the movement of the engine control lever (hereinafter - ORE). At the first moment, the engine speed does not change at all (see figure 1). Then the engine “accelerates” and, after another period of time, enters new steady revolutions.

The time from the beginning of the movement of the ore (pos. 4) to the beginning of the change in the actual engine speed (pos. 5) is called the delay time.

The time from the beginning of the change in the actual engine speed (pos. 5) to the end of the transient process (pos. 6) is called the acceleration time.

The time from the beginning of the movement of the ore (pos. 4) to the end of the transition process (pos. 6) is called the pick-up time.

These time intervals are individual for each type of engine and are approximately 0.25 - delay time and 1-3 sec - pick-up time. Therefore, the pilot selects the desired operating mode (engine speed) using the “trial and error” method, which requires considerable distraction from him. The proposed “forecast of revolutions” eliminates any delay in the movement of the mark of the predicted revolutions after the ore is deflected, since when the ore is stationary, the actual revolutions exactly coincide with the revolutions determined by the “moving average” method. With a sharp stepwise deviation of the throttle throttle, the label of the predicted revolutions moves with the rate of deviation of the throttle to a new position. After the time indicated above, the actual revolutions “catch up” with the label of the forecast revolutions (there is no need to indicate the actual revolutions). The absence of delay in the movement of the mark in response to the movement of the throttle throttle practically eliminates the double movements characteristic of the “trial and error” method, speeds up the process of establishing the estimated engine speed, thereby reducing the pilot's workload, i.e. simplifies piloting technique.

The predicted speed is determined for each engine separately.

N _i - revolutions of the corresponding engine.

- отклонение рычага управления двигателем (РУД) от среднего положения.

- deviation of the engine control lever (ORE) from the middle position.

α _{RUD_i} is the instantaneous position of the RUD.

- среднее положение РУД-а, определенное методом «скользящего среднего» за время = 0,8 сек с задержкой от реального времени τ=0.25 сек.

- the average position of the ore, determined by the method of "moving average" for a time = 0.8 seconds with a delay from real time τ = 0.25 seconds.

- коэффициент эффективности РУДа (На 1° хода РУДа ~1% оборотов двигателя).

- ORE efficiency coefficient (At 1 ° ORE stroke ~ 1% of engine speed).

Indication is as follows.

1. Indicate the calculated and predicted engine speeds.

1a. If the predicted speed is not determined and does not indicate, then the actual engine speed is indicated.

2. Indicate the difference between the estimated and predicted engine speeds.

Where

ΔN _i - excess value of revolutions.

In this case, as a zero (index) of the reference, you can use any suitable character from the ones on the display.

Indication of the indicated parameters in the form of counters is possible. This method is inconvenient for the pilot, because it requires calculations in the mind. It can be used for debugging (refinement of coefficients in equations).

Indication of the indicated parameters in the form of arrows or marks is preferable.

When indicating as a reference zero (index), it is also convenient to use the label of the velocity vector.

Control of the aircraft is as follows. Stabilization of a given flight speed is carried out by holding the mark of excess revolutions at the reference mark by moving the throttle. In this case, the excess revolution is indicated by the higher position of the excess revolution mark relative to the reference mark (ΔN _lion in Fig. 2), the lack of speed is indicated by the lower position of the excess revolution mark relative to the reference mark (ΔN _rights in Fig. 2). In the case shown in figure 2, the left throttle needs to be tidied up, and the right throttle should be added so that both marks are at the same height with the mark of the velocity vector.

Claims (2)

1. The method of stabilization of a given flight speed, including determining a given flight speed, measuring engine speed, longitudinal overload, path angle, flight speed, characterized in that the difference between the set and actual flight speeds, the difference between longitudinal overload and the sine of the path angle determine the estimated engine speed for a given speed, determine the change in the speed of each engine, for which measure the deviation of the engine control levers from their average the day position determined by the "moving average" method for the time corresponding to the change in speed with a delay corresponding to the delay time for the change in speed when moving the engine control lever, a mismatch signal is generated between the estimated speed and the actual speed of each engine, which is indicated as an excess speed mark, moving relative to the reference mark, stabilization of a given flight speed is carried out by moving or holding the engine control lever so that Oba excess speed label located at the reference mark. 2. The method according to claim 1, characterized in that the deviation of the excess speed mark is indicated relative to the speed vector mark.

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